diff options
Diffstat (limited to 'src/include/cpu/x86/mtrr.h')
| -rw-r--r-- | src/include/cpu/x86/mtrr.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h index 618a93c44e..bff736d296 100644 --- a/src/include/cpu/x86/mtrr.h +++ b/src/include/cpu/x86/mtrr.h @@ -52,6 +52,10 @@ * of the nature of the global MTRR enable flag. Therefore, all direct * or indirect callers of enable_fixed_mtrr() should ensure that the * variable MTRR MSRs do not contain bad ranges. + * 3. If CONFIG_CACHE_ROM is selected an MTRR is allocated for enabling + * the caching of the ROM. However, it is set to uncacheable (UC). It + * is the responsiblity of the caller to enable it by calling + * x86_mtrr_enable_rom_caching(). */ void x86_setup_mtrrs(void); /* @@ -67,6 +71,18 @@ void x86_setup_fixed_mtrrs(void); /* Set up fixed MTRRs but do not enable them. */ void x86_setup_fixed_mtrrs_no_enable(void); int x86_mtrr_check(void); +/* ROM caching can be used after variable MTRRs are set up. Beware that + * enabling CONFIG_CACHE_ROM will eat through quite a few MTRRs based on + * one's IO hole size and WRCOMB resources. Be sure to check the console + * log when enabling CONFIG_CACHE_ROM or adding WRCOMB resources. */ +#if CONFIG_CACHE_ROM +void x86_mtrr_enable_rom_caching(void); +void x86_mtrr_disable_rom_caching(void); +#else +static inline void x86_mtrr_enable_rom_caching(void) {} +static inline void x86_mtrr_disable_rom_caching(void) {} +#endif /* CONFIG_CACHE_ROM */ + #endif #if !defined(CONFIG_RAMTOP) |