[U-Boot] [PATCH v2 5/7] gpt: Support for GPT (GUID Partition Table) restoration

Lukasz Majewski
2012-09-12T14:50:44Z

The restoration of GPT table (both primary and secondary) is now possible.
Simple GUID generation is supported.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

---
Changes for v2:
- Move GPT Header and Page Table Entries generation code to cmd_gpt.c
- Provide clean API to use set_gpt_table function for GPT restoration on
a block device
---
disk/part_efi.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/part.h | 3 ++
2 files changed, 102 insertions(+), 0 deletions(-)

diff --git a/disk/part_efi.c b/disk/part_efi.c
index d4c61d2..531c7ad 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -403,4 +403,103 @@ static int is_pte_valid(gpt_entry * pte)
return 1;
}
}
+
+/**
+ * set_protective_mbr(): Set the EFI protective MBR
+ * @param dev_desc - block device descriptor
+ *
+ * @return - zero on success, otherwise error
+ */
+static int set_protective_mbr(block_dev_desc_t *dev_desc)
+{
+ legacy_mbr p_mbr;
+
+ /* Setup the Protective MBR */
+ memset((u32 *) &p_mbr, 0x00, sizeof(p_mbr));
+ /* Append signature */
+ p_mbr.signature = MSDOS_MBR_SIGNATURE;
+ p_mbr.partition_record[0].sys_ind = EFI_PMBR_OSTYPE_EFI_GPT;
+ p_mbr.partition_record[0].start_sect = 1;
+ p_mbr.partition_record[0].nr_sects = (u32) dev_desc->lba;
+
+ /* Write MBR sector to the MMC device */
+ if (dev_desc->block_write(dev_desc->dev, 0, 1, &p_mbr) != 1) {
+ printf("** Can't write to device %d **\n",
+ dev_desc->dev);
+ return -1;
+ }
+
+ return 0;
+}
+
+/**
+ * set_gpt_table() - Restore the GUID Partition Table
+ *
+ * @param dev_desc - block device descriptor
+ * @param parts - number of partitions
+ * @param size - pointer to array with each partition size
+ * @param name - pointer to array with each partition name
+ *
+ * @return - zero on success, otherwise error
+ */
+int set_gpt_table(block_dev_desc_t *dev_desc,
+ gpt_header *gpt_h, gpt_entry *gpt_e)
+{
+ const int pte_blk_num = (GPT_ENTRY_NUMBERS * sizeof(gpt_entry)) /
+ dev_desc->blksz;
+ u32 calc_crc32;
+ u64 val;
+
+ debug("max lba: %x\n", (u32) dev_desc->lba);
+
+ /* Setup the Protective MBR */
+ if (set_protective_mbr(dev_desc) < 0)
+ goto err;
+
+ /* Generate CRC for the Primary GPT Header */
+ calc_crc32 = efi_crc32((const unsigned char *)gpt_e,
+ le32_to_cpu(gpt_h->num_partition_entries) *
+ le32_to_cpu(gpt_h->sizeof_partition_entry));
+ gpt_h->partition_entry_array_crc32 = cpu_to_le32(calc_crc32);
+
+ calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
+ le32_to_cpu(gpt_h->header_size));
+ gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
+
+ /* Write the First GPT to the block right after the Legacy MBR */
+ if (dev_desc->block_write(dev_desc->dev, 1, 1, gpt_h) != 1)
+ goto err;
+
+ if (dev_desc->block_write(dev_desc->dev, 2, pte_blk_num, gpt_e)
+ != pte_blk_num)
+ goto err;
+
+ /* recalculate the values for the Second GPT Header*/
+ val = le64_to_cpu(gpt_h->my_lba);
+ gpt_h->my_lba = gpt_h->alternate_lba;
+ gpt_h->alternate_lba = cpu_to_le64(val);
+ gpt_h->header_crc32 = 0;
+
+ calc_crc32 = efi_crc32((const unsigned char *)gpt_h,
+ le32_to_cpu(gpt_h->header_size));
+ gpt_h->header_crc32 = cpu_to_le32(calc_crc32);
+
+ /* Write the Second GPT that is located at the end of the disk */
+ if (dev_desc->block_write(dev_desc->dev,
+ le32_to_cpu(gpt_h->last_usable_lba + 1),
+ pte_blk_num, gpt_e) != pte_blk_num)
+ goto err;
+
+ if (dev_desc->block_write(dev_desc->dev,
+ le32_to_cpu(gpt_h->my_lba), 1, gpt_h) != 1)
+ goto err;
+
+ printf("GPT successfully written to block device!\n");
+ return 0;
+
+ err:
+ printf("** Can't write to device %d **\n",
+ dev_desc->dev);
+ return -1;
+}
#endif
diff --git a/include/part.h b/include/part.h
index e1478f4..fc34ed2 100644
--- a/include/part.h
+++ b/include/part.h
@@ -157,10 +157,13 @@ int test_part_amiga (block_dev_desc_t *dev_desc);
#endif

#ifdef CONFIG_EFI_PARTITION
+#include <part_efi.h>
/* disk/part_efi.c */
int get_partition_info_efi (block_dev_desc_t * dev_desc, int part, disk_partition_t *info);
void print_part_efi (block_dev_desc_t *dev_desc);
int test_part_efi (block_dev_desc_t *dev_desc);
+int set_gpt_table(block_dev_desc_t *dev_desc,
+ gpt_header *gpt_h, gpt_entry *gpt_e);
#endif

#endif /* _PART_H */
--
1.7.2.3