On 2/15/24 16:25, Suzuki K Poulose wrote:
> On 23/01/2024 05:45, Anshuman Khandual wrote:
>> Instead of using AMBA private data field, extract the device name from AMBA
>> pid based table lookup using new coresight_get_uci_data_from_amba() helper.
>>
>> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>> Cc: Mike Leach <mike.leach@xxxxxxxxxx>
>> Cc: James Clark <james.clark@xxxxxxx>
>> Cc: coresight@xxxxxxxxxxxxxxxx
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>> ---
>> drivers/hwtracing/coresight/coresight-priv.h | 10 ++++++++++
>> drivers/hwtracing/coresight/coresight-stm.c | 14 +++++++++++++-
>> 2 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
>> index 767076e07970..68cbb036cec8 100644
>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>> @@ -221,6 +221,16 @@ static inline void *coresight_get_uci_data(const struct amba_id *id)
>> return uci_id->data;
>> }
>> +static inline void *coresight_get_uci_data_from_amba(const struct amba_id *table, u32 pid)
>> +{
>> + while (table->mask) {
>> + if ((table->id & table->mask) == pid)
>
> Why are we masking table->id ? table->id is a static value that the
> driver wants to check for "variants" of a given device. The table->mask
> is there to filter out the "irrelevant" bits of the PID that we read
> from the device. So this should instead be:
>
> if ((table->mask & pid) == table->id)
Sure, will this change as suggested.
>
>> + return coresight_get_uci_data(table);
>> + table++;
>> + };
>> + return NULL;
>> +}
>> +
>> void coresight_release_platform_data(struct coresight_device *csdev,
>> struct device *dev,
>> struct coresight_platform_data *pdata);
>> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
>> index a1c27c901ad1..9cdca4f86cab 100644
>> --- a/drivers/hwtracing/coresight/coresight-stm.c
>> +++ b/drivers/hwtracing/coresight/coresight-stm.c
>> @@ -804,6 +804,18 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata,
>> drvdata->stm.set_options = stm_generic_set_options;
>> }
>> +#define STM_AMBA_MASK 0xfffff
>> +
>> +static const struct amba_id stm_ids[];
>> +
>> +static char *stm_csdev_name(struct coresight_device *csdev)
>> +{
>> + u32 stm_pid = coresight_get_pid(&csdev->access) & STM_AMBA_MASK;
>
> Similar to above:
>
> Why do we apply a "custom" mask to the PID and later check the PID with
> that of the table->pid.
>
> The way it is supposed work is :
>
> (table->mask & dev_pid) == table->pid
>
> the table->mask is there for a reason: i.e., to get the relevant bits from the device_pid and compare it against "the" expected value (table->pid).
Understood, will change the helper as follows
static inline void *coresight_get_uci_data_from_amba(const struct amba_id *table, u32 pid)
{
while (table->mask) {
if ((pid & table->mask) == table->id)
return coresight_get_uci_data(table);
table++;
};
return NULL;
}
and also drop both the custom masks STM_AMBA_MASK and TMC_AMBA_MASK.
