[PATCH] ACPI/ADXL: Added function for ADXL DSM Function 3

[Rithvik Rama]

Current driver supports only Function Index 1 & 2 as mentioned in the
ACPI ADXL DSM Interface. Added a function for ACPI Function Index 3.

Signed-off-by: Rithvik Rama <rithvik.rama@xxxxxxxxx>
---
 drivers/acpi/acpi_adxl.c | 54 +++++++++++++++++++++++++++++++++++++++-
 include/linux/adxl.h     |  1 +
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_adxl.c b/drivers/acpi/acpi_adxl.c
index 13c8f7b50c46..5bf53662b737 100644
--- a/drivers/acpi/acpi_adxl.c
+++ b/drivers/acpi/acpi_adxl.c
@@ -14,6 +14,7 @@
 #define ADXL_REVISION			0x1
 #define ADXL_IDX_GET_ADDR_PARAMS	0x1
 #define ADXL_IDX_FORWARD_TRANSLATE	0x2
+#define ADXL_IDX_REVERSE_TRANSLATE	0X3
 #define ACPI_ADXL_PATH			"\\_SB.ADXL"
 
 /*
@@ -135,6 +136,56 @@ int adxl_decode(u64 addr, u64 component_values[])
 }
 EXPORT_SYMBOL_GPL(adxl_decode);
 
+/**
+ * adxl_reverse_decode - Ask BIOS to decode a memory address to system address
+ * @component_values: pointer to array of values for each component
+ * Returns 0 on success, negative error code otherwise
+ *
+ */
+
+int adxl_reverse_decode(u64 component_values[])
+{
+	union acpi_object *argv4, *results, *r;
+	int i, cnt;
+
+	argv4 = kzalloc((adxl_count+1)*sizeof(*argv4), GFP_KERNEL);
+	if (!argv4)
+		return -ENOMEM;
+
+	if (!adxl_component_names)
+		return -EOPNOTSUPP;
+
+	argv4[0].type = ACPI_TYPE_PACKAGE;
+	argv4[0].package.count = adxl_count;
+	argv4[0].package.elements = &argv4[1];
+
+	/*
+	 * Loop through supported memory component values
+	 */
+	for (i = 1; i <= adxl_count; i++) {
+		argv4[i].integer.type = ACPI_TYPE_INTEGER;
+		argv4[i].integer.value = component_values[i-1];
+	}
+
+	results = adxl_dsm(ADXL_IDX_REVERSE_TRANSLATE, argv4);
+	if (!results)
+		return -EINVAL;
+
+	r = results->package.elements + 1;
+	cnt = r->package.count;
+	if (cnt != adxl_count) {
+		ACPI_FREE(results);
+		return -EINVAL;
+	}
+	r = r->package.elements;
+	for (i = 0; i < cnt; i++)
+		component_values[i] = r[i].integer.value;
+
+	ACPI_FREE(results);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(adxl_reverse_decode);
+
 static int __init adxl_init(void)
 {
 	char *path = ACPI_ADXL_PATH;
@@ -155,7 +206,8 @@ static int __init adxl_init(void)
 
 	if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION,
 			    ADXL_IDX_GET_ADDR_PARAMS |
-			    ADXL_IDX_FORWARD_TRANSLATE)) {
+			    ADXL_IDX_FORWARD_TRANSLATE |
+			    ADXL_IDX_REVERSE_TRANSLATE)) {
 		pr_info("DSM method does not support forward translate\n");
 		return -ENODEV;
 	}
diff --git a/include/linux/adxl.h b/include/linux/adxl.h
index 2a629acb4c3f..f3fea64a270c 100644
--- a/include/linux/adxl.h
+++ b/include/linux/adxl.h
@@ -9,5 +9,6 @@
 
 const char * const *adxl_get_component_names(void);
 int adxl_decode(u64 addr, u64 component_values[]);
+int adxl_reverse_decode(u64 component_values[]);
 
 #endif /* _LINUX_ADXL_H */
-- 
2.34.1