| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| |
| #include <boot_device.h> |
| #include <commonlib/region.h> |
| #include <console/console.h> |
| #include <fmap.h> |
| #include <intelblocks/fast_spi.h> |
| |
| /* |
| * BIOS region on the flash is mapped right below 4GiB in the address |
| * space. However, 256KiB right below 4GiB is decoded by read-only SRAM and not |
| * boot media. |
| * |
| * +-----------+ 0 |
| * | | |
| * | | |
| * | | |
| * | | |
| * | | |
| * | | |
| * | | |
| * | | |
| * +--------+ | | |
| * | IFD | | | |
| * bios_start +---> +--------+------------------> +-----------+ 4GiB - bios_size |
| * ^ | | ^ | | |
| * | | | | | | |
| * | | | bios_mapped_size | BIOS | |
| * | | BIOS | | | | |
| * bios_size | | | | | |
| * | | | v | | |
| * | | +------------------> +-----------+ 4GiB - 256KiB |
| * | | | | Read only | |
| * v | | | SRAM | |
| * bios_end +---> +--------+ +-----------+ 4GiB |
| * | Device | |
| * | ext | |
| * +--------+ |
| * |
| */ |
| |
| static size_t bios_size; |
| |
| static struct mem_region_device shadow_dev; |
| static struct xlate_region_device real_dev; |
| |
| static void bios_mmap_init(void) |
| { |
| size_t size, start, bios_mapped_size; |
| uintptr_t base; |
| |
| size = bios_size; |
| |
| /* If bios_size is initialized, then bail out. */ |
| if (size != 0) |
| return; |
| start = fast_spi_get_bios_region(&size); |
| |
| /* BIOS region is mapped right below 4G. */ |
| base = 4ULL * GiB - size; |
| |
| /* |
| * The 256 KiB right below 4G are decoded by readonly SRAM, |
| * not boot media. |
| */ |
| bios_mapped_size = size - 256 * KiB; |
| |
| mem_region_device_ro_init(&shadow_dev, (void *)base, |
| bios_mapped_size); |
| |
| xlate_region_device_ro_init(&real_dev, &shadow_dev.rdev, |
| start, bios_mapped_size, |
| CONFIG_ROM_SIZE); |
| |
| bios_size = size; |
| |
| /* Check that the CBFS lies within the memory mapped area. It's too |
| easy to forget the SRAM mapping when crafting an FMAP file. */ |
| struct region cbfs_region; |
| if (!fmap_locate_area("COREBOOT", &cbfs_region) && |
| !region_is_subregion(&real_dev.sub_region, &cbfs_region)) |
| printk(BIOS_CRIT, |
| "ERROR: CBFS @ %zx size %zx exceeds mem-mapped area @ %zx size %zx\n", |
| region_offset(&cbfs_region), region_sz(&cbfs_region), |
| start, bios_mapped_size); |
| } |
| |
| const struct region_device *boot_device_ro(void) |
| { |
| bios_mmap_init(); |
| |
| return &real_dev.rdev; |
| } |