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Commit 6cac7866 authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Greg Kroah-Hartman
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intel_th: msu: Add a sysfs attribute to trigger window switch 



Now that we have the means to trigger a window switch for the MSU trace
store, add a sysfs file to allow triggering it from userspace.

Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4840572d

Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc

+8 −0
Original line number Diff line number Diff line
@@ -30,4 +30,12 @@ Description: (RW) Configure MSC buffer size for "single" or "multi" modes. 
		there are no active users and tracing is not enabled) and then

		allocates a new one.



What:		/sys/bus/intel_th/devices/<intel_th_id>-msc<msc-id>/win_switch

Date:		May 2019

KernelVersion:	5.2

Contact:	Alexander Shishkin <alexander.shishkin@linux.intel.com>

Description:	(RW) Trigger window switch for the MSC's buffer, in

		multi-window mode. In "multi" mode, accepts writes of "1", thereby

		triggering a window switch for the buffer. Returns an error in any

		other operating mode or attempts to write something other than "1".

drivers/hwtracing/intel_th/msu.c

+28 −0
Original line number Diff line number Diff line
@@ -1572,10 +1572,38 @@ nr_pages_store(struct device *dev, struct device_attribute *attr, 


static DEVICE_ATTR_RW(nr_pages);



static ssize_t

win_switch_store(struct device *dev, struct device_attribute *attr,

		 const char *buf, size_t size)

{

	struct msc *msc = dev_get_drvdata(dev);

	unsigned long val;

	int ret;



	ret = kstrtoul(buf, 10, &val);

	if (ret)

		return ret;



	if (val != 1)

		return -EINVAL;



	mutex_lock(&msc->buf_mutex);

	if (msc->mode != MSC_MODE_MULTI)

		ret = -ENOTSUPP;

	else

		ret = intel_th_trace_switch(msc->thdev);

	mutex_unlock(&msc->buf_mutex);



	return ret ? ret : size;

}



static DEVICE_ATTR_WO(win_switch);



static struct attribute *msc_output_attrs[] = {

	&dev_attr_wrap.attr,

	&dev_attr_mode.attr,

	&dev_attr_nr_pages.attr,

	&dev_attr_win_switch.attr,

	NULL,

};