coresight: tmc: Don't enable TMC when it's not ready.

If TMC ETR is enabled without being ready, in later use we may
see AXI bus errors caused by accessing invalid addresses.

Signed-off-by: Yabin Cui <yabinc@google.com>
[ Tweak error message ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230127231001.1920947-1-yabinc@google.com

drivers/hwtracing/coresight/coresight-tmc-core.c

@@ -31,7 +31,7 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
 DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
 DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr");
 
-void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
+int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
 {
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
@@ -40,7 +40,9 @@ void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
 	if (coresight_timeout(csa, TMC_STS, TMC_STS_TMCREADY_BIT, 1)) {
 		dev_err(&csdev->dev,
 			"timeout while waiting for TMC to be Ready\n");
+		return -EBUSY;
 	}
+	return 0;
 }
 
 void tmc_flush_and_stop(struct tmc_drvdata *drvdata)

drivers/hwtracing/coresight/coresight-tmc-etf.c

@@ -16,12 +16,20 @@
 static int tmc_set_etf_buffer(struct coresight_device *csdev,
 			      struct perf_output_handle *handle);
 
-static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 {
+	int rc = 0;
+
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev,
+			"Failed to enable: TMC not ready\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
@@ -33,6 +41,7 @@ static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
@@ -42,8 +51,10 @@ static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 	if (rc)
 		return rc;
 
-	__tmc_etb_enable_hw(drvdata);
+	rc = __tmc_etb_enable_hw(drvdata);
-	return 0;
+	if (rc)
+		coresight_disclaim_device(drvdata->csdev);
+	return rc;
 }
 
 static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
@@ -91,12 +102,20 @@ static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 	coresight_disclaim_device(drvdata->csdev);
 }
 
-static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 {
+	int rc = 0;
+
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev,
+			"Failed to enable : TMC is not ready\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI,
@@ -105,6 +124,7 @@ static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
@@ -114,8 +134,10 @@ static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 	if (rc)
 		return rc;
 
-	__tmc_etf_enable_hw(drvdata);
+	rc = __tmc_etf_enable_hw(drvdata);
-	return 0;
+	if (rc)
+		coresight_disclaim_device(drvdata->csdev);
+	return rc;
 }
 
 static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
@@ -639,6 +661,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 	char *buf = NULL;
 	enum tmc_mode mode;
 	unsigned long flags;
+	int rc = 0;
 
 	/* config types are set a boot time and never change */
 	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB &&
@@ -664,7 +687,11 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 		 * can't be NULL.
 		 */
 		memset(drvdata->buf, 0, drvdata->size);
-		__tmc_etb_enable_hw(drvdata);
+		rc = __tmc_etb_enable_hw(drvdata);
+		if (rc) {
+			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			return rc;
+		}
 	} else {
 		/*
 		 * The ETB/ETF is not tracing and the buffer was just read.

drivers/hwtracing/coresight/coresight-tmc-etr.c

@@ -983,15 +983,22 @@ static void tmc_sync_etr_buf(struct tmc_drvdata *drvdata)
 	etr_buf->ops->sync(etr_buf, rrp, rwp);
 }
 
-static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 {
 	u32 axictl, sts;
 	struct etr_buf *etr_buf = drvdata->etr_buf;
+	int rc = 0;
 
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev,
+			"Failed to enable : TMC not ready\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(etr_buf->size / 4, drvdata->base + TMC_RSZ);
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
@@ -1032,6 +1039,7 @@ static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
@@ -1060,7 +1068,12 @@ static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
 	rc = coresight_claim_device(drvdata->csdev);
 	if (!rc) {
 		drvdata->etr_buf = etr_buf;
-		__tmc_etr_enable_hw(drvdata);
+		rc = __tmc_etr_enable_hw(drvdata);
+		if (rc) {
+			drvdata->etr_buf = NULL;
+			coresight_disclaim_device(drvdata->csdev);
+			tmc_etr_disable_catu(drvdata);
+		}
 	}
 
 	return rc;

drivers/hwtracing/coresight/coresight-tmc.h

@@ -255,7 +255,7 @@ struct tmc_sg_table {
 };
 
 /* Generic functions */
-void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata);
+int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata);
 void tmc_flush_and_stop(struct tmc_drvdata *drvdata);
 void tmc_enable_hw(struct tmc_drvdata *drvdata);
 void tmc_disable_hw(struct tmc_drvdata *drvdata);