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viopath.c

/* -*- linux-c -*-
 *
 *  iSeries Virtual I/O Message Path code
 *
 *  Authors: Dave Boutcher <boutcher@us.ibm.com>
 *           Ryan Arnold <ryanarn@us.ibm.com>
 *           Colin Devilbiss <devilbis@us.ibm.com>
 *
 * (C) Copyright 2000-2005 IBM Corporation
 *
 * This code is used by the iSeries virtual disk, cd,
 * tape, and console to communicate with OS/400 in another
 * partition.
 *
 * This program is free software;  you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) anyu later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
#include <linux/dma-mapping.h>
#include <linux/wait.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/completion.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <asm/iseries/hv_types.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/hv_lp_config.h>
#include <asm/iseries/mf.h>
#include <asm/iseries/vio.h>

/* Status of the path to each other partition in the system.
 * This is overkill, since we will only ever establish connections
 * to our hosting partition and the primary partition on the system.
 * But this allows for other support in the future.
 */
00057 static struct viopathStatus {
      int isOpen;       /* Did we open the path?            */
      int isActive;           /* Do we have a mon msg outstanding */
      int users[VIO_MAX_SUBTYPES];
      HvLpInstanceId mSourceInst;
      HvLpInstanceId mTargetInst;
      int numberAllocated;
} viopathStatus[HVMAXARCHITECTEDLPS];

static DEFINE_SPINLOCK(statuslock);

/*
 * For each kind of event we allocate a buffer that is
 * guaranteed not to cross a page boundary
 */
static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256]
      __attribute__((__aligned__(4096)));
static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
static int event_buffer_initialised;

static void handleMonitorEvent(struct HvLpEvent *event);

/*
 * We use this structure to handle asynchronous responses.  The caller
 * blocks on the semaphore and the handler posts the semaphore.  However,
 * if system_state is not SYSTEM_RUNNING, then wait_atomic is used ...
 */
00084 struct alloc_parms {
      struct completion done;
      int number;
      atomic_t wait_atomic;
      int used_wait_atomic;
};

/* Put a sequence number in each mon msg.  The value is not
 * important.  Start at something other than 0 just for
 * readability.  wrapping this is ok.
 */
static u8 viomonseq = 22;

/* Our hosting logical partition.  We get this at startup
 * time, and different modules access this variable directly.
 */
HvLpIndex viopath_hostLp = HvLpIndexInvalid;
EXPORT_SYMBOL(viopath_hostLp);
HvLpIndex viopath_ourLp = HvLpIndexInvalid;
EXPORT_SYMBOL(viopath_ourLp);

/* For each kind of incoming event we set a pointer to a
 * routine to call.
 */
static vio_event_handler_t *vio_handler[VIO_MAX_SUBTYPES];

#define VIOPATH_KERN_WARN     KERN_WARNING "viopath: "
#define VIOPATH_KERN_INFO     KERN_INFO "viopath: "

static int proc_viopath_show(struct seq_file *m, void *v)
{
      char *buf;
      u16 vlanMap;
      dma_addr_t handle;
      HvLpEvent_Rc hvrc;
      DECLARE_COMPLETION(done);
      struct device_node *node;
      const char *sysid;

      buf = kzalloc(HW_PAGE_SIZE, GFP_KERNEL);
      if (!buf)
            return 0;

      handle = iseries_hv_map(buf, HW_PAGE_SIZE, DMA_FROM_DEVICE);

      hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_config | vioconfigget,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(viopath_hostLp),
                  viopath_targetinst(viopath_hostLp),
                  (u64)(unsigned long)&done, VIOVERSION << 16,
                  ((u64)handle) << 32, HW_PAGE_SIZE, 0, 0);

      if (hvrc != HvLpEvent_Rc_Good)
            printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);

      wait_for_completion(&done);

      vlanMap = HvLpConfig_getVirtualLanIndexMap();

      buf[HW_PAGE_SIZE-1] = '\0';
      seq_printf(m, "%s", buf);

      iseries_hv_unmap(handle, HW_PAGE_SIZE, DMA_FROM_DEVICE);
      kfree(buf);

      seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);

      node = of_find_node_by_path("/");
      sysid = NULL;
      if (node != NULL)
            sysid = of_get_property(node, "system-id", NULL);

      if (sysid == NULL)
            seq_printf(m, "SRLNBR=<UNKNOWN>\n");
      else
            /* Skip "IBM," on front of serial number, see dt.c */
            seq_printf(m, "SRLNBR=%s\n", sysid + 4);

      of_node_put(node);

      return 0;
}

static int proc_viopath_open(struct inode *inode, struct file *file)
{
      return single_open(file, proc_viopath_show, NULL);
}

static const struct file_operations proc_viopath_operations = {
      .open       = proc_viopath_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = single_release,
};

static int __init vio_proc_init(void)
{
      if (!firmware_has_feature(FW_FEATURE_ISERIES))
            return 0;

      proc_create("iSeries/config", 0, NULL, &proc_viopath_operations);
        return 0;
}
__initcall(vio_proc_init);

/* See if a given LP is active.  Allow for invalid lps to be passed in
 * and just return invalid
 */
int viopath_isactive(HvLpIndex lp)
{
      if (lp == HvLpIndexInvalid)
            return 0;
      if (lp < HVMAXARCHITECTEDLPS)
            return viopathStatus[lp].isActive;
      else
            return 0;
}
EXPORT_SYMBOL(viopath_isactive);

/*
 * We cache the source and target instance ids for each
 * partition.
 */
HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
{
      return viopathStatus[lp].mSourceInst;
}
EXPORT_SYMBOL(viopath_sourceinst);

HvLpInstanceId viopath_targetinst(HvLpIndex lp)
{
      return viopathStatus[lp].mTargetInst;
}
EXPORT_SYMBOL(viopath_targetinst);

/*
 * Send a monitor message.  This is a message with the acknowledge
 * bit on that the other side will NOT explicitly acknowledge.  When
 * the other side goes down, the hypervisor will acknowledge any
 * outstanding messages....so we will know when the other side dies.
 */
static void sendMonMsg(HvLpIndex remoteLp)
{
      HvLpEvent_Rc hvrc;

      viopathStatus[remoteLp].mSourceInst =
            HvCallEvent_getSourceLpInstanceId(remoteLp,
                        HvLpEvent_Type_VirtualIo);
      viopathStatus[remoteLp].mTargetInst =
            HvCallEvent_getTargetLpInstanceId(remoteLp,
                        HvLpEvent_Type_VirtualIo);

      /*
       * Deliberately ignore the return code here.  if we call this
       * more than once, we don't care.
       */
      vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);

      hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
                  HvLpEvent_AckType_DeferredAck,
                  viopathStatus[remoteLp].mSourceInst,
                  viopathStatus[remoteLp].mTargetInst,
                  viomonseq++, 0, 0, 0, 0, 0);

      if (hvrc == HvLpEvent_Rc_Good)
            viopathStatus[remoteLp].isActive = 1;
      else {
            printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
                        remoteLp);
            viopathStatus[remoteLp].isActive = 0;
      }
}

static void handleMonitorEvent(struct HvLpEvent *event)
{
      HvLpIndex remoteLp;
      int i;

      /*
       * This handler is _also_ called as part of the loop
       * at the end of this routine, so it must be able to
       * ignore NULL events...
       */
      if (!event)
            return;

      /*
       * First see if this is just a normal monitor message from the
       * other partition
       */
      if (hvlpevent_is_int(event)) {
            remoteLp = event->xSourceLp;
            if (!viopathStatus[remoteLp].isActive)
                  sendMonMsg(remoteLp);
            return;
      }

      /*
       * This path is for an acknowledgement; the other partition
       * died
       */
      remoteLp = event->xTargetLp;
      if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
          (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
            printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
            return;
      }

      printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);

      viopathStatus[remoteLp].isActive = 0;

      /*
       * For each active handler, pass them a NULL
       * message to indicate that the other partition
       * died
       */
      for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
            if (vio_handler[i] != NULL)
                  (*vio_handler[i])(NULL);
      }
}

int vio_setHandler(int subtype, vio_event_handler_t *beh)
{
      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
            return -EINVAL;
      if (vio_handler[subtype] != NULL)
            return -EBUSY;
      vio_handler[subtype] = beh;
      return 0;
}
EXPORT_SYMBOL(vio_setHandler);

int vio_clearHandler(int subtype)
{
      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
            return -EINVAL;
      if (vio_handler[subtype] == NULL)
            return -EAGAIN;
      vio_handler[subtype] = NULL;
      return 0;
}
EXPORT_SYMBOL(vio_clearHandler);

static void handleConfig(struct HvLpEvent *event)
{
      if (!event)
            return;
      if (hvlpevent_is_int(event)) {
            printk(VIOPATH_KERN_WARN
                   "unexpected config request from partition %d",
                   event->xSourceLp);

            if (hvlpevent_need_ack(event)) {
                  event->xRc = HvLpEvent_Rc_InvalidSubtype;
                  HvCallEvent_ackLpEvent(event);
            }
            return;
      }

      complete((struct completion *)event->xCorrelationToken);
}

/*
 * Initialization of the hosting partition
 */
void vio_set_hostlp(void)
{
      /*
       * If this has already been set then we DON'T want to either change
       * it or re-register the proc file system
       */
      if (viopath_hostLp != HvLpIndexInvalid)
            return;

      /*
       * Figure out our hosting partition.  This isn't allowed to change
       * while we're active
       */
      viopath_ourLp = HvLpConfig_getLpIndex();
      viopath_hostLp = HvLpConfig_getHostingLpIndex(viopath_ourLp);

      if (viopath_hostLp != HvLpIndexInvalid)
            vio_setHandler(viomajorsubtype_config, handleConfig);
}
EXPORT_SYMBOL(vio_set_hostlp);

static void vio_handleEvent(struct HvLpEvent *event)
{
      HvLpIndex remoteLp;
      int subtype = (event->xSubtype & VIOMAJOR_SUBTYPE_MASK)
            >> VIOMAJOR_SUBTYPE_SHIFT;

      if (hvlpevent_is_int(event)) {
            remoteLp = event->xSourceLp;
            /*
             * The isActive is checked because if the hosting partition
             * went down and came back up it would not be active but it
             * would have different source and target instances, in which
             * case we'd want to reset them.  This case really protects
             * against an unauthorized active partition sending interrupts
             * or acks to this linux partition.
             */
            if (viopathStatus[remoteLp].isActive
                && (event->xSourceInstanceId !=
                  viopathStatus[remoteLp].mTargetInst)) {
                  printk(VIOPATH_KERN_WARN
                         "message from invalid partition. "
                         "int msg rcvd, source inst (%d) doesnt match (%d)\n",
                         viopathStatus[remoteLp].mTargetInst,
                         event->xSourceInstanceId);
                  return;
            }

            if (viopathStatus[remoteLp].isActive
                && (event->xTargetInstanceId !=
                  viopathStatus[remoteLp].mSourceInst)) {
                  printk(VIOPATH_KERN_WARN
                         "message from invalid partition. "
                         "int msg rcvd, target inst (%d) doesnt match (%d)\n",
                         viopathStatus[remoteLp].mSourceInst,
                         event->xTargetInstanceId);
                  return;
            }
      } else {
            remoteLp = event->xTargetLp;
            if (event->xSourceInstanceId !=
                viopathStatus[remoteLp].mSourceInst) {
                  printk(VIOPATH_KERN_WARN
                         "message from invalid partition. "
                         "ack msg rcvd, source inst (%d) doesnt match (%d)\n",
                         viopathStatus[remoteLp].mSourceInst,
                         event->xSourceInstanceId);
                  return;
            }

            if (event->xTargetInstanceId !=
                viopathStatus[remoteLp].mTargetInst) {
                  printk(VIOPATH_KERN_WARN
                         "message from invalid partition. "
                         "viopath: ack msg rcvd, target inst (%d) doesnt match (%d)\n",
                         viopathStatus[remoteLp].mTargetInst,
                         event->xTargetInstanceId);
                  return;
            }
      }

      if (vio_handler[subtype] == NULL) {
            printk(VIOPATH_KERN_WARN
                   "unexpected virtual io event subtype %d from partition %d\n",
                   event->xSubtype, remoteLp);
            /* No handler.  Ack if necessary */
            if (hvlpevent_is_int(event) && hvlpevent_need_ack(event)) {
                  event->xRc = HvLpEvent_Rc_InvalidSubtype;
                  HvCallEvent_ackLpEvent(event);
            }
            return;
      }

      /* This innocuous little line is where all the real work happens */
      (*vio_handler[subtype])(event);
}

static void viopath_donealloc(void *parm, int number)
{
      struct alloc_parms *parmsp = parm;

      parmsp->number = number;
      if (parmsp->used_wait_atomic)
            atomic_set(&parmsp->wait_atomic, 0);
      else
            complete(&parmsp->done);
}

static int allocateEvents(HvLpIndex remoteLp, int numEvents)
{
      struct alloc_parms parms;

      if (system_state != SYSTEM_RUNNING) {
            parms.used_wait_atomic = 1;
            atomic_set(&parms.wait_atomic, 1);
      } else {
            parms.used_wait_atomic = 0;
            init_completion(&parms.done);
      }
      mf_allocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo, 250,    /* It would be nice to put a real number here! */
                      numEvents, &viopath_donealloc, &parms);
      if (system_state != SYSTEM_RUNNING) {
            while (atomic_read(&parms.wait_atomic))
                  mb();
      } else
            wait_for_completion(&parms.done);
      return parms.number;
}

int viopath_open(HvLpIndex remoteLp, int subtype, int numReq)
{
      int i;
      unsigned long flags;
      int tempNumAllocated;

      if ((remoteLp >= HVMAXARCHITECTEDLPS) || (remoteLp == HvLpIndexInvalid))
            return -EINVAL;

      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
            return -EINVAL;

      spin_lock_irqsave(&statuslock, flags);

      if (!event_buffer_initialised) {
            for (i = 0; i < VIO_MAX_SUBTYPES; i++)
                  atomic_set(&event_buffer_available[i], 1);
            event_buffer_initialised = 1;
      }

      viopathStatus[remoteLp].users[subtype]++;

      if (!viopathStatus[remoteLp].isOpen) {
            viopathStatus[remoteLp].isOpen = 1;
            HvCallEvent_openLpEventPath(remoteLp, HvLpEvent_Type_VirtualIo);

            /*
             * Don't hold the spinlock during an operation that
             * can sleep.
             */
            spin_unlock_irqrestore(&statuslock, flags);
            tempNumAllocated = allocateEvents(remoteLp, 1);
            spin_lock_irqsave(&statuslock, flags);

            viopathStatus[remoteLp].numberAllocated += tempNumAllocated;

            if (viopathStatus[remoteLp].numberAllocated == 0) {
                  HvCallEvent_closeLpEventPath(remoteLp,
                              HvLpEvent_Type_VirtualIo);

                  spin_unlock_irqrestore(&statuslock, flags);
                  return -ENOMEM;
            }

            viopathStatus[remoteLp].mSourceInst =
                  HvCallEvent_getSourceLpInstanceId(remoteLp,
                              HvLpEvent_Type_VirtualIo);
            viopathStatus[remoteLp].mTargetInst =
                  HvCallEvent_getTargetLpInstanceId(remoteLp,
                              HvLpEvent_Type_VirtualIo);
            HvLpEvent_registerHandler(HvLpEvent_Type_VirtualIo,
                                &vio_handleEvent);
            sendMonMsg(remoteLp);
            printk(VIOPATH_KERN_INFO "opening connection to partition %d, "
                        "setting sinst %d, tinst %d\n",
                        remoteLp, viopathStatus[remoteLp].mSourceInst,
                        viopathStatus[remoteLp].mTargetInst);
      }

      spin_unlock_irqrestore(&statuslock, flags);
      tempNumAllocated = allocateEvents(remoteLp, numReq);
      spin_lock_irqsave(&statuslock, flags);
      viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
      spin_unlock_irqrestore(&statuslock, flags);

      return 0;
}
EXPORT_SYMBOL(viopath_open);

int viopath_close(HvLpIndex remoteLp, int subtype, int numReq)
{
      unsigned long flags;
      int i;
      int numOpen;
      struct alloc_parms parms;

      if ((remoteLp >= HVMAXARCHITECTEDLPS) || (remoteLp == HvLpIndexInvalid))
            return -EINVAL;

      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
            return -EINVAL;

      spin_lock_irqsave(&statuslock, flags);
      /*
       * If the viopath_close somehow gets called before a
       * viopath_open it could decrement to -1 which is a non
       * recoverable state so we'll prevent this from
       * happening.
       */
      if (viopathStatus[remoteLp].users[subtype] > 0)
            viopathStatus[remoteLp].users[subtype]--;

      spin_unlock_irqrestore(&statuslock, flags);

      parms.used_wait_atomic = 0;
      init_completion(&parms.done);
      mf_deallocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo,
                        numReq, &viopath_donealloc, &parms);
      wait_for_completion(&parms.done);

      spin_lock_irqsave(&statuslock, flags);
      for (i = 0, numOpen = 0; i < VIO_MAX_SUBTYPES; i++)
            numOpen += viopathStatus[remoteLp].users[i];

      if ((viopathStatus[remoteLp].isOpen) && (numOpen == 0)) {
            printk(VIOPATH_KERN_INFO "closing connection to partition %d\n",
                        remoteLp);

            HvCallEvent_closeLpEventPath(remoteLp,
                                   HvLpEvent_Type_VirtualIo);
            viopathStatus[remoteLp].isOpen = 0;
            viopathStatus[remoteLp].isActive = 0;

            for (i = 0; i < VIO_MAX_SUBTYPES; i++)
                  atomic_set(&event_buffer_available[i], 0);
            event_buffer_initialised = 0;
      }
      spin_unlock_irqrestore(&statuslock, flags);
      return 0;
}
EXPORT_SYMBOL(viopath_close);

void *vio_get_event_buffer(int subtype)
{
      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
            return NULL;

      if (atomic_dec_if_positive(&event_buffer_available[subtype]) == 0)
            return &event_buffer[subtype * 256];
      else
            return NULL;
}
EXPORT_SYMBOL(vio_get_event_buffer);

void vio_free_event_buffer(int subtype, void *buffer)
{
      subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
      if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES)) {
            printk(VIOPATH_KERN_WARN
                   "unexpected subtype %d freeing event buffer\n", subtype);
            return;
      }

      if (atomic_read(&event_buffer_available[subtype]) != 0) {
            printk(VIOPATH_KERN_WARN
                   "freeing unallocated event buffer, subtype %d\n",
                   subtype);
            return;
      }

      if (buffer != &event_buffer[subtype * 256]) {
            printk(VIOPATH_KERN_WARN
                   "freeing invalid event buffer, subtype %d\n", subtype);
      }

      atomic_set(&event_buffer_available[subtype], 1);
}
EXPORT_SYMBOL(vio_free_event_buffer);

static const struct vio_error_entry vio_no_error =
    { 0, 0, "Non-VIO Error" };
static const struct vio_error_entry vio_unknown_error =
    { 0, EIO, "Unknown Error" };

static const struct vio_error_entry vio_default_errors[] = {
      {0x0001, EIO, "No Connection"},
      {0x0002, EIO, "No Receiver"},
      {0x0003, EIO, "No Buffer Available"},
      {0x0004, EBADRQC, "Invalid Message Type"},
      {0x0000, 0, NULL},
};

const struct vio_error_entry *vio_lookup_rc(
            const struct vio_error_entry *local_table, u16 rc)
{
      const struct vio_error_entry *cur;

      if (!rc)
            return &vio_no_error;
      if (local_table)
            for (cur = local_table; cur->rc; ++cur)
                  if (cur->rc == rc)
                        return cur;
      for (cur = vio_default_errors; cur->rc; ++cur)
            if (cur->rc == rc)
                  return cur;
      return &vio_unknown_error;
}
EXPORT_SYMBOL(vio_lookup_rc);

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