Messages in this thread Patch in this message | | | From | Mathieu Poirier <> | Subject | [PATCH 04/31] coresight: etm4x: Skip accessing TRCPDCR in save/restore | Date | Mon, 1 Feb 2021 11:13:24 -0700 |
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From: Suzuki K Poulose <suzuki.poulose@arm.com>
When the ETM is affected by Qualcomm errata, modifying the TRCPDCR could cause the system hang. Even though this is taken care of during enable/disable ETM, the ETM state save/restore could still access the TRCPDCR. Make sure we skip the access during the save/restore.
Found by code inspection.
Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up") Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mike Leach <mike.leach@linaro.org> Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Cc: Tingwei Zhang <tingwei@codeaurora.org> Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20210110224850.1880240-3-suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 4b615e9f3d76..0924c376e35a 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1373,7 +1373,8 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata) state->trcclaimset = readl(drvdata->base + TRCCLAIMCLR); - state->trcpdcr = readl(drvdata->base + TRCPDCR); + if (!drvdata->skip_power_up) + state->trcpdcr = readl(drvdata->base + TRCPDCR); /* wait for TRCSTATR.IDLE to go up */ if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 1)) { @@ -1391,9 +1392,9 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata) * potentially save power on systems that respect the TRCPDCR_PU * despite requesting software to save/restore state. */ - writel_relaxed((state->trcpdcr & ~TRCPDCR_PU), - drvdata->base + TRCPDCR); - + if (!drvdata->skip_power_up) + writel_relaxed((state->trcpdcr & ~TRCPDCR_PU), + drvdata->base + TRCPDCR); out: CS_LOCK(drvdata->base); return ret; @@ -1488,7 +1489,8 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) writel_relaxed(state->trcclaimset, drvdata->base + TRCCLAIMSET); - writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR); + if (!drvdata->skip_power_up) + writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR); drvdata->state_needs_restore = false; -- 2.25.1
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