Aaron Durbin (adurbin@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2918
-gerrit
commit 5e7f0ca99cb1589c50d4a45c77ed4511a2245a55 Author: Aaron Durbin adurbin@chromium.org Date: Tue Mar 26 12:47:47 2013 -0500
x86: mtrr: add CONFIG_ROM_CACHE support
The CONFIG_CACHE_ROM support in the MTRR code allocates an MTRR specifically for setting up write-protect cachine of the ROM. It is assumed that CONFIG_ROM_SIZE is the size of the ROM and the whole area should be cached just under 4GiB. If enabled, the MTRR code will allocate but not enable rom caching. It is up to the callers of the MTRR code to explicitly enable (and disable afterwards) through the use of 2 new functions: - x86_mtrr_enable_rom_caching() - x86_mtrr_disable_rom_caching()
Additionally, the CACHE_ROM option is exposed to the config menu so that it is not just selected by the chipset or board. The reasoning is that through a multitude of options CACHE_ROM may not be appropriate for enabling.
Change-Id: I4483df850f442bdcef969ffeaf7608ed70b88085 Signed-off-by: Aaron Durbin adurbin@chromium.org --- src/cpu/x86/Kconfig | 5 +++- src/cpu/x86/mtrr/mtrr.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++ src/include/cpu/x86/mtrr.h | 16 +++++++++++++ 3 files changed, 79 insertions(+), 1 deletion(-)
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig index 8f05bf3..6c6a73f 100644 --- a/src/cpu/x86/Kconfig +++ b/src/cpu/x86/Kconfig @@ -56,8 +56,11 @@ config LOGICAL_CPUS default y
config CACHE_ROM - bool + bool "Allow for caching system ROM." default n + help + When selected a variable range MTRR is allocated for coreboot and + the bootloader enable caching of the system ROM for faster access.
config SMM_TSEG bool diff --git a/src/cpu/x86/mtrr/mtrr.c b/src/cpu/x86/mtrr/mtrr.c index 8bf69c5..c847d2c 100644 --- a/src/cpu/x86/mtrr/mtrr.c +++ b/src/cpu/x86/mtrr/mtrr.c @@ -163,6 +163,16 @@ static struct memranges *get_physical_address_space(void) memranges_add_resources(addr_space, mask, match, MTRR_TYPE_WRCOMB);
+#if CONFIG_CACHE_ROM + /* Add a write-protect region covering the ROM size + * when CONFIG_CACHE_ROM is enabled. The ROM is assumed + * to be located at 4GiB - rom size. */ + resource_t rom_base = RANGE_TO_PHYS_ADDR( + RANGE_4GB - PHYS_TO_RANGE_ADDR(CONFIG_ROM_SIZE)); + memranges_insert(addr_space, rom_base, CONFIG_ROM_SIZE, + MTRR_TYPE_WRPROT); +#endif + /* The address space below 4GiB is special. It needs to be * covered entirly by range entries so that MTRR calculations * can be properly done for the full 32-bit address space. @@ -335,6 +345,44 @@ void x86_setup_fixed_mtrrs(void) enable_fixed_mtrr(); }
+/* Keep track of the MTRR that covers the ROM for caching purposes. */ +#if CONFIG_CACHE_ROM +static long rom_cache_mtrr = -1; + +void x86_mtrr_enable_rom_caching(void) +{ + msr_t msr_val; + unsigned long index; + + if (rom_cache_mtrr < 0) + return; + + index = rom_cache_mtrr; + disable_cache(); + msr_val = rdmsr(MTRRphysBase_MSR(index)); + msr_val.lo &= ~0xff; + msr_val.lo |= MTRR_TYPE_WRPROT; + wrmsr(MTRRphysBase_MSR(index), msr_val); + enable_cache(); +} + +void x86_mtrr_disable_rom_caching(void) +{ + msr_t msr_val; + unsigned long index; + + if (rom_cache_mtrr < 0) + return; + + index = rom_cache_mtrr; + disable_cache(); + msr_val = rdmsr(MTRRphysBase_MSR(index)); + msr_val.lo &= ~0xff; + wrmsr(MTRRphysBase_MSR(index), msr_val); + enable_cache(); +} +#endif + struct var_mtrr_state { struct memranges *addr_space; int above4gb; @@ -382,6 +430,17 @@ static void write_var_mtrr(struct var_mtrr_state *var_state, mask = (1ULL << var_state->address_bits) - 1; rsize = rsize & mask;
+#if CONFIG_CACHE_ROM + /* CONFIG_CACHE_ROM allocates an MTRR specifically for allowing + * one to turn on caching for faster ROM access. However, it is + * left to the MTRR callers to enable it. */ + if (mtrr_type == MTRR_TYPE_WRPROT) { + mtrr_type = MTRR_TYPE_UNCACHEABLE; + if (rom_cache_mtrr < 0) + rom_cache_mtrr = var_state->mtrr_index; + } +#endif + printk(BIOS_DEBUG, "MTRR: %d base 0x%016llx mask 0x%016llx type %d\n", var_state->mtrr_index, rbase, rsize, mtrr_type);
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h index 618a93c..bff736d 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)