[PATCH] coresight: tmc: Configure DMA mask appropriately

[Robin Murphy]

Before making any DMA API calls, the ETR driver should really be setting
its masks to ensure that DMA is possible. Especially since it can
address more than the 32-bit default mask set by the AMBA bus code.

Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index d8517d2a968c..864488793f09 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -362,6 +362,13 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 		desc.type = CORESIGHT_DEV_TYPE_SINK;
 		desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
 		desc.ops = &tmc_etr_cs_ops;
+		/*
+		 * ETR configuration uses a 40-bit AXI master in place of
+		 * the embedded SRAM of ETB/ETF.
+		 */
+		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(40));
+		if (ret)
+			goto out;
 	} else {
 		desc.type = CORESIGHT_DEV_TYPE_LINKSINK;
 		desc.subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_FIFO;
-- 
2.12.2.dirty