dmi: Let drivers walk the DMI table

Let drivers walk the DMI table for their own needs. Some drivers need
data stored in OEM-specific DMI records for proper operation.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

2 files changed, 51 insertions, 14 deletions

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index e0bade732376..1412d7bcdbd1 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -43,18 +43,12 @@ static char * __init dmi_string(const struct dmi_header *dm, u8 s)
  *	We have to be cautious here. We have seen BIOSes with DMI pointers
  *	pointing to completely the wrong place for example
  */
-static int __init dmi_table(u32 base, int len, int num,
-			    void (*decode)(const struct dmi_header *))
+static void dmi_table(u8 *buf, int len, int num,
+		      void (*decode)(const struct dmi_header *))
 {
-	u8 *buf, *data;
+	u8 *data = buf;
 	int i = 0;
 
-	buf = dmi_ioremap(base, len);
-	if (buf == NULL)
-		return -1;
-
-	data = buf;
-
 	/*
 	 *	Stop when we see all the items the table claimed to have
 	 *	OR we run off the end of the table (also happens)
@@ -75,7 +69,23 @@ static int __init dmi_table(u32 base, int len, int num,
 		data += 2;
 		i++;
 	}
-	dmi_iounmap(buf, len);
+}
+
+static u32 dmi_base;
+static u16 dmi_len;
+static u16 dmi_num;
+
+static int __init dmi_walk_early(void (*decode)(const struct dmi_header *))
+{
+	u8 *buf;
+
+	buf = dmi_ioremap(dmi_base, dmi_len);
+	if (buf == NULL)
+		return -1;
+
+	dmi_table(buf, dmi_len, dmi_num, decode);
+
+	dmi_iounmap(buf, dmi_len);
 	return 0;
 }
 
@@ -291,9 +301,9 @@ static int __init dmi_present(const char __iomem *p)
 
 	memcpy_fromio(buf, p, 15);
 	if ((memcmp(buf, "_DMI_", 5) == 0) && dmi_checksum(buf)) {
-		u16 num = (buf[13] << 8) | buf[12];
-		u16 len = (buf[7] << 8) | buf[6];
-		u32 base = (buf[11] << 24) | (buf[10] << 16) |
+		dmi_num = (buf[13] << 8) | buf[12];
+		dmi_len = (buf[7] << 8) | buf[6];
+		dmi_base = (buf[11] << 24) | (buf[10] << 16) |
 			(buf[9] << 8) | buf[8];
 
 		/*
@@ -305,7 +315,7 @@ static int __init dmi_present(const char __iomem *p)
 			       buf[14] >> 4, buf[14] & 0xF);
 		else
 			printk(KERN_INFO "DMI present.\n");
-		if (dmi_table(base,len, num, dmi_decode) == 0)
+		if (dmi_walk_early(dmi_decode) == 0)
 			return 0;
 	}
 	return 1;
@@ -489,3 +499,27 @@ int dmi_get_year(int field)
 
 	return year;
 }
+
+/**
+ *	dmi_walk - Walk the DMI table and get called back for every record
+ *	@decode: Callback function
+ *
+ *	Returns -1 when the DMI table can't be reached, 0 on success.
+ */
+int dmi_walk(void (*decode)(const struct dmi_header *))
+{
+	u8 *buf;
+
+	if (!dmi_available)
+		return -1;
+
+	buf = ioremap(dmi_base, dmi_len);
+	if (buf == NULL)
+		return -1;
+
+	dmi_table(buf, dmi_len, dmi_num, decode);
+
+	iounmap(buf);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dmi_walk);
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index b1251b2af568..bbc9992ec374 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -79,6 +79,7 @@ extern void dmi_scan_machine(void);
 extern int dmi_get_year(int field);
 extern int dmi_name_in_vendors(const char *str);
 extern int dmi_available;
+extern int dmi_walk(void (*decode)(const struct dmi_header *));
 
 #else
 
@@ -89,6 +90,8 @@ static inline const struct dmi_device * dmi_find_device(int type, const char *na
 static inline int dmi_get_year(int year) { return 0; }
 static inline int dmi_name_in_vendors(const char *s) { return 0; }
 #define dmi_available 0
+static inline int dmi_walk(void (*decode)(const struct dmi_header *))
+	{ return -1; }
 
 #endif