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x86: add rom cache variable MTRR index to tables

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Downstream payloads may need to take advantage of caching the
ROM for performance reasons. Add the ability to communicate the
variable range MTRR index to use to perform the caching enablement.

An example usage implementation would be to obtain the variable MTRR
index that covers the ROM from the coreboot tables. Then one would
disable caching and change the MTRR type from uncacheable to
write-protect and enable caching. The opposite sequence is required
to tearn down the caching.

Change-Id: I4d486cfb986629247ab2da7818486973c6720ef5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2919
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Aaron Durbin
2013-03-26 13:09:39 -05:00
committed by Stefan Reinauer
parent f567f16af4
commit bc07f5d935
4 changed files with 39 additions and 0 deletions
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23
src/lib/coreboot_table.c
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@@ -40,6 +40,9 @@
#include <vendorcode/google/chromeos/chromeos.h>
#include <vendorcode/google/chromeos/gnvs.h>
#endif
#if CONFIG_ARCH_X86
#include <cpu/x86/mtrr.h>
#endif
static struct lb_header *lb_table_init(unsigned long addr)
{
@@ -237,6 +240,24 @@ static inline void lb_vboot_handoff(struct lb_header *header) {}
#endif /* CONFIG_VBOOT_VERIFY_FIRMWARE */
#endif /* CONFIG_CHROMEOS */
static void lb_x86_rom_cache(struct lb_header *header)
{
#if CONFIG_ARCH_X86
long mtrr_index;
struct lb_x86_rom_mtrr *lb_x86_rom_mtrr;
mtrr_index = x86_mtrr_rom_cache_var_index();
if (mtrr_index < 0)
return;
lb_x86_rom_mtrr = (struct lb_x86_rom_mtrr *)lb_new_record(header);
lb_x86_rom_mtrr->tag = LB_TAG_X86_ROM_MTRR;
lb_x86_rom_mtrr->size = sizeof(struct lb_x86_rom_mtrr);
lb_x86_rom_mtrr->index = mtrr_index;
#endif
}
static void add_cbmem_pointers(struct lb_header *header)
{
/*
@@ -539,6 +560,8 @@ unsigned long write_coreboot_table(
lb_strings(head);
/* Record our framebuffer */
lb_framebuffer(head);
/* Communicate x86 variable MTRR ROM cache information. */
lb_x86_rom_cache(head);
#if CONFIG_CHROMEOS
/* Record our GPIO settings (ChromeOS specific) */