linux-kernel - [PATCH V2 12/15] coresight: tmc: keep track of memory width

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Message-Id: <1460483692-25061-13-git-send-email-mathieu.poirier@linaro.org>
Date:	Tue, 12 Apr 2016 11:54:49 -0600
From:	Mathieu Poirier <mathieu.poirier@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, Suzuki.Poulose@....com
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH V2 12/15] coresight: tmc: keep track of memory width

Accessing the HW configuration register each time the memory
width is needed simply doesn't make sense.  It is much more
efficient to read the value once and keep a reference for
later use.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 8 +++-----
 drivers/hwtracing/coresight/coresight-tmc.c     | 1 +
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 ++
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 50d32e8ef4ea..a440784e3b27 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -41,18 +41,16 @@ void tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 
 static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
 {
-	enum tmc_mem_intf_width memwidth;
 	u8 memwords;
 	char *bufp;
 	u32 read_data;
 	int i;
 
-	memwidth = BMVAL(readl_relaxed(drvdata->base + CORESIGHT_DEVID), 8, 10);
-	if (memwidth == TMC_MEM_INTF_WIDTH_32BITS)
+	if (drvdata->memwidth == TMC_MEM_INTF_WIDTH_32BITS)
 		memwords = 1;
-	else if (memwidth == TMC_MEM_INTF_WIDTH_64BITS)
+	else if (drvdata->memwidth == TMC_MEM_INTF_WIDTH_64BITS)
 		memwords = 2;
-	else if (memwidth == TMC_MEM_INTF_WIDTH_128BITS)
+	else if (drvdata->memwidth == TMC_MEM_INTF_WIDTH_128BITS)
 		memwords = 4;
 	else
 		memwords = 8;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 4d7b64f69389..bc013d5f71c3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -306,6 +306,7 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 
 	devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
 	drvdata->config_type = BMVAL(devid, 6, 7);
+	drvdata->memwidth = BMVAL(devid, 8, 10);
 
 	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
 		if (np)
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 821bdf150ac9..062dd7dcea96 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -102,6 +102,7 @@ enum tmc_mem_intf_width {
  * @size:	@buf size.
  * @mode:	how this TMC is being used.
  * @config_type: TMC variant, must be of type @tmc_config_type.
+ * @memwidth:	width of the memory interface databus, powers of two.
  * @trigger_cntr: amount of words to store after a trigger.
  */
 struct tmc_drvdata {
@@ -118,6 +119,7 @@ struct tmc_drvdata {
 	u32			size;
 	local_t			mode;
 	enum tmc_config_type	config_type;
+	enum tmc_mem_intf_width	memwidth;
 	u32			trigger_cntr;
 };
 
-- 
2.5.0