x86: ivybridge: Perform Intel microcode update on boot

Microcode updates are stored in the device tree. Work through these and
apply any that are needed.

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

arch/x86/cpu/ivybridge/Makefile

@@ -7,5 +7,6 @@
 obj-y += car.o
 obj-y += cpu.o
 obj-y += lpc.o
+obj-y += microcode_intel.o
 obj-y += pci.o
 obj-y += sdram.o

arch/x86/cpu/ivybridge/cpu.c

@@ -21,6 +21,7 @@
 #include <asm/post.h>
 #include <asm/processor.h>
 #include <asm/arch/model_206ax.h>
+#include <asm/arch/microcode.h>
 #include <asm/arch/pch.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -200,6 +201,10 @@ int print_cpuinfo(void)
 	if (ret)
 		return ret;
 
+	ret = microcode_update_intel();
+	if (ret && ret != -ENOENT && ret != -EEXIST)
+		return ret;
+
 	/* Print processor name */
 	name = cpu_get_name(processor_name);
 	printf("CPU:   %s\n", name);

arch/x86/cpu/ivybridge/microcode_intel.c

@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2014 Google, Inc
+ * Copyright (C) 2000 Ronald G. Minnich
+ *
+ * Microcode update for Intel PIII and later CPUs
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <libfdt.h>
+#include <asm/cpu.h>
+#include <asm/msr.h>
+#include <asm/processor.h>
+
+/**
+ * struct microcode_update - standard microcode header from Intel
+ *
+ * We read this information out of the device tree and use it to determine
+ * whether the update is applicable or not. We also use the same structure
+ * to read information from the CPU.
+ */
+struct microcode_update {
+	uint header_version;
+	uint update_revision;
+	uint date_code;
+	uint processor_signature;
+	uint checksum;
+	uint loader_revision;
+	uint processor_flags;
+	const void *data;
+	int size;
+};
+
+static int microcode_decode_node(const void *blob, int node,
+				 struct microcode_update *update)
+{
+	update->data = fdt_getprop(blob, node, "data", &update->size);
+	if (!update->data)
+		return -EINVAL;
+
+	update->header_version = fdtdec_get_int(blob, node,
+						"intel,header-version", 0);
+	update->update_revision = fdtdec_get_int(blob, node,
+						 "intel,update-revision", 0);
+	update->date_code = fdtdec_get_int(blob, node,
+					   "intel,date-code", 0);
+	update->processor_signature = fdtdec_get_int(blob, node,
+					"intel.processor-signature", 0);
+	update->checksum = fdtdec_get_int(blob, node, "intel,checksum", 0);
+	update->loader_revision = fdtdec_get_int(blob, node,
+						 "loader-revision", 0);
+	update->processor_flags = fdtdec_get_int(blob, node,
+						 "processor-flags", 0);
+
+	return 0;
+}
+
+static uint32_t microcode_read_rev(void)
+{
+	/*
+	 * Some Intel CPUs can be very finicky about the CPUID sequence used.
+	 * So this is implemented in assembly so that it works reliably.
+	 */
+	uint32_t low, high;
+
+	asm volatile (
+		"xorl %%eax, %%eax\n"
+		"xorl %%edx, %%edx\n"
+		"movl $0x8b, %%ecx\n"
+		"wrmsr\n"
+		"movl $0x01, %%eax\n"
+		"cpuid\n"
+		"movl $0x8b, %%ecx\n"
+		"rdmsr\n"
+		: /* outputs */
+		"=a" (low), "=d" (high)
+		: /* inputs */
+		: /* clobbers */
+		 "ebx", "ecx"
+	);
+
+	return high;
+}
+
+static void microcode_read_cpu(struct microcode_update *cpu)
+{
+	/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
+	unsigned int x86_model, x86_family;
+	struct cpuid_result result;
+	uint32_t low, high;
+
+	wrmsr(0x8b, 0, 0);
+	result = cpuid(1);
+	rdmsr(0x8b, low, cpu->update_revision);
+	x86_model = (result.eax >> 4) & 0x0f;
+	x86_family = (result.eax >> 8) & 0x0f;
+	cpu->processor_signature = result.eax;
+
+	cpu->processor_flags = 0;
+	if ((x86_model >= 5) || (x86_family > 6)) {
+		rdmsr(0x17, low, high);
+		cpu->processor_flags = 1 << ((high >> 18) & 7);
+	}
+	debug("microcode: sig=%#x pf=%#x revision=%#x\n",
+	      cpu->processor_signature, cpu->processor_flags,
+	      cpu->update_revision);
+}
+
+/* Get a microcode update from the device tree and apply it */
+int microcode_update_intel(void)
+{
+	struct microcode_update cpu, update;
+	const void *blob = gd->fdt_blob;
+	int count;
+	int node;
+	int ret;
+
+	microcode_read_cpu(&cpu);
+	node = 0;
+	count = 0;
+	do {
+		node = fdtdec_next_compatible(blob, node,
+					      COMPAT_INTEL_MICROCODE);
+		if (node < 0) {
+			debug("%s: Found %d updates\n", __func__, count);
+			return count ? 0 : -ENOENT;
+		}
+
+		ret = microcode_decode_node(blob, node, &update);
+		if (ret) {
+			debug("%s: Unable to decode update: %d\n", __func__,
+			      ret);
+			return ret;
+		}
+		if (update.processor_signature == cpu.processor_signature &&
+		    (update.processor_flags & cpu.processor_flags)) {
+			debug("%s: Update already exists\n", __func__);
+			return -EEXIST;
+		}
+
+		wrmsr(0x79, (ulong)update.data, 0);
+		debug("microcode: updated to revision 0x%x date=%04x-%02x-%02x\n",
+		      microcode_read_rev(), update.date_code & 0xffff,
+		      (update.date_code >> 24) & 0xff,
+		      (update.date_code >> 16) & 0xff);
+		count++;
+	} while (1);
+}

arch/x86/include/asm/arch-ivybridge/microcode.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ASM_ARCH_MICROCODE_H
+#define __ASM_ARCH_MICROCODE_H
+
+/**
+ * microcode_update_intel() - Apply microcode updates
+ *
+ * Applies any microcode updates in the device tree.
+ *
+ * @return 0 if OK, -EEXIST if the updates were already applied, -ENOENT if
+ * not updates were found, -EINVAL if an update was invalid
+ */
+int microcode_update_intel(void);
+
+#endif

include/fdtdec.h

@@ -118,6 +118,7 @@ enum fdt_compat_id {
 	COMPAT_SAMSUNG_EXYNOS_SYSMMU,	/* Exynos sysmmu */
 	COMPAT_PARADE_PS8625,		/* Parade PS8622 EDP->LVDS bridge */
 	COMPAT_INTEL_LPC,		/* Intel Low Pin Count I/F */
+	COMPAT_INTEL_MICROCODE,		/* Intel microcode update */
 
 	COMPAT_COUNT,
 };

lib/fdtdec.c

@@ -73,6 +73,7 @@ static const char * const compat_names[COMPAT_COUNT] = {
 	COMPAT(SAMSUNG_EXYNOS_SYSMMU, "samsung,sysmmu-v3.3"),
 	COMPAT(PARADE_PS8625, "parade,ps8625"),
 	COMPAT(COMPAT_INTEL_LPC, "intel,lpc"),
+	COMPAT(INTEL_MICROCODE, "intel,microcode"),
 };
 
 const char *fdtdec_get_compatible(enum fdt_compat_id id)