[PATCH 2/8] cdev: add diskuuid support

[Sascha Hauer]

From: Michael Olbrich <m.olbrich at pengutronix.de>

This allows identifying disks by UUID. For disks with GPT the disk GUID is
used. For DOS partition tables the NT signature ist used, similar to how
the partuuid is generated.

Signed-off-by: Michael Olbrich <m.olbrich at pengutronix.de>
Link: https://lore.barebox.org/20220124100458.2924679-3-m.olbrich@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 common/partitions/dos.c |  3 +++
 common/partitions/efi.c |  2 ++
 fs/devfs-core.c         | 14 ++++++++++++++
 include/driver.h        |  1 +
 4 files changed, 20 insertions(+)

diff --git a/common/partitions/dos.c b/common/partitions/dos.c
index 597d7bf9bc..566c8dd949 100644
--- a/common/partitions/dos.c
+++ b/common/partitions/dos.c
@@ -182,6 +182,9 @@ static void dos_partition(void *buf, struct block_device *blk,
 	struct disk_signature_priv *dsp;
 	uint32_t signature = get_unaligned_le32(buf + 0x1b8);
 
+	if (signature)
+		sprintf(blk->cdev.uuid, "%08x", signature);
+
 	table = (struct partition_entry *)&buffer[446];
 
 	for (i = 0; i < 4; i++) {
diff --git a/common/partitions/efi.c b/common/partitions/efi.c
index 6d811bfb3b..0787b93f12 100644
--- a/common/partitions/efi.c
+++ b/common/partitions/efi.c
@@ -445,6 +445,8 @@ static void efi_partition(void *buf, struct block_device *blk,
 		return;
 	}
 
+	snprintf(blk->cdev.uuid, sizeof(blk->cdev.uuid), "%pUl", &gpt->disk_guid);
+
 	nb_part = le32_to_cpu(gpt->num_partition_entries);
 
 	if (nb_part > MAX_PARTITION) {
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index 82e4811b38..2475ab959a 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -107,6 +107,20 @@ struct cdev *cdev_by_partuuid(const char *partuuid)
 	return NULL;
 }
 
+struct cdev *cdev_by_diskuuid(const char *diskuuid)
+{
+	struct cdev *cdev;
+
+	if (!diskuuid)
+		return NULL;
+
+	list_for_each_entry(cdev, &cdev_list, list) {
+		if (!cdev->master && !strcasecmp(cdev->uuid, diskuuid))
+			return cdev;
+	}
+	return NULL;
+}
+
 /**
  * device_find_partition - find a partition belonging to a physical device
  *
diff --git a/include/driver.h b/include/driver.h
index 62a1782847..3ef8bfb8a3 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -488,6 +488,7 @@ struct cdev *lcdev_by_name(const char *filename);
 struct cdev *cdev_readlink(struct cdev *cdev);
 struct cdev *cdev_by_device_node(struct device_node *node);
 struct cdev *cdev_by_partuuid(const char *partuuid);
+struct cdev *cdev_by_diskuuid(const char *partuuid);
 struct cdev *cdev_open(const char *name, unsigned long flags);
 struct cdev *cdev_create_loop(const char *path, ulong flags, loff_t offset);
 void cdev_remove_loop(struct cdev *cdev);
-- 
2.30.2