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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: mathieu.poirier@linaro.org, mike.leach@linaro.org,
	linux-kernel@vger.kernel.org, anshuman.khandual@arm.com,
	jonathan.zhouwen@huawei.com, coresight@lists.linaro.org,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Tingwei Zhang <tingwei@codeaurora.org>
Subject: [PATCH v4 02/25] coresight: etm4x: Skip accessing TRCPDCR in save/restore
Date: Thu, 19 Nov 2020 16:45:24 +0000	[thread overview]
Message-ID: <20201119164547.2982871-3-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20201119164547.2982871-1-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: commit 02510a5aa78df45 ("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>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 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 59a4a166adf4..ea2e317ddb7d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1277,7 +1277,8 @@ 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)) {
@@ -1295,9 +1296,9 @@ 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;
@@ -1392,7 +1393,8 @@ 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;
 
-- 
2.24.1


  parent reply	other threads:[~2020-11-19 16:46 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-19 16:45 [PATCH v4 00/26] coresight: etm4x: Support for system instructions Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 01/25] coresight: etm4x: Handle access to TRCSSPCICRn Suzuki K Poulose
2020-11-19 16:45 ` Suzuki K Poulose [this message]
2020-11-20  5:40   ` [PATCH v4 02/25] coresight: etm4x: Skip accessing TRCPDCR in save/restore Sai Prakash Ranjan
2020-11-27 18:55   ` Mathieu Poirier
2020-11-30  9:37     ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 03/25] coresight: Introduce device access abstraction Suzuki K Poulose
2020-11-27 19:11   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 04/25] coresight: tpiu: Prepare for using coresight " Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 05/25] coresight: Convert coresight_timeout to use " Suzuki K Poulose
2020-11-30 20:55   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 06/25] coresight: Convert claim/disclaim operations to use access wrappers Suzuki K Poulose
2020-11-30 21:04   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 07/25] coresight: etm4x: Always read the registers on the host CPU Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 08/25] coresight: etm4x: Convert all register accesses Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 09/25] coresight: etm4x: Add commentary on the registers Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 10/25] coresight: etm4x: Add sysreg access helpers Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 11/25] coresight: etm4x: Define DEVARCH register fields Suzuki K Poulose
2020-11-30 21:19   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 12/25] coresight: etm4x: Check for Software Lock Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 13/25] coresight: etm4x: Cleanup secure exception level masks Suzuki K Poulose
2020-11-30 21:25   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 14/25] coresight: etm4x: Clean up " Suzuki K Poulose
2020-11-30 21:45   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 15/25] coresight: etm4x: Handle ETM architecture version Suzuki K Poulose
2020-11-30 21:48   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 16/25] coresight: etm4x: Detect access early on the target CPU Suzuki K Poulose
2020-11-30 21:53   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 17/25] coresight: etm4x: Use TRCDEVARCH for component discovery Suzuki K Poulose
2020-11-27 18:28   ` Mathieu Poirier
2020-11-30  9:30     ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 18/25] coresight: etm4x: Expose trcdevarch via trcidr Suzuki K Poulose
2020-11-30 22:42   ` Mathieu Poirier
2020-11-19 16:45 ` [PATCH v4 19/25] coresight: etm4x: Add necessary synchronization for sysreg access Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 20/25] coresight: etm4x: Detect system instructions support Suzuki K Poulose
2020-11-23  7:58   ` Tingwei Zhang
2020-11-23  9:39     ` Suzuki K Poulose
2020-11-24  0:41       ` Tingwei Zhang
2020-11-24 11:38         ` Suzuki K Poulose
2020-11-25  4:57           ` Tingwei Zhang
2020-11-19 16:45 ` [PATCH v4 21/25] coresight: etm4x: Refactor probing routine Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 22/25] coresight: etm4x: Add support for sysreg only devices Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 23/25] dts: bindings: coresight: ETM system register access only units Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 24/25] arm64: Add TRFCR_ELx definitions Suzuki K Poulose
2020-11-19 17:18   ` Catalin Marinas
2020-11-20 10:03     ` Suzuki K Poulose
2020-11-19 16:45 ` [PATCH v4 25/25] coresight: Add support for v8.4 SelfHosted tracing Suzuki K Poulose
2020-11-19 17:22   ` Catalin Marinas
2020-11-20 10:03     ` Suzuki K Poulose

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