cmf.c

linux 内核源代码

		 */
		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
 */
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.
 */
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.
 */
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);