diff options
| -rw-r--r-- | util/flashrom/chipset_enable.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/util/flashrom/chipset_enable.c b/util/flashrom/chipset_enable.c index 63996da954..87929f58f4 100644 --- a/util/flashrom/chipset_enable.c +++ b/util/flashrom/chipset_enable.c @@ -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 @@ static int enable_flash_cs5530(struct pci_dev *dev, char *name) 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 @@ static FLASH_ENABLE enables[] = { {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. */ |