1 files changed, 81 insertions, 0 deletions
diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
new file mode 100644
index 0000000..d5a825d
--- /dev/null
+++ b/arch/x86/cpu/mtrr.c
@@ -0,0 +1,81 @@
+/*
+ * (C) Copyright 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Memory Type Range Regsters - these are used to tell the CPU whether
+ * memory is cacheable and if so the cache write mode to use.
+ *
+ * These can speed up booting. See the mtrr command.
+ *
+ * Reference: Intel Architecture Software Developer's Manual, Volume 3:
+ * System Programming
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/msr.h>
+#include <asm/mtrr.h>
+
+/* Prepare to adjust MTRRs */
+void mtrr_open(struct mtrr_state *state)
+{
+	state->enable_cache = dcache_status();
+
+	if (state->enable_cache)
+		disable_caches();
+	state->deftype = native_read_msr(MTRR_DEF_TYPE_MSR);
+	wrmsrl(MTRR_DEF_TYPE_MSR, state->deftype & ~MTRR_DEF_TYPE_EN);
+}
+
+/* Clean up after adjusting MTRRs, and enable them */
+void mtrr_close(struct mtrr_state *state)
+{
+	wrmsrl(MTRR_DEF_TYPE_MSR, state->deftype | MTRR_DEF_TYPE_EN);
+	if (state->enable_cache)
+		enable_caches();
+}
+
+int mtrr_commit(bool do_caches)
+{
+	struct mtrr_request *req = gd->arch.mtrr_req;
+	struct mtrr_state state;
+	uint64_t mask;
+	int i;
+
+	mtrr_open(&state);
+	for (i = 0; i < gd->arch.mtrr_req_count; i++, req++) {
+		mask = ~(req->size - 1);
+		mask &= (1ULL << CONFIG_CPU_ADDR_BITS) - 1;
+		wrmsrl(MTRR_PHYS_BASE_MSR(i), req->start | req->type);
+		wrmsrl(MTRR_PHYS_MASK_MSR(i), mask | MTRR_PHYS_MASK_VALID);
+	}
+
+	/* Clear the ones that are unused */
+	for (; i < MTRR_COUNT; i++)
+		wrmsrl(MTRR_PHYS_MASK_MSR(i), 0);
+	mtrr_close(&state);
+
+	return 0;
+}
+
+int mtrr_add_request(int type, uint64_t start, uint64_t size)
+{
+	struct mtrr_request *req;
+	uint64_t mask;
+
+	if (gd->arch.mtrr_req_count == MAX_MTRR_REQUESTS)
+		return -ENOSPC;
+	req = &gd->arch.mtrr_req[gd->arch.mtrr_req_count++];
+	req->type = type;
+	req->start = start;
+	req->size = size;
+	debug("%d: type=%d, %08llx  %08llx\n", gd->arch.mtrr_req_count - 1,
+	      req->type, req->start, req->size);
+	mask = ~(req->size - 1);
+	mask &= (1ULL << CONFIG_CPU_ADDR_BITS) - 1;
+	mask |= MTRR_PHYS_MASK_VALID;
+	debug("   %016llx %016llx\n", req->start | req->type, mask);
+
+	return 0;
+}