6.12-stable review patch. If anyone has any objections, please let me know.
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From: Leo Yan leo.yan@arm.com
[ Upstream commit 8a79026926b329d4ab0c6d0921373a80ec8aab6e ]
The atclk is an optional clock for the CoreSight TMC, but the driver misses to initialize it. In most cases, TMC shares the atclk clock with other CoreSight components. Since these components enable the clock before the TMC device is initialized, the TMC continues properly, which is why we don’t observe any lockup issues.
This change enables atclk in probe of the TMC driver. Given the clock is optional, it is possible to return NULL if the clock does not exist. IS_ERR() is tolerant for this case.
Dynamically disable and enable atclk during suspend and resume. The clock pointers will never be error values if the driver has successfully probed, and the case of a NULL pointer case will be handled by the clock core layer. The driver data is always valid after probe. Therefore, remove the related checks. Also in the resume flow adds error handling.
Fixes: bc4bf7fe98da ("coresight-tmc: add CoreSight TMC driver") Reviewed-by: Anshuman Khandual anshuman.khandual@arm.com Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Tested-by: James Clark james.clark@linaro.org Signed-off-by: Leo Yan leo.yan@arm.com Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Link: https://lore.kernel.org/r/20250731-arm_cs_fix_clock_v4-v6-1-1dfe10bb3f6f@arm... Signed-off-by: Sasha Levin sashal@kernel.org --- .../hwtracing/coresight/coresight-tmc-core.c | 22 ++++++++++++++----- drivers/hwtracing/coresight/coresight-tmc.h | 2 ++ 2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 475fa4bb6813b..96ef2517dd439 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -480,6 +480,10 @@ static int __tmc_probe(struct device *dev, struct resource *res) struct coresight_desc desc = { 0 }; struct coresight_dev_list *dev_list = NULL;
+ drvdata->atclk = devm_clk_get_optional_enabled(dev, "atclk"); + if (IS_ERR(drvdata->atclk)) + return PTR_ERR(drvdata->atclk); + ret = -ENOMEM;
/* Validity for the resource is already checked by the AMBA core */ @@ -700,18 +704,26 @@ static int tmc_runtime_suspend(struct device *dev) { struct tmc_drvdata *drvdata = dev_get_drvdata(dev);
- if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) - clk_disable_unprepare(drvdata->pclk); + clk_disable_unprepare(drvdata->atclk); + clk_disable_unprepare(drvdata->pclk); + return 0; }
static int tmc_runtime_resume(struct device *dev) { struct tmc_drvdata *drvdata = dev_get_drvdata(dev); + int ret;
- if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) - clk_prepare_enable(drvdata->pclk); - return 0; + ret = clk_prepare_enable(drvdata->pclk); + if (ret) + return ret; + + ret = clk_prepare_enable(drvdata->atclk); + if (ret) + clk_disable_unprepare(drvdata->pclk); + + return ret; } #endif
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 2671926be62a3..2a53acbb5990b 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -166,6 +166,7 @@ struct etr_buf {
/** * struct tmc_drvdata - specifics associated to an TMC component + * @atclk: optional clock for the core parts of the TMC. * @pclk: APB clock if present, otherwise NULL * @base: memory mapped base address for this component. * @csdev: component vitals needed by the framework. @@ -191,6 +192,7 @@ struct etr_buf { * @perf_buf: PERF buffer for ETR. */ struct tmc_drvdata { + struct clk *atclk; struct clk *pclk; void __iomem *base; struct coresight_device *csdev;