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| author | Alexander Shishkin <alexander.shishkin@linux.intel.com> | 2016-05-03 19:33:37 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-05-03 23:59:30 +0200 |
| commit | 8e996a2874bbbed30e8dfe881453825fc6b7654e (patch) | |
| tree | 3dd50be8cc4462eba2b1a87dc682258cfd986043 | |
| parent | coresight: etm4x: modify q_support type (diff) | |
| download | linux-8e996a2874bbbed30e8dfe881453825fc6b7654e.tar.xz linux-8e996a2874bbbed30e8dfe881453825fc6b7654e.zip | |
stm class: Support devices that override software assigned masters
Some STM devices adjust software assigned master numbers depending on
the trace source and its runtime state and whatnot. This patch adds
a sysfs attribute to inform the trace-side software that master numbers
assigned to software sources will not match those in the STP stream,
so that, for example, master/channel allocation policy can be adjusted
accordingly.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-stm | 10 | ||||
| -rw-r--r-- | drivers/hwtracing/stm/core.c | 15 | ||||
| -rw-r--r-- | include/linux/stm.h | 3 |
3 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-stm b/Documentation/ABI/testing/sysfs-class-stm index c9aa4f3fc9a7..77ed3da0f68e 100644 --- a/Documentation/ABI/testing/sysfs-class-stm +++ b/Documentation/ABI/testing/sysfs-class-stm @@ -12,3 +12,13 @@ KernelVersion: 4.3 Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com> Description: Shows the number of channels per master on this STM device. + +What: /sys/class/stm/<stm>/hw_override +Date: March 2016 +KernelVersion: 4.7 +Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com> +Description: + Reads as 0 if master numbers in the STP stream produced by + this stm device will match the master numbers assigned by + the software or 1 if the stm hardware overrides software + assigned masters. diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index 2591442e2c5b..ff31108b066f 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -67,9 +67,24 @@ static ssize_t channels_show(struct device *dev, static DEVICE_ATTR_RO(channels); +static ssize_t hw_override_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct stm_device *stm = to_stm_device(dev); + int ret; + + ret = sprintf(buf, "%u\n", stm->data->hw_override); + + return ret; +} + +static DEVICE_ATTR_RO(hw_override); + static struct attribute *stm_attrs[] = { &dev_attr_masters.attr, &dev_attr_channels.attr, + &dev_attr_hw_override.attr, NULL, }; diff --git a/include/linux/stm.h b/include/linux/stm.h index 1a79ed8e43da..8369d8a8cabd 100644 --- a/include/linux/stm.h +++ b/include/linux/stm.h @@ -50,6 +50,8 @@ struct stm_device; * @sw_end: last STP master available to software * @sw_nchannels: number of STP channels per master * @sw_mmiosz: size of one channel's IO space, for mmap, optional + * @hw_override: masters in the STP stream will not match the ones + * assigned by software, but are up to the STM hardware * @packet: callback that sends an STP packet * @mmio_addr: mmap callback, optional * @link: called when a new stm_source gets linked to us, optional @@ -85,6 +87,7 @@ struct stm_data { unsigned int sw_end; unsigned int sw_nchannels; unsigned int sw_mmiosz; + unsigned int hw_override; ssize_t (*packet)(struct stm_data *, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, |