diff options
author | Ronald G. Minnich <rminnich@gmail.com> | 2003-10-20 19:57:35 +0000 |
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committer | Ronald G. Minnich <rminnich@gmail.com> | 2003-10-20 19:57:35 +0000 |
commit | 4398d1e5a9e2d2d384bd917cf679d17d43cd6c57 (patch) | |
tree | 529e83f85c21372a4e61be20515f309c7ec18783 /src/cpu/p6/earlymtrr.c | |
parent | 472e74177c3f25b263ab312f9285dd41da1fe11e (diff) |
early mtrr for the p6
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@1223 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'src/cpu/p6/earlymtrr.c')
-rw-r--r-- | src/cpu/p6/earlymtrr.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/cpu/p6/earlymtrr.c b/src/cpu/p6/earlymtrr.c new file mode 100644 index 0000000000..c4563ea860 --- /dev/null +++ b/src/cpu/p6/earlymtrr.c @@ -0,0 +1,108 @@ +#include <cpu/p6/mtrr.h> +#include <cpu/p6/msr.h> + +static inline unsigned long read_cr0(void) +{ + unsigned long cr0; + asm volatile ("movl %%cr0, %0" : "=r" (cr0)); + return cr0; +} + +static inline void write_cr0(unsigned long cr0) +{ + asm volatile ("movl %0, %%cr0" : : "r" (cr0)); +} + +/* the fixed and variable MTTRs are power-up with random values, + * clear them to MTRR_TYPE_UNCACHEABLE for safty. + */ + +static void early_mtrr_init(void) +{ + static const unsigned long mtrr_msrs[] = { + /* fixed mtrr */ + 0x250, 0x258, 0x259, + 0x268, 0x269, 0x26A, + 0x26B, 0x26C, 0x26D, + 0x26E, 0x26F, + /* var mtrr */ + 0x200, 0x201, 0x202, 0x203, + 0x204, 0x205, 0x206, 0x207, + 0x208, 0x209, 0x20A, 0x20B, + 0x20C, 0x20D, 0x20E, 0x20F, + /* NULL end of table */ + 0 + }; + msr_t msr; + const unsigned long *msr_addr; + unsigned long cr0; + + print_err("Disabling cache\n"); + /* Just to be sure, take all the steps to disable the cache. + * This may not be needed, but C3's may... + * Invalidate the cache */ + asm volatile ("invd"); + + /* Disable the cache */ + cr0 = read_cr0(); + cr0 |= 0x40000000; + write_cr0(cr0); + + /* Disable Variable MTRRs */ + msr.hi = 0x00000000; + msr.lo = 0x00000000; + wrmsr(0x2ff, msr); + + /* Invalidate the cache again */ + asm volatile ("invd"); + + print_err("Clearing mtrr\n"); + + /* Inialize all of the relevant msrs to 0 */ + msr.lo = 0; + msr.hi = 0; + for(msr_addr = mtrr_msrs; *msr_addr; msr_addr++) { + wrmsr(*msr_addr, msr); + } + + /* Enable caching for 0 - 128MB using variable mtrr */ + msr = rdmsr(0x200); + msr.hi &= 0xfffffff0; + msr.hi |= 0x00000000; + msr.lo &= 0x00000f00; + msr.lo |= 0x00000006; + wrmsr(0x200, msr); + + msr = rdmsr(0x201); + msr.hi &= 0xfffffff0; + msr.hi |= 0x0000000f; + msr.lo &= 0x000007ff; + msr.lo |= 0xf0000800; + wrmsr(0x201, msr); + +#if defined(XIP_ROM_SIZE) && defined(XIP_ROM_BASE) + print_err("Setting XIP\n"); + /* enable write through caching so we can do execute in place + * on the flash rom. + */ + msr.hi = 0x00000000; + msr.lo = XIP_ROM_BASE | MTRR_TYPE_WRTHROUGH; + wrmsr(0x202, msr); + msr.hi = 0x0000000f; + msr.lo = ~(XIP_ROM_SIZE - 1) | 0x800; + wrmsr(0x203, msr); +#endif + + /* Set the default memory type and enable fixed and variable MTRRs + */ + /* Enable Variable MTRRs */ + msr.hi = 0x00000000; + msr.lo = 0x00000800; + wrmsr(0x2ff, msr); + + /* Enable the cache */ + cr0 = read_cr0(); + cr0 &= 0x9fffffff; + write_cr0(cr0); + print_err("Enabled the cache\n"); +} |