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 e0bade73237..1412d7bcdbd 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 b1251b2af56..bbc9992ec37 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