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.szyprow...@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
--
2.17.1
