[RFC Patch v1 01/13] ACPI: introduce helper interfaces to support ACPI _DSM method

[RFC Patch v1 01/13] ACPI: introduce helper interfaces to support ACPI _DSM method

[Jiang Liu]

There are several drivers making use of ACPI _DSM method to detect
and invoke device specific methods. Currently every driver has
implemented its private version to support ACPI _DSM method.
So this patch introduces three helper functions to support ACPI _DSM
method, which will be used to replace open-coded versions.

It helps to simplify code and improve code readability.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 drivers/acpi/utils.c    |   98 +++++++++++++++++++++++++++++++++++++++++++++++
 include/acpi/acpi_bus.h |   26 +++++++++++++
 2 files changed, 124 insertions(+)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 6d408bf..9517b0a 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -574,3 +574,101 @@ acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
 
 	return status;
 }
+
+/**
+ * acpi_evaluate_dsm: evaluate device's _DSM method
+ * @handle: ACPI device handle
+ * @uuid: UUID of requested functions, should be 16 bytes
+ * @rev: revision number of requested function
+ * @func: requested function number
+ * @argv4: the function specific parameter
+ *
+ * Evaluate device's _DSM method with specified UUID, revision id and
+ * function number. Caller needs to free the returned object.
+ *
+ * Though ACPI defines the fourth parameter for _DSM should be a package,
+ * some old BIOSes do expect a buffer or an integer etc.
+ */
+union acpi_object *
+acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid, int rev, int func,
+		  union acpi_object *argv4)
+{
+	acpi_status ret;
+	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
+	union acpi_object params[4];
+	struct acpi_object_list input = {
+		.count = 4,
+		.pointer = params,
+	};
+
+	params[0].type = ACPI_TYPE_BUFFER;
+	params[0].buffer.length = 16;
+	params[0].buffer.pointer = (char *)uuid;
+	params[1].type = ACPI_TYPE_INTEGER;
+	params[1].integer.value = rev;
+	params[2].type = ACPI_TYPE_INTEGER;
+	params[2].integer.value = func;
+	if (argv4) {
+		params[3] = *argv4;
+	} else {
+		params[3].type = ACPI_TYPE_PACKAGE;
+		params[3].package.count = 0;
+		params[3].package.elements = NULL;
+	}
+
+	ret = acpi_evaluate_object(handle, "_DSM", &input, &buf);
+	if (ACPI_SUCCESS(ret))
+		return (union acpi_object *)buf.pointer;
+
+	if (ret != AE_NOT_FOUND)
+		acpi_handle_warn(handle,
+				"failed to evaluate _DSM method (0x%x)\n", ret);
+
+	return NULL;
+}
+EXPORT_SYMBOL(acpi_evaluate_dsm);
+
+/**
+ * acpi_check_dsm: check whether _DSM method under @handle supports
+ *		   requested functions.
+ * @handle: ACPI device handle
+ * @uuid: UUID of requested functions, should be 16 bytes at least
+ * @rev: revision number of requested functions
+ * @funcs: bitmap of requested functions
+ * @exclude: excluding special value, used to support i915 and nouveau
+ *
+ * Evaluate device's _DSM method to check whether it supports requested
+ * functions. Currently only support 64 functions at maximum, should be
+ * enough for now.
+ */
+bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
+{
+	int i;
+	u64 mask = 0;
+	union acpi_object *obj;
+
+	if (funcs == 0)
+		return false;
+
+	obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);
+	if (!obj)
+		return false;
+
+	/* For compatibility, old BIOSes may return an integer */
+	if (obj->type == ACPI_TYPE_INTEGER)
+		mask = obj->integer.value;
+	else if (obj->type == ACPI_TYPE_BUFFER)
+		for (i = 0; i < obj->buffer.length && i < 8; i++)
+			mask |= (((u8)obj->buffer.pointer[i]) << (i * 8));
+	ACPI_FREE(obj);
+
+	/*
+	 * Bit 0 indicates whether there's support for any functions other than
+	 * function 0 for the specified UUID and revision.
+	 */
+	if ((mask & 0x1) && (mask & funcs) == funcs)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(acpi_check_dsm);
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index c602c77..efccf39 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -66,6 +66,32 @@ bool acpi_ata_match(acpi_handle handle);
 bool acpi_bay_match(acpi_handle handle);
 bool acpi_dock_match(acpi_handle handle);
 
+bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs);
+union acpi_object *acpi_evaluate_dsm(acpi_handle handle, const u8 *uuid,
+			int rev, int func, union acpi_object *argv4);
+
+static inline union acpi_object *
+acpi_evaluate_dsm_typed(acpi_handle handle, const u8 *uuid, int rev, int func,
+			union acpi_object *argv4, acpi_object_type type)
+{
+	union acpi_object *obj;
+
+	obj = acpi_evaluate_dsm(handle, uuid, rev, func, argv4);
+	if (obj && obj->type != type) {
+		ACPI_FREE(obj);
+		obj = NULL;
+	}
+
+	return obj;
+}
+
+#define	ACPI_INIT_DSM_ARGV4(cnt, eles)			\
+	{						\
+	  .type = ACPI_TYPE_PACKAGE,			\
+	  .package.count = (cnt),			\
+	  .package.elements = (eles)			\
+	}
+
 #ifdef CONFIG_ACPI
 
 #include <linux/proc_fs.h>
-- 
1.7.10.4

[RFC Patch v1 02/13] ACPI, extlog: replace open-coded _DSM specific code with helper functions

[Jiang Liu]

Use helper functions to simplify _DSM related code in acpi_extlog driver.
Also mark initialization data and functions with __init and __initdata
to reduce memory footprint.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 drivers/acpi/acpi_extlog.c |   61 +++++++++-----------------------------------
 1 file changed, 12 insertions(+), 49 deletions(-)

diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index a6869e1..928c4db 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -20,11 +20,9 @@
 #define EXT_ELOG_ENTRY_MASK	GENMASK_ULL(51, 0) /* elog entry address mask */
 
 #define EXTLOG_DSM_REV		0x0
-#define	EXTLOG_FN_QUERY		0x0
 #define	EXTLOG_FN_ADDR		0x1
 
 #define FLAG_OS_OPTIN		BIT(0)
-#define EXTLOG_QUERY_L1_EXIST	BIT(1)
 #define ELOG_ENTRY_VALID	(1ULL<<63)
 #define ELOG_ENTRY_LEN		0x1000
 
@@ -43,7 +41,7 @@ struct extlog_l1_head {
 	u8  rev1[12];
 };
 
-static u8 extlog_dsm_uuid[] = "663E35AF-CC10-41A4-88EA-5470AF055295";
+static u8 extlog_dsm_uuid[] __initdata = "663E35AF-CC10-41A4-88EA-5470AF055295";
 
 /* L1 table related physical address */
 static u64 elog_base;
@@ -153,62 +151,27 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
 	return NOTIFY_DONE;
 }
 
-static int extlog_get_dsm(acpi_handle handle, int rev, int func, u64 *ret)
+static bool __init extlog_get_l1addr(void)
 {
-	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
-	struct acpi_object_list input;
-	union acpi_object params[4], *obj;
 	u8 uuid[16];
-	int i;
+	acpi_handle handle;
+	union acpi_object *obj;
 
 	acpi_str_to_uuid(extlog_dsm_uuid, uuid);
-	input.count = 4;
-	input.pointer = params;
-	params[0].type = ACPI_TYPE_BUFFER;
-	params[0].buffer.length = 16;
-	params[0].buffer.pointer = uuid;
-	params[1].type = ACPI_TYPE_INTEGER;
-	params[1].integer.value = rev;
-	params[2].type = ACPI_TYPE_INTEGER;
-	params[2].integer.value = func;
-	params[3].type = ACPI_TYPE_PACKAGE;
-	params[3].package.count = 0;
-	params[3].package.elements = NULL;
-
-	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DSM", &input, &buf)))
-		return -1;
-
-	*ret = 0;
-	obj = (union acpi_object *)buf.pointer;
-	if (obj->type == ACPI_TYPE_INTEGER) {
-		*ret = obj->integer.value;
-	} else if (obj->type == ACPI_TYPE_BUFFER) {
-		if (obj->buffer.length <= 8) {
-			for (i = 0; i < obj->buffer.length; i++)
-				*ret |= (obj->buffer.pointer[i] << (i * 8));
-		}
-	}
-	kfree(buf.pointer);
-
-	return 0;
-}
-
-static bool extlog_get_l1addr(void)
-{
-	acpi_handle handle;
-	u64 ret;
 
 	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
 		return false;
-
-	if (extlog_get_dsm(handle, EXTLOG_DSM_REV, EXTLOG_FN_QUERY, &ret) ||
-	    !(ret & EXTLOG_QUERY_L1_EXIST))
+	if (!acpi_check_dsm(handle, uuid, EXTLOG_DSM_REV, 1 << EXTLOG_FN_ADDR))
 		return false;
-
-	if (extlog_get_dsm(handle, EXTLOG_DSM_REV, EXTLOG_FN_ADDR, &ret))
+	obj = acpi_evaluate_dsm_typed(handle, uuid, EXTLOG_DSM_REV,
+				      EXTLOG_FN_ADDR, NULL, ACPI_TYPE_INTEGER);
+	if (!obj) {
 		return false;
+	} else {
+		l1_dirbase = obj->integer.value;
+		ACPI_FREE(obj);
+	}
 
-	l1_dirbase = ret;
 	/* Spec says L1 directory must be 4K aligned, bail out if it isn't */
 	if (l1_dirbase & ((1 << 12) - 1)) {
 		pr_warn(FW_BUG "L1 Directory is invalid at physical %llx\n",
-- 
1.7.10.4