From patchwork Tue Jul 30 19:25:59 2024
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X-Patchwork-Submitter: Daniel Golle <daniel@makrotopia.org>
X-Patchwork-Id: 13747816
Date: Tue, 30 Jul 2024 20:25:59 +0100
From: Daniel Golle <daniel@makrotopia.org>
To: Rob Herring <robh@kernel.org>, Krzysztof Kozlowski <krzk+dt@kernel.org>,
 Conor Dooley <conor+dt@kernel.org>, Jens Axboe <axboe@kernel.dk>,
 Daniel Golle <daniel@makrotopia.org>, Christian Brauner <brauner@kernel.org>,
 Al Viro <viro@zeniv.linux.org.uk>, Li Lingfeng <lilingfeng3@huawei.com>,
 Ming Lei <ming.lei@redhat.com>, Christian Heusel <christian@heusel.eu>,
	=?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>,
 Felix Fietkau <nbd@nbd.name>, John Crispin <john@phrozen.org>,
 Chad Monroe <chad.monroe@adtran.com>, Yangyu Chen <cyy@cyyself.name>,
 Tianling Shen <cnsztl@immortalwrt.org>, Chuanhong Guo <gch981213@gmail.com>,
 Chen Minqiang <ptpt52@gmail.com>, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: [PATCH v5 2/4] block: partitions: populate fwnode
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 <3051ac090ad3b3e2f5adb6b67c923261ead729a5.1722365899.git.daniel@makrotopia.org>
References: <cover.1722365899.git.daniel@makrotopia.org>
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Assign matching firmware nodes to block partitions in order to allow
them to be referenced e.g. as NVMEM providers.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 block/partitions/core.c | 72 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -10,6 +10,8 @@
 #include <linux/ctype.h>
 #include <linux/vmalloc.h>
 #include <linux/raid/detect.h>
+#include <linux/property.h>
+
 #include "check.h"
 
 static int (*const check_part[])(struct parsed_partitions *) = {
@@ -295,6 +297,74 @@ static ssize_t whole_disk_show(struct de
 }
 static const DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);
 
+static bool part_meta_match(const char *attr, const char *member, size_t length)
+{
+	/* check if length of attr exceeds specified maximum length */
+	if (strnlen(attr, length) == length)
+		return false;
+
+	/* return true if strings match */
+	return !strncmp(attr, member, length);
+}
+
+static struct fwnode_handle *find_partition_fwnode(struct block_device *bdev)
+{
+	struct fwnode_handle *fw_parts, *fw_part;
+	struct device *ddev = disk_to_dev(bdev->bd_disk);
+	const char *partname, *uuid;
+	u32 partno;
+	bool got_uuid, got_partname, got_partno;
+
+	fw_parts = device_get_named_child_node(ddev, "partitions");
+	if (!fw_parts)
+		return NULL;
+
+	fwnode_for_each_child_node(fw_parts, fw_part) {
+		got_uuid = false;
+		got_partname = false;
+		got_partno = false;
+		/*
+		 * In case 'uuid' is defined in the partitions firmware node
+		 * require partition meta info being present and the specified
+		 * uuid to match.
+		 */
+		got_uuid = !fwnode_property_read_string(fw_part, "uuid", &uuid);
+		if (got_uuid && (!bdev->bd_meta_info ||
+				 !part_meta_match(uuid, bdev->bd_meta_info->uuid,
+						  PARTITION_META_INFO_UUIDLTH)))
+			continue;
+
+		/*
+		 * In case 'partname' is defined in the partitions firmware node
+		 * require partition meta info being present and the specified
+		 * volname to match.
+		 */
+		got_partname = !fwnode_property_read_string(fw_part, "partname",
+							    &partname);
+		if (got_partname && (!bdev->bd_meta_info ||
+				     !part_meta_match(partname,
+						      bdev->bd_meta_info->volname,
+						      PARTITION_META_INFO_VOLNAMELTH)))
+			continue;
+
+		/*
+		 * In case 'partno' is defined in the partitions firmware node
+		 * the specified partno needs to match.
+		 */
+		got_partno = !fwnode_property_read_u32(fw_part, "partno", &partno);
+		if (got_partno && bdev->bd_partno != partno)
+			continue;
+
+		/* Skip if no matching criteria is present in firmware node */
+		if (!got_uuid && !got_partname && !got_partno)
+			continue;
+
+		return fw_part;
+	}
+
+	return NULL;
+}
+
 /*
  * Must be called either with open_mutex held, before a disk can be opened or
  * after all disk users are gone.
@@ -377,6 +447,8 @@ static struct block_device *add_partitio
 			goto out_put;
 	}
 
+	device_set_node(pdev, find_partition_fwnode(bdev));
+
 	/* delay uevent until 'holders' subdir is created */
 	dev_set_uevent_suppress(pdev, 1);
 	err = device_add(pdev);
