This implements support for devices using AMD Geode companion chip

CS5536 that have the Boot ROM on NOR flash that is directly connected to
FLASH_CS3 (Boot Flash Chip Select).
We need to write enable it in the NORF_CTL MSR register for flashrom to
be able to write to it, including JEDEC probe commands.

This patch allows us to stop using AMD gx_utils.ko for BIOS flashing on
the DBE61.

Signed-off-by: Mart Raudsepp <mart.raudsepp@artecdesign.ee>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3097 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

diff --git a/util/flashrom/chipset_enable.c b/util/flashrom/chipset_enable.c
index 4cbb9417896ef7f47d2f89a1e6c9d525ea17b700..2ec4c7dcc761d4f1868d08ee94683b8d408ff709 100644 (file)
--- a/util/flashrom/chipset_enable.c
+++ b/util/flashrom/chipset_enable.c
@@ -228,6 +228,8 @@ static int enable_flash_cs5530(struct pci_dev *dev, const char *name)
 
 static int enable_flash_cs5536(struct pci_dev *dev, const char *name)
 {
+       #define MSR_NORF_CTL    0x51400018
+
        int fd_msr;
        unsigned char buf[8];
        unsigned int addr = 0x1808;
@@ -243,34 +245,53 @@ static int enable_flash_cs5536(struct pci_dev *dev, const char *name)
         * could have potential problems on SMP machines since it
         * assumes cpu0, but it is safe on the Geode which is not SMP.
         *
+        * Geode systems also write protect the NOR flash chip itself
+        * via MSR_NORF_CTL. To enable write to NOR Boot flash for the
+        * benefit of systems that have such a setup, raise
+        * MSR 0x51400018 WE_CS3 (write enable Boot Flash Chip Select).
+        *
         * This is probably not portable beyond Linux.
         */
 
-       fd_msr = open("/dev/cpu/0/msr", O_RDONLY);
+       fd_msr = open("/dev/cpu/0/msr", O_RDWR);
        if (!fd_msr) {
                perror("open msr");
                return -1;
        }
        lseek64(fd_msr, (off64_t) addr, SEEK_SET);
        read(fd_msr, buf, 8);
-       close(fd_msr);
+
+       printf("Enabling Geode MSR to write to flash.\n");
+
        if (buf[7] != 0x22) {
-               printf("Enabling Geode MSR to write to flash.\n");
-               buf[7] &= 0xFB;
-               fd_msr = open("/dev/cpu/0/msr", O_WRONLY);
-               if (!fd_msr) {
-                       perror("open msr");
-                       return -1;
-               }
+               buf[7] &= 0xfb;
                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");
+                       printf("Cannot write to MSR. Did you run 'modprobe msr'?\n");
                        return -1;
                }
-               close(fd_msr);
        }
+
+       lseek64(fd_msr, (off64_t) MSR_NORF_CTL, SEEK_SET);
+       if (read(fd_msr, buf, 8) != 8) {
+               perror("read msr");
+               return -1;
+       }
+
+       /* Raise WE_CS3 bit. */
+       buf[0] |= 0x08;
+
+       lseek64(fd_msr, (off64_t) MSR_NORF_CTL, SEEK_SET);
+       if (write(fd_msr, buf, 8) < 0) {
+               perror("msr write");
+               printf("Cannot write to MSR. Did you run 'modprobe msr'?\n");
+               return -1;
+       }
+
+       close(fd_msr);
+
+       #undef MSR_NORF_CTL
        return 0;
 }