Logo Search packages:      
Sourcecode: linux version File versions  Download package

dma.c

/*****************************************************************************
* Copyright 2004 - 2008 Broadcom Corporation.  All rights reserved.
*
* Unless you and Broadcom execute a separate written software license
* agreement governing use of this software, this software is licensed to you
* under the terms of the GNU General Public License version 2, available at
* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
*
* Notwithstanding the above, under no circumstances may you combine this
* software in any way with any other Broadcom software provided under a
* license other than the GPL, without Broadcom's express prior written
* consent.
*****************************************************************************/

/****************************************************************************/
/**
*   @file   dma.c
*
*   @brief  Implements the DMA interface.
*/
/****************************************************************************/

/* ---- Include Files ---------------------------------------------------- */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.h>
#include <linux/proc_fs.h>

#include <mach/timer.h>

#include <linux/mm.h>
#include <linux/pfn.h>
#include <asm/atomic.h>
#include <mach/dma.h>

/* I don't quite understand why dc4 fails when this is set to 1 and DMA is enabled */
/* especially since dc4 doesn't use kmalloc'd memory. */

#define ALLOW_MAP_OF_KMALLOC_MEMORY 0

/* ---- Public Variables ------------------------------------------------- */

/* ---- Private Constants and Types -------------------------------------- */

#define MAKE_HANDLE(controllerIdx, channelIdx)    (((controllerIdx) << 4) | (channelIdx))

#define CONTROLLER_FROM_HANDLE(handle)    (((handle) >> 4) & 0x0f)
#define CHANNEL_FROM_HANDLE(handle)       ((handle) & 0x0f)

#define DMA_MAP_DEBUG   0

#if DMA_MAP_DEBUG
#   define  DMA_MAP_PRINT(fmt, args...)   printk("%s: " fmt, __func__,  ## args)
#else
#   define  DMA_MAP_PRINT(fmt, args...)
#endif

/* ---- Private Variables ------------------------------------------------ */

static DMA_Global_t gDMA;
static struct proc_dir_entry *gDmaDir;

static atomic_t gDmaStatMemTypeKmalloc = ATOMIC_INIT(0);
static atomic_t gDmaStatMemTypeVmalloc = ATOMIC_INIT(0);
static atomic_t gDmaStatMemTypeUser = ATOMIC_INIT(0);
static atomic_t gDmaStatMemTypeCoherent = ATOMIC_INIT(0);

#include "dma_device.c"

/* ---- Private Function Prototypes -------------------------------------- */

/* ---- Functions  ------------------------------------------------------- */

/****************************************************************************/
/**
*   Displays information for /proc/dma/mem-type
*/
/****************************************************************************/

static int dma_proc_read_mem_type(char *buf, char **start, off_t offset,
                          int count, int *eof, void *data)
{
      int len = 0;

      len += sprintf(buf + len, "dma_map_mem statistics\n");
      len +=
          sprintf(buf + len, "coherent: %d\n",
                atomic_read(&gDmaStatMemTypeCoherent));
      len +=
          sprintf(buf + len, "kmalloc:  %d\n",
                atomic_read(&gDmaStatMemTypeKmalloc));
      len +=
          sprintf(buf + len, "vmalloc:  %d\n",
                atomic_read(&gDmaStatMemTypeVmalloc));
      len +=
          sprintf(buf + len, "user:     %d\n",
                atomic_read(&gDmaStatMemTypeUser));

      return len;
}

/****************************************************************************/
/**
*   Displays information for /proc/dma/channels
*/
/****************************************************************************/

static int dma_proc_read_channels(char *buf, char **start, off_t offset,
                          int count, int *eof, void *data)
{
      int controllerIdx;
      int channelIdx;
      int limit = count - 200;
      int len = 0;
      DMA_Channel_t *channel;

      if (down_interruptible(&gDMA.lock) < 0) {
            return -ERESTARTSYS;
      }

      for (controllerIdx = 0; controllerIdx < DMA_NUM_CONTROLLERS;
           controllerIdx++) {
            for (channelIdx = 0; channelIdx < DMA_NUM_CHANNELS;
                 channelIdx++) {
                  if (len >= limit) {
                        break;
                  }

                  channel =
                      &gDMA.controller[controllerIdx].channel[channelIdx];

                  len +=
                      sprintf(buf + len, "%d:%d ", controllerIdx,
                            channelIdx);

                  if ((channel->flags & DMA_CHANNEL_FLAG_IS_DEDICATED) !=
                      0) {
                        len +=
                            sprintf(buf + len, "Dedicated for %s ",
                                  DMA_gDeviceAttribute[channel->
                                                 devType].name);
                  } else {
                        len += sprintf(buf + len, "Shared ");
                  }

                  if ((channel->flags & DMA_CHANNEL_FLAG_NO_ISR) != 0) {
                        len += sprintf(buf + len, "No ISR ");
                  }

                  if ((channel->flags & DMA_CHANNEL_FLAG_LARGE_FIFO) != 0) {
                        len += sprintf(buf + len, "Fifo: 128 ");
                  } else {
                        len += sprintf(buf + len, "Fifo: 64  ");
                  }

                  if ((channel->flags & DMA_CHANNEL_FLAG_IN_USE) != 0) {
                        len +=
                            sprintf(buf + len, "InUse by %s",
                                  DMA_gDeviceAttribute[channel->
                                                 devType].name);
#if (DMA_DEBUG_TRACK_RESERVATION)
                        len +=
                            sprintf(buf + len, " (%s:%d)",
                                  channel->fileName,
                                  channel->lineNum);
#endif
                  } else {
                        len += sprintf(buf + len, "Avail ");
                  }

                  if (channel->lastDevType != DMA_DEVICE_NONE) {
                        len +=
                            sprintf(buf + len, "Last use: %s ",
                                  DMA_gDeviceAttribute[channel->
                                                 lastDevType].
                                  name);
                  }

                  len += sprintf(buf + len, "\n");
            }
      }
      up(&gDMA.lock);
      *eof = 1;

      return len;
}

/****************************************************************************/
/**
*   Displays information for /proc/dma/devices
*/
/****************************************************************************/

static int dma_proc_read_devices(char *buf, char **start, off_t offset,
                         int count, int *eof, void *data)
{
      int limit = count - 200;
      int len = 0;
      int devIdx;

      if (down_interruptible(&gDMA.lock) < 0) {
            return -ERESTARTSYS;
      }

      for (devIdx = 0; devIdx < DMA_NUM_DEVICE_ENTRIES; devIdx++) {
            DMA_DeviceAttribute_t *devAttr = &DMA_gDeviceAttribute[devIdx];

            if (devAttr->name == NULL) {
                  continue;
            }

            if (len >= limit) {
                  break;
            }

            len += sprintf(buf + len, "%-12s ", devAttr->name);

            if ((devAttr->flags & DMA_DEVICE_FLAG_IS_DEDICATED) != 0) {
                  len +=
                      sprintf(buf + len, "Dedicated %d:%d ",
                            devAttr->dedicatedController,
                            devAttr->dedicatedChannel);
            } else {
                  len += sprintf(buf + len, "Shared DMA:");
                  if ((devAttr->flags & DMA_DEVICE_FLAG_ON_DMA0) != 0) {
                        len += sprintf(buf + len, "0");
                  }
                  if ((devAttr->flags & DMA_DEVICE_FLAG_ON_DMA1) != 0) {
                        len += sprintf(buf + len, "1");
                  }
                  len += sprintf(buf + len, " ");
            }
            if ((devAttr->flags & DMA_DEVICE_FLAG_NO_ISR) != 0) {
                  len += sprintf(buf + len, "NoISR ");
            }
            if ((devAttr->flags & DMA_DEVICE_FLAG_ALLOW_LARGE_FIFO) != 0) {
                  len += sprintf(buf + len, "Allow-128 ");
            }

            len +=
                sprintf(buf + len,
                      "Xfer #: %Lu Ticks: %Lu Bytes: %Lu DescLen: %u\n",
                      devAttr->numTransfers, devAttr->transferTicks,
                      devAttr->transferBytes,
                      devAttr->ring.bytesAllocated);

      }

      up(&gDMA.lock);
      *eof = 1;

      return len;
}

/****************************************************************************/
/**
*   Determines if a DMA_Device_t is "valid".
*
*   @return
*       TRUE        - dma device is valid
*       FALSE       - dma device isn't valid
*/
/****************************************************************************/

static inline int IsDeviceValid(DMA_Device_t device)
{
      return (device >= 0) && (device < DMA_NUM_DEVICE_ENTRIES);
}

/****************************************************************************/
/**
*   Translates a DMA handle into a pointer to a channel.
*
*   @return
*       non-NULL    - pointer to DMA_Channel_t
*       NULL        - DMA Handle was invalid
*/
/****************************************************************************/

static inline DMA_Channel_t *HandleToChannel(DMA_Handle_t handle)
{
      int controllerIdx;
      int channelIdx;

      controllerIdx = CONTROLLER_FROM_HANDLE(handle);
      channelIdx = CHANNEL_FROM_HANDLE(handle);

      if ((controllerIdx > DMA_NUM_CONTROLLERS)
          || (channelIdx > DMA_NUM_CHANNELS)) {
            return NULL;
      }
      return &gDMA.controller[controllerIdx].channel[channelIdx];
}

/****************************************************************************/
/**
*   Interrupt handler which is called to process DMA interrupts.
*/
/****************************************************************************/

static irqreturn_t dma_interrupt_handler(int irq, void *dev_id)
{
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;
      int irqStatus;

      channel = (DMA_Channel_t *) dev_id;

      /* Figure out why we were called, and knock down the interrupt */

      irqStatus = dmacHw_getInterruptStatus(channel->dmacHwHandle);
      dmacHw_clearInterrupt(channel->dmacHwHandle);

      if ((channel->devType < 0)
          || (channel->devType > DMA_NUM_DEVICE_ENTRIES)) {
            printk(KERN_ERR "dma_interrupt_handler: Invalid devType: %d\n",
                   channel->devType);
            return IRQ_NONE;
      }
      devAttr = &DMA_gDeviceAttribute[channel->devType];

      /* Update stats */

      if ((irqStatus & dmacHw_INTERRUPT_STATUS_TRANS) != 0) {
            devAttr->transferTicks +=
                (timer_get_tick_count() - devAttr->transferStartTime);
      }

      if ((irqStatus & dmacHw_INTERRUPT_STATUS_ERROR) != 0) {
            printk(KERN_ERR
                   "dma_interrupt_handler: devType :%d DMA error (%s)\n",
                   channel->devType, devAttr->name);
      } else {
            devAttr->numTransfers++;
            devAttr->transferBytes += devAttr->numBytes;
      }

      /* Call any installed handler */

      if (devAttr->devHandler != NULL) {
            devAttr->devHandler(channel->devType, irqStatus,
                            devAttr->userData);
      }

      return IRQ_HANDLED;
}

/****************************************************************************/
/**
*   Allocates memory to hold a descriptor ring. The descriptor ring then
*   needs to be populated by making one or more calls to
*   dna_add_descriptors.
*
*   The returned descriptor ring will be automatically initialized.
*
*   @return
*       0           Descriptor ring was allocated successfully
*       -EINVAL     Invalid parameters passed in
*       -ENOMEM     Unable to allocate memory for the desired number of descriptors.
*/
/****************************************************************************/

int dma_alloc_descriptor_ring(DMA_DescriptorRing_t *ring,   /* Descriptor ring to populate */
                        int numDescriptors      /* Number of descriptors that need to be allocated. */
    ) {
      size_t bytesToAlloc = dmacHw_descriptorLen(numDescriptors);

      if ((ring == NULL) || (numDescriptors <= 0)) {
            return -EINVAL;
      }

      ring->physAddr = 0;
      ring->descriptorsAllocated = 0;
      ring->bytesAllocated = 0;

      ring->virtAddr = dma_alloc_writecombine(NULL,
                                         bytesToAlloc,
                                         &ring->physAddr,
                                         GFP_KERNEL);
      if (ring->virtAddr == NULL) {
            return -ENOMEM;
      }

      ring->bytesAllocated = bytesToAlloc;
      ring->descriptorsAllocated = numDescriptors;

      return dma_init_descriptor_ring(ring, numDescriptors);
}

EXPORT_SYMBOL(dma_alloc_descriptor_ring);

/****************************************************************************/
/**
*   Releases the memory which was previously allocated for a descriptor ring.
*/
/****************************************************************************/

void dma_free_descriptor_ring(DMA_DescriptorRing_t *ring    /* Descriptor to release */
    ) {
      if (ring->virtAddr != NULL) {
            dma_free_writecombine(NULL,
                              ring->bytesAllocated,
                              ring->virtAddr, ring->physAddr);
      }

      ring->bytesAllocated = 0;
      ring->descriptorsAllocated = 0;
      ring->virtAddr = NULL;
      ring->physAddr = 0;
}

EXPORT_SYMBOL(dma_free_descriptor_ring);

/****************************************************************************/
/**
*   Initializes a descriptor ring, so that descriptors can be added to it.
*   Once a descriptor ring has been allocated, it may be reinitialized for
*   use with additional/different regions of memory.
*
*   Note that if 7 descriptors are allocated, it's perfectly acceptable to
*   initialize the ring with a smaller number of descriptors. The amount
*   of memory allocated for the descriptor ring will not be reduced, and
*   the descriptor ring may be reinitialized later
*
*   @return
*       0           Descriptor ring was initialized successfully
*       -ENOMEM     The descriptor which was passed in has insufficient space
*                   to hold the desired number of descriptors.
*/
/****************************************************************************/

int dma_init_descriptor_ring(DMA_DescriptorRing_t *ring,    /* Descriptor ring to initialize */
                       int numDescriptors /* Number of descriptors to initialize. */
    ) {
      if (ring->virtAddr == NULL) {
            return -EINVAL;
      }
      if (dmacHw_initDescriptor(ring->virtAddr,
                          ring->physAddr,
                          ring->bytesAllocated, numDescriptors) < 0) {
            printk(KERN_ERR
                   "dma_init_descriptor_ring: dmacHw_initDescriptor failed\n");
            return -ENOMEM;
      }

      return 0;
}

EXPORT_SYMBOL(dma_init_descriptor_ring);

/****************************************************************************/
/**
*   Determines the number of descriptors which would be required for a
*   transfer of the indicated memory region.
*
*   This function also needs to know which DMA device this transfer will
*   be destined for, so that the appropriate DMA configuration can be retrieved.
*   DMA parameters such as transfer width, and whether this is a memory-to-memory
*   or memory-to-peripheral, etc can all affect the actual number of descriptors
*   required.
*
*   @return
*       > 0     Returns the number of descriptors required for the indicated transfer
*       -ENODEV - Device handed in is invalid.
*       -EINVAL Invalid parameters
*       -ENOMEM Memory exhausted
*/
/****************************************************************************/

int dma_calculate_descriptor_count(DMA_Device_t device,     /* DMA Device that this will be associated with */
                           dma_addr_t srcData,  /* Place to get data to write to device */
                           dma_addr_t dstData,  /* Pointer to device data address */
                           size_t numBytes      /* Number of bytes to transfer to the device */
    ) {
      int numDescriptors;
      DMA_DeviceAttribute_t *devAttr;

      if (!IsDeviceValid(device)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[device];

      numDescriptors = dmacHw_calculateDescriptorCount(&devAttr->config,
                                                (void *)srcData,
                                                (void *)dstData,
                                                numBytes);
      if (numDescriptors < 0) {
            printk(KERN_ERR
                   "dma_calculate_descriptor_count: dmacHw_calculateDescriptorCount failed\n");
            return -EINVAL;
      }

      return numDescriptors;
}

EXPORT_SYMBOL(dma_calculate_descriptor_count);

/****************************************************************************/
/**
*   Adds a region of memory to the descriptor ring. Note that it may take
*   multiple descriptors for each region of memory. It is the callers
*   responsibility to allocate a sufficiently large descriptor ring.
*
*   @return
*       0       Descriptors were added successfully
*       -ENODEV Device handed in is invalid.
*       -EINVAL Invalid parameters
*       -ENOMEM Memory exhausted
*/
/****************************************************************************/

int dma_add_descriptors(DMA_DescriptorRing_t *ring,   /* Descriptor ring to add descriptors to */
                  DMA_Device_t device,    /* DMA Device that descriptors are for */
                  dma_addr_t srcData,     /* Place to get data (memory or device) */
                  dma_addr_t dstData,     /* Place to put data (memory or device) */
                  size_t numBytes   /* Number of bytes to transfer to the device */
    ) {
      int rc;
      DMA_DeviceAttribute_t *devAttr;

      if (!IsDeviceValid(device)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[device];

      rc = dmacHw_setDataDescriptor(&devAttr->config,
                              ring->virtAddr,
                              (void *)srcData,
                              (void *)dstData, numBytes);
      if (rc < 0) {
            printk(KERN_ERR
                   "dma_add_descriptors: dmacHw_setDataDescriptor failed with code: %d\n",
                   rc);
            return -ENOMEM;
      }

      return 0;
}

EXPORT_SYMBOL(dma_add_descriptors);

/****************************************************************************/
/**
*   Sets the descriptor ring associated with a device.
*
*   Once set, the descriptor ring will be associated with the device, even
*   across channel request/free calls. Passing in a NULL descriptor ring
*   will release any descriptor ring currently associated with the device.
*
*   Note: If you call dma_transfer, or one of the other dma_alloc_ functions
*         the descriptor ring may be released and reallocated.
*
*   Note: This function will release the descriptor memory for any current
*         descriptor ring associated with this device.
*
*   @return
*       0       Descriptors were added successfully
*       -ENODEV Device handed in is invalid.
*/
/****************************************************************************/

int dma_set_device_descriptor_ring(DMA_Device_t device,     /* Device to update the descriptor ring for. */
                           DMA_DescriptorRing_t *ring /* Descriptor ring to add descriptors to */
    ) {
      DMA_DeviceAttribute_t *devAttr;

      if (!IsDeviceValid(device)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[device];

      /* Free the previously allocated descriptor ring */

      dma_free_descriptor_ring(&devAttr->ring);

      if (ring != NULL) {
            /* Copy in the new one */

            devAttr->ring = *ring;
      }

      /* Set things up so that if dma_transfer is called then this descriptor */
      /* ring will get freed. */

      devAttr->prevSrcData = 0;
      devAttr->prevDstData = 0;
      devAttr->prevNumBytes = 0;

      return 0;
}

EXPORT_SYMBOL(dma_set_device_descriptor_ring);

/****************************************************************************/
/**
*   Retrieves the descriptor ring associated with a device.
*
*   @return
*       0       Descriptors were added successfully
*       -ENODEV Device handed in is invalid.
*/
/****************************************************************************/

int dma_get_device_descriptor_ring(DMA_Device_t device,     /* Device to retrieve the descriptor ring for. */
                           DMA_DescriptorRing_t *ring /* Place to store retrieved ring */
    ) {
      DMA_DeviceAttribute_t *devAttr;

      memset(ring, 0, sizeof(*ring));

      if (!IsDeviceValid(device)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[device];

      *ring = devAttr->ring;

      return 0;
}

EXPORT_SYMBOL(dma_get_device_descriptor_ring);

/****************************************************************************/
/**
*   Configures a DMA channel.
*
*   @return
*       >= 0    - Initialization was successfull.
*
*       -EBUSY  - Device is currently being used.
*       -ENODEV - Device handed in is invalid.
*/
/****************************************************************************/

static int ConfigChannel(DMA_Handle_t handle)
{
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;
      int controllerIdx;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[channel->devType];
      controllerIdx = CONTROLLER_FROM_HANDLE(handle);

      if ((devAttr->flags & DMA_DEVICE_FLAG_PORT_PER_DMAC) != 0) {
            if (devAttr->config.transferType ==
                dmacHw_TRANSFER_TYPE_MEM_TO_PERIPHERAL) {
                  devAttr->config.dstPeripheralPort =
                      devAttr->dmacPort[controllerIdx];
            } else if (devAttr->config.transferType ==
                     dmacHw_TRANSFER_TYPE_PERIPHERAL_TO_MEM) {
                  devAttr->config.srcPeripheralPort =
                      devAttr->dmacPort[controllerIdx];
            }
      }

      if (dmacHw_configChannel(channel->dmacHwHandle, &devAttr->config) != 0) {
            printk(KERN_ERR "ConfigChannel: dmacHw_configChannel failed\n");
            return -EIO;
      }

      return 0;
}

/****************************************************************************/
/**
*   Intializes all of the data structures associated with the DMA.
*   @return
*       >= 0    - Initialization was successfull.
*
*       -EBUSY  - Device is currently being used.
*       -ENODEV - Device handed in is invalid.
*/
/****************************************************************************/

int dma_init(void)
{
      int rc = 0;
      int controllerIdx;
      int channelIdx;
      DMA_Device_t devIdx;
      DMA_Channel_t *channel;
      DMA_Handle_t dedicatedHandle;

      memset(&gDMA, 0, sizeof(gDMA));

      init_MUTEX_LOCKED(&gDMA.lock);
      init_waitqueue_head(&gDMA.freeChannelQ);

      /* Initialize the Hardware */

      dmacHw_initDma();

      /* Start off by marking all of the DMA channels as shared. */

      for (controllerIdx = 0; controllerIdx < DMA_NUM_CONTROLLERS;
           controllerIdx++) {
            for (channelIdx = 0; channelIdx < DMA_NUM_CHANNELS;
                 channelIdx++) {
                  channel =
                      &gDMA.controller[controllerIdx].channel[channelIdx];

                  channel->flags = 0;
                  channel->devType = DMA_DEVICE_NONE;
                  channel->lastDevType = DMA_DEVICE_NONE;

#if (DMA_DEBUG_TRACK_RESERVATION)
                  channel->fileName = "";
                  channel->lineNum = 0;
#endif

                  channel->dmacHwHandle =
                      dmacHw_getChannelHandle(dmacHw_MAKE_CHANNEL_ID
                                        (controllerIdx,
                                         channelIdx));
                  dmacHw_initChannel(channel->dmacHwHandle);
            }
      }

      /* Record any special attributes that channels may have */

      gDMA.controller[0].channel[0].flags |= DMA_CHANNEL_FLAG_LARGE_FIFO;
      gDMA.controller[0].channel[1].flags |= DMA_CHANNEL_FLAG_LARGE_FIFO;
      gDMA.controller[1].channel[0].flags |= DMA_CHANNEL_FLAG_LARGE_FIFO;
      gDMA.controller[1].channel[1].flags |= DMA_CHANNEL_FLAG_LARGE_FIFO;

      /* Now walk through and record the dedicated channels. */

      for (devIdx = 0; devIdx < DMA_NUM_DEVICE_ENTRIES; devIdx++) {
            DMA_DeviceAttribute_t *devAttr = &DMA_gDeviceAttribute[devIdx];

            if (((devAttr->flags & DMA_DEVICE_FLAG_NO_ISR) != 0)
                && ((devAttr->flags & DMA_DEVICE_FLAG_IS_DEDICATED) == 0)) {
                  printk(KERN_ERR
                         "DMA Device: %s Can only request NO_ISR for dedicated devices\n",
                         devAttr->name);
                  rc = -EINVAL;
                  goto out;
            }

            if ((devAttr->flags & DMA_DEVICE_FLAG_IS_DEDICATED) != 0) {
                  /* This is a dedicated device. Mark the channel as being reserved. */

                  if (devAttr->dedicatedController >= DMA_NUM_CONTROLLERS) {
                        printk(KERN_ERR
                               "DMA Device: %s DMA Controller %d is out of range\n",
                               devAttr->name,
                               devAttr->dedicatedController);
                        rc = -EINVAL;
                        goto out;
                  }

                  if (devAttr->dedicatedChannel >= DMA_NUM_CHANNELS) {
                        printk(KERN_ERR
                               "DMA Device: %s DMA Channel %d is out of range\n",
                               devAttr->name,
                               devAttr->dedicatedChannel);
                        rc = -EINVAL;
                        goto out;
                  }

                  dedicatedHandle =
                      MAKE_HANDLE(devAttr->dedicatedController,
                              devAttr->dedicatedChannel);
                  channel = HandleToChannel(dedicatedHandle);

                  if ((channel->flags & DMA_CHANNEL_FLAG_IS_DEDICATED) !=
                      0) {
                        printk
                            ("DMA Device: %s attempting to use same DMA Controller:Channel (%d:%d) as %s\n",
                             devAttr->name,
                             devAttr->dedicatedController,
                             devAttr->dedicatedChannel,
                             DMA_gDeviceAttribute[channel->devType].
                             name);
                        rc = -EBUSY;
                        goto out;
                  }

                  channel->flags |= DMA_CHANNEL_FLAG_IS_DEDICATED;
                  channel->devType = devIdx;

                  if (devAttr->flags & DMA_DEVICE_FLAG_NO_ISR) {
                        channel->flags |= DMA_CHANNEL_FLAG_NO_ISR;
                  }

                  /* For dedicated channels, we can go ahead and configure the DMA channel now */
                  /* as well. */

                  ConfigChannel(dedicatedHandle);
            }
      }

      /* Go through and register the interrupt handlers */

      for (controllerIdx = 0; controllerIdx < DMA_NUM_CONTROLLERS;
           controllerIdx++) {
            for (channelIdx = 0; channelIdx < DMA_NUM_CHANNELS;
                 channelIdx++) {
                  channel =
                      &gDMA.controller[controllerIdx].channel[channelIdx];

                  if ((channel->flags & DMA_CHANNEL_FLAG_NO_ISR) == 0) {
                        snprintf(channel->name, sizeof(channel->name),
                               "dma %d:%d %s", controllerIdx,
                               channelIdx,
                               channel->devType ==
                               DMA_DEVICE_NONE ? "" :
                               DMA_gDeviceAttribute[channel->devType].
                               name);

                        rc =
                             request_irq(IRQ_DMA0C0 +
                                     (controllerIdx *
                                      DMA_NUM_CHANNELS) +
                                     channelIdx,
                                     dma_interrupt_handler,
                                     IRQF_DISABLED, channel->name,
                                     channel);
                        if (rc != 0) {
                              printk(KERN_ERR
                                     "request_irq for IRQ_DMA%dC%d failed\n",
                                     controllerIdx, channelIdx);
                        }
                  }
            }
      }

      /* Create /proc/dma/channels and /proc/dma/devices */

      gDmaDir = create_proc_entry("dma", S_IFDIR | S_IRUGO | S_IXUGO, NULL);

      if (gDmaDir == NULL) {
            printk(KERN_ERR "Unable to create /proc/dma\n");
      } else {
            create_proc_read_entry("channels", 0, gDmaDir,
                               dma_proc_read_channels, NULL);
            create_proc_read_entry("devices", 0, gDmaDir,
                               dma_proc_read_devices, NULL);
            create_proc_read_entry("mem-type", 0, gDmaDir,
                               dma_proc_read_mem_type, NULL);
      }

out:

      up(&gDMA.lock);

      return rc;
}

/****************************************************************************/
/**
*   Reserves a channel for use with @a dev. If the device is setup to use
*   a shared channel, then this function will block until a free channel
*   becomes available.
*
*   @return
*       >= 0    - A valid DMA Handle.
*       -EBUSY  - Device is currently being used.
*       -ENODEV - Device handed in is invalid.
*/
/****************************************************************************/

#if (DMA_DEBUG_TRACK_RESERVATION)
DMA_Handle_t dma_request_channel_dbg
    (DMA_Device_t dev, const char *fileName, int lineNum)
#else
DMA_Handle_t dma_request_channel(DMA_Device_t dev)
#endif
{
      DMA_Handle_t handle;
      DMA_DeviceAttribute_t *devAttr;
      DMA_Channel_t *channel;
      int controllerIdx;
      int controllerIdx2;
      int channelIdx;

      if (down_interruptible(&gDMA.lock) < 0) {
            return -ERESTARTSYS;
      }

      if ((dev < 0) || (dev >= DMA_NUM_DEVICE_ENTRIES)) {
            handle = -ENODEV;
            goto out;
      }
      devAttr = &DMA_gDeviceAttribute[dev];

#if (DMA_DEBUG_TRACK_RESERVATION)
      {
            char *s;

            s = strrchr(fileName, '/');
            if (s != NULL) {
                  fileName = s + 1;
            }
      }
#endif
      if ((devAttr->flags & DMA_DEVICE_FLAG_IN_USE) != 0) {
            /* This device has already been requested and not been freed */

            printk(KERN_ERR "%s: device %s is already requested\n",
                   __func__, devAttr->name);
            handle = -EBUSY;
            goto out;
      }

      if ((devAttr->flags & DMA_DEVICE_FLAG_IS_DEDICATED) != 0) {
            /* This device has a dedicated channel. */

            channel =
                &gDMA.controller[devAttr->dedicatedController].
                channel[devAttr->dedicatedChannel];
            if ((channel->flags & DMA_CHANNEL_FLAG_IN_USE) != 0) {
                  handle = -EBUSY;
                  goto out;
            }

            channel->flags |= DMA_CHANNEL_FLAG_IN_USE;
            devAttr->flags |= DMA_DEVICE_FLAG_IN_USE;

#if (DMA_DEBUG_TRACK_RESERVATION)
            channel->fileName = fileName;
            channel->lineNum = lineNum;
#endif
            handle =
                MAKE_HANDLE(devAttr->dedicatedController,
                        devAttr->dedicatedChannel);
            goto out;
      }

      /* This device needs to use one of the shared channels. */

      handle = DMA_INVALID_HANDLE;
      while (handle == DMA_INVALID_HANDLE) {
            /* Scan through the shared channels and see if one is available */

            for (controllerIdx2 = 0; controllerIdx2 < DMA_NUM_CONTROLLERS;
                 controllerIdx2++) {
                  /* Check to see if we should try on controller 1 first. */

                  controllerIdx = controllerIdx2;
                  if ((devAttr->
                       flags & DMA_DEVICE_FLAG_ALLOC_DMA1_FIRST) != 0) {
                        controllerIdx = 1 - controllerIdx;
                  }

                  /* See if the device is available on the controller being tested */

                  if ((devAttr->
                       flags & (DMA_DEVICE_FLAG_ON_DMA0 << controllerIdx))
                      != 0) {
                        for (channelIdx = 0;
                             channelIdx < DMA_NUM_CHANNELS;
                             channelIdx++) {
                              channel =
                                  &gDMA.controller[controllerIdx].
                                  channel[channelIdx];

                              if (((channel->
                                    flags &
                                    DMA_CHANNEL_FLAG_IS_DEDICATED) ==
                                   0)
                                  &&
                                  ((channel->
                                    flags & DMA_CHANNEL_FLAG_IN_USE)
                                   == 0)) {
                                    if (((channel->
                                          flags &
                                          DMA_CHANNEL_FLAG_LARGE_FIFO)
                                         != 0)
                                        &&
                                        ((devAttr->
                                          flags &
                                          DMA_DEVICE_FLAG_ALLOW_LARGE_FIFO)
                                         == 0)) {
                                          /* This channel is a large fifo - don't tie it up */
                                          /* with devices that we don't want using it. */

                                          continue;
                                    }

                                    channel->flags |=
                                        DMA_CHANNEL_FLAG_IN_USE;
                                    channel->devType = dev;
                                    devAttr->flags |=
                                        DMA_DEVICE_FLAG_IN_USE;

#if (DMA_DEBUG_TRACK_RESERVATION)
                                    channel->fileName = fileName;
                                    channel->lineNum = lineNum;
#endif
                                    handle =
                                        MAKE_HANDLE(controllerIdx,
                                                channelIdx);

                                    /* Now that we've reserved the channel - we can go ahead and configure it */

                                    if (ConfigChannel(handle) != 0) {
                                          handle = -EIO;
                                          printk(KERN_ERR
                                                 "dma_request_channel: ConfigChannel failed\n");
                                    }
                                    goto out;
                              }
                        }
                  }
            }

            /* No channels are currently available. Let's wait for one to free up. */

            {
                  DEFINE_WAIT(wait);

                  prepare_to_wait(&gDMA.freeChannelQ, &wait,
                              TASK_INTERRUPTIBLE);
                  up(&gDMA.lock);
                  schedule();
                  finish_wait(&gDMA.freeChannelQ, &wait);

                  if (signal_pending(current)) {
                        /* We don't currently hold gDMA.lock, so we return directly */

                        return -ERESTARTSYS;
                  }
            }

            if (down_interruptible(&gDMA.lock)) {
                  return -ERESTARTSYS;
            }
      }

out:
      up(&gDMA.lock);

      return handle;
}

/* Create both _dbg and non _dbg functions for modules. */

#if (DMA_DEBUG_TRACK_RESERVATION)
#undef dma_request_channel
DMA_Handle_t dma_request_channel(DMA_Device_t dev)
{
      return dma_request_channel_dbg(dev, __FILE__, __LINE__);
}

EXPORT_SYMBOL(dma_request_channel_dbg);
#endif
EXPORT_SYMBOL(dma_request_channel);

/****************************************************************************/
/**
*   Frees a previously allocated DMA Handle.
*/
/****************************************************************************/

int dma_free_channel(DMA_Handle_t handle  /* DMA handle. */
    ) {
      int rc = 0;
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;

      if (down_interruptible(&gDMA.lock) < 0) {
            return -ERESTARTSYS;
      }

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            rc = -EINVAL;
            goto out;
      }

      devAttr = &DMA_gDeviceAttribute[channel->devType];

      if ((channel->flags & DMA_CHANNEL_FLAG_IS_DEDICATED) == 0) {
            channel->lastDevType = channel->devType;
            channel->devType = DMA_DEVICE_NONE;
      }
      channel->flags &= ~DMA_CHANNEL_FLAG_IN_USE;
      devAttr->flags &= ~DMA_DEVICE_FLAG_IN_USE;

out:
      up(&gDMA.lock);

      wake_up_interruptible(&gDMA.freeChannelQ);

      return rc;
}

EXPORT_SYMBOL(dma_free_channel);

/****************************************************************************/
/**
*   Determines if a given device has been configured as using a shared
*   channel.
*
*   @return
*       0           Device uses a dedicated channel
*       > zero      Device uses a shared channel
*       < zero      Error code
*/
/****************************************************************************/

int dma_device_is_channel_shared(DMA_Device_t device  /* Device to check. */
    ) {
      DMA_DeviceAttribute_t *devAttr;

      if (!IsDeviceValid(device)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[device];

      return ((devAttr->flags & DMA_DEVICE_FLAG_IS_DEDICATED) == 0);
}

EXPORT_SYMBOL(dma_device_is_channel_shared);

/****************************************************************************/
/**
*   Allocates buffers for the descriptors. This is normally done automatically
*   but needs to be done explicitly when initiating a dma from interrupt
*   context.
*
*   @return
*       0       Descriptors were allocated successfully
*       -EINVAL Invalid device type for this kind of transfer
*               (i.e. the device is _MEM_TO_DEV and not _DEV_TO_MEM)
*       -ENOMEM Memory exhausted
*/
/****************************************************************************/

int dma_alloc_descriptors(DMA_Handle_t handle,  /* DMA Handle */
                    dmacHw_TRANSFER_TYPE_e transferType,    /* Type of transfer being performed */
                    dma_addr_t srcData,   /* Place to get data to write to device */
                    dma_addr_t dstData,   /* Pointer to device data address */
                    size_t numBytes /* Number of bytes to transfer to the device */
    ) {
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;
      int numDescriptors;
      size_t ringBytesRequired;
      int rc = 0;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }

      devAttr = &DMA_gDeviceAttribute[channel->devType];

      if (devAttr->config.transferType != transferType) {
            return -EINVAL;
      }

      /* Figure out how many descriptors we need. */

      /* printk("srcData: 0x%08x dstData: 0x%08x, numBytes: %d\n", */
      /*        srcData, dstData, numBytes); */

      numDescriptors = dmacHw_calculateDescriptorCount(&devAttr->config,
                                                (void *)srcData,
                                                (void *)dstData,
                                                numBytes);
      if (numDescriptors < 0) {
            printk(KERN_ERR "%s: dmacHw_calculateDescriptorCount failed\n",
                   __func__);
            return -EINVAL;
      }

      /* Check to see if we can reuse the existing descriptor ring, or if we need to allocate */
      /* a new one. */

      ringBytesRequired = dmacHw_descriptorLen(numDescriptors);

      /* printk("ringBytesRequired: %d\n", ringBytesRequired); */

      if (ringBytesRequired > devAttr->ring.bytesAllocated) {
            /* Make sure that this code path is never taken from interrupt context. */
            /* It's OK for an interrupt to initiate a DMA transfer, but the descriptor */
            /* allocation needs to have already been done. */

            might_sleep();

            /* Free the old descriptor ring and allocate a new one. */

            dma_free_descriptor_ring(&devAttr->ring);

            /* And allocate a new one. */

            rc =
                 dma_alloc_descriptor_ring(&devAttr->ring,
                                     numDescriptors);
            if (rc < 0) {
                  printk(KERN_ERR
                         "%s: dma_alloc_descriptor_ring(%d) failed\n",
                         __func__, numDescriptors);
                  return rc;
            }
            /* Setup the descriptor for this transfer */

            if (dmacHw_initDescriptor(devAttr->ring.virtAddr,
                                devAttr->ring.physAddr,
                                devAttr->ring.bytesAllocated,
                                numDescriptors) < 0) {
                  printk(KERN_ERR "%s: dmacHw_initDescriptor failed\n",
                         __func__);
                  return -EINVAL;
            }
      } else {
            /* We've already got enough ring buffer allocated. All we need to do is reset */
            /* any control information, just in case the previous DMA was stopped. */

            dmacHw_resetDescriptorControl(devAttr->ring.virtAddr);
      }

      /* dma_alloc/free both set the prevSrc/DstData to 0. If they happen to be the same */
      /* as last time, then we don't need to call setDataDescriptor again. */

      if (dmacHw_setDataDescriptor(&devAttr->config,
                             devAttr->ring.virtAddr,
                             (void *)srcData,
                             (void *)dstData, numBytes) < 0) {
            printk(KERN_ERR "%s: dmacHw_setDataDescriptor failed\n",
                   __func__);
            return -EINVAL;
      }

      /* Remember the critical information for this transfer so that we can eliminate */
      /* another call to dma_alloc_descriptors if the caller reuses the same buffers */

      devAttr->prevSrcData = srcData;
      devAttr->prevDstData = dstData;
      devAttr->prevNumBytes = numBytes;

      return 0;
}

EXPORT_SYMBOL(dma_alloc_descriptors);

/****************************************************************************/
/**
*   Allocates and sets up descriptors for a double buffered circular buffer.
*
*   This is primarily intended to be used for things like the ingress samples
*   from a microphone.
*
*   @return
*       > 0     Number of descriptors actually allocated.
*       -EINVAL Invalid device type for this kind of transfer
*               (i.e. the device is _MEM_TO_DEV and not _DEV_TO_MEM)
*       -ENOMEM Memory exhausted
*/
/****************************************************************************/

int dma_alloc_double_dst_descriptors(DMA_Handle_t handle,   /* DMA Handle */
                             dma_addr_t srcData,      /* Physical address of source data */
                             dma_addr_t dstData1,     /* Physical address of first destination buffer */
                             dma_addr_t dstData2,     /* Physical address of second destination buffer */
                             size_t numBytes    /* Number of bytes in each destination buffer */
    ) {
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;
      int numDst1Descriptors;
      int numDst2Descriptors;
      int numDescriptors;
      size_t ringBytesRequired;
      int rc = 0;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }

      devAttr = &DMA_gDeviceAttribute[channel->devType];

      /* Figure out how many descriptors we need. */

      /* printk("srcData: 0x%08x dstData: 0x%08x, numBytes: %d\n", */
      /*        srcData, dstData, numBytes); */

      numDst1Descriptors =
           dmacHw_calculateDescriptorCount(&devAttr->config, (void *)srcData,
                                   (void *)dstData1, numBytes);
      if (numDst1Descriptors < 0) {
            return -EINVAL;
      }
      numDst2Descriptors =
           dmacHw_calculateDescriptorCount(&devAttr->config, (void *)srcData,
                                   (void *)dstData2, numBytes);
      if (numDst2Descriptors < 0) {
            return -EINVAL;
      }
      numDescriptors = numDst1Descriptors + numDst2Descriptors;
      /* printk("numDescriptors: %d\n", numDescriptors); */

      /* Check to see if we can reuse the existing descriptor ring, or if we need to allocate */
      /* a new one. */

      ringBytesRequired = dmacHw_descriptorLen(numDescriptors);

      /* printk("ringBytesRequired: %d\n", ringBytesRequired); */

      if (ringBytesRequired > devAttr->ring.bytesAllocated) {
            /* Make sure that this code path is never taken from interrupt context. */
            /* It's OK for an interrupt to initiate a DMA transfer, but the descriptor */
            /* allocation needs to have already been done. */

            might_sleep();

            /* Free the old descriptor ring and allocate a new one. */

            dma_free_descriptor_ring(&devAttr->ring);

            /* And allocate a new one. */

            rc =
                 dma_alloc_descriptor_ring(&devAttr->ring,
                                     numDescriptors);
            if (rc < 0) {
                  printk(KERN_ERR
                         "%s: dma_alloc_descriptor_ring(%d) failed\n",
                         __func__, ringBytesRequired);
                  return rc;
            }
      }

      /* Setup the descriptor for this transfer. Since this function is used with */
      /* CONTINUOUS DMA operations, we need to reinitialize every time, otherwise */
      /* setDataDescriptor will keep trying to append onto the end. */

      if (dmacHw_initDescriptor(devAttr->ring.virtAddr,
                          devAttr->ring.physAddr,
                          devAttr->ring.bytesAllocated,
                          numDescriptors) < 0) {
            printk(KERN_ERR "%s: dmacHw_initDescriptor failed\n", __func__);
            return -EINVAL;
      }

      /* dma_alloc/free both set the prevSrc/DstData to 0. If they happen to be the same */
      /* as last time, then we don't need to call setDataDescriptor again. */

      if (dmacHw_setDataDescriptor(&devAttr->config,
                             devAttr->ring.virtAddr,
                             (void *)srcData,
                             (void *)dstData1, numBytes) < 0) {
            printk(KERN_ERR "%s: dmacHw_setDataDescriptor 1 failed\n",
                   __func__);
            return -EINVAL;
      }
      if (dmacHw_setDataDescriptor(&devAttr->config,
                             devAttr->ring.virtAddr,
                             (void *)srcData,
                             (void *)dstData2, numBytes) < 0) {
            printk(KERN_ERR "%s: dmacHw_setDataDescriptor 2 failed\n",
                   __func__);
            return -EINVAL;
      }

      /* You should use dma_start_transfer rather than dma_transfer_xxx so we don't */
      /* try to make the 'prev' variables right. */

      devAttr->prevSrcData = 0;
      devAttr->prevDstData = 0;
      devAttr->prevNumBytes = 0;

      return numDescriptors;
}

EXPORT_SYMBOL(dma_alloc_double_dst_descriptors);

/****************************************************************************/
/**
*   Initiates a transfer when the descriptors have already been setup.
*
*   This is a special case, and normally, the dma_transfer_xxx functions should
*   be used.
*
*   @return
*       0       Transfer was started successfully
*       -ENODEV Invalid handle
*/
/****************************************************************************/

int dma_start_transfer(DMA_Handle_t handle)
{
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[channel->devType];

      dmacHw_initiateTransfer(channel->dmacHwHandle, &devAttr->config,
                        devAttr->ring.virtAddr);

      /* Since we got this far, everything went successfully */

      return 0;
}

EXPORT_SYMBOL(dma_start_transfer);

/****************************************************************************/
/**
*   Stops a previously started DMA transfer.
*
*   @return
*       0       Transfer was stopped successfully
*       -ENODEV Invalid handle
*/
/****************************************************************************/

int dma_stop_transfer(DMA_Handle_t handle)
{
      DMA_Channel_t *channel;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }

      dmacHw_stopTransfer(channel->dmacHwHandle);

      return 0;
}

EXPORT_SYMBOL(dma_stop_transfer);

/****************************************************************************/
/**
*   Waits for a DMA to complete by polling. This function is only intended
*   to be used for testing. Interrupts should be used for most DMA operations.
*/
/****************************************************************************/

int dma_wait_transfer_done(DMA_Handle_t handle)
{
      DMA_Channel_t *channel;
      dmacHw_TRANSFER_STATUS_e status;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }

      while ((status =
            dmacHw_transferCompleted(channel->dmacHwHandle)) ==
             dmacHw_TRANSFER_STATUS_BUSY) {
            ;
      }

      if (status == dmacHw_TRANSFER_STATUS_ERROR) {
            printk(KERN_ERR "%s: DMA transfer failed\n", __func__);
            return -EIO;
      }
      return 0;
}

EXPORT_SYMBOL(dma_wait_transfer_done);

/****************************************************************************/
/**
*   Initiates a DMA, allocating the descriptors as required.
*
*   @return
*       0       Transfer was started successfully
*       -EINVAL Invalid device type for this kind of transfer
*               (i.e. the device is _DEV_TO_MEM and not _MEM_TO_DEV)
*/
/****************************************************************************/

int dma_transfer(DMA_Handle_t handle,     /* DMA Handle */
             dmacHw_TRANSFER_TYPE_e transferType,     /* Type of transfer being performed */
             dma_addr_t srcData,    /* Place to get data to write to device */
             dma_addr_t dstData,    /* Pointer to device data address */
             size_t numBytes  /* Number of bytes to transfer to the device */
    ) {
      DMA_Channel_t *channel;
      DMA_DeviceAttribute_t *devAttr;
      int rc = 0;

      channel = HandleToChannel(handle);
      if (channel == NULL) {
            return -ENODEV;
      }

      devAttr = &DMA_gDeviceAttribute[channel->devType];

      if (devAttr->config.transferType != transferType) {
            return -EINVAL;
      }

      /* We keep track of the information about the previous request for this */
      /* device, and if the attributes match, then we can use the descriptors we setup */
      /* the last time, and not have to reinitialize everything. */

      {
            rc =
                 dma_alloc_descriptors(handle, transferType, srcData,
                                 dstData, numBytes);
            if (rc != 0) {
                  return rc;
            }
      }

      /* And kick off the transfer */

      devAttr->numBytes = numBytes;
      devAttr->transferStartTime = timer_get_tick_count();

      dmacHw_initiateTransfer(channel->dmacHwHandle, &devAttr->config,
                        devAttr->ring.virtAddr);

      /* Since we got this far, everything went successfully */

      return 0;
}

EXPORT_SYMBOL(dma_transfer);

/****************************************************************************/
/**
*   Set the callback function which will be called when a transfer completes.
*   If a NULL callback function is set, then no callback will occur.
*
*   @note   @a devHandler will be called from IRQ context.
*
*   @return
*       0       - Success
*       -ENODEV - Device handed in is invalid.
*/
/****************************************************************************/

int dma_set_device_handler(DMA_Device_t dev,    /* Device to set the callback for. */
                     DMA_DeviceHandler_t devHandler,  /* Function to call when the DMA completes */
                     void *userData /* Pointer which will be passed to devHandler. */
    ) {
      DMA_DeviceAttribute_t *devAttr;
      unsigned long flags;

      if (!IsDeviceValid(dev)) {
            return -ENODEV;
      }
      devAttr = &DMA_gDeviceAttribute[dev];

      local_irq_save(flags);

      devAttr->userData = userData;
      devAttr->devHandler = devHandler;

      local_irq_restore(flags);

      return 0;
}

EXPORT_SYMBOL(dma_set_device_handler);

/****************************************************************************/
/**
*   Initializes a memory mapping structure
*/
/****************************************************************************/

int dma_init_mem_map(DMA_MemMap_t *memMap)
{
      memset(memMap, 0, sizeof(*memMap));

      init_MUTEX(&memMap->lock);

      return 0;
}

EXPORT_SYMBOL(dma_init_mem_map);

/****************************************************************************/
/**
*   Releases any memory currently being held by a memory mapping structure.
*/
/****************************************************************************/

int dma_term_mem_map(DMA_MemMap_t *memMap)
{
      down(&memMap->lock);    /* Just being paranoid */

      /* Free up any allocated memory */

      up(&memMap->lock);
      memset(memMap, 0, sizeof(*memMap));

      return 0;
}

EXPORT_SYMBOL(dma_term_mem_map);

/****************************************************************************/
/**
*   Looks at a memory address and categorizes it.
*
*   @return One of the values from the DMA_MemType_t enumeration.
*/
/****************************************************************************/

DMA_MemType_t dma_mem_type(void *addr)
{
      unsigned long addrVal = (unsigned long)addr;

      if (addrVal >= VMALLOC_END) {
            /* NOTE: DMA virtual memory space starts at 0xFFxxxxxx */

            /* dma_alloc_xxx pages are physically and virtually contiguous */

            return DMA_MEM_TYPE_DMA;
      }

      /* Technically, we could add one more classification. Addresses between VMALLOC_END */
      /* and the beginning of the DMA virtual address could be considered to be I/O space. */
      /* Right now, nobody cares about this particular classification, so we ignore it. */

      if (is_vmalloc_addr(addr)) {
            /* Address comes from the vmalloc'd region. Pages are virtually */
            /* contiguous but NOT physically contiguous */

            return DMA_MEM_TYPE_VMALLOC;
      }

      if (addrVal >= PAGE_OFFSET) {
            /* PAGE_OFFSET is typically 0xC0000000 */

            /* kmalloc'd pages are physically contiguous */

            return DMA_MEM_TYPE_KMALLOC;
      }

      return DMA_MEM_TYPE_USER;
}

EXPORT_SYMBOL(dma_mem_type);

/****************************************************************************/
/**
*   Looks at a memory address and determines if we support DMA'ing to/from
*   that type of memory.
*
*   @return boolean -
*               return value != 0 means dma supported
*               return value == 0 means dma not supported
*/
/****************************************************************************/

int dma_mem_supports_dma(void *addr)
{
      DMA_MemType_t memType = dma_mem_type(addr);

      return (memType == DMA_MEM_TYPE_DMA)
#if ALLOW_MAP_OF_KMALLOC_MEMORY
          || (memType == DMA_MEM_TYPE_KMALLOC)
#endif
          || (memType == DMA_MEM_TYPE_USER);
}

EXPORT_SYMBOL(dma_mem_supports_dma);

/****************************************************************************/
/**
*   Maps in a memory region such that it can be used for performing a DMA.
*
*   @return
*/
/****************************************************************************/

int dma_map_start(DMA_MemMap_t *memMap,   /* Stores state information about the map */
              enum dma_data_direction dir /* Direction that the mapping will be going */
    ) {
      int rc;

      down(&memMap->lock);

      DMA_MAP_PRINT("memMap: %p\n", memMap);

      if (memMap->inUse) {
            printk(KERN_ERR "%s: memory map %p is already being used\n",
                   __func__, memMap);
            rc = -EBUSY;
            goto out;
      }

      memMap->inUse = 1;
      memMap->dir = dir;
      memMap->numRegionsUsed = 0;

      rc = 0;

out:

      DMA_MAP_PRINT("returning %d", rc);

      up(&memMap->lock);

      return rc;
}

EXPORT_SYMBOL(dma_map_start);

/****************************************************************************/
/**
*   Adds a segment of memory to a memory map. Each segment is both
*   physically and virtually contiguous.
*
*   @return     0 on success, error code otherwise.
*/
/****************************************************************************/

static int dma_map_add_segment(DMA_MemMap_t *memMap,  /* Stores state information about the map */
                         DMA_Region_t *region,  /* Region that the segment belongs to */
                         void *virtAddr,  /* Virtual address of the segment being added */
                         dma_addr_t physAddr,   /* Physical address of the segment being added */
                         size_t numBytes  /* Number of bytes of the segment being added */
    ) {
      DMA_Segment_t *segment;

      DMA_MAP_PRINT("memMap:%p va:%p pa:0x%x #:%d\n", memMap, virtAddr,
                  physAddr, numBytes);

      /* Sanity check */

      if (((unsigned long)virtAddr < (unsigned long)region->virtAddr)
          || (((unsigned long)virtAddr + numBytes)) >
          ((unsigned long)region->virtAddr + region->numBytes)) {
            printk(KERN_ERR
                   "%s: virtAddr %p is outside region @ %p len: %d\n",
                   __func__, virtAddr, region->virtAddr, region->numBytes);
            return -EINVAL;
      }

      if (region->numSegmentsUsed > 0) {
            /* Check to see if this segment is physically contiguous with the previous one */

            segment = &region->segment[region->numSegmentsUsed - 1];

            if ((segment->physAddr + segment->numBytes) == physAddr) {
                  /* It is - just add on to the end */

                  DMA_MAP_PRINT("appending %d bytes to last segment\n",
                              numBytes);

                  segment->numBytes += numBytes;

                  return 0;
            }
      }

      /* Reallocate to hold more segments, if required. */

      if (region->numSegmentsUsed >= region->numSegmentsAllocated) {
            DMA_Segment_t *newSegment;
            size_t oldSize =
                region->numSegmentsAllocated * sizeof(*newSegment);
            int newAlloc = region->numSegmentsAllocated + 4;
            size_t newSize = newAlloc * sizeof(*newSegment);

            newSegment = kmalloc(newSize, GFP_KERNEL);
            if (newSegment == NULL) {
                  return -ENOMEM;
            }
            memcpy(newSegment, region->segment, oldSize);
            memset(&((uint8_t *) newSegment)[oldSize], 0,
                   newSize - oldSize);
            kfree(region->segment);

            region->numSegmentsAllocated = newAlloc;
            region->segment = newSegment;
      }

      segment = &region->segment[region->numSegmentsUsed];
      region->numSegmentsUsed++;

      segment->virtAddr = virtAddr;
      segment->physAddr = physAddr;
      segment->numBytes = numBytes;

      DMA_MAP_PRINT("returning success\n");

      return 0;
}

/****************************************************************************/
/**
*   Adds a region of memory to a memory map. Each region is virtually
*   contiguous, but not necessarily physically contiguous.
*
*   @return     0 on success, error code otherwise.
*/
/****************************************************************************/

int dma_map_add_region(DMA_MemMap_t *memMap,    /* Stores state information about the map */
                   void *mem, /* Virtual address that we want to get a map of */
                   size_t numBytes  /* Number of bytes being mapped */
    ) {
      unsigned long addr = (unsigned long)mem;
      unsigned int offset;
      int rc = 0;
      DMA_Region_t *region;
      dma_addr_t physAddr;

      down(&memMap->lock);

      DMA_MAP_PRINT("memMap:%p va:%p #:%d\n", memMap, mem, numBytes);

      if (!memMap->inUse) {
            printk(KERN_ERR "%s: Make sure you call dma_map_start first\n",
                   __func__);
            rc = -EINVAL;
            goto out;
      }

      /* Reallocate to hold more regions. */

      if (memMap->numRegionsUsed >= memMap->numRegionsAllocated) {
            DMA_Region_t *newRegion;
            size_t oldSize =
                memMap->numRegionsAllocated * sizeof(*newRegion);
            int newAlloc = memMap->numRegionsAllocated + 4;
            size_t newSize = newAlloc * sizeof(*newRegion);

            newRegion = kmalloc(newSize, GFP_KERNEL);
            if (newRegion == NULL) {
                  rc = -ENOMEM;
                  goto out;
            }
            memcpy(newRegion, memMap->region, oldSize);
            memset(&((uint8_t *) newRegion)[oldSize], 0, newSize - oldSize);

            kfree(memMap->region);

            memMap->numRegionsAllocated = newAlloc;
            memMap->region = newRegion;
      }

      region = &memMap->region[memMap->numRegionsUsed];
      memMap->numRegionsUsed++;

      offset = addr & ~PAGE_MASK;

      region->memType = dma_mem_type(mem);
      region->virtAddr = mem;
      region->numBytes = numBytes;
      region->numSegmentsUsed = 0;
      region->numLockedPages = 0;
      region->lockedPages = NULL;

      switch (region->memType) {
      case DMA_MEM_TYPE_VMALLOC:
            {
                  atomic_inc(&gDmaStatMemTypeVmalloc);

                  /* printk(KERN_ERR "%s: vmalloc'd pages are not supported\n", __func__); */

                  /* vmalloc'd pages are not physically contiguous */

                  rc = -EINVAL;
                  break;
            }

      case DMA_MEM_TYPE_KMALLOC:
            {
                  atomic_inc(&gDmaStatMemTypeKmalloc);

                  /* kmalloc'd pages are physically contiguous, so they'll have exactly */
                  /* one segment */

#if ALLOW_MAP_OF_KMALLOC_MEMORY
                  physAddr =
                      dma_map_single(NULL, mem, numBytes, memMap->dir);
                  rc = dma_map_add_segment(memMap, region, mem, physAddr,
                                     numBytes);
#else
                  rc = -EINVAL;
#endif
                  break;
            }

      case DMA_MEM_TYPE_DMA:
            {
                  /* dma_alloc_xxx pages are physically contiguous */

                  atomic_inc(&gDmaStatMemTypeCoherent);

                  physAddr = (vmalloc_to_pfn(mem) << PAGE_SHIFT) + offset;

                  dma_sync_single_for_cpu(NULL, physAddr, numBytes,
                                    memMap->dir);
                  rc = dma_map_add_segment(memMap, region, mem, physAddr,
                                     numBytes);
                  break;
            }

      case DMA_MEM_TYPE_USER:
            {
                  size_t firstPageOffset;
                  size_t firstPageSize;
                  struct page **pages;
                  struct task_struct *userTask;

                  atomic_inc(&gDmaStatMemTypeUser);

#if 1
                  /* If the pages are user pages, then the dma_mem_map_set_user_task function */
                  /* must have been previously called. */

                  if (memMap->userTask == NULL) {
                        printk(KERN_ERR
                               "%s: must call dma_mem_map_set_user_task when using user-mode memory\n",
                               __func__);
                        return -EINVAL;
                  }

                  /* User pages need to be locked. */

                  firstPageOffset =
                      (unsigned long)region->virtAddr & (PAGE_SIZE - 1);
                  firstPageSize = PAGE_SIZE - firstPageOffset;

                  region->numLockedPages = (firstPageOffset
                                      + region->numBytes +
                                      PAGE_SIZE - 1) / PAGE_SIZE;
                  pages =
                      kmalloc(region->numLockedPages *
                            sizeof(struct page *), GFP_KERNEL);

                  if (pages == NULL) {
                        region->numLockedPages = 0;
                        return -ENOMEM;
                  }

                  userTask = memMap->userTask;

                  down_read(&userTask->mm->mmap_sem);
                  rc = get_user_pages(userTask, /* task */
                                  userTask->mm, /* mm */
                                  (unsigned long)region->virtAddr,      /* start */
                                  region->numLockedPages,   /* len */
                                  memMap->dir == DMA_FROM_DEVICE, /* write */
                                  0,      /* force */
                                  pages,  /* pages (array of pointers to page) */
                                  NULL);  /* vmas */
                  up_read(&userTask->mm->mmap_sem);

                  if (rc != region->numLockedPages) {
                        kfree(pages);
                        region->numLockedPages = 0;

                        if (rc >= 0) {
                              rc = -EINVAL;
                        }
                  } else {
                        uint8_t *virtAddr = region->virtAddr;
                        size_t bytesRemaining;
                        int pageIdx;

                        rc = 0;     /* Since get_user_pages returns +ve number */

                        region->lockedPages = pages;

                        /* We've locked the user pages. Now we need to walk them and figure */
                        /* out the physical addresses. */

                        /* The first page may be partial */

                        dma_map_add_segment(memMap,
                                        region,
                                        virtAddr,
                                        PFN_PHYS(page_to_pfn
                                               (pages[0])) +
                                        firstPageOffset,
                                        firstPageSize);

                        virtAddr += firstPageSize;
                        bytesRemaining =
                            region->numBytes - firstPageSize;

                        for (pageIdx = 1;
                             pageIdx < region->numLockedPages;
                             pageIdx++) {
                              size_t bytesThisPage =
                                  (bytesRemaining >
                                   PAGE_SIZE ? PAGE_SIZE :
                                   bytesRemaining);

                              DMA_MAP_PRINT
                                  ("pageIdx:%d pages[pageIdx]=%p pfn=%u phys=%u\n",
                                   pageIdx, pages[pageIdx],
                                   page_to_pfn(pages[pageIdx]),
                                   PFN_PHYS(page_to_pfn
                                          (pages[pageIdx])));

                              dma_map_add_segment(memMap,
                                              region,
                                              virtAddr,
                                              PFN_PHYS(page_to_pfn
                                                     (pages
                                                      [pageIdx])),
                                              bytesThisPage);

                              virtAddr += bytesThisPage;
                              bytesRemaining -= bytesThisPage;
                        }
                  }
#else
                  printk(KERN_ERR
                         "%s: User mode pages are not yet supported\n",
                         __func__);

                  /* user pages are not physically contiguous */

                  rc = -EINVAL;
#endif
                  break;
            }

      default:
            {
                  printk(KERN_ERR "%s: Unsupported memory type: %d\n",
                         __func__, region->memType);

                  rc = -EINVAL;
                  break;
            }
      }

      if (rc != 0) {
            memMap->numRegionsUsed--;
      }

out:

      DMA_MAP_PRINT("returning %d\n", rc);

      up(&memMap->lock);

      return rc;
}

EXPORT_SYMBOL(dma_map_add_segment);

/****************************************************************************/
/**
*   Maps in a memory region such that it can be used for performing a DMA.
*
*   @return     0 on success, error code otherwise.
*/
/****************************************************************************/

int dma_map_mem(DMA_MemMap_t *memMap,     /* Stores state information about the map */
            void *mem,  /* Virtual address that we want to get a map of */
            size_t numBytes,  /* Number of bytes being mapped */
            enum dma_data_direction dir   /* Direction that the mapping will be going */
    ) {
      int rc;

      rc = dma_map_start(memMap, dir);
      if (rc == 0) {
            rc = dma_map_add_region(memMap, mem, numBytes);
            if (rc < 0) {
                  /* Since the add fails, this function will fail, and the caller won't */
                  /* call unmap, so we need to do it here. */

                  dma_unmap(memMap, 0);
            }
      }

      return rc;
}

EXPORT_SYMBOL(dma_map_mem);

/****************************************************************************/
/**
*   Setup a descriptor ring for a given memory map.
*
*   It is assumed that the descriptor ring has already been initialized, and
*   this routine will only reallocate a new descriptor ring if the existing
*   one is too small.
*
*   @return     0 on success, error code otherwise.
*/
/****************************************************************************/

int dma_map_create_descriptor_ring(DMA_Device_t dev,  /* DMA device (where the ring is stored) */
                           DMA_MemMap_t *memMap,      /* Memory map that will be used */
                           dma_addr_t devPhysAddr     /* Physical address of device */
    ) {
      int rc;
      int numDescriptors;
      DMA_DeviceAttribute_t *devAttr;
      DMA_Region_t *region;
      DMA_Segment_t *segment;
      dma_addr_t srcPhysAddr;
      dma_addr_t dstPhysAddr;
      int regionIdx;
      int segmentIdx;

      devAttr = &DMA_gDeviceAttribute[dev];

      down(&memMap->lock);

      /* Figure out how many descriptors we need */

      numDescriptors = 0;
      for (regionIdx = 0; regionIdx < memMap->numRegionsUsed; regionIdx++) {
            region = &memMap->region[regionIdx];

            for (segmentIdx = 0; segmentIdx < region->numSegmentsUsed;
                 segmentIdx++) {
                  segment = &region->segment[segmentIdx];

                  if (memMap->dir == DMA_TO_DEVICE) {
                        srcPhysAddr = segment->physAddr;
                        dstPhysAddr = devPhysAddr;
                  } else {
                        srcPhysAddr = devPhysAddr;
                        dstPhysAddr = segment->physAddr;
                  }

                  rc =
                       dma_calculate_descriptor_count(dev, srcPhysAddr,
                                              dstPhysAddr,
                                              segment->
                                              numBytes);
                  if (rc < 0) {
                        printk(KERN_ERR
                               "%s: dma_calculate_descriptor_count failed: %d\n",
                               __func__, rc);
                        goto out;
                  }
                  numDescriptors += rc;
            }
      }

      /* Adjust the size of the ring, if it isn't big enough */

      if (numDescriptors > devAttr->ring.descriptorsAllocated) {
            dma_free_descriptor_ring(&devAttr->ring);
            rc =
                 dma_alloc_descriptor_ring(&devAttr->ring,
                                     numDescriptors);
            if (rc < 0) {
                  printk(KERN_ERR
                         "%s: dma_alloc_descriptor_ring failed: %d\n",
                         __func__, rc);
                  goto out;
            }
      } else {
            rc =
                 dma_init_descriptor_ring(&devAttr->ring,
                                    numDescriptors);
            if (rc < 0) {
                  printk(KERN_ERR
                         "%s: dma_init_descriptor_ring failed: %d\n",
                         __func__, rc);
                  goto out;
            }
      }

      /* Populate the descriptors */

      for (regionIdx = 0; regionIdx < memMap->numRegionsUsed; regionIdx++) {
            region = &memMap->region[regionIdx];

            for (segmentIdx = 0; segmentIdx < region->numSegmentsUsed;
                 segmentIdx++) {
                  segment = &region->segment[segmentIdx];

                  if (memMap->dir == DMA_TO_DEVICE) {
                        srcPhysAddr = segment->physAddr;
                        dstPhysAddr = devPhysAddr;
                  } else {
                        srcPhysAddr = devPhysAddr;
                        dstPhysAddr = segment->physAddr;
                  }

                  rc =
                       dma_add_descriptors(&devAttr->ring, dev,
                                     srcPhysAddr, dstPhysAddr,
                                     segment->numBytes);
                  if (rc < 0) {
                        printk(KERN_ERR
                               "%s: dma_add_descriptors failed: %d\n",
                               __func__, rc);
                        goto out;
                  }
            }
      }

      rc = 0;

out:

      up(&memMap->lock);
      return rc;
}

EXPORT_SYMBOL(dma_map_create_descriptor_ring);

/****************************************************************************/
/**
*   Maps in a memory region such that it can be used for performing a DMA.
*
*   @return
*/
/****************************************************************************/

int dma_unmap(DMA_MemMap_t *memMap, /* Stores state information about the map */
            int dirtied /* non-zero if any of the pages were modified */
    ) {
      int regionIdx;
      int segmentIdx;
      DMA_Region_t *region;
      DMA_Segment_t *segment;

      for (regionIdx = 0; regionIdx < memMap->numRegionsUsed; regionIdx++) {
            region = &memMap->region[regionIdx];

            for (segmentIdx = 0; segmentIdx < region->numSegmentsUsed;
                 segmentIdx++) {
                  segment = &region->segment[segmentIdx];

                  switch (region->memType) {
                  case DMA_MEM_TYPE_VMALLOC:
                        {
                              printk(KERN_ERR
                                     "%s: vmalloc'd pages are not yet supported\n",
                                     __func__);
                              return -EINVAL;
                        }

                  case DMA_MEM_TYPE_KMALLOC:
                        {
#if ALLOW_MAP_OF_KMALLOC_MEMORY
                              dma_unmap_single(NULL,
                                           segment->physAddr,
                                           segment->numBytes,
                                           memMap->dir);
#endif
                              break;
                        }

                  case DMA_MEM_TYPE_DMA:
                        {
                              dma_sync_single_for_cpu(NULL,
                                                segment->
                                                physAddr,
                                                segment->
                                                numBytes,
                                                memMap->dir);
                              break;
                        }

                  case DMA_MEM_TYPE_USER:
                        {
                              /* Nothing to do here. */

                              break;
                        }

                  default:
                        {
                              printk(KERN_ERR
                                     "%s: Unsupported memory type: %d\n",
                                     __func__, region->memType);
                              return -EINVAL;
                        }
                  }

                  segment->virtAddr = NULL;
                  segment->physAddr = 0;
                  segment->numBytes = 0;
            }

            if (region->numLockedPages > 0) {
                  int pageIdx;

                  /* Some user pages were locked. We need to go and unlock them now. */

                  for (pageIdx = 0; pageIdx < region->numLockedPages;
                       pageIdx++) {
                        struct page *page =
                            region->lockedPages[pageIdx];

                        if (memMap->dir == DMA_FROM_DEVICE) {
                              SetPageDirty(page);
                        }
                        page_cache_release(page);
                  }
                  kfree(region->lockedPages);
                  region->numLockedPages = 0;
                  region->lockedPages = NULL;
            }

            region->memType = DMA_MEM_TYPE_NONE;
            region->virtAddr = NULL;
            region->numBytes = 0;
            region->numSegmentsUsed = 0;
      }
      memMap->userTask = NULL;
      memMap->numRegionsUsed = 0;
      memMap->inUse = 0;

      up(&memMap->lock);

      return 0;
}

EXPORT_SYMBOL(dma_unmap);

Generated by  Doxygen 1.6.0   Back to index