x86: Add an 'mtrr' command to list and adjust MTRRs

It is useful to be able to see the MTRR setup in U-Boot. Add a command
to list the state of the variable MTRR registers and allow them to be
changed.

Update the documentation to list some of the available commands.

This does not support fixed MTRRs as yet.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 139 insertions, 0 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 73262d7263..32d7b98fa6 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_HAVE_FSP) += cmd_hob.o
 obj-y	+= gcc.o
 obj-y	+= init_helpers.o
 obj-y	+= interrupts.o
+obj-y += cmd_mtrr.o
 obj-$(CONFIG_SYS_PCAT_INTERRUPTS) += pcat_interrupts.o
 obj-$(CONFIG_SYS_PCAT_TIMER) += pcat_timer.o
 obj-$(CONFIG_PCI) += pci_type1.o
diff --git a/arch/x86/lib/cmd_mtrr.c b/arch/x86/lib/cmd_mtrr.c
new file mode 100644
index 0000000000..7e0506b75d
--- /dev/null
+++ b/arch/x86/lib/cmd_mtrr.c
@@ -0,0 +1,138 @@
+/*
+ * (C) Copyright 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/msr.h>
+#include <asm/mtrr.h>
+
+static const char *const mtrr_type_name[MTRR_TYPE_COUNT] = {
+	"Uncacheable",
+	"Combine",
+	"2",
+	"3",
+	"Through",
+	"Protect",
+	"Back",
+};
+
+static int do_mtrr_list(void)
+{
+	int i;
+
+	printf("Reg Valid Write-type   %-16s %-16s %-16s\n", "Base   ||",
+	       "Mask   ||", "Size   ||");
+	for (i = 0; i < MTRR_COUNT; i++) {
+		const char *type = "Invalid";
+		uint64_t base, mask, size;
+		bool valid;
+
+		base = native_read_msr(MTRR_PHYS_BASE_MSR(i));
+		mask = native_read_msr(MTRR_PHYS_MASK_MSR(i));
+		size = ~mask & ((1ULL << CONFIG_CPU_ADDR_BITS) - 1);
+		size |= (1 << 12) - 1;
+		size += 1;
+		valid = mask & MTRR_PHYS_MASK_VALID;
+		type = mtrr_type_name[base & MTRR_BASE_TYPE_MASK];
+		printf("%d   %-5s %-12s %016llx %016llx %016llx\n", i,
+		       valid ? "Y" : "N", type, base, mask, size);
+	}
+
+	return 0;
+}
+
+static int do_mtrr_set(uint reg, int argc, char * const argv[])
+{
+	const char *typename = argv[0];
+	struct mtrr_state state;
+	uint32_t start, size;
+	uint64_t base, mask;
+	int i, type = -1;
+	bool valid;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+	for (i = 0; i < MTRR_TYPE_COUNT; i++) {
+		if (*typename == *mtrr_type_name[i])
+			type = i;
+	}
+	if (type == -1) {
+		printf("Invalid type name %s\n", typename);
+		return CMD_RET_USAGE;
+	}
+	start = simple_strtoul(argv[1], NULL, 16);
+	size = simple_strtoul(argv[2], NULL, 16);
+
+	base = start | type;
+	valid = native_read_msr(MTRR_PHYS_MASK_MSR(reg)) & MTRR_PHYS_MASK_VALID;
+	mask = ~((uint64_t)size - 1);
+	mask &= (1ULL << CONFIG_CPU_ADDR_BITS) - 1;
+	if (valid)
+		mask |= MTRR_PHYS_MASK_VALID;
+
+	printf("base=%llx, mask=%llx\n", base, mask);
+	mtrr_open(&state);
+	wrmsrl(MTRR_PHYS_BASE_MSR(reg), base);
+	wrmsrl(MTRR_PHYS_MASK_MSR(reg), mask);
+	mtrr_close(&state);
+
+	return 0;
+}
+
+static int mtrr_set_valid(int reg, bool valid)
+{
+	struct mtrr_state state;
+	uint64_t mask;
+
+	mtrr_open(&state);
+	mask = native_read_msr(MTRR_PHYS_MASK_MSR(reg));
+	if (valid)
+		mask |= MTRR_PHYS_MASK_VALID;
+	else
+		mask &= ~MTRR_PHYS_MASK_VALID;
+	wrmsrl(MTRR_PHYS_MASK_MSR(reg), mask);
+	mtrr_close(&state);
+
+	return 0;
+}
+
+static int do_mtrr(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	const char *cmd;
+	uint reg;
+
+	cmd = argv[1];
+	if (argc < 2 || *cmd == 'l')
+		return do_mtrr_list();
+	argc -= 2;
+	argv += 2;
+	if (argc <= 0)
+		return CMD_RET_USAGE;
+	reg = simple_strtoul(argv[0], NULL, 16);
+	if (reg >= MTRR_COUNT) {
+		printf("Invalid register number\n");
+		return CMD_RET_USAGE;
+	}
+	if (*cmd == 'e')
+		return mtrr_set_valid(reg, true);
+	else if (*cmd == 'd')
+		return mtrr_set_valid(reg, false);
+	else if (*cmd == 's')
+		return do_mtrr_set(reg, argc - 1, argv + 1);
+	else
+		return CMD_RET_USAGE;
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	mtrr,	6,	1,	do_mtrr,
+	"Use x86 memory type range registers (32-bit only)",
+	"[list]        - list current registers\n"
+	"set <reg> <type> <start> <size>   - set a register\n"
+	"\t<type> is Uncacheable, Combine, Through, Protect, Back\n"
+	"disable <reg>      - disable a register\n"
+	"ensable <reg>      - enable a register"
+);