src/lib/cbfs_spi.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright 2014 Google Inc.
 *
 * 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.
 */

/*
 * This file provides a common CBFS wrapper for SPI storage. SPI driver
 * context is expanded with the buffer descriptor used to store data read from
 * SPI.
 */

#include <boot_device.h>
#include <spi_flash.h>
#include <symbols.h>
#include <cbmem.h>

static struct spi_flash *spi_flash_info;

static ssize_t spi_readat(const struct region_device *rd, void *b,
				size_t offset, size_t size)
{
	if (spi_flash_info->read(spi_flash_info, offset, size, b))
		return -1;
	return size;
}

static const struct region_device_ops spi_ops = {
	.mmap = mmap_helper_rdev_mmap,
	.munmap = mmap_helper_rdev_munmap,
	.readat = spi_readat,
};

static struct mmap_helper_region_device mdev =
	MMAP_HELPER_REGION_INIT(&spi_ops, 0, CONFIG_ROM_SIZE);

static void switch_to_postram_cache(int unused)
{
	/*
	 * Call boot_device_init() to ensure spi_flash is initialized before
	 * backing mdev with postram cache. This prevents the mdev backing from
	 * being overwritten if spi_flash was not accessed before dram was up.
	 */
	boot_device_init();
	if (_preram_cbfs_cache != _postram_cbfs_cache)
		mmap_helper_device_init(&mdev, _postram_cbfs_cache,
					_postram_cbfs_cache_size);
}
ROMSTAGE_CBMEM_INIT_HOOK(switch_to_postram_cache);

void boot_device_init(void)
{
	int bus = CONFIG_BOOT_MEDIA_SPI_BUS;
	int cs = 0;

	if (spi_flash_info != NULL)
		return;

	spi_flash_info = spi_flash_probe(bus, cs);

	mmap_helper_device_init(&mdev, _cbfs_cache, _cbfs_cache_size);
}

/* Return the CBFS boot device. */
const struct region_device *boot_device_ro(void)
{
	if (spi_flash_info == NULL)
		return NULL;

	return &mdev.rdev;
}