[PATCH 23/25] coresight: stm: ACPI support for parsing stimulus base

[Suzuki K Poulose <suzuki.poulose@xxxxxxx>]

The stimulus base for STM device must be listed as the second memory
resource, followed by the programming base address. Add support for
parsing the information for ACPI.

Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
 drivers/hwtracing/coresight/coresight-stm.c | 43 +++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index d94ae22..995443a 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -16,6 +16,7 @@
  * (C) 2015-2016 Chunyan Zhang <zhang.chunyan@xxxxxxxxxx>
  */
 #include <asm/local.h>
+#include <linux/acpi.h>
 #include <linux/amba/bus.h>
 #include <linux/bitmap.h>
 #include <linux/clk.h>
@@ -717,10 +718,52 @@ static inline int of_stm_get_stimulus_area(struct device *dev,
 }
 #endif
 
+#ifdef CONFIG_ACPI
+static int acpi_stm_get_stimulus_area(struct device *dev, struct resource *res)
+{
+	int rc;
+	bool found_base = false;
+	struct resource_entry *rent;
+	LIST_HEAD(res_list);
+
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (!adev)
+		return -ENODEV;
+	rc = acpi_dev_get_resources(adev, &res_list, NULL, NULL);
+	if (rc < 0)
+		return rc;
+
+	rc = -ENOENT;
+	list_for_each_entry(rent, &res_list, node) {
+		if (resource_type(rent->res) != IORESOURCE_MEM)
+			continue;
+		if (found_base) {
+			*res = *rent->res;
+			rc = 0;
+			break;
+		}
+
+		found_base = true;
+	}
+
+	acpi_dev_free_resource_list(&res_list);
+	return rc;
+}
+#else
+static inline int acpi_stm_get_stimulus_area(struct device *dev,
+					     struct resource *res)
+{
+	return -ENOENT;
+}
+#endif
+
 static int stm_get_stimulus_area(struct device *dev, struct resource *res)
 {
 	if (dev->of_node)
 		return of_stm_get_stimulus_area(dev, res);
+	else if (is_acpi_node(dev->fwnode))
+		return acpi_stm_get_stimulus_area(dev, res);
 	return -ENOENT;
 }
 
-- 
2.7.4