Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1305 insertions, 0 deletions

diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c
new file mode 100644
index 000000000..5584aa46c
--- /dev/null
+++ b/drivers/s390/cio/cmf.c
@@ -0,0 +1,1305 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Linux on zSeries Channel Measurement Facility support
+ *
+ * Copyright IBM Corp. 2000, 2006
+ *
+ * Authors: Arnd Bergmann <arndb@de.ibm.com>
+ *	    Cornelia Huck <cornelia.huck@de.ibm.com>
+ *
+ * original idea from Natarajan Krishnaswami <nkrishna@us.ibm.com>
+ */
+
+#define KMSG_COMPONENT "cio"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/memblock.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/export.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/timex.h>	/* get_tod_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 {
+	avg_utilization = -1,
+ /* basic and exended format: */
+	cmb_ssch_rsch_count = 0,
+	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, bint, 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
+ */
+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 *);
+/* 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 µsec */
+	ret = time_to_nsec(value);
+	do_div(ret, count);
+
+	return ret;
+}
+
+#define CMF_OFF 0
+#define CMF_ON	2
+
+/*
+ * 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)
+{
+	/* activate channel measurement */
+	asm volatile(
+		"	lgr	1,%[r1]\n"
+		"	lgr	2,%[mbo]\n"
+		"	schm\n"
+		:
+		: [r1] "d" ((unsigned long)onoff), [mbo] "d" (area)
+		: "1", "2");
+}
+
+static int set_schib(struct ccw_device *cdev, u32 mme, int mbfc,
+		     unsigned long address)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	int ret;
+
+	sch->config.mme = mme;
+	sch->config.mbfc = mbfc;
+	/* address can be either a block address or a block index */
+	if (mbfc)
+		sch->config.mba = address;
+	else
+		sch->config.mbi = address;
+
+	ret = cio_commit_config(sch);
+	if (!mme && ret == -ENODEV) {
+		/*
+		 * The task was to disable measurement block updates but
+		 * the subchannel is already gone. Report success.
+		 */
+		ret = 0;
+	}
+	return ret;
+}
+
+struct set_schib_struct {
+	u32 mme;
+	int mbfc;
+	unsigned long address;
+	wait_queue_head_t wait;
+	int ret;
+};
+
+#define CMF_PENDING 1
+#define SET_SCHIB_TIMEOUT (10 * HZ)
+
+static int set_schib_wait(struct ccw_device *cdev, u32 mme,
+			  int mbfc, unsigned long address)
+{
+	struct set_schib_struct set_data;
+	int ret = -ENODEV;
+
+	spin_lock_irq(cdev->ccwlock);
+	if (!cdev->private->cmb)
+		goto out;
+
+	ret = set_schib(cdev, mme, mbfc, address);
+	if (ret != -EBUSY)
+		goto out;
+
+	/* if the device is not online, don't even try again */
+	if (cdev->private->state != DEV_STATE_ONLINE)
+		goto out;
+
+	init_waitqueue_head(&set_data.wait);
+	set_data.mme = mme;
+	set_data.mbfc = mbfc;
+	set_data.address = address;
+	set_data.ret = CMF_PENDING;
+
+	cdev->private->state = DEV_STATE_CMFCHANGE;
+	cdev->private->cmb_wait = &set_data;
+	spin_unlock_irq(cdev->ccwlock);
+
+	ret = wait_event_interruptible_timeout(set_data.wait,
+					       set_data.ret != CMF_PENDING,
+					       SET_SCHIB_TIMEOUT);
+	spin_lock_irq(cdev->ccwlock);
+	if (ret <= 0) {
+		if (set_data.ret == CMF_PENDING) {
+			set_data.ret = (ret == 0) ? -ETIME : ret;
+			if (cdev->private->state == DEV_STATE_CMFCHANGE)
+				cdev->private->state = DEV_STATE_ONLINE;
+		}
+	}
+	cdev->private->cmb_wait = NULL;
+	ret = set_data.ret;
+out:
+	spin_unlock_irq(cdev->ccwlock);
+	return ret;
+}
+
+void retry_set_schib(struct ccw_device *cdev)
+{
+	struct set_schib_struct *set_data = cdev->private->cmb_wait;
+
+	if (!set_data)
+		return;
+
+	set_data->ret = set_schib(cdev, set_data->mme, set_data->mbfc,
+				  set_data->address);
+	wake_up(&set_data->wait);
+}
+
+static int cmf_copy_block(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	struct cmb_data *cmb_data;
+	void *hw_block;
+
+	if (cio_update_schib(sch))
+		return -ENODEV;
+
+	if (scsw_fctl(&sch->schib.scsw) & SCSW_FCTL_START_FUNC) {
+		/* Don't copy if a start function is in progress. */
+		if ((!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_SUSPENDED)) &&
+		    (scsw_actl(&sch->schib.scsw) &
+		     (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT)) &&
+		    (!(scsw_stctl(&sch->schib.scsw) & SCSW_STCTL_SEC_STATUS)))
+			return -EBUSY;
+	}
+	cmb_data = cdev->private->cmb;
+	hw_block = cmb_data->hw_block;
+	memcpy(cmb_data->last_block, hw_block, cmb_data->size);
+	cmb_data->last_update = get_tod_clock();
+	return 0;
+}
+
+struct copy_block_struct {
+	wait_queue_head_t wait;
+	int ret;
+};
+
+static int cmf_cmb_copy_wait(struct ccw_device *cdev)
+{
+	struct copy_block_struct copy_block;
+	int ret = -ENODEV;
+
+	spin_lock_irq(cdev->ccwlock);
+	if (!cdev->private->cmb)
+		goto out;
+
+	ret = cmf_copy_block(cdev);
+	if (ret != -EBUSY)
+		goto out;
+
+	if (cdev->private->state != DEV_STATE_ONLINE)
+		goto out;
+
+	init_waitqueue_head(&copy_block.wait);
+	copy_block.ret = CMF_PENDING;
+
+	cdev->private->state = DEV_STATE_CMFUPDATE;
+	cdev->private->cmb_wait = &copy_block;
+	spin_unlock_irq(cdev->ccwlock);
+
+	ret = wait_event_interruptible(copy_block.wait,
+				       copy_block.ret != CMF_PENDING);
+	spin_lock_irq(cdev->ccwlock);
+	if (ret) {
+		if (copy_block.ret == CMF_PENDING) {
+			copy_block.ret = -ERESTARTSYS;
+			if (cdev->private->state == DEV_STATE_CMFUPDATE)
+				cdev->private->state = DEV_STATE_ONLINE;
+		}
+	}
+	cdev->private->cmb_wait = NULL;
+	ret = copy_block.ret;
+out:
+	spin_unlock_irq(cdev->ccwlock);
+	return ret;
+}
+
+void cmf_retry_copy_block(struct ccw_device *cdev)
+{
+	struct copy_block_struct *copy_block = cdev->private->cmb_wait;
+
+	if (!copy_block)
+		return;
+
+	copy_block->ret = cmf_copy_block(cdev);
+	wake_up(&copy_block->wait);
+}
+
+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(cmb_data->hw_block, 0, cmb_data->size);
+		cmb_data->last_update = 0;
+	}
+	cdev->private->cmb_start_time = get_tod_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
+ */
+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 reasonable 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.
+ */
+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 */
+			ret = -ENOMEM;
+			goto out;
+		} else {
+			/* everything ok */
+			memset(mem, 0, size);
+			cmb_area.mem = mem;
+			cmf_activate(cmb_area.mem, CMF_ON);
+		}
+	}
+
+	/* 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;
+	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, CMF_OFF);
+		free_pages((unsigned long)cmb_area.mem, get_order(size));
+		cmb_area.mem = NULL;
+	}
+	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);
+}
+
+/* calculate utilization in 0.1 percent units */
+static u64 __cmb_utilization(u64 device_connect_time, u64 function_pending_time,
+			     u64 device_disconnect_time, u64 start_time)
+{
+	u64 utilization, elapsed_time;
+
+	utilization = time_to_nsec(device_connect_time +
+				   function_pending_time +
+				   device_disconnect_time);
+
+	elapsed_time = get_tod_clock() - start_time;
+	elapsed_time = tod_to_ns(elapsed_time);
+	elapsed_time /= 1000;
+
+	return elapsed_time ? (utilization / elapsed_time) : 0;
+}
+
+static u64 read_cmb(struct ccw_device *cdev, int index)
+{
+	struct cmb_data *cmb_data;
+	unsigned long flags;
+	struct cmb *cmb;
+	u64 ret = 0;
+	u32 val;
+
+	spin_lock_irqsave(cdev->ccwlock, flags);
+	cmb_data = cdev->private->cmb;
+	if (!cmb_data)
+		goto out;
+
+	cmb = cmb_data->hw_block;
+	switch (index) {
+	case avg_utilization:
+		ret = __cmb_utilization(cmb->device_connect_time,
+					cmb->function_pending_time,
+					cmb->device_disconnect_time,
+					cdev->private->cmb_start_time);
+		goto out;
+	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:
+		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);
+
+	data->elapsed_time = tod_to_ns(time);
+
+	/* 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 int cmf_enabled(struct ccw_device *cdev)
+{
+	int enabled;
+
+	spin_lock_irq(cdev->ccwlock);
+	enabled = !!cdev->private->cmb;
+	spin_unlock_irq(cdev->ccwlock);
+
+	return enabled;
+}
+
+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,
+};
+
+/* ******** 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.
+ */
+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];
+} __packed __aligned(64);
+
+static struct kmem_cache *cmbe_cache;
+
+static int alloc_cmbe(struct ccw_device *cdev)
+{
+	struct cmb_data *cmb_data;
+	struct cmbe *cmbe;
+	int ret = -ENOMEM;
+
+	cmbe = kmem_cache_zalloc(cmbe_cache, GFP_KERNEL);
+	if (!cmbe)
+		return ret;
+
+	cmb_data = kzalloc(sizeof(*cmb_data), GFP_KERNEL);
+	if (!cmb_data)
+		goto out_free;
+
+	cmb_data->last_block = kzalloc(sizeof(struct cmbe), GFP_KERNEL);
+	if (!cmb_data->last_block)
+		goto out_free;
+
+	cmb_data->size = sizeof(*cmbe);
+	cmb_data->hw_block = cmbe;
+
+	spin_lock(&cmb_area.lock);
+	spin_lock_irq(cdev->ccwlock);
+	if (cdev->private->cmb)
+		goto out_unlock;
+
+	cdev->private->cmb = cmb_data;
+
+	/* activate global measurement if this is the first channel */
+	if (list_empty(&cmb_area.list))
+		cmf_activate(NULL, CMF_ON);
+	list_add_tail(&cdev->private->cmb_list, &cmb_area.list);
+
+	spin_unlock_irq(cdev->ccwlock);
+	spin_unlock(&cmb_area.lock);
+	return 0;
+
+out_unlock:
+	spin_unlock_irq(cdev->ccwlock);
+	spin_unlock(&cmb_area.lock);
+	ret = -EBUSY;
+out_free:
+	if (cmb_data)
+		kfree(cmb_data->last_block);
+	kfree(cmb_data);
+	kmem_cache_free(cmbe_cache, cmbe);
+
+	return ret;
+}
+
+static void free_cmbe(struct ccw_device *cdev)
+{
+	struct cmb_data *cmb_data;
+
+	spin_lock(&cmb_area.lock);
+	spin_lock_irq(cdev->ccwlock);
+	cmb_data = cdev->private->cmb;
+	cdev->private->cmb = NULL;
+	if (cmb_data) {
+		kfree(cmb_data->last_block);
+		kmem_cache_free(cmbe_cache, cmb_data->hw_block);
+	}
+	kfree(cmb_data);
+
+	/* deactivate global measurement if this is the last channel */
+	list_del_init(&cdev->private->cmb_list);
+	if (list_empty(&cmb_area.list))
+		cmf_activate(NULL, CMF_OFF);
+	spin_unlock_irq(cdev->ccwlock);
+	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) 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 cmb_data *cmb_data;
+	unsigned long flags;
+	struct cmbe *cmb;
+	u64 ret = 0;
+	u32 val;
+
+	spin_lock_irqsave(cdev->ccwlock, flags);
+	cmb_data = cdev->private->cmb;
+	if (!cmb_data)
+		goto out;
+
+	cmb = cmb_data->hw_block;
+	switch (index) {
+	case avg_utilization:
+		ret = __cmb_utilization(cmb->device_connect_time,
+					cmb->function_pending_time,
+					cmb->device_disconnect_time,
+					cdev->private->cmb_start_time);
+		goto out;
+	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:
+		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);
+
+	data->elapsed_time = tod_to_ns(time);
+
+	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 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,
+};
+
+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 = to_ccwdev(dev);
+	unsigned long count;
+	long interval;
+
+	count = cmf_read(cdev, cmb_sample_count);
+	spin_lock_irq(cdev->ccwlock);
+	if (count) {
+		interval = get_tod_clock() - cdev->private->cmb_start_time;
+		interval = tod_to_ns(interval);
+		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)
+{
+	unsigned long u = cmf_read(to_ccwdev(dev), avg_utilization);
+
+	return sprintf(buf, "%02lu.%01lu%%\n", u / 10, u % 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)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+
+	return sprintf(buf, "%d\n", cmf_enabled(cdev));
+}
+
+static ssize_t cmb_enable_store(struct device *dev,
+				struct device_attribute *attr, const char *buf,
+				size_t c)
+{
+	struct ccw_device *cdev = to_ccwdev(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 16, &val);
+	if (ret)
+		return ret;
+
+	switch (val) {
+	case 0:
+		ret = disable_cmf(cdev);
+		break;
+	case 1:
+		ret = enable_cmf(cdev);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret ? ret : c;
+}
+DEVICE_ATTR_RW(cmb_enable);
+
+/**
+ * enable_cmf() - switch on the channel measurement for a specific device
+ *  @cdev:	The ccw device to be enabled
+ *
+ *  Enable channel measurements for @cdev. If this is called on a device
+ *  for which channel measurement is already enabled a reset of the
+ *  measurement data is triggered.
+ *  Returns: %0 for success or a negative error value.
+ *  Context:
+ *    non-atomic
+ */
+int enable_cmf(struct ccw_device *cdev)
+{
+	int ret = 0;
+
+	device_lock(&cdev->dev);
+	if (cmf_enabled(cdev)) {
+		cmbops->reset(cdev);
+		goto out_unlock;
+	}
+	get_device(&cdev->dev);
+	ret = cmbops->alloc(cdev);
+	if (ret)
+		goto out;
+	cmbops->reset(cdev);
+	ret = sysfs_create_group(&cdev->dev.kobj, cmbops->attr_group);
+	if (ret) {
+		cmbops->free(cdev);
+		goto out;
+	}
+	ret = cmbops->set(cdev, 2);
+	if (ret) {
+		sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
+		cmbops->free(cdev);
+	}
+out:
+	if (ret)
+		put_device(&cdev->dev);
+out_unlock:
+	device_unlock(&cdev->dev);
+	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, device_lock() held.
+ */
+int __disable_cmf(struct ccw_device *cdev)
+{
+	int ret;
+
+	ret = cmbops->set(cdev, 0);
+	if (ret)
+		return ret;
+
+	sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
+	cmbops->free(cdev);
+	put_device(&cdev->dev);
+
+	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;
+
+	device_lock(&cdev->dev);
+	ret = __disable_cmf(cdev);
+	device_unlock(&cdev->dev);
+
+	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);
+}
+
+/**
+ * cmf_reactivate() - reactivate measurement block updates
+ *
+ * Use this during resume from hibernate.
+ */
+void cmf_reactivate(void)
+{
+	spin_lock(&cmb_area.lock);
+	if (!list_empty(&cmb_area.list))
+		cmf_activate(cmb_area.mem, CMF_ON);
+	spin_unlock(&cmb_area.lock);
+}
+
+static int __init init_cmbe(void)
+{
+	cmbe_cache = kmem_cache_create("cmbe_cache", sizeof(struct cmbe),
+				       __alignof__(struct cmbe), 0, NULL);
+
+	return cmbe_cache ? 0 : -ENOMEM;
+}
+
+static int __init init_cmf(void)
+{
+	char *format_string;
+	char *detect_string;
+	int ret;
+
+	/*
+	 * 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_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;
+
+		ret = init_cmbe();
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EINVAL;
+	}
+	pr_info("Channel measurement facility initialized using format "
+		"%s (mode %s)\n", format_string, detect_string);
+	return 0;
+}
+device_initcall(init_cmf);
+
+EXPORT_SYMBOL_GPL(enable_cmf);
+EXPORT_SYMBOL_GPL(disable_cmf);
+EXPORT_SYMBOL_GPL(cmf_read);
+EXPORT_SYMBOL_GPL(cmf_readall);