[PATCH v10 05/10] block: partitions: of: Attach partition fwnode to the block device

The OF partition parser reads offset, size and label from each
"fixed-partitions" child node but does not associate that node with the
resulting partition block device. As a result a partition has no
of_node, unlike the whole-disk device which gets its firmware node via
add_disk_fwnode().

Carry the partition's device tree node through the parser and attach it
to the partition's block device with device_set_node(), mirroring the
whole-disk case. This lets consumers describe per-partition properties
in the device tree (for example an NVMEM layout on a partition node) and
look them up through the partition device.

No functional change for existing users, partitions without a matching
device tree node simply get a NULL fwnode.

Reviewed-by: Bartosz Golaszewski <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Loic Poulain <[email protected]>
---
 block/partitions/check.h |  1 +
 block/partitions/core.c  | 20 +++++++++++++++++---
 block/partitions/of.c    |  3 +++
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/block/partitions/check.h b/block/partitions/check.h
index b0997467b61a54a8a621b9c155c8329289649460..326081499d9a6be730dbd659c110449cfa06921f 100644
--- a/block/partitions/check.h
+++ b/block/partitions/check.h
@@ -17,6 +17,7 @@ struct parsed_partitions {
 		int flags;
 		bool has_info;
 		struct partition_meta_info info;
+		struct fwnode_handle *fwnode;
 	} *parts;
 	int next;
 	int limit;
diff --git a/block/partitions/core.c b/block/partitions/core.c
index b5c59b79ca7cbb28d4d93478ee1c80908f76ee9f..eee954df1ac6ef7dd4f02ad5c9d49aed778bf015 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -11,6 +11,7 @@
 #include <linux/sysfs.h>
 #include <linux/ctype.h>
 #include <linux/vmalloc.h>
+#include <linux/property.h>
 #include <linux/raid/detect.h>
 #include "check.h"
 
@@ -110,8 +111,17 @@ static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
 	return state;
 }
 
+static void drop_partitions_fwnodes(struct parsed_partitions *state)
+{
+	for (int i = 0; i < state->limit; i++) {
+		fwnode_handle_put(state->parts[i].fwnode);
+		state->parts[i].fwnode = NULL;
+	}
+}
+
 static void free_partitions(struct parsed_partitions *state)
 {
+	drop_partitions_fwnodes(state);
 	vfree(state->parts);
 	kfree(state);
 }
@@ -139,6 +149,7 @@ static struct parsed_partitions *check_partition(struct gendisk *hd)
 
 	i = res = err = 0;
 	while (!res && check_part[i]) {
+		drop_partitions_fwnodes(state);
 		memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
 		res = check_part[i++](state);
 		if (res < 0) {
@@ -247,6 +258,7 @@ static const struct attribute_group *part_attr_groups[] = {
 
 static void part_release(struct device *dev)
 {
+	fwnode_handle_put(dev_fwnode(dev));
 	put_disk(dev_to_bdev(dev)->bd_disk);
 	bdev_drop(dev_to_bdev(dev));
 }
@@ -294,7 +306,8 @@ static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
  */
 static struct block_device *add_partition(struct gendisk *disk, int partno,
 				sector_t start, sector_t len, int flags,
-				struct partition_meta_info *info)
+				struct partition_meta_info *info,
+				struct fwnode_handle *fwnode)
 {
 	dev_t devt = MKDEV(0, 0);
 	struct device *ddev = disk_to_dev(disk);
@@ -343,6 +356,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 	pdev->class = &block_class;
 	pdev->type = &part_type;
 	pdev->parent = ddev;
+	device_set_node(pdev, fwnode_handle_get(fwnode));
 
 	/* in consecutive minor range? */
 	if (bdev_partno(bdev) < disk->minors) {
@@ -449,7 +463,7 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
 	}
 
 	part = add_partition(disk, partno, start, length,
-			ADDPART_FLAG_NONE, NULL);
+			ADDPART_FLAG_NONE, NULL, NULL);
 	ret = PTR_ERR_OR_ZERO(part);
 out:
 	mutex_unlock(&disk->open_mutex);
@@ -564,7 +578,7 @@ static bool blk_add_partition(struct gendisk *disk,
 	}
 
 	part = add_partition(disk, p, from, size, state->parts[p].flags,
-			     &state->parts[p].info);
+			     &state->parts[p].info, state->parts[p].fwnode);
 	if (IS_ERR(part)) {
 		if (PTR_ERR(part) != -ENXIO) {
 			printk(KERN_ERR " %s: p%d could not be added: %pe\n",
diff --git a/block/partitions/of.c b/block/partitions/of.c
index dab36513eba336344c9558d486a8915624b0fca8..d4016f9b77ec078eb1adb32923107c012ca4a751 100644
--- a/block/partitions/of.c
+++ b/block/partitions/of.c
@@ -3,6 +3,7 @@
 #include <linux/blkdev.h>
 #include <linux/major.h>
 #include <linux/of.h>
+#include <linux/property.h>
 #include <linux/string.h>
 #include "check.h"
 
@@ -65,6 +66,8 @@ static void add_of_partition(struct parsed_partitions *state, int slot,
 		partname = of_get_property(np, "name", &len);
 	strscpy(info->volname, partname, sizeof(info->volname));
 
+	state->parts[slot].fwnode = fwnode_handle_get(of_fwnode_handle(np));
+
 	seq_buf_printf(&state->pp_buf, "(%s)", info->volname);
 }
 

-- 
2.34.1