Subject: Re: [PATCH 5/8] coresight: etm4x: Improve usability of sysfs API.

From: Mathieu Poirier <[email-masked]>
Date: Tue, 27 Aug 2019 15:35:14 -0600

On Mon, Aug 19, 2019 at 09:57:17PM +0100, Mike Leach wrote:
> Some changes to make the sysfs programming more intuitive.
> 
> 1) Setting include / exclude on a range had to be done by setting
> the bit in 'mode' before setting the range. However, setting this
> bit also had the effect of altering the current range as well.
> 
> Changed to only set include / exclude setting of a range at the point of
> setting that range. Either use a 3rd input parameter as the include exclude
> value, or if not present use the current value of 'mode'. Do not change
> current range when 'mode' changes.
> 
> 2) Context ID and VM ID masks required 2 value inputs, even when the
> second value is ignored as insufficient CID / VMID comparators are
> implemented.
> Permit a single value to be used if that is sufficient to cover all
> implemented comparators.

Please split in two patches.  With that:

Reviewed-by: Mathieu Poirier <[email-masked]>

> 
> Signed-off-by: Mike Leach <[email-masked]>
> ---
>  .../coresight/coresight-etm4x-sysfs.c         | 24 +++++++++++++------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index 3bcc260c9e55..baac5b48b7ac 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -297,8 +297,6 @@ static ssize_t mode_store(struct device *dev,
>  
>  	spin_lock(&drvdata->spinlock);
>  	config->mode = val & ETMv4_MODE_ALL;
> -	etm4_set_mode_exclude(drvdata,
> -			      config->mode & ETM_MODE_EXCLUDE ? true : false);
>  
>  	if (drvdata->instrp0 == true) {
>  		/* start by clearing instruction P0 field */
> @@ -972,8 +970,12 @@ static ssize_t addr_range_store(struct device *dev,
>  	unsigned long val1, val2;
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>  	struct etmv4_config *config = &drvdata->config;
> +	int elements, exclude;
>  
> -	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> +	elements = sscanf(buf, "%lx %lx %x", &val1, &val2, &exclude);
> +
> +	/*  exclude is optional, but need at least two parameter */
> +	if (elements < 2)
>  		return -EINVAL;
>  	/* lower address comparator cannot have a higher address value */
>  	if (val1 > val2)
> @@ -1001,9 +1003,11 @@ static ssize_t addr_range_store(struct device *dev,
>  	/*
>  	 * Program include or exclude control bits for vinst or vdata
>  	 * whenever we change addr comparators to ETM_ADDR_TYPE_RANGE
> +	 * use supplied value, or default to bit set in 'mode'
>  	 */
> -	etm4_set_mode_exclude(drvdata,
> -			      config->mode & ETM_MODE_EXCLUDE ? true : false);
> +	if (elements != 3)
> +		exclude = config->mode & ETM_MODE_EXCLUDE;
> +	etm4_set_mode_exclude(drvdata, exclude ? true : false);
>  
>  	spin_unlock(&drvdata->spinlock);
>  	return size;
> @@ -1787,6 +1791,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
>  	unsigned long val1, val2, mask;
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>  	struct etmv4_config *config = &drvdata->config;
> +	int nr_inputs;
>  
>  	/*
>  	 * Don't use contextID tracing if coming from a PID namespace.  See
> @@ -1802,7 +1807,9 @@ static ssize_t ctxid_masks_store(struct device *dev,
>  	 */
>  	if (!drvdata->ctxid_size || !drvdata->numcidc)
>  		return -EINVAL;
> -	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> +	/* one mask if < 4 comparators, two for up to 8 */
> +	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
> +	if ((drvdata->numcidc > 4) && (nr_inputs != 2))
>  		return -EINVAL;
>  
>  	spin_lock(&drvdata->spinlock);
> @@ -1976,6 +1983,7 @@ static ssize_t vmid_masks_store(struct device *dev,
>  	unsigned long val1, val2, mask;
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>  	struct etmv4_config *config = &drvdata->config;
> +	int nr_inputs;
>  
>  	/*
>  	 * only implemented when vmid tracing is enabled, i.e. at least one
> @@ -1983,7 +1991,9 @@ static ssize_t vmid_masks_store(struct device *dev,
>  	 */
>  	if (!drvdata->vmid_size || !drvdata->numvmidc)
>  		return -EINVAL;
> -	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> +	/* one mask if < 4 comparators, two for up to 8 */
> +	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
> +	if ((drvdata->numvmidc > 4) && (nr_inputs != 2))
>  		return -EINVAL;
>  
>  	spin_lock(&drvdata->spinlock);
> -- 
> 2.17.1
> 

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