Re: [PATCH v4 06/11] coresight-tpdm: Add node to set dsb programming mode

[Tao Zhang <quic_taozha@quicinc.com>]

On 6/2/2023 4:25 PM, Suzuki K Poulose wrote:
> On 02/06/2023 03:58, Tao Zhang wrote:
>>
>> On 6/1/2023 5:23 PM, Suzuki K Poulose wrote:
>>> On 27/04/2023 10:00, 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.
>>>>
>>>> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
>>>> ---
>>>>   .../ABI/testing/sysfs-bus-coresight-devices-tpdm   | 15 ++++++
>>>>   drivers/hwtracing/coresight/coresight-tpdm.c       | 62 
>>>> ++++++++++++++++++++++
>>>>   drivers/hwtracing/coresight/coresight-tpdm.h       | 16 ++++++
>>>>   3 files changed, 93 insertions(+)
>>>>
>>>> diff --git 
>>>> a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm 
>>>> b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>> index 77e67f2..348e167 100644
>>>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
>>>> @@ -45,3 +45,18 @@ 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. What data
>>>> +        bits do is listed below.
>>>> +        Bit[0:1] : Test mode control bit for choosing the inputs.
>>>> +        Bit[3] : Set to 0 for low performance mode.
>>>> +                 Set to 1 for high performance mode.
>>>> +        Bit[4:8] : Select byte lane for high performance mode.
>>>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
>>>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>>>> index 14f4352..1bacaa5 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>
>>>> @@ -43,6 +44,32 @@ static void tpdm_reset_datasets(struct 
>>>> tpdm_drvdata *drvdata)
>>>>       }
>>>>   }
>>>>   +static void set_dsb_test_mode(struct tpdm_drvdata *drvdata, u32 
>>>> *val)
>>>> +{
>>>> +    u32 mode;
>>>> +
>>>> +    mode = TPDM_DSB_MODE_TEST(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)
>>>> @@ -64,6 +91,12 @@ 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 test accurate mode */
>>>> +    set_dsb_test_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 */
>>>> @@ -252,6 +285,34 @@ 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)
>>>>   {
>>>> @@ -323,6 +384,7 @@ 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..79df07e 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-tpdm.h
>>>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.h
>>>> @@ -15,11 +15,25 @@
>>>>     /* 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 */
>>>> +/* Test mode control bit*/
>>>> +#define TPDM_DSB_MODE_TEST(val)    (val & GENMASK(1, 0))
>>>> +/* Perforceman mode */
>>>
>>> minor nit: typo ^^
>> I will update this in the next patch series.
>>>
>>>> +#define TPDM_DSB_MODE_PERF BIT(3)
>>>> +/* High performance mode */
>>>> +#define TPDM_DSB_MODE_HPBYTESEL(val)    (val & GENMASK(8, 4))
>>>> +#define TPDM_MODE_ALL            (0xFFFFFFF)
>>>
>>> GENMASK(27, 0) ?
>>>
>>> Also, why do we cover bits 27-0 ?
>>
>> The TPDM mode is only represented by [0:8]bits.
>>
>> Can I replace it with "#define TPDM_DSB_MODE(val)    (VAL & 
>> GENMASK(8, 0))"?
>
> #define TPDM_DSB_MODE_MASK        GENMASK(8, 0) ?

Sure, I will change it in the next patch series.


Best,

Tao

>
> Suzuki
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