linux-kernel - [PATCH v3 2/3] coresight: tmc: Update error logging in tmc common functions

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Message-Id: <20241218230118.999859-3-mike.leach@linaro.org>
Date: Wed, 18 Dec 2024 23:01:17 +0000
From: Mike Leach <mike.leach@...aro.org>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	coresight@...ts.linaro.org
Cc: james.clark@...aro.org,
	mike.leach@...aro.org,
	suzuki.poulose@....com,
	alexander.shishkin@...ux.intel.com
Subject: [PATCH v3 2/3] coresight: tmc: Update error logging in tmc common functions

Enhance the error logging in the tmc_wait_for_tmcready() and
tmc_flush_and_stop() to print key tmc  register values on error
conditions to improve hardware debug information.

Signed-off-by: Mike Leach <mike.leach@...aro.org>
---
 .../hwtracing/coresight/coresight-tmc-core.c  | 44 +++++++++++++++----
 drivers/hwtracing/coresight/coresight-tmc.h   |  2 +-
 2 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index e9876252a789..dff82facada3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -34,25 +34,39 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
 DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
 DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr");
 
+#define TMC_WAIT_READY_FMT_STR "timeout while waiting for TMC to be Ready [STS=0x%04x]\n"
+
 int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
 {
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
+	u32 tmc_sts = 0;
 
 	/* Ensure formatter, unformatter and hardware fifo are empty */
-	if (coresight_timeout(csa, TMC_STS, TMC_STS_TMCREADY_BIT, 1)) {
-		dev_err(&csdev->dev,
-			"timeout while waiting for TMC to be Ready\n");
+	if (coresight_timeout_retval(csa, TMC_STS, TMC_STS_TMCREADY_BIT, 1,
+				     &tmc_sts)) {
+		dev_err(&csdev->dev, TMC_WAIT_READY_FMT_STR, tmc_sts);
+		if (tmc_sts & TMC_STS_MEMERR)
+			dev_err(&csdev->dev,
+				"MemErr in STS reg waiting for TMC ready\n");
 		return -EBUSY;
 	}
 	return 0;
 }
 
-void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
+int tmc_flush_and_stop(struct tmc_drvdata *drvdata)
 {
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
-	u32 ffcr;
+	u32 ffcr, ffsr, tmc_sts;
+	int rc = 0;
+
+	/* note any MemErr present when stopping TMC */
+	tmc_sts = readl_relaxed(drvdata->base + TMC_STS);
+	if (tmc_sts & TMC_STS_MEMERR)
+		dev_err(&csdev->dev,
+			"MemErr detected before Manual Flush; STS[0x%02x]\n",
+			tmc_sts);
 
 	ffcr = readl_relaxed(drvdata->base + TMC_FFCR);
 	ffcr |= TMC_FFCR_STOP_ON_FLUSH;
@@ -60,12 +74,26 @@ void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
 	ffcr |= BIT(TMC_FFCR_FLUSHMAN_BIT);
 	writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
 	/* Ensure flush completes */
-	if (coresight_timeout(csa, TMC_FFCR, TMC_FFCR_FLUSHMAN_BIT, 0)) {
+	if (coresight_timeout_retval(csa, TMC_FFCR, TMC_FFCR_FLUSHMAN_BIT, 0,
+				     &ffcr)) {
+		ffsr = readl_relaxed(drvdata->base + TMC_FFSR);
+		tmc_sts = readl_relaxed(drvdata->base + TMC_STS);
 		dev_err(&csdev->dev,
-		"timeout while waiting for completion of Manual Flush\n");
+			"timeout while waiting for completion of Manual Flush\n");
+		dev_err(&csdev->dev,
+			"regs: FFCR[0x%02x] FFSR[0x%02x] STS[0x%02x]\n",
+			ffcr, ffsr, tmc_sts);
+		if (tmc_sts & TMC_STS_MEMERR)
+			dev_err(&csdev->dev,
+				"MemErr in STS reg waiting for flush complete\n");
+		rc = -EBUSY;
 	}
 
-	tmc_wait_for_tmcready(drvdata);
+	if (tmc_wait_for_tmcready(drvdata)) {
+		dev_err(&csdev->dev, "TMC ready error after Manual flush\n");
+		rc = -EBUSY;
+	}
+	return rc;
 }
 
 void tmc_enable_hw(struct tmc_drvdata *drvdata)
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 2671926be62a..34513f07c3aa 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -259,7 +259,7 @@ struct tmc_sg_table {
 
 /* Generic functions */
 int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata);
-void tmc_flush_and_stop(struct tmc_drvdata *drvdata);
+int tmc_flush_and_stop(struct tmc_drvdata *drvdata);
 void tmc_enable_hw(struct tmc_drvdata *drvdata);
 void tmc_disable_hw(struct tmc_drvdata *drvdata);
 u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata);
-- 
2.25.1