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Date: Mon, 1 Jun 2020 14:35:37 +0100
From: Mike Leach <mike.leach@...aro.org>
To: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Cc: Mathieu Poirier <mathieu.poirier@...aro.org>,
Suzuki K Poulose <suzuki.poulose@....com>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-arm-msm@...r.kernel.org,
Coresight ML <coresight@...ts.linaro.org>,
Stephen Boyd <swboyd@...omium.org>
Subject: Re: [PATCH 2/2] coresight: tmc: Add shutdown callback for TMC ETR/ETF
Hi,
On Mon, 1 Jun 2020 at 09:02, Sai Prakash Ranjan
<saiprakash.ranjan@...eaurora.org> wrote:
>
> Implement a shutdown callback to ensure ETR/ETF hardware is
> properly shutdown in reboot/shutdown path. This is required
> for ETR/ETF 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/ETF 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@...eaurora.org>
> ---
> .../hwtracing/coresight/coresight-tmc-etf.c | 4 +--
> .../hwtracing/coresight/coresight-tmc-etr.c | 2 +-
> drivers/hwtracing/coresight/coresight-tmc.c | 29 +++++++++++++++++++
> drivers/hwtracing/coresight/coresight-tmc.h | 3 ++
> 4 files changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
> index 36cce2bfb744..cba3e7592820 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
> @@ -85,7 +85,7 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
> CS_LOCK(drvdata->base);
> }
>
> -static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
> +void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
> {
> __tmc_etb_disable_hw(drvdata);
> coresight_disclaim_device(drvdata->base);
> @@ -118,7 +118,7 @@ static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
> return 0;
> }
>
> -static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
> +void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
> {
> CS_UNLOCK(drvdata->base);
>
> 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 5a271ebc4585..7e687a356fe0 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
> @@ -540,6 +540,34 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
> return ret;
> }
>
> +static void tmc_shutdown(struct amba_device *adev)
> +{
> + struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
> +
Take drvdata->spinlock here? The tmc_xxx_disable_hw functions are
normally called with the spinlock claimed.
> + if (!drvdata->enable)
As per previous patch drvdata->mode can be used here.
Regards
Mike
> + goto out;
> +
> + /*
> + * We do not care about the active trace sessions here
> + * since the system is going down unlike remove callback,
> + * just make sure that the hardware is shutdown.
> + */
> + switch (drvdata->config_type) {
> + case TMC_CONFIG_TYPE_ETB:
> + tmc_etb_disable_hw(drvdata);
> + break;
> + case TMC_CONFIG_TYPE_ETF:
> + tmc_etf_disable_hw(drvdata);
> + break;
> + case TMC_CONFIG_TYPE_ETR:
> + tmc_etr_disable_hw(drvdata);
> + }
> +
> +out:
> + misc_deregister(&drvdata->miscdev);
> + coresight_unregister(drvdata->csdev);
> +}
> +
> static const struct amba_id tmc_ids[] = {
> CS_AMBA_ID(0x000bb961),
> /* Coresight SoC 600 TMC-ETR/ETS */
> @@ -558,6 +586,7 @@ 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 d156860495c7..f4f56c474e58 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -262,6 +262,8 @@ u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata);
> /* ETB/ETF functions */
> int tmc_read_prepare_etb(struct tmc_drvdata *drvdata);
> int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata);
> +void tmc_etb_disable_hw(struct tmc_drvdata *drvdata);
> +void tmc_etf_disable_hw(struct tmc_drvdata *drvdata);
> extern const struct coresight_ops tmc_etb_cs_ops;
> extern const struct coresight_ops tmc_etf_cs_ops;
>
> @@ -270,6 +272,7 @@ 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);
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
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