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Message-ID: <6c3d9c5c-8185-bcdf-2897-0db13c00a843@arm.com>
Date: Mon, 11 Dec 2023 10:12:35 +0000
From: James Clark <james.clark@....com>
To: Anshuman Khandual <anshuman.khandual@....com>,
linux-arm-kernel@...ts.infradead.org, suzuki.poulose@....com
Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>,
Sudeep Holla <sudeep.holla@....com>,
Mike Leach <mike.leach@...aro.org>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>,
linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
coresight@...ts.linaro.org,
linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH V3 04/10] coresight: replicator: Move ACPI support from
AMBA driver to platform driver
On 11/12/2023 07:51, Anshuman Khandual wrote:
>
>
> On 12/8/23 11:09, Anshuman Khandual wrote:
>> Add support for the dynamic replicator device in the platform driver, which
>> can then be used on ACPI based platforms. This change would now allow
>> runtime power management for repliacator devices on ACPI based systems.
>>
>> The driver would try to enable the APB clock if available. Also, rename the
>> code to reflect the fact that it now handles both static and dynamic
>> replicators.
>>
>> Cc: Lorenzo Pieralisi <lpieralisi@...nel.org>
>> Cc: Sudeep Holla <sudeep.holla@....com>
>> Cc: Suzuki K Poulose <suzuki.poulose@....com>
>> Cc: Mike Leach <mike.leach@...aro.org>
>> Cc: James Clark <james.clark@....com>
>> Cc: linux-acpi@...r.kernel.org
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-kernel@...r.kernel.org
>> Cc: coresight@...ts.linaro.org
>> Tested-by: Sudeep Holla <sudeep.holla@....com> # Boot and driver probe only
>> Acked-by: Sudeep Holla <sudeep.holla@....com> # For ACPI related changes
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
>> ---
>> Changes in V3:
>>
>> - Added commnets for 'drvdata->pclk'
>> - Used coresight_init_driver()/coresight_remove_driver() helpers instead
>> - Dropped pm_runtime_put() from replicator_probe()
>> - Added pm_runtime_put() on success path in dynamic_replicator_probe()
>> - Added pm_runtime_put() on success/error paths in
>> replicator_platform_probe()
>>
>> drivers/acpi/arm64/amba.c | 1 -
>> .../coresight/coresight-replicator.c | 81 ++++++++++---------
>> 2 files changed, 42 insertions(+), 40 deletions(-)
>>
>> diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
>> index 171b5c2c7edd..270f4e3819a2 100644
>> --- a/drivers/acpi/arm64/amba.c
>> +++ b/drivers/acpi/arm64/amba.c
>> @@ -27,7 +27,6 @@ static const struct acpi_device_id amba_id_list[] = {
>> {"ARMHC503", 0}, /* ARM CoreSight Debug */
>> {"ARMHC979", 0}, /* ARM CoreSight TPIU */
>> {"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
>> - {"ARMHC98D", 0}, /* ARM CoreSight Dynamic Replicator */
>> {"ARMHC9CA", 0}, /* ARM CoreSight CATU */
>> {"ARMHC9FF", 0}, /* ARM CoreSight Dynamic Funnel */
>> {"", 0},
>> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
>> index b6be73034996..125b256cb8db 100644
>> --- a/drivers/hwtracing/coresight/coresight-replicator.c
>> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
>> @@ -31,6 +31,7 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
>> * @base: memory mapped base address for this component. Also indicates
>> * whether this one is programmable or not.
>> * @atclk: optional clock for the core parts of the replicator.
>> + * @pclk: APB clock if present, otherwise NULL
>> * @csdev: component vitals needed by the framework
>> * @spinlock: serialize enable/disable operations.
>> * @check_idfilter_val: check if the context is lost upon clock removal.
>> @@ -38,6 +39,7 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
>> struct replicator_drvdata {
>> void __iomem *base;
>> struct clk *atclk;
>> + struct clk *pclk;
>> struct coresight_device *csdev;
>> spinlock_t spinlock;
>> bool check_idfilter_val;
>> @@ -243,6 +245,10 @@ static int replicator_probe(struct device *dev, struct resource *res)
>> return ret;
>> }
>>
>> + drvdata->pclk = coresight_get_enable_apb_pclk(dev);
>> + if (IS_ERR(drvdata->pclk))
>> + return -ENODEV;
>> +
>> /*
>> * Map the device base for dynamic-replicator, which has been
>> * validated by AMBA core
>> @@ -285,7 +291,6 @@ static int replicator_probe(struct device *dev, struct resource *res)
>> }
>>
>> replicator_reset(drvdata);
>> - pm_runtime_put(dev);
>>
>> out_disable_clk:
>> if (ret && !IS_ERR_OR_NULL(drvdata->atclk))
>> @@ -301,29 +306,31 @@ static int replicator_remove(struct device *dev)
>> return 0;
>> }
>>
>> -static int static_replicator_probe(struct platform_device *pdev)
>> +static int replicator_platform_probe(struct platform_device *pdev)
>> {
>> + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> int ret;
>>
>> pm_runtime_get_noresume(&pdev->dev);
>> pm_runtime_set_active(&pdev->dev);
>> pm_runtime_enable(&pdev->dev);
>>
>> - /* Static replicators do not have programming base */
>> - ret = replicator_probe(&pdev->dev, NULL);
>> -
>> - if (ret) {
>> - pm_runtime_put_noidle(&pdev->dev);
>> - pm_runtime_disable(&pdev->dev);
>> - }
>> + ret = replicator_probe(&pdev->dev, res);
>> + pm_runtime_put(&pdev->dev);
>
> I believe pm_runtime_disable() would still be needed on the error path. Otherwise
> pm_runtime_enable() will remain unbalanced on this error path when the replicator
> module could not be loaded.
>
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -317,6 +317,8 @@ static int replicator_platform_probe(struct platform_device *pdev)
>
> ret = replicator_probe(&pdev->dev, res);
> pm_runtime_put(&pdev->dev);
> + if (ret)
> + pm_runtime_disable(&pdev->dev);
>
> return ret;
> }
>
> Similar constructs in this error path are also required in all other drivers (except
> cpu debug) as well.
Would that not need to be done as a fixes commit first with more detail
about the issue if that's true? Maybe simulate the error and paste any
error logs. For example etm4 already has this:
pm_runtime_get_noresume(&pdev->dev);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
ret = etm4_probe(&pdev->dev);
pm_runtime_put(&pdev->dev);
I'm wondering if the disable is already covered by the platform code if
the probe fails so no change is required?
if (drv->probe) {
ret = drv->probe(dev);
if (ret)
dev_pm_domain_detach(_dev, true);
}
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