Linux 2.6.17.7

[linux/fpc-iii.git] / drivers / s390 / cio / cmf.c

/*
 * linux/drivers/s390/cio/cmf.c
 *
 * Linux on zSeries Channel Measurement Facility support
 *
 * Copyright 2000,2003 IBM Corporation
 *
 * Author: Arnd Bergmann <arndb@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 z990
 *                  or later machine, 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
 *
 * all these functions operate on a struct cmf_device. There is only
 * one instance of struct cmb_operations because all cmf_device
 * objects are guaranteed to be of the same type.
 *
 * @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
 * @readall:    read a measurement block in a common format
 * @reset:      clear the data in the associated measurement block and
 *              reset its time stamp
 */
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*);

        struct attribute_group *attr_group;
};
static struct cmb_operations *cmbops;

/* 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 µsec */
        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;
};

static int set_schib_wait(struct ccw_device *cdev, u32 mme,
                                int mbfc, unsigned long address)
{
        struct set_schib_struct s = {
                .mme = mme,
                .mbfc = mbfc,
                .address = address,
                .wait = __WAIT_QUEUE_HEAD_INITIALIZER(s.wait),
        };

        spin_lock_irq(cdev->ccwlock);
        s.ret = set_schib(cdev, mme, mbfc, address);
        if (s.ret != -EBUSY) {
                goto out_nowait;
        }

        if (cdev->private->state != DEV_STATE_ONLINE) {
                s.ret = -EBUSY;
                /* if the device is not online, don't even try again */
                goto out_nowait;
        }
        cdev->private->state = DEV_STATE_CMFCHANGE;
        cdev->private->cmb_wait = &s;
        s.ret = 1;

        spin_unlock_irq(cdev->ccwlock);
        if (wait_event_interruptible(s.wait, s.ret != 1)) {
                spin_lock_irq(cdev->ccwlock);
                if (s.ret == 1) {
                        s.ret = -ERESTARTSYS;
                        cdev->private->cmb_wait = 0;
                        if (cdev->private->state == DEV_STATE_CMFCHANGE)
                                cdev->private->state = DEV_STATE_ONLINE;
                }
                spin_unlock_irq(cdev->ccwlock);
        }
        return s.ret;

out_nowait:
        spin_unlock_irq(cdev->ccwlock);
        return s.ret;
}

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

        s = cdev->private->cmb_wait;
        cdev->private->cmb_wait = 0;
        if (!s) {
                WARN_ON(1);
                return;
        }
        s->ret = set_schib(cdev, s->mme, s->mbfc, s->address);
        wake_up(&s->wait);
}

/**
 * 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
 * @lock:       protect concurrent access to @mem and @list
 */
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,
        .list = LIST_HEAD_INIT(cmb_area.list),
        .num_channels  = 1024,
};

\f
/* ****** old style CMB handling ********/

/** int maxchannels
 *
 * 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
 *
 * cmb as used by the hardware the fields are described in z/Architecture
 * Principles of Operation, chapter 17.
 * The area to be a contiguous array and may not be reallocated or freed.
 * Only one cmb area can be present in the system.
 */
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 inline int
alloc_cmb_single (struct ccw_device *cdev)
{
        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 pointers */
        cmb = cmb_area.mem;
        list_for_each_entry(node, &cmb_area.list, cmb_list) {
                if ((struct cmb*)node->cmb > 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);
        cdev->private->cmb = cmb;
        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;

        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 */
                        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);
out:
        spin_unlock(&cmb_area.lock);

        return ret;
}

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

        priv = cdev->private;

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

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

        priv->cmb = NULL;
        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;

        if (!cdev->private->cmb)
                return -EINVAL;

        offset = mme ? (struct cmb *)cdev->private->cmb - cmb_area.mem : 0;

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

static u64
read_cmb (struct ccw_device *cdev, int index)
{
        /* yes, we have to put it on the stack
         * because the cmb must only be accessed
         * atomically, e.g. with mvc */
        struct cmb cmb;
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(cdev->ccwlock, flags);
        if (!cdev->private->cmb) {
                spin_unlock_irqrestore(cdev->ccwlock, flags);
                return 0;
        }

        cmb = *(struct cmb*)cdev->private->cmb;
        spin_unlock_irqrestore(cdev->ccwlock, flags);

        switch (index) {
        case cmb_ssch_rsch_count:
                return cmb.ssch_rsch_count;
        case cmb_sample_count:
                return cmb.sample_count;
        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:
                return 0;
        }
        return time_to_avg_nsec(val, cmb.sample_count);
}

static int
readall_cmb (struct ccw_device *cdev, struct cmbdata *data)
{
        /* yes, we have to put it on the stack
         * because the cmb must only be accessed
         * atomically, e.g. with mvc */
        struct cmb cmb;
        unsigned long flags;
        u64 time;

        spin_lock_irqsave(cdev->ccwlock, flags);
        if (!cdev->private->cmb) {
                spin_unlock_irqrestore(cdev->ccwlock, flags);
                return -ENODEV;
        }

        cmb = *(struct cmb*)cdev->private->cmb;
        time = get_clock() - cdev->private->cmb_start_time;
        spin_unlock_irqrestore(cdev->ccwlock, flags);

        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);

        return 0;
}

static void
reset_cmb(struct ccw_device *cdev)
{
        struct cmb *cmb;
        spin_lock_irq(cdev->ccwlock);
        cmb = cdev->private->cmb;
        if (cmb)
                memset (cmb, 0, sizeof (*cmb));
        cdev->private->cmb_start_time = get_clock();
        spin_unlock_irq(cdev->ccwlock);
}

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,
        .attr_group = &cmf_attr_group,
};
\f
/* ******** extended cmb handling ********/

/**
 * struct cmbe - extended channel measurement block
 *
 * cmb as used by the hardware, may be in any 64 bit physical location,
 * the fields are described in z/Architecture Principles of Operation,
 * third edition, chapter 17.
 */
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;
        cmbe = kmalloc (sizeof (*cmbe) * 2, GFP_KERNEL);
        if (!cmbe)
                return -ENOMEM;

        spin_lock_irq(cdev->ccwlock);
        if (cdev->private->cmb) {
                kfree(cmbe);
                spin_unlock_irq(cdev->ccwlock);
                return -EBUSY;
        }

        cdev->private->cmb = cmbe;
        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;
}

static void
free_cmbe (struct ccw_device *cdev)
{
        spin_lock_irq(cdev->ccwlock);
        kfree(cdev->private->cmb);
        cdev->private->cmb = NULL;
        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;

        if (!cdev->private->cmb)
                return -EINVAL;
        mba = mme ? (unsigned long) cmbe_align(cdev->private->cmb) : 0;

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


u64
read_cmbe (struct ccw_device *cdev, int index)
{
        /* yes, we have to put it on the stack
         * because the cmb must only be accessed
         * atomically, e.g. with mvc */
        struct cmbe cmb;
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(cdev->ccwlock, flags);
        if (!cdev->private->cmb) {
                spin_unlock_irqrestore(cdev->ccwlock, flags);
                return 0;
        }

        cmb = *cmbe_align(cdev->private->cmb);
        spin_unlock_irqrestore(cdev->ccwlock, flags);

        switch (index) {
        case cmb_ssch_rsch_count:
                return cmb.ssch_rsch_count;
        case cmb_sample_count:
                return cmb.sample_count;
        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:
                return 0;
        }
        return time_to_avg_nsec(val, cmb.sample_count);
}

static int
readall_cmbe (struct ccw_device *cdev, struct cmbdata *data)
{
        /* yes, we have to put it on the stack
         * because the cmb must only be accessed
         * atomically, e.g. with mvc */
        struct cmbe cmb;
        unsigned long flags;
        u64 time;

        spin_lock_irqsave(cdev->ccwlock, flags);
        if (!cdev->private->cmb) {
                spin_unlock_irqrestore(cdev->ccwlock, flags);
                return -ENODEV;
        }

        cmb = *cmbe_align(cdev->private->cmb);
        time = get_clock() - cdev->private->cmb_start_time;
        spin_unlock_irqrestore(cdev->ccwlock, flags);

        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;

        /* 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);

        return 0;
}

static void
reset_cmbe(struct ccw_device *cdev)
{
        struct cmbe *cmb;
        spin_lock_irq(cdev->ccwlock);
        cmb = cmbe_align(cdev->private->cmb);
        if (cmb)
                memset (cmb, 0, sizeof (*cmb));
        cdev->private->cmb_start_time = get_clock();
        spin_unlock_irq(cdev->ccwlock);
}

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,
        .attr_group = &cmf_attr_group_ext,
};
\f

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;

        cdev = to_ccwdev(dev);
        interval  = get_clock() - cdev->private->cmb_start_time;
        count = cmf_read(cdev, cmb_sample_count);
        if (count)
                interval /= count;
        else
                interval = -1;
        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)
                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,
        0,
};

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,
        0,
};

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)
                        printk(KERN_INFO "disable_cmf failed (%d)\n", ret);
                break;
        case '1':
                ret = enable_cmf(cdev);
                if (ret && ret != -EBUSY)
                        printk(KERN_INFO "enable_cmf failed (%d)\n", ret);
                break;
        }

        return c;
}

DEVICE_ATTR(cmb_enable, 0644, cmb_enable_show, cmb_enable_store);

/* enable_cmf/disable_cmf: module interface for cmf (de)activation */
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;
}

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;
}

u64
cmf_read(struct ccw_device *cdev, int index)
{
        return cmbops->read(cdev, index);
}

int
cmf_readall(struct ccw_device *cdev, struct cmbdata *data)
{
        return cmbops->readall(cdev, data);
}

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

        /* We cannot really autoprobe this. If the user did not give a parameter,
           see if we are running on z990 or up, 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;
                if (cmb_area.num_channels > 4096 || cmb_area.num_channels < 1) {
                        printk(KERN_ERR "Basic channel measurement facility"
                                        " can only use 1 to 4096 devices\n"
                               KERN_ERR "when the cmf driver is built"
                                        " as a loadable module\n");
                        return 1;
                }
                break;
        case CMF_EXTENDED:
                format_string = "extended";
                cmbops = &cmbops_extended;
                break;
        default:
                printk(KERN_ERR "Invalid format %d for channel "
                        "measurement facility\n", format);
                return 1;
        }

        printk(KERN_INFO "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);