Author: jcrouse
Date: 2007-11-13 17:45:22 +0100 (Tue, 13 Nov 2007)
New Revision: 2967

Modified:
   trunk/util/flashrom/chipset_enable.c
Log:
[LinuxBIOS] flashrom support for AMD Geode CS5536

Attached is a patch that enables AMD Geode CS5536 chipset support.  I
have tested it successfully on a MSM800 board from digital logic.

Signed-off-by: Lane Brooks <[EMAIL PROTECTED]>
Acked-by: Jordan Crouse <[EMAIL PROTECTED]>



Modified: trunk/util/flashrom/chipset_enable.c
===================================================================
--- trunk/util/flashrom/chipset_enable.c        2007-11-13 16:24:15 UTC (rev 
2966)
+++ trunk/util/flashrom/chipset_enable.c        2007-11-13 16:45:22 UTC (rev 
2967)
@@ -23,9 +23,15 @@
  * Contains the chipset specific flash enables.
  */
 
+#define _LARGEFILE64_SOURCE
+
 #include <stdio.h>
 #include <pci/pci.h>
 #include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
 #include "flash.h"
 
 static int enable_flash_ali_m1533(struct pci_dev *dev, char *name)
@@ -218,6 +224,54 @@
        return 0;
 }
 
+static int enable_flash_cs5536(struct pci_dev *dev, char *name)
+{
+       int fd_msr;
+       unsigned char buf[8];
+       unsigned int addr = 0x1808;
+
+       /* Geode systems write protect the BIOS via RCONFs (cache
+        * settings similar to MTRRs). To unlock, change MSR 0x1808
+        * top byte to 0x22. Reading and writing to msr, however
+        * requires instrucitons rdmsr/wrmsr, which are ring0 privileged
+        * instructions so only the kernel can do the read/write.  This
+        * function, therefore, requires that the msr kernel module be
+        * loaded to access these instructions from user space using
+        * device /dev/cpu/0/msr.  This hard-coded driver location
+        * could have potential problems on SMP machines since it
+        * assumes cpu0, but it is safe on the geode which is not SMP.
+        *
+        * This is probably not portable beyond linux.
+        */
+
+       fd_msr = open("/dev/cpu/0/msr", O_RDONLY);
+       if (!fd_msr) {
+               perror("open msr");
+               return -1;
+       }
+       lseek64(fd_msr, (off64_t) addr, SEEK_SET);
+       read(fd_msr, buf, 8);
+       close(fd_msr);
+       if (buf[7] != 0x22) {
+               printf("Enabling Geode MSR to write to flash.\n");
+               buf[7] = 0x22;
+               fd_msr = open("/dev/cpu/0/msr", O_WRONLY);
+               if (!fd_msr) {
+                       perror("open msr");
+                       return -1;
+               }
+               lseek64(fd_msr, (off64_t) addr, SEEK_SET);
+               if (write(fd_msr, buf, 8) < 0) {
+                       perror("msr write");
+                       printf
+                           ("Cannot write to MSR.  Make sure msr kernel is 
loaded: 'modprobe msr'\n");
+                       return -1;
+               }
+               close(fd_msr);
+       }
+       return 0;
+}
+
 static int enable_flash_sc1100(struct pci_dev *dev, char *name)
 {
        uint8_t new;
@@ -460,6 +514,7 @@
        {0x1078, 0x0100, "CS5530/CS5530A", enable_flash_cs5530},
        {0x100b, 0x0510, "SC1100", enable_flash_sc1100},
        {0x1039, 0x0008, "SIS5595", enable_flash_sis5595},
+       {0x1022, 0x2080, "AMD GEODE CS5536", enable_flash_cs5536},
        {0x1022, 0x7468, "AMD8111", enable_flash_amd8111},
        {0x10B9, 0x1533, "ALi M1533", enable_flash_ali_m1533},
        /* this fallthrough looks broken. */


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