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@xxxxxxxxxxxxxx>
> ---
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
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
