coreboot-kgpe-d16/src/soc/intel/skylake/bootblock/cpu.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2014 Google Inc.
 * Copyright (C) 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc.
 */

#include <stdint.h>
#include <arch/cpu.h>
#include <cpu/x86/cache.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/mtrr.h>
#include <device/pci_def.h>
#include <arch/io.h>
#include <cpu/intel/microcode/microcode.c>
#include <reset.h>
#include <soc/msr.h>
#include <soc/pci_devs.h>
#include <soc/spi.h>

/* Soft Reset Data Register Bit 12 = MAX Boot Frequency */
#define SPI_STRAP_MAX_FREQ	(1<<12)
/* Soft Reset Data Register Bit 6-11 = Flex Ratio */
#define FLEX_RATIO_BIT	6

static void set_var_mtrr(
	unsigned reg, unsigned base, unsigned size, unsigned type)

{
	/* Bit Bit 32-35 of MTRRphysMask should be set to 1 */
	msr_t basem, maskm;
	basem.lo = base | type;
	basem.hi = 0;
	wrmsr(MTRRphysBase_MSR(reg), basem);
	maskm.lo = ~(size - 1) | MTRRphysMaskValid;
	maskm.hi = (1 << (CONFIG_CPU_ADDR_BITS - 32)) - 1;
	wrmsr(MTRRphysMask_MSR(reg), maskm);
}

static void enable_rom_caching(void)
{
	msr_t msr;

	disable_cache();
	set_var_mtrr(1, CACHE_ROM_BASE, CACHE_ROM_SIZE, MTRR_TYPE_WRPROT);
	enable_cache();

	/* Enable Variable MTRRs */
	msr.hi = 0x00000000;
	msr.lo = 0x00000800;
	wrmsr(MTRRdefType_MSR, msr);
}

static void bootblock_mdelay(int ms)
{
	u32 target = ms * 24 * 1000;
	msr_t current;
	msr_t start = rdmsr(MSR_COUNTER_24_MHZ);

	do {
		current = rdmsr(MSR_COUNTER_24_MHZ);
	} while ((current.lo - start.lo) < target);
}

static void set_pch_cpu_strap(u8 flex_ratio)
{
	device_t dev = PCH_DEV_SPI;
	uint8_t *spibar = (void *)TEMP_SPI_BAR;
	u32 ssl, ssms, soft_reset_data;
	u8 pcireg;

	/* Assign Resources to SPI Controller */
	/* Clear BIT 1-2 SPI Command Register */
	pcireg = pci_read_config8(dev, PCI_COMMAND);
	pcireg &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
	pci_write_config8(dev, PCI_COMMAND, pcireg);

	/* Program Temporary BAR for SPI */
	pci_write_config32(dev, PCH_SPI_BASE_ADDRESS, TEMP_SPI_BAR);

	/* Enable Bus Master and MMIO Space */
	pcireg = pci_read_config8(dev, PCI_COMMAND);
	pcireg |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY;
	pci_write_config8(dev, PCI_COMMAND, pcireg);

	/* Set Strap Lock Disable*/
	ssl = read32(spibar + SPIBAR_RESET_LOCK);
	ssl |= SPIBAR_RESET_LOCK_DISABLE;
	write32(spibar + SPIBAR_RESET_LOCK, ssl);

	/* Soft Reset Data Register Bit 12 = MAX Boot Frequency
	 * Bit 6-11 = Flex Ratio
	 * Soft Reset Data register located at SPIBAR0 offset 0xF8[0:15].
	 */
	soft_reset_data = SPI_STRAP_MAX_FREQ;
	soft_reset_data |= (flex_ratio << FLEX_RATIO_BIT);
	write32(spibar + SPIBAR_RESET_DATA, soft_reset_data);

	/* Set Strap Mux Select  set to '1' */
	ssms = read32(spibar + SPIBAR_RESET_CTRL);
	ssms |= SPIBAR_RESET_CTRL_SSMC;
	write32(spibar + SPIBAR_RESET_CTRL, ssms);

	/* Set Strap Lock Enable*/
	ssl = read32(spibar + SPIBAR_RESET_LOCK);
	ssl |= SPIBAR_RESET_LOCK_ENABLE;
	write32(spibar + SPIBAR_RESET_LOCK, ssl);

	/* Disable SPI Controller MMIO space */
	pcireg = pci_read_config8(dev, PCI_COMMAND);
	pcireg &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
	pci_write_config8(dev, PCI_COMMAND, pcireg);
}

static void set_flex_ratio_to_tdp_nominal(void)
{
	msr_t flex_ratio, msr;
	u8 nominal_ratio;

	/* Check for Flex Ratio support */
	flex_ratio = rdmsr(MSR_FLEX_RATIO);
	if (!(flex_ratio.lo & FLEX_RATIO_EN))
		return;

	/* Check for >0 configurable TDPs */
	msr = rdmsr(MSR_PLATFORM_INFO);
	if (((msr.hi >> 1) & 3) == 0)
		return;

	/* Use nominal TDP ratio for flex ratio */
	msr = rdmsr(MSR_CONFIG_TDP_NOMINAL);
	nominal_ratio = msr.lo & 0xff;

	/* See if flex ratio is already set to nominal TDP ratio */
	if (((flex_ratio.lo >> 8) & 0xff) == nominal_ratio)
		return;

	/* Set flex ratio to nominal TDP ratio */
	flex_ratio.lo &= ~0xff00;
	flex_ratio.lo |= nominal_ratio << 8;
	flex_ratio.lo |= FLEX_RATIO_LOCK;
	wrmsr(MSR_FLEX_RATIO, flex_ratio);

	/* Set PCH Soft Reset Data Register with new Flex Ratio */
	set_pch_cpu_strap(nominal_ratio);

	/* Delay before reset to avoid potential TPM lockout */
	bootblock_mdelay(30);

	/* Issue soft reset, will be "CPU only" due to soft reset data */
	soft_reset();
}

static void check_for_clean_reset(void)
{
	msr_t msr;
	msr = rdmsr(MTRRdefType_MSR);

	/*
	 * Use the MTRR default type MSR as a proxy for detecting INIT#.
	 * Reset the system if any known bits are set in that MSR. That is
	 * an indication of the CPU not being properly reset.
	 */
	if (msr.lo & (MTRRdefTypeEn | MTRRdefTypeFixEn))
		soft_reset();
}

static int need_microcode_update(void)
{
	/* If PRMRR/SGX is supported the FIT microcode load step will set
	 * msr 0x08b with the Patch revision id one less than the id in the
	 * microcode binary. The PRMRR support is indicated in the MSR
	 * MTRRCAP[12]. Check for this feature and avoid reloading the
	 * same microcode during early cpu initialization.
	 */
	msr = rdmsr(MTRRcap_MSR);
	return (msr.lo & PRMRR_SUPPORTED) && (current_rev != patch->rev - 1);
}

static void bootblock_cpu_init(void)
{
	const struct microcode *patch;
	u32 current_rev;
	msr_t msr;

	/* Set flex ratio and reset if needed */
	set_flex_ratio_to_tdp_nominal();
	check_for_clean_reset();
	enable_rom_caching();

	patch = intel_microcode_find();

	current_rev = read_microcode_rev();

	if (need_microcode_update())
		intel_update_microcode_from_cbfs();
}