x86: ivybridge: Request MTRRs for DRAM regions

We should use MTRRs to speed up execution. Add a list of MTRR requests which
will dealt with when we relocate and run from RAM.

We set RAM as cacheable (with write-back) and registers as non-cacheable.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/x86/cpu/ivybridge/sdram.c b/arch/x86/cpu/ivybridge/sdram.c
index b95e781..9504735 100644 (file)
--- a/arch/x86/cpu/ivybridge/sdram.c
+++ b/arch/x86/cpu/ivybridge/sdram.c
@@ -17,6 +17,7 @@
 #include <asm/processor.h>
 #include <asm/gpio.h>
 #include <asm/global_data.h>
+#include <asm/mtrr.h>
 #include <asm/pci.h>
 #include <asm/arch/me.h>
 #include <asm/arch/pei_data.h>
@@ -430,6 +431,15 @@ static int sdram_find(pci_dev_t dev)
        add_memory_area(info, (2 << 28) + (2 << 20), 4 << 28);
        add_memory_area(info, (4 << 28) + (2 << 20), tseg_base);
        add_memory_area(info, 1ULL << 32, touud);
+
+       /* Add MTRRs for memory */
+       mtrr_add_request(MTRR_TYPE_WRBACK, 0, 2ULL << 30);
+       mtrr_add_request(MTRR_TYPE_WRBACK, 2ULL << 30, 512 << 20);
+       mtrr_add_request(MTRR_TYPE_WRBACK, 0xaULL << 28, 256 << 20);
+       mtrr_add_request(MTRR_TYPE_UNCACHEABLE, tseg_base, 16 << 20);
+       mtrr_add_request(MTRR_TYPE_UNCACHEABLE, tseg_base + (16 << 20),
+                        32 << 20);
+
        /*
         * If >= 4GB installed then memory from TOLUD to 4GB
         * is remapped above TOM, TOUUD will account for both