On Tue, Jun 16, 2020 at 10:26:23AM +0530, Sai Prakash Ranjan wrote:

Implement a shutdown callback to ensure ETR hardware is properly shutdown in reboot/shutdown path. This is required for ETR which has SMMU address translation enabled like on SC7180 SoC and few others. If the hardware is still accessing memory after SMMU translation is disabled as part of SMMU shutdown callback in system reboot or shutdown path, then IOVAs(I/O virtual address) which it was using will go on the bus as the physical addresses which might result in unknown crashes (NoC/interconnect errors). So we make sure from this shutdown callback that the ETR is shutdown before SMMU translation is disabled and device_link in SMMU driver will take care of ordering of shutdown callbacks such that SMMU shutdown callback is not called before any of its consumer shutdown callbacks.

Signed-off-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org

I have applied your patch.

Thanks, Mathieu

Changes since v2:

• Remove ETF/ETB disable as suggested by Mathieu and Mike since they are not really affected.
• Remove coresight and misc device unregister since it is not required for shutdown callback unlike remove callback and userspace is long gone by this time.

Changes since v1:

• Use mode flag and drop enable flag as Mike suggested.
• Use spinlock before tmc hw disable as Mike suggested.

---

.../hwtracing/coresight/coresight-tmc-etr.c | 2 +- drivers/hwtracing/coresight/coresight-tmc.c | 23 +++++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.h | 1 + 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 625882bc8b08..b29c2db94d96 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1110,7 +1110,7 @@ static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata) } -static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata) +void tmc_etr_disable_hw(struct tmc_drvdata *drvdata) { __tmc_etr_disable_hw(drvdata); /* Disable CATU device if this ETR is connected to one */ diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c index 39fba1d16e6e..b13ce0daa572 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.c +++ b/drivers/hwtracing/coresight/coresight-tmc.c @@ -538,6 +538,28 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id) return ret; } +static void tmc_shutdown(struct amba_device *adev) +{

• unsigned long flags;
• struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
• spin_lock_irqsave(&drvdata->spinlock, flags);
• if (drvdata->mode == CS_MODE_DISABLED)

• goto out;
  

• if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)

• tmc_etr_disable_hw(drvdata);
  

• /*

• * We do not care about coresight unregister here unlike remove
  

• * callback which is required for making coresight modular since
  

• * the system is going down after this.
  

• */
  

+out:

• spin_unlock_irqrestore(&drvdata->spinlock, flags);

+}

static const struct amba_id tmc_ids[] = { CS_AMBA_ID(0x000bb961), /* Coresight SoC 600 TMC-ETR/ETS */ @@ -556,6 +578,7 @@ static struct amba_driver tmc_driver = { .suppress_bind_attrs = true, }, .probe = tmc_probe,

• .shutdown = tmc_shutdown, .id_table = tmc_ids,

}; builtin_amba_driver(tmc_driver); diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 71de978575f3..6e8d2dc33d17 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -268,6 +268,7 @@ ssize_t tmc_etb_get_sysfs_trace(struct tmc_drvdata *drvdata, /* ETR functions */ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata); int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata); +void tmc_etr_disable_hw(struct tmc_drvdata *drvdata); extern const struct coresight_ops tmc_etr_cs_ops; ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata, loff_t pos, size_t len, char **bufpp);

base-commit: 059e38815950dbec65beafe03757bce9436e89a4

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