diff options
Diffstat (limited to 'src/northbridge/intel')
-rw-r--r-- | src/northbridge/intel/haswell/gma.c | 39 | ||||
-rw-r--r-- | src/northbridge/intel/haswell/haswell.h | 1 |
2 files changed, 40 insertions, 0 deletions
diff --git a/src/northbridge/intel/haswell/gma.c b/src/northbridge/intel/haswell/gma.c index 057d65ad55..8be25e785f 100644 --- a/src/northbridge/intel/haswell/gma.c +++ b/src/northbridge/intel/haswell/gma.c @@ -127,6 +127,45 @@ u32 map_oprom_vendev(u32 vendev) return new_vendev; } +/* GTT is the Global Translation Table for the graphics pipeline. + * It is used to translate graphics addresses to physical + * memory addresses. As in the CPU, GTTs map 4K pages. + * The setgtt function adds a further bit of flexibility: + * it allows you to set a range (the first two parameters) to point + * to a physical address (third parameter);the physical address is + * incremented by a count (fourth parameter) for each GTT in the + * range. + * Why do it this way? For ultrafast startup, + * we can point all the GTT entries to point to one page, + * and set that page to 0s: + * memset(physbase, 0, 4096); + * setgtt(0, 4250, physbase, 0); + * this takes about 2 ms, and is a win because zeroing + * the page takes a up to 200 ms. + * This call sets the GTT to point to a linear range of pages + * starting at physbase. + */ + +#define GTT_PTE_BASE (2 << 20) + +void +set_translation_table(int start, int end, u64 base, int inc) +{ + int i; + + for(i = start; i < end; i++){ + u64 physical_address = base + i*inc; + /* swizzle the 32:39 bits to 4:11 */ + u32 word = physical_address | ((physical_address >> 28) & 0xff0) | 1; + /* note: we've confirmed by checking + * the values that mrc does no + * useful setup before we run this. + */ + gtt_write(GTT_PTE_BASE + i * 4, word); + gtt_read(GTT_PTE_BASE + i * 4); + } +} + static struct resource *gtt_res = NULL; u32 gtt_read(u32 reg) diff --git a/src/northbridge/intel/haswell/haswell.h b/src/northbridge/intel/haswell/haswell.h index bcd22d1be6..55f6f284e4 100644 --- a/src/northbridge/intel/haswell/haswell.h +++ b/src/northbridge/intel/haswell/haswell.h @@ -202,6 +202,7 @@ void intel_northbridge_haswell_finalize_smm(void); #else /* !__SMM__ */ void haswell_early_initialization(int chipset_type); void haswell_late_initialization(void); +void set_translation_table(int start, int end, u64 base, int inc); /* debugging functions */ void print_pci_devices(void); |