Subject: Re: [PATCH 4/8] coresight: etm4x: Fix issues with start-stop logic.

From: Leo Yan <[email-masked]>
Date: Wed, 28 Aug 2019 11:17:50 +0800

Hi Mike,

On Mon, Aug 19, 2019 at 09:57:16PM +0100, Mike Leach wrote:
> Fixes the following issues when using the ETMv4 start-stop logic.
> 
> 1) Setting a start or a stop address should not automatically set the
> start-stop status to 'on'. The value set by the user in 'mode' must
> be respected or start instances could be missed.
> 2) Missing API for controlling TRCVIPCSSCTLR - start stop control by
> PE comparators.
> 3) Default ETM configuration sets a trace all range, and correctly sets
> the start-stop status bit. This was not being correctly reflected in
> the 'mode' parameter.
> 
> Signed-off-by: Mike Leach <[email-masked]>
> ---
>  .../coresight/coresight-etm4x-sysfs.c         | 39 +++++++++++++++++--
>  drivers/hwtracing/coresight/coresight-etm4x.c |  1 +
>  2 files changed, 36 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index 7eab5d7d0b62..3bcc260c9e55 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -217,6 +217,7 @@ static ssize_t reset_store(struct device *dev,
>  
>  	/* No start-stop filtering for ViewInst */
>  	config->vissctlr = 0x0;
> +	config->vipcssctlr = 0x0;
>  
>  	/* Disable seq events */
>  	for (i = 0; i < drvdata->nrseqstate-1; i++)
> @@ -1059,8 +1060,6 @@ static ssize_t addr_start_store(struct device *dev,
>  	config->addr_val[idx] = (u64)val;
>  	config->addr_type[idx] = ETM_ADDR_TYPE_START;
>  	config->vissctlr |= BIT(idx);
> -	/* SSSTATUS, bit[9] - turn on start/stop logic */
> -	config->vinst_ctrl |= BIT(9);
>  	spin_unlock(&drvdata->spinlock);
>  	return size;
>  }
> @@ -1116,8 +1115,6 @@ static ssize_t addr_stop_store(struct device *dev,
>  	config->addr_val[idx] = (u64)val;
>  	config->addr_type[idx] = ETM_ADDR_TYPE_STOP;
>  	config->vissctlr |= BIT(idx + 16);
> -	/* SSSTATUS, bit[9] - turn on start/stop logic */
> -	config->vinst_ctrl |= BIT(9);
>  	spin_unlock(&drvdata->spinlock);
>  	return size;
>  }
> @@ -1271,6 +1268,39 @@ static ssize_t addr_exlevel_s_ns_store(struct device *dev,
>  }
>  static DEVICE_ATTR_RW(addr_exlevel_s_ns);
>  
> +static ssize_t vinst_pe_cmp_start_stop_show(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)
> +{
> +	unsigned long val;
> +	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	struct etmv4_config *config = &drvdata->config;
> +
> +	if (!drvdata->nr_pe_cmp)
> +		return -EINVAL;
> +	val = config->vipcssctlr;
> +	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
> +}
> +static ssize_t vinst_pe_cmp_start_stop_store(struct device *dev,
> +					     struct device_attribute *attr,
> +					     const char *buf, size_t size)
> +{
> +	unsigned long val;
> +	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	struct etmv4_config *config = &drvdata->config;
> +
> +	if (kstrtoul(buf, 16, &val))
> +		return -EINVAL;
> +	if (!drvdata->nr_pe_cmp)
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->spinlock);
> +	config->vipcssctlr = val;
> +	spin_unlock(&drvdata->spinlock);

I don't find the code to set 'config->vipcssctlr' into hardware register
TRCVIPCSSCTLR.

And based on the register definition, here we also should clamp the
value for START/STOP?

Thanks,
Leo Yan

> +	return size;
> +}
> +static DEVICE_ATTR_RW(vinst_pe_cmp_start_stop);
> +
>  static ssize_t seq_idx_show(struct device *dev,
>  			    struct device_attribute *attr,
>  			    char *buf)
> @@ -2077,6 +2107,7 @@ static struct attribute *coresight_etmv4_attrs[] = {
>  	&dev_attr_addr_ctxtype.attr,
>  	&dev_attr_addr_context.attr,
>  	&dev_attr_addr_exlevel_s_ns.attr,
> +	&dev_attr_vinst_pe_cmp_start_stop.attr,
>  	&dev_attr_seq_idx.attr,
>  	&dev_attr_seq_state.attr,
>  	&dev_attr_seq_event.attr,
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
> index 52b8876de157..d8b078d0cc7f 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -868,6 +868,7 @@ static void etm4_set_default_filter(struct etmv4_config *config)
>  	 * in the started state
>  	 */
>  	config->vinst_ctrl |= BIT(9);
> +	config->mode |= ETM_MODE_VIEWINST_STARTSTOP;
>  
>  	/* No start-stop filtering for ViewInst */
>  	config->vissctlr = 0x0;
> -- 
> 2.17.1
> 
> _______________________________________________
> CoreSight mailing list
> [email-masked]
> https://lists.linaro.org/mailman/listinfo/coresight

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