coresight: tmc: Make memory width mask computation into a function

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>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Link: https://lore.kernel.org/r/20190829202842.580-16-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 0 deletions

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;