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cmf.c

/*
 * linux/drivers/s390/cio/cmf.c
 *
 * Linux on zSeries Channel Measurement Facility support
 *
 * Copyright 2000,2006 IBM Corporation
 *
 * Authors: Arnd Bergmann <arndb@de.ibm.com>
 *        Cornelia Huck <cornelia.huck@de.ibm.com>
 *
 * original idea from Natarajan Krishnaswami <nkrishna@us.ibm.com>
 *
 * 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, or (at your option)
 * any 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/bootmem.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/timex.h>      /* get_clock() */

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/cmb.h>
#include <asm/div64.h>

#include "cio.h"
#include "css.h"
#include "device.h"
#include "ioasm.h"
#include "chsc.h"

/*
 * parameter to enable cmf during boot, possible uses are:
 *  "s390cmf" -- enable cmf and allocate 2 MB of ram so measuring can be
 *               used on any subchannel
 *  "s390cmf=<num>" -- enable cmf and allocate enough memory to measure
 *                     <num> subchannel, where <num> is an integer
 *                     between 1 and 65535, default is 1024
 */
#define ARGSTRING "s390cmf"

/* indices for READCMB */
enum cmb_index {
 /* basic and exended format: */
      cmb_ssch_rsch_count,
      cmb_sample_count,
      cmb_device_connect_time,
      cmb_function_pending_time,
      cmb_device_disconnect_time,
      cmb_control_unit_queuing_time,
      cmb_device_active_only_time,
 /* extended format only: */
      cmb_device_busy_time,
      cmb_initial_command_response_time,
};

/**
 * enum cmb_format - types of supported measurement block formats
 *
 * @CMF_BASIC:      traditional channel measurement blocks supported
 *              by all machines that we run on
 * @CMF_EXTENDED:   improved format that was introduced with the z990
 *              machine
 * @CMF_AUTODETECT: default: use extended format when running on a machine
 *              supporting extended format, otherwise fall back to
 *              basic format
 */
enum cmb_format {
      CMF_BASIC,
      CMF_EXTENDED,
      CMF_AUTODETECT = -1,
};

/*
 * format - actual format for all measurement blocks
 *
 * The format module parameter can be set to a value of 0 (zero)
 * or 1, indicating basic or extended format as described for
 * enum cmb_format.
 */
static int format = CMF_AUTODETECT;
module_param(format, bool, 0444);

/**
 * struct cmb_operations - functions to use depending on cmb_format
 *
 * Most of these functions operate on a struct ccw_device. There is only
 * one instance of struct cmb_operations because the format of the measurement
 * data is guaranteed to be the same for every ccw_device.
 *
 * @alloc:  allocate memory for a channel measurement block,
 *          either with the help of a special pool or with kmalloc
 * @free:   free memory allocated with @alloc
 * @set:    enable or disable measurement
 * @read:   read a measurement entry at an index
 * @readall:      read a measurement block in a common format
 * @reset:  clear the data in the associated measurement block and
 *          reset its time stamp
 * @align:  align an allocated block so that the hardware can use it
 */
00117 struct cmb_operations {
      int  (*alloc)  (struct ccw_device *);
      void (*free)   (struct ccw_device *);
      int  (*set)    (struct ccw_device *, u32);
      u64  (*read)   (struct ccw_device *, int);
      int  (*readall)(struct ccw_device *, struct cmbdata *);
      void (*reset)  (struct ccw_device *);
      void *(*align) (void *);
/* private: */
      struct attribute_group *attr_group;
};
static struct cmb_operations *cmbops;

struct cmb_data {
      void *hw_block;   /* Pointer to block updated by hardware */
      void *last_block; /* Last changed block copied from hardware block */
      int size;     /* Size of hw_block and last_block */
      unsigned long long last_update;  /* when last_block was updated */
};

/*
 * Our user interface is designed in terms of nanoseconds,
 * while the hardware measures total times in its own
 * unit.
 */
static inline u64 time_to_nsec(u32 value)
{
      return ((u64)value) * 128000ull;
}

/*
 * Users are usually interested in average times,
 * not accumulated time.
 * This also helps us with atomicity problems
 * when reading sinlge values.
 */
static inline u64 time_to_avg_nsec(u32 value, u32 count)
{
      u64 ret;

      /* no samples yet, avoid division by 0 */
      if (count == 0)
            return 0;

      /* value comes in units of 128 ┬Ásec */
      ret = time_to_nsec(value);
      do_div(ret, count);

      return ret;
}

/*
 * Activate or deactivate the channel monitor. When area is NULL,
 * the monitor is deactivated. The channel monitor needs to
 * be active in order to measure subchannels, which also need
 * to be enabled.
 */
static inline void cmf_activate(void *area, unsigned int onoff)
{
      register void * __gpr2 asm("2");
      register long __gpr1 asm("1");

      __gpr2 = area;
      __gpr1 = onoff ? 2 : 0;
      /* activate channel measurement */
      asm("schm" : : "d" (__gpr2), "d" (__gpr1) );
}

static int set_schib(struct ccw_device *cdev, u32 mme, int mbfc,
                 unsigned long address)
{
      int ret;
      int retry;
      struct subchannel *sch;
      struct schib *schib;

      sch = to_subchannel(cdev->dev.parent);
      schib = &sch->schib;
      /* msch can silently fail, so do it again if necessary */
      for (retry = 0; retry < 3; retry++) {
            /* prepare schib */
            stsch(sch->schid, schib);
            schib->pmcw.mme  = mme;
            schib->pmcw.mbfc = mbfc;
            /* address can be either a block address or a block index */
            if (mbfc)
                  schib->mba = address;
            else
                  schib->pmcw.mbi = address;

            /* try to submit it */
            switch(ret = msch_err(sch->schid, schib)) {
                  case 0:
                        break;
                  case 1:
                  case 2: /* in I/O or status pending */
                        ret = -EBUSY;
                        break;
                  case 3: /* subchannel is no longer valid */
                        ret = -ENODEV;
                        break;
                  default: /* msch caught an exception */
                        ret = -EINVAL;
                        break;
            }
            stsch(sch->schid, schib); /* restore the schib */

            if (ret)
                  break;

            /* check if it worked */
            if (schib->pmcw.mme  == mme &&
                schib->pmcw.mbfc == mbfc &&
                (mbfc ? (schib->mba == address)
                    : (schib->pmcw.mbi == address)))
                  return 0;

            ret = -EINVAL;
      }

      return ret;
}

struct set_schib_struct {
      u32 mme;
      int mbfc;
      unsigned long address;
      wait_queue_head_t wait;
      int ret;
      struct kref kref;
};

static void cmf_set_schib_release(struct kref *kref)
{
      struct set_schib_struct *set_data;

      set_data = container_of(kref, struct set_schib_struct, kref);
      kfree(set_data);
}

#define CMF_PENDING 1

static int set_schib_wait(struct ccw_device *cdev, u32 mme,
                        int mbfc, unsigned long address)
{
      struct set_schib_struct *set_data;
      int ret;

      spin_lock_irq(cdev->ccwlock);
      if (!cdev->private->cmb) {
            ret = -ENODEV;
            goto out;
      }
      set_data = kzalloc(sizeof(struct set_schib_struct), GFP_ATOMIC);
      if (!set_data) {
            ret = -ENOMEM;
            goto out;
      }
      init_waitqueue_head(&set_data->wait);
      kref_init(&set_data->kref);
      set_data->mme = mme;
      set_data->mbfc = mbfc;
      set_data->address = address;

      ret = set_schib(cdev, mme, mbfc, address);
      if (ret != -EBUSY)
            goto out_put;

      if (cdev->private->state != DEV_STATE_ONLINE) {
            /* if the device is not online, don't even try again */
            ret = -EBUSY;
            goto out_put;
      }

      cdev->private->state = DEV_STATE_CMFCHANGE;
      set_data->ret = CMF_PENDING;
      cdev->private->cmb_wait = set_data;

      spin_unlock_irq(cdev->ccwlock);
      if (wait_event_interruptible(set_data->wait,
                             set_data->ret != CMF_PENDING)) {
            spin_lock_irq(cdev->ccwlock);
            if (set_data->ret == CMF_PENDING) {
                  set_data->ret = -ERESTARTSYS;
                  if (cdev->private->state == DEV_STATE_CMFCHANGE)
                        cdev->private->state = DEV_STATE_ONLINE;
            }
            spin_unlock_irq(cdev->ccwlock);
      }
      spin_lock_irq(cdev->ccwlock);
      cdev->private->cmb_wait = NULL;
      ret = set_data->ret;
out_put:
      kref_put(&set_data->kref, cmf_set_schib_release);
out:
      spin_unlock_irq(cdev->ccwlock);
      return ret;
}

void retry_set_schib(struct ccw_device *cdev)
{
      struct set_schib_struct *set_data;

      set_data = cdev->private->cmb_wait;
      if (!set_data) {
            WARN_ON(1);
            return;
      }
      kref_get(&set_data->kref);
      set_data->ret = set_schib(cdev, set_data->mme, set_data->mbfc,
                          set_data->address);
      wake_up(&set_data->wait);
      kref_put(&set_data->kref, cmf_set_schib_release);
}

static int cmf_copy_block(struct ccw_device *cdev)
{
      struct subchannel *sch;
      void *reference_buf;
      void *hw_block;
      struct cmb_data *cmb_data;

      sch = to_subchannel(cdev->dev.parent);

      if (stsch(sch->schid, &sch->schib))
            return -ENODEV;

      if (sch->schib.scsw.fctl & SCSW_FCTL_START_FUNC) {
            /* Don't copy if a start function is in progress. */
            if ((!(sch->schib.scsw.actl & SCSW_ACTL_SUSPENDED)) &&
                (sch->schib.scsw.actl &
                 (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT)) &&
                (!(sch->schib.scsw.stctl & SCSW_STCTL_SEC_STATUS)))
                  return -EBUSY;
      }
      cmb_data = cdev->private->cmb;
      hw_block = cmbops->align(cmb_data->hw_block);
      if (!memcmp(cmb_data->last_block, hw_block, cmb_data->size))
            /* No need to copy. */
            return 0;
      reference_buf = kzalloc(cmb_data->size, GFP_ATOMIC);
      if (!reference_buf)
            return -ENOMEM;
      /* Ensure consistency of block copied from hardware. */
      do {
            memcpy(cmb_data->last_block, hw_block, cmb_data->size);
            memcpy(reference_buf, hw_block, cmb_data->size);
      } while (memcmp(cmb_data->last_block, reference_buf, cmb_data->size));
      cmb_data->last_update = get_clock();
      kfree(reference_buf);
      return 0;
}

struct copy_block_struct {
      wait_queue_head_t wait;
      int ret;
      struct kref kref;
};

static void cmf_copy_block_release(struct kref *kref)
{
      struct copy_block_struct *copy_block;

      copy_block = container_of(kref, struct copy_block_struct, kref);
      kfree(copy_block);
}

static int cmf_cmb_copy_wait(struct ccw_device *cdev)
{
      struct copy_block_struct *copy_block;
      int ret;
      unsigned long flags;

      spin_lock_irqsave(cdev->ccwlock, flags);
      if (!cdev->private->cmb) {
            ret = -ENODEV;
            goto out;
      }
      copy_block = kzalloc(sizeof(struct copy_block_struct), GFP_ATOMIC);
      if (!copy_block) {
            ret = -ENOMEM;
            goto out;
      }
      init_waitqueue_head(&copy_block->wait);
      kref_init(&copy_block->kref);

      ret = cmf_copy_block(cdev);
      if (ret != -EBUSY)
            goto out_put;

      if (cdev->private->state != DEV_STATE_ONLINE) {
            ret = -EBUSY;
            goto out_put;
      }

      cdev->private->state = DEV_STATE_CMFUPDATE;
      copy_block->ret = CMF_PENDING;
      cdev->private->cmb_wait = copy_block;

      spin_unlock_irqrestore(cdev->ccwlock, flags);
      if (wait_event_interruptible(copy_block->wait,
                             copy_block->ret != CMF_PENDING)) {
            spin_lock_irqsave(cdev->ccwlock, flags);
            if (copy_block->ret == CMF_PENDING) {
                  copy_block->ret = -ERESTARTSYS;
                  if (cdev->private->state == DEV_STATE_CMFUPDATE)
                        cdev->private->state = DEV_STATE_ONLINE;
            }
            spin_unlock_irqrestore(cdev->ccwlock, flags);
      }
      spin_lock_irqsave(cdev->ccwlock, flags);
      cdev->private->cmb_wait = NULL;
      ret = copy_block->ret;
out_put:
      kref_put(&copy_block->kref, cmf_copy_block_release);
out:
      spin_unlock_irqrestore(cdev->ccwlock, flags);
      return ret;
}

void cmf_retry_copy_block(struct ccw_device *cdev)
{
      struct copy_block_struct *copy_block;

      copy_block = cdev->private->cmb_wait;
      if (!copy_block) {
            WARN_ON(1);
            return;
      }
      kref_get(&copy_block->kref);
      copy_block->ret = cmf_copy_block(cdev);
      wake_up(&copy_block->wait);
      kref_put(&copy_block->kref, cmf_copy_block_release);
}

static void cmf_generic_reset(struct ccw_device *cdev)
{
      struct cmb_data *cmb_data;

      spin_lock_irq(cdev->ccwlock);
      cmb_data = cdev->private->cmb;
      if (cmb_data) {
            memset(cmb_data->last_block, 0, cmb_data->size);
            /*
             * Need to reset hw block as well to make the hardware start
             * from 0 again.
             */
            memset(cmbops->align(cmb_data->hw_block), 0, cmb_data->size);
            cmb_data->last_update = 0;
      }
      cdev->private->cmb_start_time = get_clock();
      spin_unlock_irq(cdev->ccwlock);
}

/**
 * struct cmb_area - container for global cmb data
 *
 * @mem:    pointer to CMBs (only in basic measurement mode)
 * @list:   contains a linked list of all subchannels
 * @num_channels: number of channels to be measured
 * @lock:   protect concurrent access to @mem and @list
 */
00479 struct cmb_area {
      struct cmb *mem;
      struct list_head list;
      int num_channels;
      spinlock_t lock;
};

static struct cmb_area cmb_area = {
      .lock = __SPIN_LOCK_UNLOCKED(cmb_area.lock),
      .list = LIST_HEAD_INIT(cmb_area.list),
      .num_channels  = 1024,
};

/* ****** old style CMB handling ********/

/*
 * Basic channel measurement blocks are allocated in one contiguous
 * block of memory, which can not be moved as long as any channel
 * is active. Therefore, a maximum number of subchannels needs to
 * be defined somewhere. This is a module parameter, defaulting to
 * a resonable value of 1024, or 32 kb of memory.
 * Current kernels don't allow kmalloc with more than 128kb, so the
 * maximum is 4096.
 */

module_param_named(maxchannels, cmb_area.num_channels, uint, 0444);

/**
 * struct cmb - basic channel measurement block
 * @ssch_rsch_count: number of ssch and rsch
 * @sample_count: number of samples
 * @device_connect_time: time of device connect
 * @function_pending_time: time of function pending
 * @device_disconnect_time: time of device disconnect
 * @control_unit_queuing_time: time of control unit queuing
 * @device_active_only_time: time of device active only
 * @reserved: unused in basic measurement mode
 *
 * The measurement block as used by the hardware. The fields are described
 * further in z/Architecture Principles of Operation, chapter 17.
 *
 * The cmb area made up from these blocks must be a contiguous array and may
 * not be reallocated or freed.
 * Only one cmb area can be present in the system.
 */
00524 struct cmb {
      u16 ssch_rsch_count;
      u16 sample_count;
      u32 device_connect_time;
      u32 function_pending_time;
      u32 device_disconnect_time;
      u32 control_unit_queuing_time;
      u32 device_active_only_time;
      u32 reserved[2];
};

/*
 * Insert a single device into the cmb_area list.
 * Called with cmb_area.lock held from alloc_cmb.
 */
static int alloc_cmb_single(struct ccw_device *cdev,
                      struct cmb_data *cmb_data)
{
      struct cmb *cmb;
      struct ccw_device_private *node;
      int ret;

      spin_lock_irq(cdev->ccwlock);
      if (!list_empty(&cdev->private->cmb_list)) {
            ret = -EBUSY;
            goto out;
      }

      /*
       * Find first unused cmb in cmb_area.mem.
       * This is a little tricky: cmb_area.list
       * remains sorted by ->cmb->hw_data pointers.
       */
      cmb = cmb_area.mem;
      list_for_each_entry(node, &cmb_area.list, cmb_list) {
            struct cmb_data *data;
            data = node->cmb;
            if ((struct cmb*)data->hw_block > cmb)
                  break;
            cmb++;
      }
      if (cmb - cmb_area.mem >= cmb_area.num_channels) {
            ret = -ENOMEM;
            goto out;
      }

      /* insert new cmb */
      list_add_tail(&cdev->private->cmb_list, &node->cmb_list);
      cmb_data->hw_block = cmb;
      cdev->private->cmb = cmb_data;
      ret = 0;
out:
      spin_unlock_irq(cdev->ccwlock);
      return ret;
}

static int alloc_cmb(struct ccw_device *cdev)
{
      int ret;
      struct cmb *mem;
      ssize_t size;
      struct cmb_data *cmb_data;

      /* Allocate private cmb_data. */
      cmb_data = kzalloc(sizeof(struct cmb_data), GFP_KERNEL);
      if (!cmb_data)
            return -ENOMEM;

      cmb_data->last_block = kzalloc(sizeof(struct cmb), GFP_KERNEL);
      if (!cmb_data->last_block) {
            kfree(cmb_data);
            return -ENOMEM;
      }
      cmb_data->size = sizeof(struct cmb);
      spin_lock(&cmb_area.lock);

      if (!cmb_area.mem) {
            /* there is no user yet, so we need a new area */
            size = sizeof(struct cmb) * cmb_area.num_channels;
            WARN_ON(!list_empty(&cmb_area.list));

            spin_unlock(&cmb_area.lock);
            mem = (void*)__get_free_pages(GFP_KERNEL | GFP_DMA,
                         get_order(size));
            spin_lock(&cmb_area.lock);

            if (cmb_area.mem) {
                  /* ok, another thread was faster */
                  free_pages((unsigned long)mem, get_order(size));
            } else if (!mem) {
                  /* no luck */
                  printk(KERN_WARNING "cio: failed to allocate area "
                         "for measuring %d subchannels\n",
                         cmb_area.num_channels);
                  ret = -ENOMEM;
                  goto out;
            } else {
                  /* everything ok */
                  memset(mem, 0, size);
                  cmb_area.mem = mem;
                  cmf_activate(cmb_area.mem, 1);
            }
      }

      /* do the actual allocation */
      ret = alloc_cmb_single(cdev, cmb_data);
out:
      spin_unlock(&cmb_area.lock);
      if (ret) {
            kfree(cmb_data->last_block);
            kfree(cmb_data);
      }
      return ret;
}

static void free_cmb(struct ccw_device *cdev)
{
      struct ccw_device_private *priv;
      struct cmb_data *cmb_data;

      spin_lock(&cmb_area.lock);
      spin_lock_irq(cdev->ccwlock);

      priv = cdev->private;

      if (list_empty(&priv->cmb_list)) {
            /* already freed */
            goto out;
      }

      cmb_data = priv->cmb;
      priv->cmb = NULL;
      if (cmb_data)
            kfree(cmb_data->last_block);
      kfree(cmb_data);
      list_del_init(&priv->cmb_list);

      if (list_empty(&cmb_area.list)) {
            ssize_t size;
            size = sizeof(struct cmb) * cmb_area.num_channels;
            cmf_activate(NULL, 0);
            free_pages((unsigned long)cmb_area.mem, get_order(size));
            cmb_area.mem = NULL;
      }
out:
      spin_unlock_irq(cdev->ccwlock);
      spin_unlock(&cmb_area.lock);
}

static int set_cmb(struct ccw_device *cdev, u32 mme)
{
      u16 offset;
      struct cmb_data *cmb_data;
      unsigned long flags;

      spin_lock_irqsave(cdev->ccwlock, flags);
      if (!cdev->private->cmb) {
            spin_unlock_irqrestore(cdev->ccwlock, flags);
            return -EINVAL;
      }
      cmb_data = cdev->private->cmb;
      offset = mme ? (struct cmb *)cmb_data->hw_block - cmb_area.mem : 0;
      spin_unlock_irqrestore(cdev->ccwlock, flags);

      return set_schib_wait(cdev, mme, 0, offset);
}

static u64 read_cmb(struct ccw_device *cdev, int index)
{
      struct cmb *cmb;
      u32 val;
      int ret;
      unsigned long flags;

      ret = cmf_cmb_copy_wait(cdev);
      if (ret < 0)
            return 0;

      spin_lock_irqsave(cdev->ccwlock, flags);
      if (!cdev->private->cmb) {
            ret = 0;
            goto out;
      }
      cmb = ((struct cmb_data *)cdev->private->cmb)->last_block;

      switch (index) {
      case cmb_ssch_rsch_count:
            ret = cmb->ssch_rsch_count;
            goto out;
      case cmb_sample_count:
            ret = cmb->sample_count;
            goto out;
      case cmb_device_connect_time:
            val = cmb->device_connect_time;
            break;
      case cmb_function_pending_time:
            val = cmb->function_pending_time;
            break;
      case cmb_device_disconnect_time:
            val = cmb->device_disconnect_time;
            break;
      case cmb_control_unit_queuing_time:
            val = cmb->control_unit_queuing_time;
            break;
      case cmb_device_active_only_time:
            val = cmb->device_active_only_time;
            break;
      default:
            ret = 0;
            goto out;
      }
      ret = time_to_avg_nsec(val, cmb->sample_count);
out:
      spin_unlock_irqrestore(cdev->ccwlock, flags);
      return ret;
}

static int readall_cmb(struct ccw_device *cdev, struct cmbdata *data)
{
      struct cmb *cmb;
      struct cmb_data *cmb_data;
      u64 time;
      unsigned long flags;
      int ret;

      ret = cmf_cmb_copy_wait(cdev);
      if (ret < 0)
            return ret;
      spin_lock_irqsave(cdev->ccwlock, flags);
      cmb_data = cdev->private->cmb;
      if (!cmb_data) {
            ret = -ENODEV;
            goto out;
      }
      if (cmb_data->last_update == 0) {
            ret = -EAGAIN;
            goto out;
      }
      cmb = cmb_data->last_block;
      time = cmb_data->last_update - cdev->private->cmb_start_time;

      memset(data, 0, sizeof(struct cmbdata));

      /* we only know values before device_busy_time */
      data->size = offsetof(struct cmbdata, device_busy_time);

      /* convert to nanoseconds */
      data->elapsed_time = (time * 1000) >> 12;

      /* copy data to new structure */
      data->ssch_rsch_count = cmb->ssch_rsch_count;
      data->sample_count = cmb->sample_count;

      /* time fields are converted to nanoseconds while copying */
      data->device_connect_time = time_to_nsec(cmb->device_connect_time);
      data->function_pending_time = time_to_nsec(cmb->function_pending_time);
      data->device_disconnect_time =
            time_to_nsec(cmb->device_disconnect_time);
      data->control_unit_queuing_time
            = time_to_nsec(cmb->control_unit_queuing_time);
      data->device_active_only_time
            = time_to_nsec(cmb->device_active_only_time);
      ret = 0;
out:
      spin_unlock_irqrestore(cdev->ccwlock, flags);
      return ret;
}

static void reset_cmb(struct ccw_device *cdev)
{
      cmf_generic_reset(cdev);
}

static void * align_cmb(void *area)
{
      return area;
}

static struct attribute_group cmf_attr_group;

static struct cmb_operations cmbops_basic = {
      .alloc      = alloc_cmb,
      .free = free_cmb,
      .set  = set_cmb,
      .read = read_cmb,
      .readall    = readall_cmb,
      .reset          = reset_cmb,
      .align          = align_cmb,
      .attr_group = &cmf_attr_group,
};

/* ******** extended cmb handling ********/

/**
 * struct cmbe - extended channel measurement block
 * @ssch_rsch_count: number of ssch and rsch
 * @sample_count: number of samples
 * @device_connect_time: time of device connect
 * @function_pending_time: time of function pending
 * @device_disconnect_time: time of device disconnect
 * @control_unit_queuing_time: time of control unit queuing
 * @device_active_only_time: time of device active only
 * @device_busy_time: time of device busy
 * @initial_command_response_time: initial command response time
 * @reserved: unused
 *
 * The measurement block as used by the hardware. May be in any 64 bit physical
 * location.
 * The fields are described further in z/Architecture Principles of Operation,
 * third edition, chapter 17.
 */
00835 struct cmbe {
      u32 ssch_rsch_count;
      u32 sample_count;
      u32 device_connect_time;
      u32 function_pending_time;
      u32 device_disconnect_time;
      u32 control_unit_queuing_time;
      u32 device_active_only_time;
      u32 device_busy_time;
      u32 initial_command_response_time;
      u32 reserved[7];
};

/*
 * kmalloc only guarantees 8 byte alignment, but we need cmbe
 * pointers to be naturally aligned. Make sure to allocate
 * enough space for two cmbes.
 */
static inline struct cmbe *cmbe_align(struct cmbe *c)
{
      unsigned long addr;
      addr = ((unsigned long)c + sizeof (struct cmbe) - sizeof(long)) &
                         ~(sizeof (struct cmbe) - sizeof(long));
      return (struct cmbe*)addr;
}

static int alloc_cmbe(struct ccw_device *cdev)
{
      struct cmbe *cmbe;
      struct cmb_data *cmb_data;
      int ret;

      cmbe = kzalloc (sizeof (*cmbe) * 2, GFP_KERNEL);
      if (!cmbe)
            return -ENOMEM;
      cmb_data = kzalloc(sizeof(struct cmb_data), GFP_KERNEL);
      if (!cmb_data) {
            ret = -ENOMEM;
            goto out_free;
      }
      cmb_data->last_block = kzalloc(sizeof(struct cmbe), GFP_KERNEL);
      if (!cmb_data->last_block) {
            ret = -ENOMEM;
            goto out_free;
      }
      cmb_data->size = sizeof(struct cmbe);
      spin_lock_irq(cdev->ccwlock);
      if (cdev->private->cmb) {
            spin_unlock_irq(cdev->ccwlock);
            ret = -EBUSY;
            goto out_free;
      }
      cmb_data->hw_block = cmbe;
      cdev->private->cmb = cmb_data;
      spin_unlock_irq(cdev->ccwlock);

      /* activate global measurement if this is the first channel */
      spin_lock(&cmb_area.lock);
      if (list_empty(&cmb_area.list))
            cmf_activate(NULL, 1);
      list_add_tail(&cdev->private->cmb_list, &cmb_area.list);
      spin_unlock(&cmb_area.lock);

      return 0;
out_free:
      if (cmb_data)
            kfree(cmb_data->last_block);
      kfree(cmb_data);
      kfree(cmbe);
      return ret;
}

static void free_cmbe(struct ccw_device *cdev)
{
      struct cmb_data *cmb_data;

      spin_lock_irq(cdev->ccwlock);
      cmb_data = cdev->private->cmb;
      cdev->private->cmb = NULL;
      if (cmb_data)
            kfree(cmb_data->last_block);
      kfree(cmb_data);
      spin_unlock_irq(cdev->ccwlock);

      /* deactivate global measurement if this is the last channel */
      spin_lock(&cmb_area.lock);
      list_del_init(&cdev->private->cmb_list);
      if (list_empty(&cmb_area.list))
            cmf_activate(NULL, 0);
      spin_unlock(&cmb_area.lock);
}

static int set_cmbe(struct ccw_device *cdev, u32 mme)
{
      unsigned long mba;
      struct cmb_data *cmb_data;
      unsigned long flags;

      spin_lock_irqsave(cdev->ccwlock, flags);
      if (!cdev->private->cmb) {
            spin_unlock_irqrestore(cdev->ccwlock, flags);
            return -EINVAL;
      }
      cmb_data = cdev->private->cmb;
      mba = mme ? (unsigned long) cmbe_align(cmb_data->hw_block) : 0;
      spin_unlock_irqrestore(cdev->ccwlock, flags);

      return set_schib_wait(cdev, mme, 1, mba);
}


static u64 read_cmbe(struct ccw_device *cdev, int index)
{
      struct cmbe *cmb;
      struct cmb_data *cmb_data;
      u32 val;
      int ret;
      unsigned long flags;

      ret = cmf_cmb_copy_wait(cdev);
      if (ret < 0)
            return 0;

      spin_lock_irqsave(cdev->ccwlock, flags);
      cmb_data = cdev->private->cmb;
      if (!cmb_data) {
            ret = 0;
            goto out;
      }
      cmb = cmb_data->last_block;

      switch (index) {
      case cmb_ssch_rsch_count:
            ret = cmb->ssch_rsch_count;
            goto out;
      case cmb_sample_count:
            ret = cmb->sample_count;
            goto out;
      case cmb_device_connect_time:
            val = cmb->device_connect_time;
            break;
      case cmb_function_pending_time:
            val = cmb->function_pending_time;
            break;
      case cmb_device_disconnect_time:
            val = cmb->device_disconnect_time;
            break;
      case cmb_control_unit_queuing_time:
            val = cmb->control_unit_queuing_time;
            break;
      case cmb_device_active_only_time:
            val = cmb->device_active_only_time;
            break;
      case cmb_device_busy_time:
            val = cmb->device_busy_time;
            break;
      case cmb_initial_command_response_time:
            val = cmb->initial_command_response_time;
            break;
      default:
            ret = 0;
            goto out;
      }
      ret = time_to_avg_nsec(val, cmb->sample_count);
out:
      spin_unlock_irqrestore(cdev->ccwlock, flags);
      return ret;
}

static int readall_cmbe(struct ccw_device *cdev, struct cmbdata *data)
{
      struct cmbe *cmb;
      struct cmb_data *cmb_data;
      u64 time;
      unsigned long flags;
      int ret;

      ret = cmf_cmb_copy_wait(cdev);
      if (ret < 0)
            return ret;
      spin_lock_irqsave(cdev->ccwlock, flags);
      cmb_data = cdev->private->cmb;
      if (!cmb_data) {
            ret = -ENODEV;
            goto out;
      }
      if (cmb_data->last_update == 0) {
            ret = -EAGAIN;
            goto out;
      }
      time = cmb_data->last_update - cdev->private->cmb_start_time;

      memset (data, 0, sizeof(struct cmbdata));

      /* we only know values before device_busy_time */
      data->size = offsetof(struct cmbdata, device_busy_time);

      /* conver to nanoseconds */
      data->elapsed_time = (time * 1000) >> 12;

      cmb = cmb_data->last_block;
      /* copy data to new structure */
      data->ssch_rsch_count = cmb->ssch_rsch_count;
      data->sample_count = cmb->sample_count;

      /* time fields are converted to nanoseconds while copying */
      data->device_connect_time = time_to_nsec(cmb->device_connect_time);
      data->function_pending_time = time_to_nsec(cmb->function_pending_time);
      data->device_disconnect_time =
            time_to_nsec(cmb->device_disconnect_time);
      data->control_unit_queuing_time
            = time_to_nsec(cmb->control_unit_queuing_time);
      data->device_active_only_time
            = time_to_nsec(cmb->device_active_only_time);
      data->device_busy_time = time_to_nsec(cmb->device_busy_time);
      data->initial_command_response_time
            = time_to_nsec(cmb->initial_command_response_time);

      ret = 0;
out:
      spin_unlock_irqrestore(cdev->ccwlock, flags);
      return ret;
}

static void reset_cmbe(struct ccw_device *cdev)
{
      cmf_generic_reset(cdev);
}

static void * align_cmbe(void *area)
{
      return cmbe_align(area);
}

static struct attribute_group cmf_attr_group_ext;

static struct cmb_operations cmbops_extended = {
      .alloc          = alloc_cmbe,
      .free     = free_cmbe,
      .set      = set_cmbe,
      .read     = read_cmbe,
      .readall    = readall_cmbe,
      .reset          = reset_cmbe,
      .align          = align_cmbe,
      .attr_group = &cmf_attr_group_ext,
};

static ssize_t cmb_show_attr(struct device *dev, char *buf, enum cmb_index idx)
{
      return sprintf(buf, "%lld\n",
            (unsigned long long) cmf_read(to_ccwdev(dev), idx));
}

static ssize_t cmb_show_avg_sample_interval(struct device *dev,
                                  struct device_attribute *attr,
                                  char *buf)
{
      struct ccw_device *cdev;
      long interval;
      unsigned long count;
      struct cmb_data *cmb_data;

      cdev = to_ccwdev(dev);
      count = cmf_read(cdev, cmb_sample_count);
      spin_lock_irq(cdev->ccwlock);
      cmb_data = cdev->private->cmb;
      if (count) {
            interval = cmb_data->last_update -
                  cdev->private->cmb_start_time;
            interval = (interval * 1000) >> 12;
            interval /= count;
      } else
            interval = -1;
      spin_unlock_irq(cdev->ccwlock);
      return sprintf(buf, "%ld\n", interval);
}

static ssize_t cmb_show_avg_utilization(struct device *dev,
                              struct device_attribute *attr,
                              char *buf)
{
      struct cmbdata data;
      u64 utilization;
      unsigned long t, u;
      int ret;

      ret = cmf_readall(to_ccwdev(dev), &data);
      if (ret == -EAGAIN || ret == -ENODEV)
            /* No data (yet/currently) available to use for calculation. */
            return sprintf(buf, "n/a\n");
      else if (ret)
            return ret;

      utilization = data.device_connect_time +
                  data.function_pending_time +
                  data.device_disconnect_time;

      /* shift to avoid long long division */
      while (-1ul < (data.elapsed_time | utilization)) {
            utilization >>= 8;
            data.elapsed_time >>= 8;
      }

      /* calculate value in 0.1 percent units */
      t = (unsigned long) data.elapsed_time / 1000;
      u = (unsigned long) utilization / t;

      return sprintf(buf, "%02ld.%01ld%%\n", u/ 10, u - (u/ 10) * 10);
}

#define cmf_attr(name) \
static ssize_t show_##name(struct device *dev, \
                     struct device_attribute *attr, char *buf)    \
{ return cmb_show_attr((dev), buf, cmb_##name); } \
static DEVICE_ATTR(name, 0444, show_##name, NULL);

#define cmf_attr_avg(name) \
static ssize_t show_avg_##name(struct device *dev, \
                         struct device_attribute *attr, char *buf) \
{ return cmb_show_attr((dev), buf, cmb_##name); } \
static DEVICE_ATTR(avg_##name, 0444, show_avg_##name, NULL);

cmf_attr(ssch_rsch_count);
cmf_attr(sample_count);
cmf_attr_avg(device_connect_time);
cmf_attr_avg(function_pending_time);
cmf_attr_avg(device_disconnect_time);
cmf_attr_avg(control_unit_queuing_time);
cmf_attr_avg(device_active_only_time);
cmf_attr_avg(device_busy_time);
cmf_attr_avg(initial_command_response_time);

static DEVICE_ATTR(avg_sample_interval, 0444, cmb_show_avg_sample_interval,
               NULL);
static DEVICE_ATTR(avg_utilization, 0444, cmb_show_avg_utilization, NULL);

static struct attribute *cmf_attributes[] = {
      &dev_attr_avg_sample_interval.attr,
      &dev_attr_avg_utilization.attr,
      &dev_attr_ssch_rsch_count.attr,
      &dev_attr_sample_count.attr,
      &dev_attr_avg_device_connect_time.attr,
      &dev_attr_avg_function_pending_time.attr,
      &dev_attr_avg_device_disconnect_time.attr,
      &dev_attr_avg_control_unit_queuing_time.attr,
      &dev_attr_avg_device_active_only_time.attr,
      NULL,
};

static struct attribute_group cmf_attr_group = {
      .name  = "cmf",
      .attrs = cmf_attributes,
};

static struct attribute *cmf_attributes_ext[] = {
      &dev_attr_avg_sample_interval.attr,
      &dev_attr_avg_utilization.attr,
      &dev_attr_ssch_rsch_count.attr,
      &dev_attr_sample_count.attr,
      &dev_attr_avg_device_connect_time.attr,
      &dev_attr_avg_function_pending_time.attr,
      &dev_attr_avg_device_disconnect_time.attr,
      &dev_attr_avg_control_unit_queuing_time.attr,
      &dev_attr_avg_device_active_only_time.attr,
      &dev_attr_avg_device_busy_time.attr,
      &dev_attr_avg_initial_command_response_time.attr,
      NULL,
};

static struct attribute_group cmf_attr_group_ext = {
      .name  = "cmf",
      .attrs = cmf_attributes_ext,
};

static ssize_t cmb_enable_show(struct device *dev,
                         struct device_attribute *attr,
                         char *buf)
{
      return sprintf(buf, "%d\n", to_ccwdev(dev)->private->cmb ? 1 : 0);
}

static ssize_t cmb_enable_store(struct device *dev,
                        struct device_attribute *attr, const char *buf,
                        size_t c)
{
      struct ccw_device *cdev;
      int ret;

      cdev = to_ccwdev(dev);

      switch (buf[0]) {
      case '0':
            ret = disable_cmf(cdev);
            if (ret)
                  dev_info(&cdev->dev, "disable_cmf failed (%d)\n", ret);
            break;
      case '1':
            ret = enable_cmf(cdev);
            if (ret && ret != -EBUSY)
                  dev_info(&cdev->dev, "enable_cmf failed (%d)\n", ret);
            break;
      }

      return c;
}

DEVICE_ATTR(cmb_enable, 0644, cmb_enable_show, cmb_enable_store);

/**
 * enable_cmf() - switch on the channel measurement for a specific device
 *  @cdev:  The ccw device to be enabled
 *
 *  Returns %0 for success or a negative error value.
 *
 *  Context:
 *    non-atomic
 */
int enable_cmf(struct ccw_device *cdev)
{
      int ret;

      ret = cmbops->alloc(cdev);
      cmbops->reset(cdev);
      if (ret)
            return ret;
      ret = cmbops->set(cdev, 2);
      if (ret) {
            cmbops->free(cdev);
            return ret;
      }
      ret = sysfs_create_group(&cdev->dev.kobj, cmbops->attr_group);
      if (!ret)
            return 0;
      cmbops->set(cdev, 0);  //FIXME: this can fail
      cmbops->free(cdev);
      return ret;
}

/**
 * disable_cmf() - switch off the channel measurement for a specific device
 *  @cdev:  The ccw device to be disabled
 *
 *  Returns %0 for success or a negative error value.
 *
 *  Context:
 *    non-atomic
 */
int disable_cmf(struct ccw_device *cdev)
{
      int ret;

      ret = cmbops->set(cdev, 0);
      if (ret)
            return ret;
      cmbops->free(cdev);
      sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
      return ret;
}

/**
 * cmf_read() - read one value from the current channel measurement block
 * @cdev:   the channel to be read
 * @index:  the index of the value to be read
 *
 * Returns the value read or %0 if the value cannot be read.
 *
 *  Context:
 *    any
 */
u64 cmf_read(struct ccw_device *cdev, int index)
{
      return cmbops->read(cdev, index);
}

/**
 * cmf_readall() - read the current channel measurement block
 * @cdev:   the channel to be read
 * @data:   a pointer to a data block that will be filled
 *
 * Returns %0 on success, a negative error value otherwise.
 *
 *  Context:
 *    any
 */
int cmf_readall(struct ccw_device *cdev, struct cmbdata *data)
{
      return cmbops->readall(cdev, data);
}

/* Reenable cmf when a disconnected device becomes available again. */
int cmf_reenable(struct ccw_device *cdev)
{
      cmbops->reset(cdev);
      return cmbops->set(cdev, 2);
}

static int __init init_cmf(void)
{
      char *format_string;
      char *detect_string = "parameter";

      /*
       * If the user did not give a parameter, see if we are running on a
       * machine supporting extended measurement blocks, otherwise fall back
       * to basic mode.
       */
      if (format == CMF_AUTODETECT) {
            if (!css_characteristics_avail ||
                !css_general_characteristics.ext_mb) {
                  format = CMF_BASIC;
            } else {
                  format = CMF_EXTENDED;
            }
            detect_string = "autodetected";
      } else {
            detect_string = "parameter";
      }

      switch (format) {
      case CMF_BASIC:
            format_string = "basic";
            cmbops = &cmbops_basic;
            break;
      case CMF_EXTENDED:
            format_string = "extended";
            cmbops = &cmbops_extended;
            break;
      default:
            printk(KERN_ERR "cio: Invalid format %d for channel "
                  "measurement facility\n", format);
            return 1;
      }

      printk(KERN_INFO "cio: Channel measurement facility using %s "
             "format (%s)\n", format_string, detect_string);
      return 0;
}

module_init(init_cmf);


MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("channel measurement facility base driver\n"
               "Copyright 2003 IBM Corporation\n");

EXPORT_SYMBOL_GPL(enable_cmf);
EXPORT_SYMBOL_GPL(disable_cmf);
EXPORT_SYMBOL_GPL(cmf_read);
EXPORT_SYMBOL_GPL(cmf_readall);

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