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 --- disk/part_dos.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++ disk/part_dos.h | 2 + include/part.h | 5 ++ 3 files changed, 174 insertions(+)
diff --git a/disk/part_dos.c b/disk/part_dos.c index 2c4ad0b6ba..f77f927995 100644 --- a/disk/part_dos.c +++ b/disk/part_dos.c @@ -319,6 +319,173 @@ int is_valid_dos_buf(void *buf) return test_block_type(buf) == DOS_MBR ? 0 : -1; }
+#if CONFIG_IS_ENABLED(CMD_MBR) +static void lba_to_chs(lbaint_t lba, unsigned char *rc, unsigned char *rh, + unsigned char *rs) +{ + unsigned int c, h, s; + /* use fixed CHS geometry */ + unsigned int sectpertrack = 63; + unsigned int heads = 255; + + c = (lba + 1) / sectpertrack / heads; + h = (lba + 1) / sectpertrack - c * heads; + s = (lba + 1) - (c * heads + h) * sectpertrack; + + if (c > 1023) { + c = 1023; + h = 254; + s = 63; + } + + *rc = c & 0xff; + *rh = h; + *rs = s + ((c & 0x300) >> 2); +} + +static void mbr_fill_pt_entry(dos_partition_t *pt, lbaint_t start, + lbaint_t relative, lbaint_t size, uchar sys_ind, bool bootable) +{ + pt->boot_ind = bootable ? 0x80 : 0x00; + pt->sys_ind = sys_ind; + lba_to_chs(start, &pt->cyl, &pt->head, &pt->sector); + lba_to_chs(start + size - 1, &pt->end_cyl, &pt->end_head, &pt->end_sector); + put_unaligned_le32(relative, &pt->start4); + put_unaligned_le32(size, &pt->size4); +} + +int write_mbr_partitions(struct blk_desc *dev, + struct disk_partition *p, int count, unsigned int disksig) +{ + ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev->blksz); + lbaint_t ext_part_start = 0, ext_part_size = 0, ext_part_sect = 0; + dos_partition_t *pt; + int i; + + memset(buffer, 0, dev->blksz); + buffer[DOS_PART_MAGIC_OFFSET] = 0x55; + buffer[DOS_PART_MAGIC_OFFSET + 1] = 0xaa; + put_unaligned_le32(disksig, &buffer[DOS_PART_DISKSIG_OFFSET]); + pt = (dos_partition_t *) (buffer + DOS_PART_TBL_OFFSET); + + /* create all primary partitions */ + for (i = 0; i < 4 && i < count; i++, pt++) { + mbr_fill_pt_entry(pt, p[i].start, p[i].start, p[i].size, + p[i].sys_ind, p[i].bootable); + if (is_extended(p[i].sys_ind)) { + ext_part_start = p[i].start; + ext_part_size = p[i].size; + ext_part_sect = p[i].start; + } + } + + if (i < count && !ext_part_start) { + printf("%s: extended partition is needed for more than 4 partitions\n", + __func__); + return -1; + } + + /* write MBR */ + if (blk_dwrite(dev, 0, 1, buffer) != 1) { + printf("%s: failed writing 'MBR' (1 blks at 0x0)\n", + __func__); + return -1; + } + + /* create extended volumes */ + for (; i < count; i++) { + lbaint_t next_ebr = 0; + + memset(buffer, 0, dev->blksz); + buffer[DOS_PART_MAGIC_OFFSET] = 0x55; + buffer[DOS_PART_MAGIC_OFFSET + 1] = 0xaa; + pt = (dos_partition_t *) (buffer + DOS_PART_TBL_OFFSET); + + mbr_fill_pt_entry(pt, p[i].start, p[i].start - ext_part_sect, + p[i].size, p[i].sys_ind, p[i].bootable); + + if (i + 1 < count) { + pt++; + next_ebr = p[i].start + p[i].size; + mbr_fill_pt_entry(pt, next_ebr, + next_ebr - ext_part_start, + p[i+1].start + p[i+1].size - next_ebr, + DOS_PART_TYPE_EXTENDED, 0); + } + + /* write EBR */ + if (blk_dwrite(dev, ext_part_sect, 1, buffer) != 1) { + printf("%s: failed writing 'EBR' (1 blks at 0x%lx)\n", + __func__, ext_part_sect); + return -1; + } + ext_part_sect = next_ebr; + } + + return 0; +} + +int layout_mbr_partitions(struct disk_partition *p, int count, + lbaint_t total_sectors) +{ + struct disk_partition *ext = NULL; + int i, j; + lbaint_t ext_vol_start; + + /* calculate primary partitions start and size if needed */ + if (!p[0].start) + p[0].start = DOS_PART_DEFAULT_GAP; + for (i = 0; i < 4 && i < count; i++) { + if (!p[i].start) + p[i].start = p[i - 1].start + p[i - 1].size; + if (!p[i].size) { + lbaint_t end = total_sectors; + lbaint_t allocated = 0; + + for (j = i + 1; j < 4 && j < count; j++) { + if (p[j].start) { + end = p[j].start; + break; + } + allocated += p[j].size; + } + p[i].size = end - allocated - p[i].start; + } + if (p[i].sys_ind == 0x05) + ext = &p[i]; + } + + if (i >= 4 && !ext) { + printf("%s: extended partition is needed for more than 4 partitions\n", + __func__); + return -1; + } + + /* calculate extended volumes start and size if needed */ + ext_vol_start = ext->start; + for (i = 4; i < count; i++) { + if (!p[i].start) + p[i].start = ext_vol_start + DOS_PART_DEFAULT_GAP; + if (!p[i].size) { + lbaint_t end = ext->start + ext->size; + lbaint_t allocated = 0; + + for (j = i + 1; j < count; j++) { + if (p[j].start) { + end = p[j].start - DOS_PART_DEFAULT_GAP; + break; + } + allocated += p[j].size + DOS_PART_DEFAULT_GAP; + } + p[i].size = end - allocated - p[i].start; + } + ext_vol_start = p[i].start + p[i].size; + } + + return 0; +} +#endif + int write_mbr_sector(struct blk_desc *dev_desc, void *buf) { if (is_valid_dos_buf(buf)) diff --git a/disk/part_dos.h b/disk/part_dos.h index dd909a9317..5055822422 100644 --- a/disk/part_dos.h +++ b/disk/part_dos.h @@ -19,6 +19,8 @@ #define DOS_PART_TYPE_EXTENDED_LBA 0x0F #define DOS_PART_TYPE_EXTENDED_LINUX 0x85
+#define DOS_PART_DEFAULT_GAP 2048 + typedef struct dos_partition { unsigned char boot_ind; /* 0x80 - active */ unsigned char head; /* starting head */ diff --git a/include/part.h b/include/part.h index 67b8b2a5cc..fac36364bd 100644 --- a/include/part.h +++ b/include/part.h @@ -474,6 +474,11 @@ int is_valid_dos_buf(void *buf); */ int write_mbr_sector(struct blk_desc *dev_desc, void *buf);
+int write_mbr_partitions(struct blk_desc *dev, + struct disk_partition *p, int count, unsigned int disksig); +int layout_mbr_partitions(struct disk_partition *p, int count, + lbaint_t total_sectors); + #endif