diff options
| -rw-r--r-- | chipset_enable.c | 45 |
1 files changed, 33 insertions, 12 deletions
diff --git a/chipset_enable.c b/chipset_enable.c index 4cbb9417..2ec4c7dc 100644 --- a/chipset_enable.c +++ b/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; } |