From: Suzuki K Poulose suzuki.poulose@arm.com
[ Upstream commit df81b43802f43c0954a55e5d513e8750a1ab4d31 ]
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.
Link: https://lore.kernel.org/r/20210110224850.1880240-3-suzuki.poulose@arm.com 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 Tested-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org Reviewed-by: Sai Prakash Ranjan saiprakash.ranjan@codeaurora.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Link: https://lore.kernel.org/r/20210201181351.1475223-5-mathieu.poirier@linaro.or... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.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 95b54b0a36252..8b6666e6fddbf 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1254,7 +1254,8 @@ 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)) { @@ -1272,9 +1273,9 @@ 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; @@ -1368,7 +1369,8 @@ 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;