On 12/6/2024 4:02 PM, yuanfang zhang wrote:
From: Yuanfang Zhang quic_yuanfang@quicinc.com
As recommended by section 4.3.7 ("Synchronization when using system instructions to progrom the trace unit") of ARM IHI 0064H.b, the self-hosted trace analyzer must perform a Context synchronization event between writing to the TRCPRGCTLR and reading the TRCSTATR.
Fixes: ebddaad09e10 ("coresight: etm4x: Add missing single-shot control API to sysfs") Signed-off-by: Yuanfang Zhang quic_yuanfang@quicinc.com
Changes in V3:
- Remove dsb(sy) after polling TRCSTATR.
- Add isb() after polling TRCSTATR.
.../hwtracing/coresight/coresight-etm4x-core.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 66d44a404ad0..c6ea00bba0cc 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -531,7 +531,6 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) * As recommended by section 4.3.7 ("Synchronization when using the * memory-mapped interface") of ARM IHI 0064D */
- dsb(sy); isb();
done: @@ -906,10 +905,25 @@ static void etm4_disable_hw(void *info) tsb_csync(); etm4x_relaxed_write32(csa, control, TRCPRGCTLR);
- /*
* As recommended by section 4.3.7 ("Synchronization when using system* instructions to progrom the trace unit") of ARM IHI 0064H.b, the* self-hosted trace analyzer must perform a Context synchronization* event between writing to the TRCPRGCTLR and reading the TRCSTATR.*/- if (!csa->io_mem)
isb();- /* wait for TRCSTATR.PMSTABLE to go to '1' */ if (coresight_timeout(csa, TRCSTATR, TRCSTATR_PMSTABLE_BIT, 1)) dev_err(etm_dev, "timeout while waiting for PM stable Trace Status\n");
- /*
* As recommended by section 4.3.7 (Synchronization of register updates)* of ARM IHI 0064H.b.*/- isb();
- /* read the status of the single shot comparators */ for (i = 0; i < drvdata->nr_ss_cmp; i++) { config->ss_status[i] =
gently reminder