[U-Boot] [PATCH v0 04/20] part: extract MBR signature from partitions

[Rob Clark <robdclark@gmail.com>]

From: Peter Jones <pjones@redhat.com>

EFI client programs need the signature information from the partition
table to determine the disk a partition is on, so we need to fill that
in here.

Signed-off-by: Peter Jones <pjones@redhat.com>
[separated from efi_loader part, and fixed build-errors for non-
 CONFIG_EFI_PARTITION case]
Signed-off-by: Rob Clark <robdclark@gmail.com>
---
 disk/part_dos.c    | 12 +++++++++---
 disk/part_efi.c    | 20 ++++++++++++++++++++
 include/blk.h      | 15 +++++++++++++++
 include/efi.h      |  4 ++++
 include/part.h     |  3 ++-
 include/part_efi.h |  4 ----
 6 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 7ede15ec26..850a538e83 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -89,14 +89,20 @@ static int test_block_type(unsigned char *buffer)
 
 static int part_test_dos(struct blk_desc *dev_desc)
 {
-	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
+	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, dev_desc->blksz);
 
-	if (blk_dread(dev_desc, 0, 1, (ulong *)buffer) != 1)
+	if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1)
 		return -1;
 
-	if (test_block_type(buffer) != DOS_MBR)
+	if (test_block_type((unsigned char *)mbr) != DOS_MBR)
 		return -1;
 
+	if (dev_desc->sig_type == SIG_TYPE_NONE &&
+	    mbr->unique_mbr_signature != 0) {
+		dev_desc->sig_type = SIG_TYPE_MBR;
+		dev_desc->mbr_sig = mbr->unique_mbr_signature;
+	}
+
 	return 0;
 }
 
diff --git a/disk/part_efi.c b/disk/part_efi.c
index 1b7ba27947..71e4188455 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -871,11 +871,19 @@ static int is_pmbr_valid(legacy_mbr * mbr)
 static int is_gpt_valid(struct blk_desc *dev_desc, u64 lba,
 			gpt_header *pgpt_head, gpt_entry **pgpt_pte)
 {
+	ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, dev_desc->blksz);
+
 	if (!dev_desc || !pgpt_head) {
 		printf("%s: Invalid Argument(s)\n", __func__);
 		return 0;
 	}
 
+	/* Read MBR Header from device */
+	if (blk_dread(dev_desc, 0, 1, (ulong *)mbr) != 1) {
+		printf("*** ERROR: Can't read MBR header ***\n");
+		return 0;
+	}
+
 	/* Read GPT Header from device */
 	if (blk_dread(dev_desc, (lbaint_t)lba, 1, pgpt_head) != 1) {
 		printf("*** ERROR: Can't read GPT header ***\n");
@@ -885,6 +893,18 @@ static int is_gpt_valid(struct blk_desc *dev_desc, u64 lba,
 	if (validate_gpt_header(pgpt_head, (lbaint_t)lba, dev_desc->lba))
 		return 0;
 
+	if (dev_desc->sig_type == SIG_TYPE_NONE) {
+		efi_guid_t empty = {};
+		if (memcmp(&pgpt_head->disk_guid, &empty, sizeof(empty))) {
+			dev_desc->sig_type = SIG_TYPE_GUID;
+			memcpy(&dev_desc->guid_sig, &pgpt_head->disk_guid,
+			      sizeof(empty));
+		} else if (mbr->unique_mbr_signature != 0) {
+			dev_desc->sig_type = SIG_TYPE_MBR;
+			dev_desc->mbr_sig = mbr->unique_mbr_signature;
+		}
+	}
+
 	/* Read and allocate Partition Table Entries */
 	*pgpt_pte = alloc_read_gpt_entries(dev_desc, pgpt_head);
 	if (*pgpt_pte == NULL) {
diff --git a/include/blk.h b/include/blk.h
index ef29a07ee2..3a5e04c00d 100644
--- a/include/blk.h
+++ b/include/blk.h
@@ -8,6 +8,8 @@
 #ifndef BLK_H
 #define BLK_H
 
+#include <efi.h>
+
 #ifdef CONFIG_SYS_64BIT_LBA
 typedef uint64_t lbaint_t;
 #define LBAFlength "ll"
@@ -35,6 +37,14 @@ enum if_type {
 	IF_TYPE_COUNT,			/* Number of interface types */
 };
 
+enum sig_type {
+	SIG_TYPE_NONE,
+	SIG_TYPE_MBR,
+	SIG_TYPE_GUID,
+
+	SIG_TYPE_COUNT			/* Number of signature types */
+};
+
 /*
  * With driver model (CONFIG_BLK) this is uclass platform data, accessible
  * with dev_get_uclass_platdata(dev)
@@ -62,6 +72,11 @@ struct blk_desc {
 	char		vendor[40+1];	/* IDE model, SCSI Vendor */
 	char		product[20+1];	/* IDE Serial no, SCSI product */
 	char		revision[8+1];	/* firmware revision */
+	enum sig_type	sig_type;	/* Partition table signature type */
+	union {
+		uint32_t mbr_sig;	/* MBR integer signature */
+		efi_guid_t guid_sig;	/* GPT GUID Signature */
+	};
 #ifdef CONFIG_BLK
 	/*
 	 * For now we have a few functions which take struct blk_desc as a
diff --git a/include/efi.h b/include/efi.h
index 02b78b31b1..87b0b43f20 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -28,6 +28,10 @@
 
 struct efi_device_path;
 
+typedef struct {
+	u8 b[16];
+} efi_guid_t;
+
 #define EFI_BITS_PER_LONG	BITS_PER_LONG
 
 /*
diff --git a/include/part.h b/include/part.h
index 83bce05a43..ac5ee895e9 100644
--- a/include/part.h
+++ b/include/part.h
@@ -259,8 +259,9 @@ struct part_driver {
 #define U_BOOT_PART_TYPE(__name)					\
 	ll_entry_declare(struct part_driver, __name, part_driver)
 
-#if CONFIG_IS_ENABLED(EFI_PARTITION)
 #include <part_efi.h>
+
+#if CONFIG_IS_ENABLED(EFI_PARTITION)
 /* disk/part_efi.c */
 /**
  * write_gpt_table() - Write the GUID Partition Table to disk
diff --git a/include/part_efi.h b/include/part_efi.h
index 317c044795..31e6bc6e14 100644
--- a/include/part_efi.h
+++ b/include/part_efi.h
@@ -58,10 +58,6 @@
 /* linux/include/efi.h */
 typedef u16 efi_char16_t;
 
-typedef struct {
-	u8 b[16];
-} efi_guid_t;
-
 /* based on linux/include/genhd.h */
 struct partition {
 	u8 boot_ind;		/* 0x80 - active */
-- 
2.13.0