[PATCH v2 1/3] coresight: tmc: Make memory width mask computation into a function

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Make the computation of a memory mask representing the width of the memory
bus into a function so that it can be re-used by the ETR driver.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../hwtracing/coresight/coresight-tmc-etf.c   | 23 ++-------------
 drivers/hwtracing/coresight/coresight-tmc.c   | 28 +++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tmc.h   |  1 +
 3 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 23b7ff00af5c..807416b75ecc 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -479,30 +479,11 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
 	 * traces.
 	 */
 	if (!buf->snapshot && to_read > handle->size) {
-		u32 mask = 0;
-
-		/*
-		 * The value written to RRP must be byte-address aligned to
-		 * the width of the trace memory databus _and_ to a frame
-		 * boundary (16 byte), whichever is the biggest. For example,
-		 * for 32-bit, 64-bit and 128-bit wide trace memory, the four
-		 * LSBs must be 0s. For 256-bit wide trace memory, the five
-		 * LSBs must be 0s.
-		 */
-		switch (drvdata->memwidth) {
-		case TMC_MEM_INTF_WIDTH_32BITS:
-		case TMC_MEM_INTF_WIDTH_64BITS:
-		case TMC_MEM_INTF_WIDTH_128BITS:
-			mask = GENMASK(31, 4);
-			break;
-		case TMC_MEM_INTF_WIDTH_256BITS:
-			mask = GENMASK(31, 5);
-			break;
-		}
+		u32 mask = tmc_get_memwidth_mask(drvdata);
 
 		/*
 		 * Make sure the new size is aligned in accordance with the
-		 * requirement explained above.
+		 * requirement explained in function tmc_get_memwidth_mask().
 		 */
 		to_read = handle->size & mask;
 		/* Move the RAM read pointer up */
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 3055bf8e2236..1cf82fa58289 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -70,6 +70,34 @@ void tmc_disable_hw(struct tmc_drvdata *drvdata)
 	writel_relaxed(0x0, drvdata->base + TMC_CTL);
 }
 
+u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata)
+{
+	u32 mask = 0;
+
+	/*
+	 * When moving RRP or an offset address forward, the new values must
+	 * be byte-address aligned to the width of the trace memory databus
+	 * _and_ to a frame boundary (16 byte), whichever is the biggest. For
+	 * example, for 32-bit, 64-bit and 128-bit wide trace memory, the four
+	 * LSBs must be 0s. For 256-bit wide trace memory, the five LSBs must
+	 * be 0s.
+	 */
+	switch (drvdata->memwidth) {
+	case TMC_MEM_INTF_WIDTH_32BITS:
+	/* fallthrough */
+	case TMC_MEM_INTF_WIDTH_64BITS:
+	/* fallthrough */
+	case TMC_MEM_INTF_WIDTH_128BITS:
+		mask = GENMASK(31, 4);
+		break;
+	case TMC_MEM_INTF_WIDTH_256BITS:
+		mask = GENMASK(31, 5);
+		break;
+	}
+
+	return mask;
+}
+
 static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 {
 	int ret = 0;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 9dbcdf453e22..71de978575f3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -255,6 +255,7 @@ void 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);
+u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata);
 
 /* ETB/ETF functions */
 int tmc_read_prepare_etb(struct tmc_drvdata *drvdata);
-- 
2.17.1