coresight tmc etr: Add capabilitiy information

With new version of TMC ETR, there are differing set of
features supported by the TMC. Add the capability of a
given TMC ETR for making safer decisions at runtime.

The device configuration register of the TMC (DEVID) lists
some of the capabilities. So, we can detect some of them at
probe. However, some of the features (or changes in behavior)
are not advertised and we have to depend on the PID to infer
the features. So we use a static description of the "unadvertised"
capabilities attached to the PID. Combining both, the static
and the dynamic capabilities, we maintain a bitmask of the
available features which can be later checked to take
appropriate actions.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 5 deletions

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 6adf74689a85..0c99ef7b9b2b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -299,6 +299,20 @@ const struct attribute_group *coresight_tmc_groups[] = {
 	NULL,
 };
 
+/* Detect and initialise the capabilities of a TMC ETR */
+static int tmc_etr_setup_caps(struct tmc_drvdata *drvdata,
+			     u32 devid, void *dev_caps)
+{
+	/* Set the unadvertised capabilities */
+	tmc_etr_init_caps(drvdata, (u32)(unsigned long)dev_caps);
+
+	/*
+	 * ETR configuration uses a 40-bit AXI master in place of
+	 * the embedded SRAM of ETB/ETF.
+	 */
+	return dma_set_mask_and_coherent(drvdata->dev, DMA_BIT_MASK(40));
+}
+
 static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	int ret = 0;
@@ -370,11 +384,7 @@ 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));
+		ret = tmc_etr_setup_caps(drvdata, devid, id->data);
 		if (ret)
 			goto out;
 		break;