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dell_rbu.c

/*
 * dell_rbu.c
 * Bios Update driver for Dell systems
 * Author: Dell Inc
 *         Abhay Salunke <abhay_salunke@dell.com>
 *
 * Copyright (C) 2005 Dell Inc.
 *
 * Remote BIOS Update (rbu) driver is used for updating DELL BIOS by
 * creating entries in the /sys file systems on Linux 2.6 and higher
 * kernels. The driver supports two mechanism to update the BIOS namely
 * contiguous and packetized. Both these methods still require having some
 * application to set the CMOS bit indicating the BIOS to update itself
 * after a reboot.
 *
 * Contiguous method:
 * This driver writes the incoming data in a monolithic image by allocating
 * contiguous physical pages large enough to accommodate the incoming BIOS
 * image size.
 *
 * Packetized method:
 * The driver writes the incoming packet image by allocating a new packet
 * on every time the packet data is written. This driver requires an
 * application to break the BIOS image in to fixed sized packet chunks.
 *
 * See Documentation/dell_rbu.txt for more info.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2.0 as published by
 * the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/blkdev.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/firmware.h>
#include <linux/dma-mapping.h>

MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
MODULE_LICENSE("GPL");
MODULE_VERSION("3.2");

#define BIOS_SCAN_LIMIT 0xffffffff
#define MAX_IMAGE_LENGTH 16
static struct _rbu_data {
      void *image_update_buffer;
      unsigned long image_update_buffer_size;
      unsigned long bios_image_size;
      int image_update_ordernum;
      int dma_alloc;
      spinlock_t lock;
      unsigned long packet_read_count;
      unsigned long num_packets;
      unsigned long packetsize;
      unsigned long imagesize;
      int entry_created;
} rbu_data;

static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
module_param_string(image_type, image_type, sizeof (image_type), 0);
MODULE_PARM_DESC(image_type,
      "BIOS image type. choose- mono or packet or init");

static unsigned long allocation_floor = 0x100000;
module_param(allocation_floor, ulong, 0644);
MODULE_PARM_DESC(allocation_floor,
    "Minimum address for allocations when using Packet mode");

struct packet_data {
      struct list_head list;
      size_t length;
      void *data;
      int ordernum;
};

static struct packet_data packet_data_head;

static struct platform_device *rbu_device;
static int context;
static dma_addr_t dell_rbu_dmaaddr;

static void init_packet_head(void)
{
      INIT_LIST_HEAD(&packet_data_head.list);
      rbu_data.packet_read_count = 0;
      rbu_data.num_packets = 0;
      rbu_data.packetsize = 0;
      rbu_data.imagesize = 0;
}

static int create_packet(void *data, size_t length)
{
      struct packet_data *newpacket;
      int ordernum = 0;
      int retval = 0;
      unsigned int packet_array_size = 0;
      void **invalid_addr_packet_array = NULL;
      void *packet_data_temp_buf = NULL;
      unsigned int idx = 0;

      pr_debug("create_packet: entry \n");

      if (!rbu_data.packetsize) {
            pr_debug("create_packet: packetsize not specified\n");
            retval = -EINVAL;
            goto out_noalloc;
      }

      spin_unlock(&rbu_data.lock);

      newpacket = kzalloc(sizeof (struct packet_data), GFP_KERNEL);

      if (!newpacket) {
            printk(KERN_WARNING
                  "dell_rbu:%s: failed to allocate new "
                  "packet\n", __FUNCTION__);
            retval = -ENOMEM;
            spin_lock(&rbu_data.lock);
            goto out_noalloc;
      }

      ordernum = get_order(length);

      /*
       * BIOS errata mean we cannot allocate packets below 1MB or they will
       * be overwritten by BIOS.
       *
       * array to temporarily hold packets
       * that are below the allocation floor
       *
       * NOTE: very simplistic because we only need the floor to be at 1MB
       *       due to BIOS errata. This shouldn't be used for higher floors
       *       or you will run out of mem trying to allocate the array.
       */
      packet_array_size = max(
                        (unsigned int)(allocation_floor / rbu_data.packetsize),
                  (unsigned int)1);
      invalid_addr_packet_array = kzalloc(packet_array_size * sizeof(void*),
                                    GFP_KERNEL);

      if (!invalid_addr_packet_array) {
            printk(KERN_WARNING
                  "dell_rbu:%s: failed to allocate "
                  "invalid_addr_packet_array \n",
                  __FUNCTION__);
            retval = -ENOMEM;
            spin_lock(&rbu_data.lock);
            goto out_alloc_packet;
      }

      while (!packet_data_temp_buf) {
            packet_data_temp_buf = (unsigned char *)
                  __get_free_pages(GFP_KERNEL, ordernum);
            if (!packet_data_temp_buf) {
                  printk(KERN_WARNING
                        "dell_rbu:%s: failed to allocate new "
                        "packet\n", __FUNCTION__);
                  retval = -ENOMEM;
                  spin_lock(&rbu_data.lock);
                  goto out_alloc_packet_array;
            }

            if ((unsigned long)virt_to_phys(packet_data_temp_buf)
                        < allocation_floor) {
                  pr_debug("packet 0x%lx below floor at 0x%lx.\n",
                              (unsigned long)virt_to_phys(
                                    packet_data_temp_buf),
                              allocation_floor);
                  invalid_addr_packet_array[idx++] = packet_data_temp_buf;
                  packet_data_temp_buf = NULL;
            }
      }
      spin_lock(&rbu_data.lock);

      newpacket->data = packet_data_temp_buf;

      pr_debug("create_packet: newpacket at physical addr %lx\n",
            (unsigned long)virt_to_phys(newpacket->data));

      /* packets may not have fixed size */
      newpacket->length = length;
      newpacket->ordernum = ordernum;
      ++rbu_data.num_packets;

      /* initialize the newly created packet headers */
      INIT_LIST_HEAD(&newpacket->list);
      list_add_tail(&newpacket->list, &packet_data_head.list);

      memcpy(newpacket->data, data, length);

      pr_debug("create_packet: exit \n");

out_alloc_packet_array:
      /* always free packet array */
      for (;idx>0;idx--) {
            pr_debug("freeing unused packet below floor 0x%lx.\n",
                  (unsigned long)virt_to_phys(
                        invalid_addr_packet_array[idx-1]));
            free_pages((unsigned long)invalid_addr_packet_array[idx-1],
                  ordernum);
      }
      kfree(invalid_addr_packet_array);

out_alloc_packet:
      /* if error, free data */
      if (retval)
            kfree(newpacket);

out_noalloc:
      return retval;
}

static int packetize_data(void *data, size_t length)
{
      int rc = 0;
      int done = 0;
      int packet_length;
      u8 *temp;
      u8 *end = (u8 *) data + length;
      pr_debug("packetize_data: data length %zd\n", length);
      if (!rbu_data.packetsize) {
            printk(KERN_WARNING
                  "dell_rbu: packetsize not specified\n");
            return -EIO;
      }

      temp = (u8 *) data;

      /* packetize the hunk */
      while (!done) {
            if ((temp + rbu_data.packetsize) < end)
                  packet_length = rbu_data.packetsize;
            else {
                  /* this is the last packet */
                  packet_length = end - temp;
                  done = 1;
            }

            if ((rc = create_packet(temp, packet_length)))
                  return rc;

            pr_debug("%p:%td\n", temp, (end - temp));
            temp += packet_length;
      }

      rbu_data.imagesize = length;

      return rc;
}

static int do_packet_read(char *data, struct list_head *ptemp_list,
      int length, int bytes_read, int *list_read_count)
{
      void *ptemp_buf;
      struct packet_data *newpacket = NULL;
      int bytes_copied = 0;
      int j = 0;

      newpacket = list_entry(ptemp_list, struct packet_data, list);
      *list_read_count += newpacket->length;

      if (*list_read_count > bytes_read) {
            /* point to the start of unread data */
            j = newpacket->length - (*list_read_count - bytes_read);
            /* point to the offset in the packet buffer */
            ptemp_buf = (u8 *) newpacket->data + j;
            /*
             * check if there is enough room in
             * * the incoming buffer
             */
            if (length > (*list_read_count - bytes_read))
                  /*
                   * copy what ever is there in this
                   * packet and move on
                   */
                  bytes_copied = (*list_read_count - bytes_read);
            else
                  /* copy the remaining */
                  bytes_copied = length;
            memcpy(data, ptemp_buf, bytes_copied);
      }
      return bytes_copied;
}

static int packet_read_list(char *data, size_t * pread_length)
{
      struct list_head *ptemp_list;
      int temp_count = 0;
      int bytes_copied = 0;
      int bytes_read = 0;
      int remaining_bytes = 0;
      char *pdest = data;

      /* check if we have any packets */
      if (0 == rbu_data.num_packets)
            return -ENOMEM;

      remaining_bytes = *pread_length;
      bytes_read = rbu_data.packet_read_count;

      ptemp_list = (&packet_data_head.list)->next;
      while (!list_empty(ptemp_list)) {
            bytes_copied = do_packet_read(pdest, ptemp_list,
                  remaining_bytes, bytes_read, &temp_count);
            remaining_bytes -= bytes_copied;
            bytes_read += bytes_copied;
            pdest += bytes_copied;
            /*
             * check if we reached end of buffer before reaching the
             * last packet
             */
            if (remaining_bytes == 0)
                  break;

            ptemp_list = ptemp_list->next;
      }
      /*finally set the bytes read */
      *pread_length = bytes_read - rbu_data.packet_read_count;
      rbu_data.packet_read_count = bytes_read;
      return 0;
}

static void packet_empty_list(void)
{
      struct list_head *ptemp_list;
      struct list_head *pnext_list;
      struct packet_data *newpacket;

      ptemp_list = (&packet_data_head.list)->next;
      while (!list_empty(ptemp_list)) {
            newpacket =
                  list_entry(ptemp_list, struct packet_data, list);
            pnext_list = ptemp_list->next;
            list_del(ptemp_list);
            ptemp_list = pnext_list;
            /*
             * zero out the RBU packet memory before freeing
             * to make sure there are no stale RBU packets left in memory
             */
            memset(newpacket->data, 0, rbu_data.packetsize);
            free_pages((unsigned long) newpacket->data,
                  newpacket->ordernum);
            kfree(newpacket);
      }
      rbu_data.packet_read_count = 0;
      rbu_data.num_packets = 0;
      rbu_data.imagesize = 0;
}

/*
 * img_update_free: Frees the buffer allocated for storing BIOS image
 * Always called with lock held and returned with lock held
 */
static void img_update_free(void)
{
      if (!rbu_data.image_update_buffer)
            return;
      /*
       * zero out this buffer before freeing it to get rid of any stale
       * BIOS image copied in memory.
       */
      memset(rbu_data.image_update_buffer, 0,
            rbu_data.image_update_buffer_size);
      if (rbu_data.dma_alloc == 1)
            dma_free_coherent(NULL, rbu_data.bios_image_size,
                  rbu_data.image_update_buffer, dell_rbu_dmaaddr);
      else
            free_pages((unsigned long) rbu_data.image_update_buffer,
                  rbu_data.image_update_ordernum);

      /*
       * Re-initialize the rbu_data variables after a free
       */
      rbu_data.image_update_ordernum = -1;
      rbu_data.image_update_buffer = NULL;
      rbu_data.image_update_buffer_size = 0;
      rbu_data.bios_image_size = 0;
      rbu_data.dma_alloc = 0;
}

/*
 * img_update_realloc: This function allocates the contiguous pages to
 * accommodate the requested size of data. The memory address and size
 * values are stored globally and on every call to this function the new
 * size is checked to see if more data is required than the existing size.
 * If true the previous memory is freed and new allocation is done to
 * accommodate the new size. If the incoming size is less then than the
 * already allocated size, then that memory is reused. This function is
 * called with lock held and returns with lock held.
 */
static int img_update_realloc(unsigned long size)
{
      unsigned char *image_update_buffer = NULL;
      unsigned long rc;
      unsigned long img_buf_phys_addr;
      int ordernum;
      int dma_alloc = 0;

      /*
       * check if the buffer of sufficient size has been
       * already allocated
       */
      if (rbu_data.image_update_buffer_size >= size) {
            /*
             * check for corruption
             */
            if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
                  printk(KERN_ERR "dell_rbu:%s: corruption "
                        "check failed\n", __FUNCTION__);
                  return -EINVAL;
            }
            /*
             * we have a valid pre-allocated buffer with
             * sufficient size
             */
            return 0;
      }

      /*
       * free any previously allocated buffer
       */
      img_update_free();

      spin_unlock(&rbu_data.lock);

      ordernum = get_order(size);
      image_update_buffer =
            (unsigned char *) __get_free_pages(GFP_KERNEL, ordernum);

      img_buf_phys_addr =
            (unsigned long) virt_to_phys(image_update_buffer);

      if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {
            free_pages((unsigned long) image_update_buffer, ordernum);
            ordernum = -1;
            image_update_buffer = dma_alloc_coherent(NULL, size,
                  &dell_rbu_dmaaddr, GFP_KERNEL);
            dma_alloc = 1;
      }

      spin_lock(&rbu_data.lock);

      if (image_update_buffer != NULL) {
            rbu_data.image_update_buffer = image_update_buffer;
            rbu_data.image_update_buffer_size = size;
            rbu_data.bios_image_size =
                  rbu_data.image_update_buffer_size;
            rbu_data.image_update_ordernum = ordernum;
            rbu_data.dma_alloc = dma_alloc;
            rc = 0;
      } else {
            pr_debug("Not enough memory for image update:"
                  "size = %ld\n", size);
            rc = -ENOMEM;
      }

      return rc;
}

static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
{
      int retval;
      size_t bytes_left;
      size_t data_length;
      char *ptempBuf = buffer;

      /* check to see if we have something to return */
      if (rbu_data.num_packets == 0) {
            pr_debug("read_packet_data: no packets written\n");
            retval = -ENOMEM;
            goto read_rbu_data_exit;
      }

      if (pos > rbu_data.imagesize) {
            retval = 0;
            printk(KERN_WARNING "dell_rbu:read_packet_data: "
                  "data underrun\n");
            goto read_rbu_data_exit;
      }

      bytes_left = rbu_data.imagesize - pos;
      data_length = min(bytes_left, count);

      if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
            goto read_rbu_data_exit;

      if ((pos + count) > rbu_data.imagesize) {
            rbu_data.packet_read_count = 0;
            /* this was the last copy */
            retval = bytes_left;
      } else
            retval = count;

      read_rbu_data_exit:
      return retval;
}

static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
{
      unsigned char *ptemp = NULL;
      size_t bytes_left = 0;
      size_t data_length = 0;
      ssize_t ret_count = 0;

      /* check to see if we have something to return */
      if ((rbu_data.image_update_buffer == NULL) ||
            (rbu_data.bios_image_size == 0)) {
            pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
                  "bios_image_size %lu\n",
                  rbu_data.image_update_buffer,
                  rbu_data.bios_image_size);
            ret_count = -ENOMEM;
            goto read_rbu_data_exit;
      }

      if (pos > rbu_data.bios_image_size) {
            ret_count = 0;
            goto read_rbu_data_exit;
      }

      bytes_left = rbu_data.bios_image_size - pos;
      data_length = min(bytes_left, count);

      ptemp = rbu_data.image_update_buffer;
      memcpy(buffer, (ptemp + pos), data_length);

      if ((pos + count) > rbu_data.bios_image_size)
            /* this was the last copy */
            ret_count = bytes_left;
      else
            ret_count = count;
      read_rbu_data_exit:
      return ret_count;
}

static ssize_t read_rbu_data(struct kobject *kobj,
                       struct bin_attribute *bin_attr,
                       char *buffer, loff_t pos, size_t count)
{
      ssize_t ret_count = 0;

      spin_lock(&rbu_data.lock);

      if (!strcmp(image_type, "mono"))
            ret_count = read_rbu_mono_data(buffer, pos, count);
      else if (!strcmp(image_type, "packet"))
            ret_count = read_packet_data(buffer, pos, count);
      else
            pr_debug("read_rbu_data: invalid image type specified\n");

      spin_unlock(&rbu_data.lock);
      return ret_count;
}

static void callbackfn_rbu(const struct firmware *fw, void *context)
{
      rbu_data.entry_created = 0;

      if (!fw || !fw->size)
            return;

      spin_lock(&rbu_data.lock);
      if (!strcmp(image_type, "mono")) {
            if (!img_update_realloc(fw->size))
                  memcpy(rbu_data.image_update_buffer,
                        fw->data, fw->size);
      } else if (!strcmp(image_type, "packet")) {
            /*
             * we need to free previous packets if a
             * new hunk of packets needs to be downloaded
             */
            packet_empty_list();
            if (packetize_data(fw->data, fw->size))
                  /* Incase something goes wrong when we are
                   * in middle of packetizing the data, we
                   * need to free up whatever packets might
                   * have been created before we quit.
                   */
                  packet_empty_list();
      } else
            pr_debug("invalid image type specified.\n");
      spin_unlock(&rbu_data.lock);
}

static ssize_t read_rbu_image_type(struct kobject *kobj,
                           struct bin_attribute *bin_attr,
                           char *buffer, loff_t pos, size_t count)
{
      int size = 0;
      if (!pos)
            size = sprintf(buffer, "%s\n", image_type);
      return size;
}

static ssize_t write_rbu_image_type(struct kobject *kobj,
                            struct bin_attribute *bin_attr,
                            char *buffer, loff_t pos, size_t count)
{
      int rc = count;
      int req_firm_rc = 0;
      int i;
      spin_lock(&rbu_data.lock);
      /*
       * Find the first newline or space
       */
      for (i = 0; i < count; ++i)
            if (buffer[i] == '\n' || buffer[i] == ' ') {
                  buffer[i] = '\0';
                  break;
            }
      if (i == count)
            buffer[count] = '\0';

      if (strstr(buffer, "mono"))
            strcpy(image_type, "mono");
      else if (strstr(buffer, "packet"))
            strcpy(image_type, "packet");
      else if (strstr(buffer, "init")) {
            /*
             * If due to the user error the driver gets in a bad
             * state where even though it is loaded , the
             * /sys/class/firmware/dell_rbu entries are missing.
             * to cover this situation the user can recreate entries
             * by writing init to image_type.
             */
            if (!rbu_data.entry_created) {
                  spin_unlock(&rbu_data.lock);
                  req_firm_rc = request_firmware_nowait(THIS_MODULE,
                        FW_ACTION_NOHOTPLUG, "dell_rbu",
                        &rbu_device->dev, &context,
                        callbackfn_rbu);
                  if (req_firm_rc) {
                        printk(KERN_ERR
                              "dell_rbu:%s request_firmware_nowait"
                              " failed %d\n", __FUNCTION__, rc);
                        rc = -EIO;
                  } else
                        rbu_data.entry_created = 1;

                  spin_lock(&rbu_data.lock);
            }
      } else {
            printk(KERN_WARNING "dell_rbu: image_type is invalid\n");
            spin_unlock(&rbu_data.lock);
            return -EINVAL;
      }

      /* we must free all previous allocations */
      packet_empty_list();
      img_update_free();
      spin_unlock(&rbu_data.lock);

      return rc;
}

static ssize_t read_rbu_packet_size(struct kobject *kobj,
                            struct bin_attribute *bin_attr,
                            char *buffer, loff_t pos, size_t count)
{
      int size = 0;
      if (!pos) {
            spin_lock(&rbu_data.lock);
            size = sprintf(buffer, "%lu\n", rbu_data.packetsize);
            spin_unlock(&rbu_data.lock);
      }
      return size;
}

static ssize_t write_rbu_packet_size(struct kobject *kobj,
                             struct bin_attribute *bin_attr,
                             char *buffer, loff_t pos, size_t count)
{
      unsigned long temp;
      spin_lock(&rbu_data.lock);
      packet_empty_list();
      sscanf(buffer, "%lu", &temp);
      if (temp < 0xffffffff)
            rbu_data.packetsize = temp;

      spin_unlock(&rbu_data.lock);
      return count;
}

static struct bin_attribute rbu_data_attr = {
      .attr = {.name = "data", .mode = 0444},
      .read = read_rbu_data,
};

static struct bin_attribute rbu_image_type_attr = {
      .attr = {.name = "image_type", .mode = 0644},
      .read = read_rbu_image_type,
      .write = write_rbu_image_type,
};

static struct bin_attribute rbu_packet_size_attr = {
      .attr = {.name = "packet_size", .mode = 0644},
      .read = read_rbu_packet_size,
      .write = write_rbu_packet_size,
};

static int __init dcdrbu_init(void)
{
      int rc;
      spin_lock_init(&rbu_data.lock);

      init_packet_head();
      rbu_device = platform_device_register_simple("dell_rbu", -1, NULL, 0);
      if (IS_ERR(rbu_device)) {
            printk(KERN_ERR
                  "dell_rbu:%s:platform_device_register_simple "
                  "failed\n", __FUNCTION__);
            return PTR_ERR(rbu_device);
      }

      rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
      if (rc)
            goto out_devreg;
      rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
      if (rc)
            goto out_data;
      rc = sysfs_create_bin_file(&rbu_device->dev.kobj,
            &rbu_packet_size_attr);
      if (rc)
            goto out_imtype;

      rbu_data.entry_created = 0;
      return 0;

out_imtype:
      sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
out_data:
      sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
out_devreg:
      platform_device_unregister(rbu_device);
      return rc;
}

static __exit void dcdrbu_exit(void)
{
      spin_lock(&rbu_data.lock);
      packet_empty_list();
      img_update_free();
      spin_unlock(&rbu_data.lock);
      platform_device_unregister(rbu_device);
}

module_exit(dcdrbu_exit);
module_init(dcdrbu_init);

/* vim:noet:ts=8:sw=8
*/

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