Re: [PATCH v5 03/14] coresight: cti: Add sysfs access to program function regs

Suzuki Kuruppassery Poulose
2019-11-27T18:27:01Z

On 19/11/2019 23:19, Mike Leach wrote:
> Adds in sysfs programming support for the CTI function register sets.
> Allows direct manipulation of channel / trigger association registers.
>
> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
> .../hwtracing/coresight/coresight-cti-sysfs.c | 362 ++++++++++++++++++
> drivers/hwtracing/coresight/coresight-cti.c | 19 +
> drivers/hwtracing/coresight/coresight-cti.h | 5 +
> 3 files changed, 386 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> index 507f8eb487fe..02d3ee0c1278 100644
> --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> @@ -109,6 +109,362 @@ static struct attribute *coresight_cti_mgmt_attrs[] = {
> NULL,
> };
>
> +/* CTI low level programming registers */
> +
> +/*
> + * Show a simple 32 bit value if enabled and powered.
> + * If inaccessible & pcached_val not NULL then show cached value.
> + */

Also I am not sure if it makes sense to mention that the value is cached.

> +static ssize_t cti_reg32_show(struct device *dev, char *buf,
> + u32 *pcached_val, int reg_offset)
> +{
> + u32 val = 0;
+ char *state = "";

> + struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + struct cti_config *config = &drvdata->config;
> +
> + spin_lock(&drvdata->spinlock);
> + if ((reg_offset >= 0) && CTI_PWR_ENA(config)) {

minor nit: Personally I don't like the naming here. This could simply
be: cti_accessible(config) , may be defined as a static inline function
instead of a macro:

static inline bool cti_accessible(struct cti_drvdata *drvdata)
{
struct cti_config *cfg = &drvdata->config;

return cfg->hw_powered && cfg->hw_enabled;
}

> + CS_UNLOCK(drvdata->base);
> + val = readl_relaxed(drvdata->base + reg_offset);
> + if (pcached_val)
> + *pcached_val = val;
> + CS_LOCK(drvdata->base);
> + } else if (pcached_val) {
> + val = *pcached_val;

+ state = " (cached)";
> + }
> + spin_unlock(&drvdata->spinlock);
> + return scnprintf(buf, PAGE_SIZE, "%#x\n", val);
+ return scnprintf(buf, PAGE_SIZE, "%#x%s\n", val, state);

> +}
> +
> +/*
> + * Store a simple 32 bit value.
> + * If pcached_val not NULL, then copy to here too,
> + * if reg_offset >= 0 then write through if enabled.
> + */
> +static ssize_t cti_reg32_store(struct device *dev, const char *buf,
> + size_t size, u32 *pcached_val, int reg_offset)

> +static ssize_t appclear_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + unsigned long val;
> + struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
> + struct cti_config *config = &drvdata->config;
> +
> + if (kstrtoul(buf, 0, &val))
> + return -EINVAL;
> +
> + spin_lock(&drvdata->spinlock);
> +
> + /* a 1'b1 in appclr clears down the same bit in appset*/

nit: a 0b1 ?

> + config->ctiappset &= ~val;
> +
> + /* write through if enabled */
> + if (CTI_PWR_ENA(config))
> + cti_write_single_reg(drvdata, CTIAPPCLEAR, val);
> + spin_unlock(&drvdata->spinlock);
> + return size;
> +}
> +static DEVICE_ATTR_WO(appclear);
> +

Otherwise looks good to me.

Suzuki