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Date:   Wed, 3 Nov 2021 13:43:00 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Tao Zhang <quic_taozha@quicinc.com>
Cc:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Mao Jinlong <quic_jinlmao@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>
Subject: Re: [PATCH 04/10] Coresight: Enable BC and GPR for TPDM driver
Message-ID: <20211103194300.GA383984@p14s>
References: <1634801936-15080-1-git-send-email-quic_taozha@quicinc.com>
 <1634801936-15080-5-git-send-email-quic_taozha@quicinc.com>
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In-Reply-To: <1634801936-15080-5-git-send-email-quic_taozha@quicinc.com>
Precedence: bulk

On Thu, Oct 21, 2021 at 03:38:50PM +0800, Tao Zhang wrote:
> Enable GPR and Basic Counts(BC) for TPDM. Add GPR interface and

But what is GPR?  What does it stand for?  Where is this documented?

> basic control sysFS interface for TPDM. The GPR interface has RW
> and RO fields for controlling external logic and mapping core
> signals to an APB accessible address in the TPDM address map.
> 
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
>  drivers/hwtracing/coresight/coresight-tpdm.c | 334 +++++++++++++++++++
>  1 file changed, 334 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 906776c859d6..c0a01979e42f 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -276,6 +276,93 @@ struct tpdm_drvdata {
>  
>  static void tpdm_init_default_data(struct tpdm_drvdata *drvdata);
>  
> +static void __tpdm_enable_gpr(struct tpdm_drvdata *drvdata)

There is no need for the double underscore at the beginning of the function
name, please remove.  The same goes for __tpdm_config_bc_msr() and
__tpdm_enable_bc().

> +{
> +	int i;
> +
> +	for (i = 0; i < TPDM_GPR_REGS_MAX; i++) {
> +		if (!test_bit(i, drvdata->gpr->gpr_dirty))
> +			continue;
> +		tpdm_writel(drvdata, drvdata->gpr->gp_regs[i], TPDM_GPR_CR(i));
> +	}
> +}
> +
> +static void __tpdm_config_bc_msr(struct tpdm_drvdata *drvdata)
> +{
> +	int i;
> +
> +	if (!drvdata->msr_support)

Shouldn't msr_support be part of bc_dataset?  And why do we have a function for
this when an if() condition would work just as well, as it is done in
bc_trig_type below?

> +		return;
> +
> +	for (i = 0; i < TPDM_BC_MAX_MSR; i++)
> +		tpdm_writel(drvdata, drvdata->bc->msr[i], TPDM_BC_MSR(i));
> +}
> +
> +static void __tpdm_enable_bc(struct tpdm_drvdata *drvdata)
> +{
> +	int i;
> +	uint32_t val;
> +
> +	if (drvdata->bc->sat_mode)
> +		tpdm_writel(drvdata, drvdata->bc->sat_mode,
> +			    TPDM_BC_SATROLL);
> +	else
> +		tpdm_writel(drvdata, 0x0, TPDM_BC_SATROLL);
> +
> +	if (drvdata->bc->enable_counters) {
> +		tpdm_writel(drvdata, 0xFFFFFFFF, TPDM_BC_CNTENCLR);
> +		tpdm_writel(drvdata, drvdata->bc->enable_counters,
> +			    TPDM_BC_CNTENSET);
> +	}
> +	if (drvdata->bc->clear_counters)
> +		tpdm_writel(drvdata, drvdata->bc->clear_counters,
> +			    TPDM_BC_CNTENCLR);
> +
> +	if (drvdata->bc->enable_irq) {
> +		tpdm_writel(drvdata, 0xFFFFFFFF, TPDM_BC_INTENCLR);
> +		tpdm_writel(drvdata, drvdata->bc->enable_irq,
> +			    TPDM_BC_INTENSET);
> +	}
> +	if (drvdata->bc->clear_irq)
> +		tpdm_writel(drvdata, drvdata->bc->clear_irq,
> +			    TPDM_BC_INTENCLR);
> +
> +	if (drvdata->bc_trig_type == TPDM_SUPPORT_TYPE_FULL) {
> +		for (i = 0; i < drvdata->bc_counters_avail; i++) {

Same here - shouldn't bc_trig_type and bc_counters_avail be part of bc_dataset?

> +			tpdm_writel(drvdata, drvdata->bc->trig_val_lo[i],
> +				    TPDM_BC_TRIG_LO(i));
> +			tpdm_writel(drvdata, drvdata->bc->trig_val_hi[i],
> +				    TPDM_BC_TRIG_HI(i));
> +		}
> +	} else if (drvdata->bc_trig_type == TPDM_SUPPORT_TYPE_PARTIAL) {
> +		tpdm_writel(drvdata, drvdata->bc->trig_val_lo[0],
> +			    TPDM_BC_TRIG_LO(0));
> +		tpdm_writel(drvdata, drvdata->bc->trig_val_hi[0],
> +			    TPDM_BC_TRIG_HI(0));
> +	}
> +
> +	if (drvdata->bc->enable_ganging)
> +		tpdm_writel(drvdata, drvdata->bc->enable_ganging, TPDM_BC_GANG);
> +
> +	for (i = 0; i < TPDM_BC_MAX_OVERFLOW; i++)
> +		tpdm_writel(drvdata, drvdata->bc->overflow_val[i],
> +			    TPDM_BC_OVERFLOW(i));
> +
> +	__tpdm_config_bc_msr(drvdata);
> +
> +	val = tpdm_readl(drvdata, TPDM_BC_CR);
> +	if (drvdata->bc->retrieval_mode == TPDM_MODE_APB)
> +		val = val | BIT(2);
> +	else
> +		val = val & ~BIT(2);
> +	tpdm_writel(drvdata, val, TPDM_BC_CR);
> +
> +	val = tpdm_readl(drvdata, TPDM_BC_CR);
> +	/* Set the enable bit */
> +	val = val | BIT(0);
> +	tpdm_writel(drvdata, val, TPDM_BC_CR);

As a whole, this function is very hard to read and understand due to the lack of
comments.

> +}
> +
>  static void __tpdm_enable(struct tpdm_drvdata *drvdata)
>  {
>  	TPDM_UNLOCK(drvdata);
> @@ -283,6 +370,12 @@ static void __tpdm_enable(struct tpdm_drvdata *drvdata)
>  	if (drvdata->clk_enable)
>  		tpdm_writel(drvdata, 0x1, TPDM_CLK_CTRL);
>  
> +	if (test_bit(TPDM_DS_GPR, drvdata->enable_ds))
> +		__tpdm_enable_gpr(drvdata);
> +
> +	if (test_bit(TPDM_DS_BC, drvdata->enable_ds))
> +		__tpdm_enable_bc(drvdata);
> +
>  	TPDM_LOCK(drvdata);
>  }
>  
> @@ -307,10 +400,22 @@ static int tpdm_enable(struct coresight_device *csdev,
>  	return 0;
>  }
>  
> +static void __tpdm_disable_bc(struct tpdm_drvdata *drvdata)
> +{
> +	uint32_t config;
> +
> +	config = tpdm_readl(drvdata, TPDM_BC_CR);
> +	config = config & ~BIT(0);
> +	tpdm_writel(drvdata, config, TPDM_BC_CR);
> +}
> +
>  static void __tpdm_disable(struct tpdm_drvdata *drvdata)
>  {
>  	TPDM_UNLOCK(drvdata);
>  
> +	if (test_bit(TPDM_DS_BC, drvdata->enable_ds))
> +		__tpdm_disable_bc(drvdata);
> +

Shouldn't GPRs be disabled as well?  If not why is it the case?  A comment
should be explaining what is going on.

>  	if (drvdata->clk_enable)
>  		tpdm_writel(drvdata, 0x0, TPDM_CLK_CTRL);
>  
> @@ -352,6 +457,234 @@ static const struct coresight_ops tpdm_cs_ops = {
>  	.source_ops	= &tpdm_source_ops,
>  };

Everything related to sysfs should be in a patch on its own.

>  
> +static ssize_t available_datasets_show(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)

Indentation problem here and for the rest of the patch.

> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	ssize_t size = 0;
> +
> +	if (test_bit(TPDM_DS_IMPLDEF, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s",
> +				  "IMPLDEF");
> +
> +	if (test_bit(TPDM_DS_DSB, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "DSB");
> +
> +	if (test_bit(TPDM_DS_CMB, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "CMB");
> +
> +	if (test_bit(TPDM_DS_TC, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "TC");
> +
> +	if (test_bit(TPDM_DS_BC, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "BC");
> +
> +	if (test_bit(TPDM_DS_GPR, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "GPR");
> +
> +	if (test_bit(TPDM_DS_MCMB, drvdata->datasets))
> +		size += scnprintf(buf + size, PAGE_SIZE - size, "%-8s", "MCMB");
> +
> +	size += scnprintf(buf + size, PAGE_SIZE - size, "\n");
> +	return size;
> +}
> +static DEVICE_ATTR_RO(available_datasets);
> +
> +static ssize_t enable_datasets_show(struct device *dev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	ssize_t size;
> +
> +	size = scnprintf(buf, PAGE_SIZE, "%*pb\n", TPDM_DATASETS,
> +			 drvdata->enable_ds);
> +
> +	if (PAGE_SIZE - size < 2)
> +		size = -EINVAL;

TPDM_DATASETS is set to 32 - is this realistic? 

> +	else
> +		size += scnprintf(buf + size, 2, "\n");

...and what is going on here?

> +	return size;
> +}
> +
> +static ssize_t enable_datasets_store(struct device *dev,
> +					  struct device_attribute *attr,
> +					  const char *buf,
> +					  size_t size)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	unsigned long val;
> +	int i;
> +
> +	if (kstrtoul(buf, 16, &val))
> +		return -EINVAL;
> +
> +	mutex_lock(&drvdata->lock);
> +	if (drvdata->enable) {
> +		mutex_unlock(&drvdata->lock);
> +		return -EPERM;
> +	}
> +
> +	for (i = 0; i < TPDM_DATASETS; i++) {
> +		if (test_bit(i, drvdata->datasets) && (val & BIT(i)))
> +			__set_bit(i, drvdata->enable_ds);
> +		else
> +			__clear_bit(i, drvdata->enable_ds);
> +	}
> +	mutex_unlock(&drvdata->lock);
> +	return size;
> +}
> +static DEVICE_ATTR_RW(enable_datasets);
> +
> +static ssize_t reset_store(struct device *dev,
> +					  struct device_attribute *attr,
> +					  const char *buf,
> +					  size_t size)
> +{
> +	int ret = 0;
> +	unsigned long val;
> +	struct mcmb_dataset *mcmb_temp = NULL;
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> +	ret = kstrtoul(buf, 10, &val);

The coresight subsystem normally uses the hexadecimal base.

> +	if (ret)
> +		return ret;

Shouldn't this be "if (!ret)" ? 

> +
> +	mutex_lock(&drvdata->lock);
> +	/* Reset all datasets to ZERO */
> +	if (drvdata->gpr != NULL)
> +		memset(drvdata->gpr, 0, sizeof(struct gpr_dataset));
> +
> +	if (drvdata->bc != NULL)
> +		memset(drvdata->bc, 0, sizeof(struct bc_dataset));
> +
> +	if (drvdata->tc != NULL)
> +		memset(drvdata->tc, 0, sizeof(struct tc_dataset));
> +
> +	if (drvdata->dsb != NULL)
> +		memset(drvdata->dsb, 0, sizeof(struct dsb_dataset));
> +
> +	if (drvdata->cmb != NULL) {
> +		if (drvdata->cmb->mcmb != NULL) {
> +			mcmb_temp = drvdata->cmb->mcmb;
> +			memset(drvdata->cmb->mcmb, 0,
> +				sizeof(struct mcmb_dataset));
> +			}
> +
> +		memset(drvdata->cmb, 0, sizeof(struct cmb_dataset));
> +		drvdata->cmb->mcmb = mcmb_temp;
> +	}
> +	/* Init the default data */
> +	tpdm_init_default_data(drvdata);
> +
> +	mutex_unlock(&drvdata->lock);
> +
> +	/* Disable tpdm if enabled */
> +	if (drvdata->enable)
> +		coresight_disable(drvdata->csdev);

Why is this done out of the lock?

> +
> +	return size;
> +}
> +static DEVICE_ATTR_WO(reset);
> +
> +static ssize_t integration_test_store(struct device *dev,
> +					  struct device_attribute *attr,
> +					  const char *buf,
> +					  size_t size)
> +{
> +	int i, ret = 0;
> +	unsigned long val;
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +
> +	ret = kstrtoul(buf, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val != 1 && val != 2)
> +		return -EINVAL;
> +
> +	if (!drvdata->enable)
> +		return -EINVAL;
> +
> +	if (val == 1)
> +		val = ATBCNTRL_VAL_64;
> +	else
> +		val = ATBCNTRL_VAL_32;
> +	TPDM_UNLOCK(drvdata);
> +	tpdm_writel(drvdata, 0x1, TPDM_ITCNTRL);
> +
> +	for (i = 1; i < 5; i++)
> +		tpdm_writel(drvdata, val, TPDM_ITATBCNTRL);
> +
> +	tpdm_writel(drvdata, 0, TPDM_ITCNTRL);
> +	TPDM_LOCK(drvdata);
> +	return size;
> +}
> +static DEVICE_ATTR_WO(integration_test);

Integration test interface should be conditional to a compile time option.  Have
a look at what was done for CTIs.

> +
> +static ssize_t gp_regs_show(struct device *dev,
> +				 struct device_attribute *attr,
> +				 char *buf)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	ssize_t size = 0;
> +	int i = 0;
> +
> +	if (!test_bit(TPDM_DS_GPR, drvdata->datasets))
> +		return -EPERM;

                return -EINVAL;

> +
> +	mutex_lock(&drvdata->lock);
> +	for (i = 0; i < TPDM_GPR_REGS_MAX; i++) {
> +		if (!test_bit(i, drvdata->gpr->gpr_dirty))
> +			continue;
> +		size += scnprintf(buf + size, PAGE_SIZE - size,
> +				  "Index: 0x%x Value: 0x%x\n", i,
> +				  drvdata->gpr->gp_regs[i]);

This should not be - the sysfs interface requires outputs of a single line.

> +	}
> +	mutex_unlock(&drvdata->lock);
> +	return size;
> +}
> +
> +static ssize_t gp_regs_store(struct device *dev,
> +				  struct device_attribute *attr,
> +				  const char *buf,
> +				  size_t size)
> +{
> +	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> +	unsigned long index, val;
> +
> +	if (sscanf(buf, "%lx %lx", &index, &val) != 2)
> +		return -EINVAL;
> +	if (!test_bit(TPDM_DS_GPR, drvdata->datasets) ||
> +	    index >= TPDM_GPR_REGS_MAX)
> +		return -EPERM;
> +
> +	mutex_lock(&drvdata->lock);
> +	drvdata->gpr->gp_regs[index] = val;
> +	__set_bit(index, drvdata->gpr->gpr_dirty);
> +	mutex_unlock(&drvdata->lock);
> +	return size;
> +}
> +static DEVICE_ATTR_RW(gp_regs);
> +
> +static struct attribute *tpdm_attrs[] = {
> +	&dev_attr_available_datasets.attr,
> +	&dev_attr_enable_datasets.attr,
> +	&dev_attr_reset.attr,
> +	&dev_attr_integration_test.attr,
> +	&dev_attr_gp_regs.attr,
> +	NULL,
> +};

All new sysfs interface need to be documented.  See here:

Documentation/ABI/testing/sysfs-bus-coresight-devices-xyz

More comments to come...

Thanks,
Mathieu

> +
> +static struct attribute_group tpdm_attr_grp = {
> +	.attrs = tpdm_attrs,
> +};
> +static const struct attribute_group *tpdm_attr_grps[] = {
> +	&tpdm_attr_grp,
> +	NULL,
> +};
> +
>  static int tpdm_datasets_alloc(struct tpdm_drvdata *drvdata)
>  {
>  	if (test_bit(TPDM_DS_GPR, drvdata->datasets)) {
> @@ -513,6 +846,7 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
>  	desc.ops = &tpdm_cs_ops;
>  	desc.pdata = adev->dev.platform_data;
>  	desc.dev = &adev->dev;
> +	desc.groups = tpdm_attr_grps;
>  	drvdata->csdev = coresight_register(&desc);
>  	if (IS_ERR(drvdata->csdev))
>  		return PTR_ERR(drvdata->csdev);
> -- 
> 2.17.1
>