On Thu, Oct 19, 2017 at 06:15:44PM +0100, Suzuki K Poulose wrote:
> Now that we can dynamically switch between contiguous memory and
> SG table depending on the trace buffer size, provide the support
> for selecting an appropriate buffer size.
>
> Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
> ---
> .../ABI/testing/sysfs-bus-coresight-devices-tmc | 8 ++++++
> drivers/hwtracing/coresight/coresight-tmc.c | 32
> ++++++++++++++++++++++
> 2 files changed, 40 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> index 4fe677ed1305..3675c380caf8 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
> @@ -83,3 +83,11 @@ KernelVersion: 4.7
> Contact: Mathieu Poirier <mathieu.poir...@linaro.org>
> Description: (R) Indicates the capabilities of the Coresight TMC.
> The value is read directly from the DEVID register, 0xFC8,
> +
> +What: /sys/bus/coresight/devices/<memory_map>.tmc/buffer-size
> +Date: September 2017
> +KernelVersion: 4.15
More like 4.16 now.
> +Contact: Mathieu Poirier <mathieu.poir...@linaro.org>
> +Description: (RW) Size of the trace buffer for TMC-ETR when used in SYSFS
> + mode. Writable only for TMC-ETR configurations. The value
> + should be aligned to the kernel pagesize.
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.c
> b/drivers/hwtracing/coresight/coresight-tmc.c
> index c7201e40d737..2349b1805694 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
> @@ -283,8 +283,40 @@ static ssize_t trigger_cntr_store(struct device *dev,
> }
> static DEVICE_ATTR_RW(trigger_cntr);
>
> +static ssize_t buffer_size_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> + return sprintf(buf, "%#x\n", drvdata->size);
> +}
> +
> +static ssize_t buffer_size_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
Indentation (I know trigger_cntr_store() is wrong).
> +{
> + int ret;
> + unsigned long val;
> + struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> + if (drvdata->config_type != TMC_CONFIG_TYPE_ETR)
> + return -EPERM;
I think -EINVAL would be more appropriate but definitely not a big deal.
> +
> + ret = kstrtoul(buf, 0, &val);
> + if (ret)
> + return ret;
> + /* The buffer size should be page aligned */
> + if (val & (PAGE_SIZE - 1))
> + return -EINVAL;
> + drvdata->size = val;
> + return size;
> +}
> +
> +static DEVICE_ATTR_RW(buffer_size);
> +
> static struct attribute *coresight_tmc_attrs[] = {
> &dev_attr_trigger_cntr.attr,
> + &dev_attr_buffer_size.attr,
> NULL,
> };
>
> --
> 2.13.6
>
