src/arch/arm/boot.c

/*
 * Copyright 2013 Google Inc.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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; either version 2 of
 * the License, or (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <libpayload.h>

#include "arch/arm/boot.h"
#include "base/cleanup_funcs.h"
#include "vboot/boot.h"

static inline uint32_t get_cpsr(void)
{
	uint32_t cpsr;
	__asm__ __volatile__("mrs %0, cpsr\n" : "=r"(cpsr));
	return cpsr;
}

static inline void set_cpsr(uint32_t cpsr)
{
	__asm__ __volatile__("msr cpsr_cxsf, %0\n" :: "r"(cpsr));
}

static inline uint32_t get_sctlr(void)
{
	uint32_t val;
	asm("mrc p15, 0, %0, c1, c0, 0" : "=r" (val));
	return val;
}

static inline void set_sctlr(uint32_t val)
{
	asm volatile("mcr p15, 0, %0, c1, c0, 0" :: "r" (val));
	asm volatile("" ::: "memory");
}

void boot_arm_linux_jump(void *entry, uint32_t machine_type, void *fdt)
	__attribute__((noreturn));

int boot_arm_linux(uint32_t machine_type, void *fdt, void *entry)
{
	arch_final_cleanup();

	static const uint32_t CpsrF = (0x1 << 6);
	static const uint32_t CpsrI = (0x1 << 7);
	static const uint32_t CpsrA = (0x1 << 8);
	static const uint32_t CpsrModeMask = 0x1f;
	static const uint32_t CpsrModeSvc = 0x13;

	static const uint32_t SctlrM = (0x1 << 0);
	static const uint32_t SctlrC = (0x1 << 2);

	uint32_t cpsr = get_cpsr();
	uint32_t sctlr = get_sctlr();

	// Set the I, and F bits to disable interrupts.
	cpsr |= (CpsrF | CpsrI);
	// Clear the A bit to enable aborts.
	cpsr &= ~CpsrA;

	// Set the mode to SVC.
	cpsr &= ~CpsrModeMask;
	cpsr |= CpsrModeSvc;

	// Turn off the MMU.
	sctlr &= ~SctlrM;

	// Disable the data/unified cache.
	sctlr &= ~SctlrC;

	set_sctlr(sctlr);
	set_cpsr(cpsr);

	boot_arm_linux_jump(entry, machine_type, fdt);

	return 0;
}


int arch_final_cleanup(void)
{
	run_cleanup_funcs(CleanupOnHandoff);

	return 0;
}