[PATCH v2 23/28] x86: emulation: Set an MTRR for the RAM

[Simon Glass]

QEMU likes to have an MTRR set up, just like real machines. Add an MTRR
which covers the total RAM size.

This does nothing on machines without MTRRs.

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

Changes in v2:
- Add new patch to set an MTRR for the RAM in QEMU

 arch/x86/cpu/qemu/dram.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/cpu/qemu/dram.c b/arch/x86/cpu/qemu/dram.c
index 62a301c0fd3..efacc7b3457 100644
--- a/arch/x86/cpu/qemu/dram.c
+++ b/arch/x86/cpu/qemu/dram.c
@@ -4,7 +4,9 @@
  */
 
 #include <init.h>
+#include <spl.h>
 #include <asm/global_data.h>
+#include <asm/mtrr.h>
 #include <asm/post.h>
 #include <asm/arch/qemu.h>
 #include <linux/sizes.h>
@@ -40,10 +42,23 @@ u64 qemu_get_high_memory_size(void)
 
 int dram_init(void)
 {
+	int ret;
+
 	gd->ram_size = qemu_get_low_memory_size();
 	gd->ram_size += qemu_get_high_memory_size();
 	post_code(POST_DRAM);
 
+	if (xpl_phase() == PHASE_BOARD_F) {
+		ret = mtrr_add_request(MTRR_TYPE_WRBACK, 0, gd->ram_size);
+		if (ret != -ENOSYS) {
+			if (ret)
+				return log_msg_ret("mta", ret);
+			ret = mtrr_commit(false);
+			if (ret)
+				return log_msg_ret("mtc", ret);
+		}
+	}
+
 	return 0;
 }
 
-- 
2.43.0