drivers/firmware/dmi_scan.c: fetch dmi version from SMBIOS if it exists

The right dmi version is in SMBIOS if it's zero in DMI region

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: Feng Jin <joe.jin@oracle.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 3714e3c03df6ba50ff9c9c1df1128972a481bb4b..111f3bab3a320665164474a57464f49bca810659 100644 (file)
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -119,12 +119,12 @@ static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
        return 0;
 }
 
-static int __init dmi_checksum(const u8 *buf)
+static int __init dmi_checksum(const u8 *buf, u8 len)
 {
        u8 sum = 0;
        int a;
 
-       for (a = 0; a < 15; a++)
+       for (a = 0; a < len; a++)
                sum += buf[a];
 
        return sum == 0;
@@ -415,30 +415,58 @@ static int __init dmi_present(const char __iomem *p)
        u8 buf[15];
 
        memcpy_fromio(buf, p, 15);
-       if ((memcmp(buf, "_DMI_", 5) == 0) && dmi_checksum(buf)) {
+       if (dmi_checksum(buf, 15)) {
                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];
 
-               /*
-                * DMI version 0.0 means that the real version is taken from
-                * the SMBIOS version, which we don't know at this point.
-                */
-               dmi_ver = (buf[14] & 0xf0) << 4 | (buf[14] & 0x0f);
-               if (buf[14] != 0)
-                       printk(KERN_INFO "DMI %d.%d present.\n",
-                              buf[14] >> 4, buf[14] & 0xF);
-               else
-                       printk(KERN_INFO "DMI present.\n");
                if (dmi_walk_early(dmi_decode) == 0) {
+                       if (dmi_ver)
+                               printk(KERN_INFO "SMBIOS %d.%d present.\n",
+                                      dmi_ver >> 8, dmi_ver & 0xFF);
+                       else {
+                               dmi_ver = (buf[14] & 0xF0) << 4 |
+                                          (buf[14] & 0x0F);
+                               printk(KERN_INFO "Legacy DMI %d.%d present.\n",
+                                      dmi_ver >> 8, dmi_ver & 0xFF);
+                       }
                        dmi_dump_ids();
                        return 0;
                }
        }
+       dmi_ver = 0;
        return 1;
 }
 
+static int __init smbios_present(const char __iomem *p)
+{
+       u8 buf[32];
+       int offset = 0;
+
+       memcpy_fromio(buf, p, 32);
+       if ((buf[5] < 32) && dmi_checksum(buf, buf[5])) {
+               dmi_ver = (buf[6] << 8) + buf[7];
+
+               /* Some BIOS report weird SMBIOS version, fix that up */
+               switch (dmi_ver) {
+               case 0x021F:
+               case 0x0221:
+                       printk(KERN_DEBUG "SMBIOS version fixup(2.%d->2.%d)\n",
+                              dmi_ver & 0xFF, 3);
+                       dmi_ver = 0x0203;
+                       break;
+               case 0x0233:
+                       printk(KERN_DEBUG "SMBIOS version fixup(2.%d->2.%d)\n",
+                              51, 6);
+                       dmi_ver = 0x0206;
+                       break;
+               }
+               offset = 16;
+       }
+       return dmi_present(buf + offset);
+}
+
 void __init dmi_scan_machine(void)
 {
        char __iomem *p, *q;
@@ -456,7 +484,7 @@ void __init dmi_scan_machine(void)
                if (p == NULL)
                        goto error;
 
-               rc = dmi_present(p + 0x10); /* offset of _DMI_ string */
+               rc = smbios_present(p);
                dmi_iounmap(p, 32);
                if (!rc) {
                        dmi_available = 1;
@@ -474,7 +502,12 @@ void __init dmi_scan_machine(void)
                        goto error;
 
                for (q = p; q < p + 0x10000; q += 16) {
-                       rc = dmi_present(q);
+                       if (memcmp(q, "_SM_", 4) == 0 && q - p <= 0xFFE0)
+                               rc = smbios_present(q);
+                       else if (memcmp(q, "_DMI_", 5) == 0)
+                               rc = dmi_present(q);
+                       else
+                               continue;
                        if (!rc) {
                                dmi_available = 1;
                                dmi_iounmap(p, 0x10000);