linux-kernel - [PATCH 11/27] coresight: tmc: waiting for TMCReady bit before programming

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Date:	Tue,  3 May 2016 11:33:45 -0600
From:	Mathieu Poirier <mathieu.poirier@...aro.org>
To:	gregkh@...uxfoundation.org
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 11/27] coresight: tmc: waiting for TMCReady bit before programming

According to the TRM before programming the TMC in circular
buffer mode (and that for any configuration, ETB, ETR, ETF),
the TMCReady bit in the status register has to be set.

This patch adds a check to make sure the state machine is in
a state where it can be configured, and complains otherwise.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 drivers/hwtracing/coresight/coresight-tmc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 3f646e29a99b..66fa7736d12f 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -180,6 +180,9 @@ static void tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 
 	CS_UNLOCK(drvdata->base);
 
+	/* Wait for TMCSReady bit to be set */
+	tmc_wait_for_tmcready(drvdata);
+
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
 		       TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT |
@@ -201,6 +204,9 @@ static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 
 	CS_UNLOCK(drvdata->base);
 
+	/* Wait for TMCSReady bit to be set */
+	tmc_wait_for_tmcready(drvdata);
+
 	writel_relaxed(drvdata->size / 4, drvdata->base + TMC_RSZ);
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
 
@@ -230,6 +236,9 @@ static void tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 {
 	CS_UNLOCK(drvdata->base);
 
+	/* Wait for TMCSReady bit to be set */
+	tmc_wait_for_tmcready(drvdata);
+
 	writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI,
 		       drvdata->base + TMC_FFCR);
-- 
2.5.0