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

[Lukasz Majewski]

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

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