Re: [PATCH v3 06/11] coresight-tpdm: Add node to set dsb programming mode

On 23/03/2023 06:04, Tao Zhang wrote:

Add node to set and show programming mode for TPDM DSB subunit. Once the DSB programming mode is set, it will be written to the register DSB_CR. Bit[10:9] of the DSB_CR register is used to set the DSB test mode.

Signed-off-by: Tao Zhang quic_taozha@quicinc.com

.../ABI/testing/sysfs-bus-coresight-devices-tpdm | 10 ++++ drivers/hwtracing/coresight/coresight-tpdm.c | 62 ++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tpdm.h | 13 +++++ 3 files changed, 85 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm index 27ce681..f13e282 100644 --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm @@ -35,3 +35,13 @@ Description: Accepts only one of the 2 values - 0 or 1. 0 : Set the DSB trigger type to false 1 : Set the DSB trigger type to true

+What: /sys/bus/coresight/devices/<tpdm-name>/dsb_mode +Date: March 2023 +KernelVersion 6.3 +Contact: Jinlong Mao (QUIC) quic_jinlmao@quicinc.com, Tao Zhang (QUIC) quic_taozha@quicinc.com +Description:

• (Write) Set the mode of DSB tpdm. Read the mode of DSB
  

• tpdm.
  

• Accepts the value needs to be greater than 0.
  

Please could you document the values ?

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c index e28cf10..8cd822f 100644 --- a/drivers/hwtracing/coresight/coresight-tpdm.c +++ b/drivers/hwtracing/coresight/coresight-tpdm.c @@ -4,6 +4,7 @@ */ #include <linux/amba/bus.h> +#include <linux/bitfield.h> #include <linux/bitmap.h> #include <linux/coresight.h> #include <linux/coresight-pmu.h> @@ -51,6 +52,32 @@ static int tpdm_init_datasets(struct tpdm_drvdata *drvdata) return 0; } +static void set_dsb_cycacc_mode(struct tpdm_drvdata *drvdata, u32 *val) +{

• u32 mode;
• mode = TPDM_DSB_MODE_CYCACC(drvdata->dsb->mode);
• *val &= ~TPDM_DSB_TEST_MODE;
• *val |= FIELD_PREP(TPDM_DSB_TEST_MODE, mode);

+}

+static void set_dsb_hpsel_mode(struct tpdm_drvdata *drvdata, u32 *val) +{

• u32 mode;
• mode = TPDM_DSB_MODE_HPBYTESEL(drvdata->dsb->mode);
• *val &= ~TPDM_DSB_HPSEL;
• *val |= FIELD_PREP(TPDM_DSB_HPSEL, mode);

+}

+static void set_dsb_perf_mode(struct tpdm_drvdata *drvdata, u32 *val) +{

• if (drvdata->dsb->mode & TPDM_DSB_MODE_PERF)

• *val |= TPDM_DSB_CR_MODE;
  

• else

• *val &= ~TPDM_DSB_CR_MODE;
  

+}

• static void set_trigger_type(struct tpdm_drvdata *drvdata, u32 *val) { if (drvdata->dsb->trig_type)

@@ -72,6 +99,12 @@ static void tpdm_enable_dsb(struct tpdm_drvdata *drvdata) writel_relaxed(val, drvdata->base + TPDM_DSB_TIER); val = readl_relaxed(drvdata->base + TPDM_DSB_CR);

• /* Set the cycle accurate mode */
• set_dsb_cycacc_mode(drvdata, &val);
• /* Set the byte lane for high-performance mode */
• set_dsb_hpsel_mode(drvdata, &val);
• /* Set the performance mode */
• set_dsb_perf_mode(drvdata, &val); /* Set trigger type */ set_trigger_type(drvdata, &val); /* Set the enable bit of DSB control register to 1 */

@@ -250,6 +283,34 @@ static struct attribute_group tpdm_attr_grp = { .attrs = tpdm_attrs, }; +static ssize_t dsb_mode_show(struct device *dev,

• 		  struct device_attribute *attr,
  

• 		  char *buf)
  

+{

• struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
• return sysfs_emit(buf, "%lx\n",

• 	 (unsigned long)drvdata->dsb->mode);
  

+}

+static ssize_t dsb_mode_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;
• if ((kstrtoul(buf, 0, &val)) || val < 0)

• return -EINVAL;
  

• spin_lock(&drvdata->spinlock);
• drvdata->dsb->mode = val & TPDM_MODE_ALL;
• spin_unlock(&drvdata->spinlock);
• return size;

+} +static DEVICE_ATTR_RW(dsb_mode);

• static ssize_t dsb_trig_type_show(struct device *dev, struct device_attribute *attr, char *buf)

@@ -321,6 +382,7 @@ static ssize_t dsb_trig_ts_store(struct device *dev, static DEVICE_ATTR_RW(dsb_trig_ts); static struct attribute *tpdm_dsb_attrs[] = {

• &dev_attr_dsb_mode.attr, &dev_attr_dsb_trig_ts.attr, &dev_attr_dsb_trig_type.attr, NULL,

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h index 68f33bd..8fee562 100644 --- a/drivers/hwtracing/coresight/coresight-tpdm.h +++ b/drivers/hwtracing/coresight/coresight-tpdm.h @@ -15,11 +15,22 @@ /* Enable bit for DSB subunit */ #define TPDM_DSB_CR_ENA BIT(0) +/* Enable bit for DSB subunit perfmance mode */ +#define TPDM_DSB_CR_MODE BIT(1) /* Enable bit for DSB subunit trigger type */ #define TPDM_DSB_CR_TRIG_TYPE BIT(12)

• /* Enable bit for DSB subunit trigger timestamp */ #define TPDM_DSB_TIER_XTRIG_TSENAB BIT(1)

+/* DSB programming modes */ +#define TPDM_DSB_MODE_CYCACC(val) (val & GENMASK(2, 0))

What do the values for the CYCACC mode mean ?

+#define TPDM_DSB_MODE_PERF BIT(3) +#define TPDM_DSB_MODE_HPBYTESEL(val) (val & GENMASK(8, 4)) +#define TPDM_MODE_ALL (0xFFFFFFF) +#define TPDM_DSB_TEST_MODE GENMASK(11, 9) +#define TPDM_DSB_HPSEL GENMASK(6, 2)

Again what do the values mean ? Even if the kernel doesn't use them it would be good to document it.

Suzuki

• /* TPDM integration test registers */ #define TPDM_ITATBCNTRL (0xEF0) #define TPDM_ITCNTRL (0xF00)

@@ -48,10 +59,12 @@ /**

• struct dsb_dataset - specifics associated to dsb dataset

• • @mode: DSB programming mode
  • @trig_ts: Enable/Disable trigger timestamp.
  • @trig_type: Enable/Disable trigger type.
  */ struct dsb_dataset {
• u32 mode; bool trig_ts; bool trig_type; };