coresight tmc etr: Detect address width at runtime

TMC in Coresight SoC-600 advertises the AXI address width
in the device configuration register.

Bit 16 - AXIAW_VALID
 0 - AXI Address Width not valid
 1 - Valid AXI Address width in Bits[23-17]

Bits [23-17] - AXIAW. If AXIAW_VALID = b01 then
 0x20 - 32bit AXI address bus
 0x28 - 40bit AXI address bus
 0x2c - 44bit AXI address bus
 0x30 - 48bit AXI address bus
 0x34 - 52bit AXI address bus

Use the address bits from the device configuration register, if
available. Otherwise, default to 40bit.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
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>

2 files changed, 27 insertions, 3 deletions

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index bb409c485d05..5bfc1b3ab80c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -303,16 +303,36 @@ const struct attribute_group *coresight_tmc_groups[] = {
 static int tmc_etr_setup_caps(struct tmc_drvdata *drvdata,
                              u32 devid, void *dev_caps)
 {
+        u32 dma_mask = 0;
+
         /* Set the unadvertised capabilities */
         tmc_etr_init_caps(drvdata, (u32)(unsigned long)dev_caps);
 
         if (!(devid & TMC_DEVID_NOSCAT))
                 tmc_etr_set_cap(drvdata, TMC_ETR_SG);
+
+        /* Check if the AXI address width is available */
+        if (devid & TMC_DEVID_AXIAW_VALID)
+                dma_mask = ((devid >> TMC_DEVID_AXIAW_SHIFT) &
+                                TMC_DEVID_AXIAW_MASK);
+
         /*
-         * ETR configuration uses a 40-bit AXI master in place of
-         * the embedded SRAM of ETB/ETF.
+         * Unless specified in the device configuration, ETR 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));
+        switch (dma_mask) {
+        case 32:
+        case 40:
+        case 44:
+        case 48:
+        case 52:
+                dev_info(drvdata->dev, "Detected dma mask %dbits\n", dma_mask);
+                break;
+        default:
+                dma_mask = 40;
+        }
+
+        return dma_set_mask_and_coherent(drvdata->dev, DMA_BIT_MASK(dma_mask));
 }
 
 static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index bb6a3e3314b8..f55203d48673 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -71,6 +71,10 @@
 
 #define TMC_DEVID_NOSCAT        BIT(24)
 
+#define TMC_DEVID_AXIAW_VALID   BIT(16)
+#define TMC_DEVID_AXIAW_SHIFT   17
+#define TMC_DEVID_AXIAW_MASK    0x7f
+
 enum tmc_config_type {
         TMC_CONFIG_TYPE_ETB,
         TMC_CONFIG_TYPE_ETR,