"Das U-Boot" Source Tree
disk: dos: add code for creating MBR partition layout
Add a code for creating and writing MBR partition layout. The code generates
similar layout of EBRs (Exteneded Block Records) and logical volumes as
Linux's fdisk utility.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
authored by
Marek Szyprowski
and committed by
Tom Rini
20bd5ac6
cb571f91
+174
+167
disk/part_dos.c
+167
disk/part_dos.c
···
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return test_block_type(buf) == DOS_MBR ? 0 : -1;
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}
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#if CONFIG_IS_ENABLED(CMD_MBR)
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static void lba_to_chs(lbaint_t lba, unsigned char *rc, unsigned char *rh,
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unsigned char *rs)
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{
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unsigned int c, h, s;
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/* use fixed CHS geometry */
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unsigned int sectpertrack = 63;
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unsigned int heads = 255;
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c = (lba + 1) / sectpertrack / heads;
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h = (lba + 1) / sectpertrack - c * heads;
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s = (lba + 1) - (c * heads + h) * sectpertrack;
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+
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if (c > 1023) {
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c = 1023;
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h = 254;
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s = 63;
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}
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*rc = c & 0xff;
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*rh = h;
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*rs = s + ((c & 0x300) >> 2);
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}
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static void mbr_fill_pt_entry(dos_partition_t *pt, lbaint_t start,
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lbaint_t relative, lbaint_t size, uchar sys_ind, bool bootable)
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{
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pt->boot_ind = bootable ? 0x80 : 0x00;
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pt->sys_ind = sys_ind;
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lba_to_chs(start, &pt->cyl, &pt->head, &pt->sector);
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lba_to_chs(start + size - 1, &pt->end_cyl, &pt->end_head, &pt->end_sector);
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put_unaligned_le32(relative, &pt->start4);
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put_unaligned_le32(size, &pt->size4);
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}
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int write_mbr_partitions(struct blk_desc *dev,
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struct disk_partition *p, int count, unsigned int disksig)
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{
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ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev->blksz);
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lbaint_t ext_part_start = 0, ext_part_size = 0, ext_part_sect = 0;
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dos_partition_t *pt;
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int i;
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memset(buffer, 0, dev->blksz);
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buffer[DOS_PART_MAGIC_OFFSET] = 0x55;
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buffer[DOS_PART_MAGIC_OFFSET + 1] = 0xaa;
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put_unaligned_le32(disksig, &buffer[DOS_PART_DISKSIG_OFFSET]);
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pt = (dos_partition_t *) (buffer + DOS_PART_TBL_OFFSET);
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+
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/* create all primary partitions */
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for (i = 0; i < 4 && i < count; i++, pt++) {
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mbr_fill_pt_entry(pt, p[i].start, p[i].start, p[i].size,
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p[i].sys_ind, p[i].bootable);
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if (is_extended(p[i].sys_ind)) {
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ext_part_start = p[i].start;
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ext_part_size = p[i].size;
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ext_part_sect = p[i].start;
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}
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}
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if (i < count && !ext_part_start) {
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printf("%s: extended partition is needed for more than 4 partitions\n",
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__func__);
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return -1;
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}
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/* write MBR */
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if (blk_dwrite(dev, 0, 1, buffer) != 1) {
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printf("%s: failed writing 'MBR' (1 blks at 0x0)\n",
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__func__);
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return -1;
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}
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/* create extended volumes */
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for (; i < count; i++) {
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lbaint_t next_ebr = 0;
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memset(buffer, 0, dev->blksz);
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buffer[DOS_PART_MAGIC_OFFSET] = 0x55;
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buffer[DOS_PART_MAGIC_OFFSET + 1] = 0xaa;
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pt = (dos_partition_t *) (buffer + DOS_PART_TBL_OFFSET);
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mbr_fill_pt_entry(pt, p[i].start, p[i].start - ext_part_sect,
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p[i].size, p[i].sys_ind, p[i].bootable);
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if (i + 1 < count) {
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pt++;
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next_ebr = p[i].start + p[i].size;
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mbr_fill_pt_entry(pt, next_ebr,
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next_ebr - ext_part_start,
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p[i+1].start + p[i+1].size - next_ebr,
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DOS_PART_TYPE_EXTENDED, 0);
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}
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/* write EBR */
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if (blk_dwrite(dev, ext_part_sect, 1, buffer) != 1) {
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printf("%s: failed writing 'EBR' (1 blks at 0x%lx)\n",
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__func__, ext_part_sect);
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return -1;
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}
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ext_part_sect = next_ebr;
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}
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return 0;
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}
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int layout_mbr_partitions(struct disk_partition *p, int count,
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lbaint_t total_sectors)
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{
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struct disk_partition *ext = NULL;
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int i, j;
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lbaint_t ext_vol_start;
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/* calculate primary partitions start and size if needed */
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if (!p[0].start)
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p[0].start = DOS_PART_DEFAULT_GAP;
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for (i = 0; i < 4 && i < count; i++) {
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if (!p[i].start)
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p[i].start = p[i - 1].start + p[i - 1].size;
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if (!p[i].size) {
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lbaint_t end = total_sectors;
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lbaint_t allocated = 0;
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for (j = i + 1; j < 4 && j < count; j++) {
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if (p[j].start) {
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end = p[j].start;
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break;
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}
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allocated += p[j].size;
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}
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p[i].size = end - allocated - p[i].start;
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}
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if (p[i].sys_ind == 0x05)
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ext = &p[i];
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}
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if (i >= 4 && !ext) {
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printf("%s: extended partition is needed for more than 4 partitions\n",
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__func__);
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return -1;
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}
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/* calculate extended volumes start and size if needed */
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ext_vol_start = ext->start;
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for (i = 4; i < count; i++) {
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if (!p[i].start)
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p[i].start = ext_vol_start + DOS_PART_DEFAULT_GAP;
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if (!p[i].size) {
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lbaint_t end = ext->start + ext->size;
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lbaint_t allocated = 0;
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for (j = i + 1; j < count; j++) {
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if (p[j].start) {
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end = p[j].start - DOS_PART_DEFAULT_GAP;
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break;
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}
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allocated += p[j].size + DOS_PART_DEFAULT_GAP;
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}
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p[i].size = end - allocated - p[i].start;
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}
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ext_vol_start = p[i].start + p[i].size;
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}
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return 0;
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}
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#endif
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int write_mbr_sector(struct blk_desc *dev_desc, void *buf)
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{
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if (is_valid_dos_buf(buf))
+2
disk/part_dos.h
+2
disk/part_dos.h
+5
include/part.h
+5
include/part.h
···
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*/
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int write_mbr_sector(struct blk_desc *dev_desc, void *buf);
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int write_mbr_partitions(struct blk_desc *dev,
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struct disk_partition *p, int count, unsigned int disksig);
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int layout_mbr_partitions(struct disk_partition *p, int count,
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lbaint_t total_sectors);
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#endif
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