coresight: stm: ACPI support for parsing stimulus base

The stimulus base for STM device must be listed as the second memory
resource, followed by the programming base address as described in
"Section 2.3 Resources" in ACPI for CoreSightTM 1.0 Platform Design
documen (DEN0067).

Add support for parsing the information for ACPI.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
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>

drivers/hwtracing/coresight/coresight-stm.c

@@ -16,6 +16,7 @@
  * (C) 2015-2016 Chunyan Zhang <zhang.chunyan@linaro.org>
  */
 #include <asm/local.h>
+#include <linux/acpi.h>
 #include <linux/amba/bus.h>
 #include <linux/bitmap.h>
 #include <linux/clk.h>
@@ -716,10 +717,60 @@ 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;
+
+	/*
+	 * The stimulus base for STM device must be listed as the second memory
+	 * resource, followed by the programming base address as described in
+	 * "Section 2.3 Resources" in ACPI for CoreSightTM 1.0 Platform Design
+	 * document (DEN0067).
+	 */
+	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 (is_of_node(dev_fwnode(dev)))
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+
+	if (is_of_node(fwnode))
 		return of_stm_get_stimulus_area(dev, res);
+	else if (is_acpi_node(fwnode))
+		return acpi_stm_get_stimulus_area(dev, res);
 	return -ENOENT;
 }