To use barebox as a BIOS based bootloader for x86 architectures, the binary
must be patched to get it bootstrapped at runtime. The 'setupmbr' tool installs
the barebox-binary to the given device node or image file and patch it in
accordance to the needed sector information at runtime.
Signed-off by: Juergen Beisert <jbe@xxxxxxxxxxxxxx>
---
Doxyfile | 3
scripts/Makefile | 4
scripts/setupmbr/Makefile | 4
scripts/setupmbr/arch.h | 55 +++
scripts/setupmbr/setupmbr.c | 705 ++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 769 insertions(+), 2 deletions(-)
Index: u-boot-2.0.0-rc10/scripts/Makefile
===================================================================
--- u-boot-2.0.0-rc10.orig/scripts/Makefile
+++ u-boot-2.0.0-rc10/scripts/Makefile
@@ -24,5 +24,7 @@ hostprogs-y += unifdef
#subdir-$(CONFIG_MODVERSIONS) += genksyms
subdir-y += mod
+subdir-$(CONFIG_X86) += setupmbr
+
# Let clean descend into subdirs
-subdir- += basic kconfig
+subdir- += basic kconfig setupmbr
Index: u-boot-2.0.0-rc10/scripts/setupmbr/Makefile
===================================================================
--- /dev/null
+++ u-boot-2.0.0-rc10/scripts/setupmbr/Makefile
@@ -0,0 +1,4 @@
+HOST_EXTRACFLAGS=-I$(srctree)
+
+hostprogs-y := setupmbr
+always := $(hostprogs-y)
Index: u-boot-2.0.0-rc10/scripts/setupmbr/arch.h
===================================================================
--- /dev/null
+++ u-boot-2.0.0-rc10/scripts/setupmbr/arch.h
@@ -0,0 +1,55 @@
+
+/* we need the one from the host */
+#include <endian.h>
+#include <stdint.h>
+
+/* Byte-orders. */
+#define swap16(x) \
+({ \
+ uint16_t _x = (x); \
+ (uint16_t) ((_x << 8) | (_x >> 8)); \
+})
+
+#define swap32(x) \
+({ \
+ uint32_t _x = (x); \
+ (uint32_t) ((_x << 24) \
+ | ((_x & (uint32_t) 0xFF00UL) << 8) \
+ | ((_x & (uint32_t) 0xFF0000UL) >> 8) \
+ | (_x >> 24)); \
+})
+
+#define swap64(x) \
+({ \
+ uint64_t _x = (x); \
+ (uint64_t) ((_x << 56) \
+ | ((_x & (uint64_t) 0xFF00ULL) << 40) \
+ | ((_x & (uint64_t) 0xFF0000ULL) << 24) \
+ | ((_x & (uint64_t) 0xFF000000ULL) << 8) \
+ | ((_x & (uint64_t) 0xFF00000000ULL) >> 8) \
+ | ((_x & (uint64_t) 0xFF0000000000ULL) >> 24) \
+ | ((_x & (uint64_t) 0xFF000000000000ULL) >> 40) \
+ | (_x >> 56)); \
+})
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+
+/* Our target is a ia32 machine, always little endian */
+
+# define host2target_16(x) swap16(x)
+# define host2target_32(x) swap32(x)
+# define host2target_64(x) swap64(x)
+# define target2host_16(x) swap16(x)
+# define target2host_32(x) swap32(x)
+# define target2host_64(x) swap64(x)
+
+#else
+
+# define host2target_16(x) (x)
+# define host2target_32(x) (x)
+# define host2target_64(x) (x)
+# define target2host_16(x) (x)
+# define target2host_32(x) (x)
+# define target2host_64(x) (x)
+
+#endif
Index: u-boot-2.0.0-rc10/scripts/setupmbr/setupmbr.c
===================================================================
--- /dev/null
+++ u-boot-2.0.0-rc10/scripts/setupmbr/setupmbr.c
@@ -0,0 +1,705 @@
+/*
+ * Copyright (C) 2009 Juergen Beisert, Pengutronix
+ *
+ * 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
+ *
+ */
+
+/**
+ * @file
+ * @brief Write the barebox binary to the MBR and the following disk sectors
+ *
+ * Also patch dedicated locations in the image to make it work at runtime
+ *
+ * Current restrictions are:
+ * - only installs into MBR and the sectors after it
+ * - tested only with QEMU
+ * - and maybe some others
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <assert.h>
+
+/* include the info from this barebox release */
+#include "include/linux/utsrelease.h"
+#include "arch/x86/include/asm/u-boot.lds.h"
+
+/** define to disable integrity tests and debug messages */
+#define NDEBUG
+
+/* some infos about our target architecture */
+#include "arch.h"
+
+/**
+ * "Disk Address Packet Structure" to be used when calling int13,
+ * function 0x42
+ *
+ * @note All entries are in target endianess
+ */
+struct DAPS
+{
+ uint8_t size; /**< size of this data set, 0 marks it as invalid */
+ uint8_t res1; /**< always 0 */
+ int8_t count; /**< number of sectors 0...127 to handle */
+ uint8_t res2; /**< always 0 */
+ uint16_t offset; /**< store address: offset */
+ uint16_t segment; /**< store address: segment */
+ uint64_t lba; /**< start sector number in LBA */
+} __attribute__ ((packed));
+
+/**
+ * Description of one partition table entry (D*S type)
+ *
+ * @note All entries are in target endianess
+ */
+struct partition_entry {
+ uint8_t boot_indicator;
+ uint8_t chs_begin[3];
+ uint8_t type;
+ uint8_t chs_end[3];
+ uint32_t partition_start; /* LE */
+ uint32_t partition_size; /* LE */
+} __attribute__ ((packed));
+
+#ifndef NDEBUG
+static void debugout(const struct DAPS *entry, int supress_entry)
+{
+ if (supress_entry)
+ printf("DAPS entry: ");
+ else
+ printf("DAPS entry % 3u: ", ((unsigned)entry & ( SECTOR_SIZE - 1)) / sizeof(struct DAPS));
+
+ printf("Size: % 2u, Count: % 3d, Offset: 0x%04hX, Segment: 0x%04hX, LBA: %llu\n",
+ entry->size, entry->count,
+ target2host_16(entry->offset), target2host_16(entry->segment),
+ target2host_64(entry->lba));
+}
+#else
+# define debugout(x,y) (__ASSERT_VOID_CAST(0))
+#endif
+
+/**
+ * Fill *one* DAPS
+ * @param sector The DAPS to fill
+ * @param count Sector count
+ * @param offset Realmode offset in the segment
+ * @param segment Real mode segment
+ * @param lba LBA of the first sector to read
+ * @return 0 on success
+ */
+static int fill_daps(struct DAPS *sector, unsigned count, unsigned offset, unsigned segment, uint64_t lba)
+{
+ assert(sector != NULL);
+ assert(count < 128);
+ assert(offset < 0x10000);
+ assert(segment < 0x10000);
+
+ sector->size = sizeof(struct DAPS);
+ sector->res1 = 0;
+ sector->count = (int8_t)count;
+ sector->res2 = 0;
+ sector->offset = host2target_16(offset);
+ sector->segment = host2target_16(segment);
+ sector->lba = host2target_64(lba);
+
+ return 0;
+}
+
+/**
+ * Mark a DAPS invalid to let the boot loader code stop at this entry.
+ * @param sector The DAPS to be marked as invalid
+ *
+ * Marking as invalid must be done in accordance to the detection method
+ * the assembler routine in the boot loader uses:
+ * The current code tests for zero in the first two bytes of the DAPS.
+ */
+static void invalidate_daps(struct DAPS *sector)
+{
+ sector->size = MARK_DAPS_INVALID;
+ sector->res1 = 0;
+}
+
+/**
+ * Create the indirect sector with the DAPS entries
+ * @param daps_table Where to store the entries
+ * @param size Size of the whole image in bytes
+ * @param pers_sector_count Count of sectors to skip after MBR for the persistant environment storage
+ * @return 0 on success
+ *
+ * This routine calculates the DAPS entries for the case the whole
+ * barebox images fits into the MBR itself and the sectors after it.
+ * This means the start of the first partition must keep enough sectors
+ * unused.
+ * It also skips 'pers_sector_count' sectors after the MBR for special
+ * usage if given.
+ */
+static int barebox_linear_image(struct DAPS *daps_table, off_t size, long pers_sector_count)
+{
+ unsigned offset = LOAD_AREA, next_offset;
+ unsigned segment = LOAD_SEGMENT;
+ unsigned chunk_size, i = 0;
+ uint64_t lba = 2 + pers_sector_count;
+ int rc;
+
+ /*
+ * We can load up to 127 sectors in one chunk. What a bad number...
+ * So, we will load in chunks of 32 kiB.
+ */
+
+ /* at runtime two sectors from the image are already loaded: MBR and indirect */
+ size -= 2 * SECTOR_SIZE;
+ /* and now round up to multiple of sector size */
+ size = (size + SECTOR_SIZE - 1) & ~(SECTOR_SIZE - 1);
+
+ /*
+ * The largest image we can load with this method is:
+ * (SECTOR_SIZE / sizeof(DAPS) - 1) * 32 kiB
+ * For a 512 byte sector and a 16 byte DAPS:
+ * (512 / 16 - 1) * 32 kiB = 992 kiB
+ * Note: '- 1' to consider one entry is required to pad to a 32 kiB boundary
+ */
+
+ if (size >= (SECTOR_SIZE / sizeof(struct DAPS) - 1) * 32 * 1024) {
+ fprintf(stderr, "Image too large to boot. Max size is %u kiB, image size is %lu kiB\n",
+ (SECTOR_SIZE / sizeof(struct DAPS) - 1) * 32, size / 1024);
+ return -1;
+ }
+
+ if (size > 32 * 1024) {
+ /* first fill up until the next 32 k boundary */
+ next_offset = (offset + 32 * 1024 -1) & ~0x7fff;
+ chunk_size = next_offset - offset;
+ if (chunk_size & (SECTOR_SIZE-1)) {
+ fprintf(stderr, "Unable to pad from %X to %X in multiple of sectors\n", offset, next_offset);
+ return -1;
+ }
+
+ rc = fill_daps(&daps_table[i], chunk_size / SECTOR_SIZE, offset, segment, lba);
+ if (rc != 0)
+ return -1;
+ debugout(&daps_table[i], 0);
+
+ /* calculate values to enter the loop for the other entries */
+ size -= chunk_size;
+ i++;
+ lba += chunk_size / SECTOR_SIZE;
+ offset += chunk_size;
+ if (offset >= 0x10000) {
+ segment += 4096;
+ offset = 0;
+ }
+
+ /*
+ * Now load the remaining image part in 32 kiB chunks
+ */
+ while (size) {
+ if (size >= 32 * 1024 ) {
+ if (i >= (SECTOR_SIZE / sizeof(struct DAPS))) {
+ fprintf(stderr, "Internal tool error: Too many DAPS entries!\n");
+ return -1;
+ }
+ rc = fill_daps(&daps_table[i], 64, offset, segment, lba);
+ if (rc != 0)
+ return -1;
+ debugout(&daps_table[i], 0);
+
+ size -= 32 * 1024;
+ lba += 64;
+ offset += 32 * 1024;
+ if (offset >= 0x10000) {
+ segment += 4096;
+ offset = 0;
+ }
+ i++;
+ } else {
+ if (i >= (SECTOR_SIZE / sizeof(struct DAPS))) {
+ fprintf(stderr, "Internal tool error: Too many DAPS entries!\n");
+ return -1;
+ }
+ rc = fill_daps(&daps_table[i], size / SECTOR_SIZE, offset, segment, lba);
+ if (rc != 0)
+ return -1;
+ debugout(&daps_table[i], 0);
+ size = 0; /* finished */
+ i++;
+ }
+ };
+ } else {
+ /* less than 32 kiB. Very small image... */
+ rc = fill_daps(&daps_table[i], size / SECTOR_SIZE, offset, segment, lba);
+ if (rc != 0)
+ return -1;
+ debugout(&daps_table[i], 0);
+ i++;
+ }
+
+ /*
+ * Do not mark an entry as invalid if the buffer is full. The
+ * boot code stops if all entries of a buffer are read.
+ */
+ if (i >= (SECTOR_SIZE / sizeof(struct DAPS)))
+ return 0;
+
+ /* mark the last DAPS invalid */
+ invalidate_daps(&daps_table[i]);
+ debugout(&daps_table[i], 0);
+
+ return 0;
+}
+
+/**
+ * Do some simple sanity checks if this sector could be an MBR
+ * @param sector Sector with data to check
+ * @param size Size of the buffer
+ * @return 0 if successfull
+ */
+static int check_for_valid_mbr(const uint8_t *sector, off_t size)
+{
+ if (size < SECTOR_SIZE) {
+ fprintf(stderr, "MBR too small to be valid\n");
+ return -1;
+ }
+
+ if ((sector[OFFSET_OF_SIGNATURE] != 0x55) ||
+ (sector[OFFSET_OF_SIGNATURE + 1] != 0xAA)) {
+ fprintf(stderr, "No MBR signature found\n");
+ return -1;
+ }
+
+ /* FIXME: try to check if there is a valid partition table */
+ return 0;
+}
+
+/**
+ * Check space between start of the image and the start of the first partition
+ * @param hd_image HD image to examine
+ * @param size Size of the barebox image
+ * @return 0 on success, -1 if the barebox image is too large
+ */
+static int check_for_space(const void *hd_image, off_t size)
+{
+ struct partition_entry *partition;
+ uint8_t *mbr_disk_sector = (uint8_t*)hd_image;
+ off_t spare_sector_count;
+
+ assert(hd_image != NULL);
+ assert(size > 0);
+
+ if (check_for_valid_mbr(hd_image, size) != 0)
+ return -1;
+
+ /* where to read */
+ partition = (struct partition_entry*) &mbr_disk_sector[OFFSET_OF_PARTITION_TABLE];
+
+ /* TODO describes the first entry always the first partition? */
+ spare_sector_count = target2host_32(partition->partition_start);
+
+#ifdef DEBUG
+ printf("Debug: Required free sectors for barebox prior first partition: %lu, hd image provides: %lu\n",
+ (size + SECTOR_SIZE - 1) / SECTOR_SIZE, spare_sector_count);
+#endif
+ spare_sector_count *= SECTOR_SIZE;
+ if (spare_sector_count < size) {
+ fprintf(stderr, "Not enough space after MBR to store barebox\n");
+ fprintf(stderr, "Move begin of the first partition beyond sector %lu\n", (size + SECTOR_SIZE - 1) / SECTOR_SIZE);
+ return -1;
+ }
+
+ return 0;
+}
+
+/**
+ * Setup the persistant environment storage information
+ * @param patch_area Where to patch
+ * @param pers_sector_start Start sector of the persistant environment storage
+ * @param pers_sector_count Count of sectors for the persistant environment storage
+ * @return 0 on success
+ */
+static int store_pers_env_info(void *patch_area, uint64_t pers_sector_start, long pers_sector_count)
+{
+ uint64_t *start_lba = (uint64_t*)(patch_area + PATCH_AREA_PERS_START);
+ uint16_t *count_lba = (uint16_t*)(patch_area + PATCH_AREA_PERS_SIZE);
+
+ assert(patch_area != NULL);
+ assert(pers_sector_count >= 0);
+
+ if (pers_sector_count == 0) {
+ *count_lba = host2target_16(PATCH_AREA_PERS_SIZE_UNUSED);
+ return 0;
+ }
+
+ *start_lba = host2target_64(pers_sector_start);
+ *count_lba = host2target_16(pers_sector_count);
+
+ return 0;
+}
+
+/**
+ * Prepare the MBR and indirect sector for runtime
+ * @param fd_barebox barebox image to use
+ * @param fd_hd Hard disk image to prepare
+ * @param pers_sector_count Count of sectors to skip after MBR for the persistant environment storage
+ * @return 0 on success
+ *
+ * This routine expects a prepared hard disk image file with a partition table
+ * in its first sector. This method only is currently supported.
+ */
+static int barebox_overlay_mbr(int fd_barebox, int fd_hd, long pers_sector_count)
+{
+ const void *barebox_image;
+ void *hd_image;
+ int rc;
+ struct stat sb;
+ struct DAPS *embed; /* part of the MBR */
+ struct DAPS *indirect; /* sector with indirect DAPS */
+ off_t required_size;
+
+ if (fstat(fd_barebox, &sb) == -1) {
+ perror("fstat");
+ return -1;
+ }
+
+ /* the barebox image won't be touched */
+ barebox_image = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, fd_barebox, 0);
+ if (barebox_image == MAP_FAILED) {
+ perror("mmap");
+ return -1;
+ }
+
+ rc = check_for_valid_mbr(barebox_image, sb.st_size);
+ if (rc != 0) {
+ fprintf(stderr, "barebox image seems not valid: Bad MBR signature\n");
+ goto on_error_hd;
+ }
+
+ /*
+ * the persistant environment storage is in front of the main
+ * barebox image. To handle both, we need more space in front of the
+ * the first partition.
+ */
+ required_size = sb.st_size + pers_sector_count * SECTOR_SIZE;
+
+ /* the hd image will be modified */
+ hd_image = mmap(NULL, required_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fd_hd, 0);
+ if (hd_image == MAP_FAILED) {
+ perror("mmap");
+ rc = -1;
+ goto on_error_hd;
+ }
+
+ /* check for space */
+ rc = check_for_space(hd_image, required_size);
+ if (rc != 0)
+ goto on_error_space;
+
+ /* embed barebox's boot code into the disk drive image */
+ memcpy(hd_image, barebox_image, OFFSET_OF_PARTITION_TABLE);
+
+ /*
+ * embed the barebox main image into the disk drive image,
+ * but keep the persistant environment storage untouched
+ * (if defined), e.g. store the main image behind this special area.
+ */
+ memcpy(hd_image + ((pers_sector_count + 1) * SECTOR_SIZE),
+ barebox_image + SECTOR_SIZE, sb.st_size - SECTOR_SIZE);
+
+ /* now, prepare this hard disk image for BIOS based booting */
+ embed = hd_image + PATCH_AREA;
+ indirect = hd_image + ((pers_sector_count + 1) * SECTOR_SIZE);
+
+ /*
+ * Fill the embedded DAPS to let the basic boot code find the
+ * indirect sector at runtime
+ */
+#ifdef DEBUG
+ printf("Debug: Fill in embedded DAPS\n");
+#endif
+ rc = fill_daps(embed, 1, INDIRECT_AREA, INDIRECT_SEGMENT,
+ 1 + pers_sector_count);
+ if (rc != 0)
+ goto on_error_space;
+ debugout(embed, 1);
+
+#ifdef DEBUG
+ printf("Debug: Fill in indirect sector\n");
+#endif
+ /*
+ * fill the indirect sector with the remaining DAPS to load the
+ * whole barebox image at runtime
+ */
+ rc = barebox_linear_image(indirect, sb.st_size, pers_sector_count);
+ if (rc != 0)
+ goto on_error_space;
+
+ /*
+ * TODO: Replace the fixed LBA starting number by a calculated one,
+ * to support barebox as a chained loader in a different start
+ * sector than the MBR
+ */
+ rc = store_pers_env_info(embed, 1, pers_sector_count);
+ if (rc != 0)
+ goto on_error_space;
+
+on_error_space:
+ munmap(hd_image, required_size);
+
+on_error_hd:
+ munmap((void*)barebox_image, sb.st_size);
+
+ return rc;
+}
+
+static void print_usage(const char *pname)
+{
+ printf("%s: Preparing a hard disk image for boot with barebox on x86.\n", pname);
+ printf("Usage is\n %s [options] -m <barebox image> -d <hd image>\n", pname);
+ printf(" [options] are:\n -s <count> sector count of the persistant environment storage\n");
+ printf(" <barebox image> barebox's boot image file\n");
+ printf(" <hd image> HD image to store the barebox image\n");
+ printf(" If no '-s <x>' was given, barebox occupies sectors 0 to n, else sector 0 and x+1 to n\n");
+}
+
+int main(int argc, char *argv[])
+{
+ int rc = 0, c;
+ char *barebox_image_filename = NULL, *hd_image_filename = NULL;
+ int fd_barebox_image = 0, fd_hd_image = 0;
+ long barebox_pers_size = -1;
+
+ if (argc == 1) {
+ print_usage(argv[0]);
+ exit(0);
+ }
+
+ /* handle command line options first */
+ while (1) {
+ c = getopt(argc, argv, "m:d:s:hv");
+ if (c == -1)
+ break;
+
+ switch (c) {
+ case 's':
+ barebox_pers_size = strtol(optarg, NULL, 0);
+ break;
+ case 'm':
+ barebox_image_filename = strdup(optarg);
+ break;
+ case 'd':
+ hd_image_filename = strdup(optarg);
+ break;
+ case 'h':
+ print_usage(argv[0]);
+ rc = 0;
+ goto on_error;
+ case 'v':
+ printf("setupmbr for u-boot-v%s\n", UTS_RELEASE);
+ printf("Send bug reports to 'u-boot-v2@xxxxxxxxxxxxxxxxxxx'\n");
+ rc = 0;
+ goto on_error;
+ }
+ }
+
+ if (barebox_image_filename == NULL) {
+ print_usage(argv[0]);
+ rc = -1;
+ goto on_error;
+ }
+
+ fd_barebox_image = open(barebox_image_filename, O_RDONLY);
+ if (fd_barebox_image == -1) {
+ fprintf(stderr, "Cannot open '%s' for reading\n",
+ barebox_image_filename);
+ rc = -1;
+ goto on_error;
+ }
+
+ fd_hd_image = open(hd_image_filename, O_RDWR);
+ if (fd_hd_image == -1) {
+ fprintf(stderr, "Cannot open '%s'\n", hd_image_filename);
+ rc = -1;
+ goto on_error;
+ }
+
+ if (barebox_pers_size < 0)
+ barebox_pers_size = 0;
+
+ rc = barebox_overlay_mbr(fd_barebox_image, fd_hd_image, barebox_pers_size);
+
+on_error:
+ if (fd_barebox_image != -1)
+ close(fd_barebox_image);
+ if (fd_hd_image != -1)
+ close(fd_hd_image);
+
+ if (barebox_image_filename != NULL)
+ free(barebox_image_filename);
+ if (hd_image_filename != NULL)
+ free(hd_image_filename);
+
+ return rc;
+}
+
+/** @page x86_bootloader barebox acting as PC bootloader
+
+@section x86_bootloader_features Features
+
+@a barebox can act as a bootloader for PC based systems. In this case a special
+binary layout will be created to be able to store it on some media the PC
+BIOS can boot from. It can boot Linux kernels stored also on the same boot
+media and be configured at runtime, with the possibility to store the changed
+configuration on the boot media.
+
+@section x86_bootloader_restrictions Restrictions
+
+Due to some BIOS and @a barebox restrictions the boot media must be
+prepared in some special way:
+
+@li @a barebox must be stored in the MBR (Master Boot Record) of the boot media.
+ Currently its not possible to store and boot it in one of the partition
+ sectors (to use it as a second stage loader). This is no eternal
+ restriction. It only needs further effort to add this feature.
+@li @a barebox currently cannot run a chained boot loader. Also, this is no
+ eternal restriction, only further effort needed.
+@li @a barebox comes with limited filesystem support. There is currently no
+ support for the most common and popular filesystems used in the *NIX world.
+ This restricts locations where to store a kernel and other runtime
+ information
+@li @a barebox must be stored to the first n sectors of the boot media. To ensure
+ this does not collide with partitions on the boot media, the first
+ partition must start at a sector behind the ones @a barebox occupies.
+@li @a barebox handles its runtime configuration in a special way: It stores it
+ in a binary way into some reserved sectors ("persistant storage").
+
+@section x86_bootloader_preparations Boot Preparations
+
+To store the @a barebox image to a boot media, it comes with the tool
+@p setupmbr in the directory @p scripts/setupmbr/ . To be able to use it on
+the boot media of your choice, some preparations are required:
+
+@subsection x86_bootloader_preparations_partition Keep Sectors free
+
+Build the @a barebox image and check its size. At least this amount of
+sectors must be kept free after the MBR prior the first partition. Do this
+simple calulation:
+
+ sectors = (\<size of barebox image\> + 511) / 512
+
+To be able to store the runtime configuration, further free sectors are
+required. Its up to you and your requirements, how large this persistant
+storage must be. If you need 16 kiB for this purpose, you need to keep
+additional 32 sectors free.
+
+For this example we are reserving 300 sectors for the @a barebox image and
+additionaly 32 sectors for the persistant storage. So, the first partition on
+the boot media must start at sector 333 or later.
+
+Run the @p fdisk tool to setup such a partition table:
+
+@verbatim
+[jb@host]~> fdisk /dev/sda
+Command (m for help): p
+
+Disk /dev/sda: 20.7 MB, 212680704 bytes
+16 heads, 63 sectors/track, 406 cylinders
+Units = cylinders of 1008 * 512 = 516096 bytes
+
+ Device Boot Start End Blocks Id System
+@endverbatim
+
+Change the used units to @p sectors for easier handling.
+
+@verbatim
+Command (m for help): u
+Changing display/entry units to sectors
+
+Command (m for help): p
+
+Disk /dev/sda: 20.7 MB, 212680704 bytes
+16 heads, 63 sectors/track, 406 cylinders, total 409248 sectors
+Units = sectors of 1 * 512 = 512 bytes
+
+ Device Boot Start End Blocks Id System
+@endverbatim
+
+Now its possible to create the first partition with the required offset:
+
+@verbatim
+Command (m for help): n
+Command action
+ e extended
+ p primary partition (1-4)
+p
+Partition number (1-4): 1
+First sector (63-409247, default 63): 333
+Last sector or +size or +sizeM or +sizeK (333-409247, default 409247): +18M
+Command (m for help): p
+
+Disk /dev/sda: 20.7 MB, 212680704 bytes
+16 heads, 63 sectors/track, 406 cylinders, total 409248 sectors
+Units = sectors of 1 * 512 = 512 bytes
+
+ Device Boot Start End Blocks Id System
+/dev/sda 333 35489 17578+ 83 Linux
+@endverbatim
+
+That's all. Do whatever is required now with the new partition (formatting
+and populating the root filesystem for example) to make it useful.
+
+In the next step, @a barebox gets installed to this boot media:
+
+@verbatim
+[jb@host]~> scripts/setupmbr/setupmbr -s 32 -m ./barebox -d /dev/sda
+@endverbatim
+
+This command writes the @a barebox image file './barebox' onto the device
+@p /dev/sda.
+
+The @p -s option will keep the persistant storage sectors free and untouched
+and set flags in the MBR to forward its existance, size and location to
+@a barebox at runtime. @p setupmbr also does not change the partition table.
+
+The @a barebox image gets stored on the boot media like this:
+
+@verbatim
+sector 0 1 33 333
+ |---|-------------|--------------- ~~~ ------------|--------------
+ MBR persistant barebox first
+ storage main image partition
+@endverbatim
+
+If the @p -s option is omitted, the "persistant storage" part simply does
+not exist:
+
+@verbatim
+sector 0 1 333
+ |---|--------------- ~~~ ------------|--------------
+ MBR barebox first
+ main image partition
+@endverbatim
+
+@note The @p setupmbr tool is also working on real image file than on device
+ nodes only. So, there is no restriction what kind of file will be
+ modified.
+*/
Index: u-boot-2.0.0-rc10/Doxyfile
===================================================================
--- u-boot-2.0.0-rc10.orig/Doxyfile
+++ u-boot-2.0.0-rc10/Doxyfile
@@ -484,7 +484,8 @@ INPUT = Documentation \
commands \
common \
board \
- lib
+ lib \
+ scripts/setupmbr
# This tag can be used to specify the character encoding of the source files that
# doxygen parses. Internally doxygen uses the UTF-8 encoding, which is also the default
--
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