[V4,1/2] mtd: partitions: add of_match_table parser matching

Submitted by Rafał Miłecki on June 24, 2017, 11:10 p.m.

Details

Message ID 20170624231025.23292-1-zajec5@gmail.com
State New
Delegated to: Brian Norris
Headers show

Commit Message

Rafał Miłecki June 24, 2017, 11:10 p.m.
From: Brian Norris <computersforpeace@gmail.com>

Partition parsers can now provide an of_match_table to enable
flash<-->parser matching via device tree.

This support is currently limited to built-in parsers as it uses
request_module() and friends. This should be sufficient for most cases
though as compiling parsers as modules isn't a common choice.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
This is based on Brian's patches:
[RFC PATCH 4/7] mtd: add of_match_mtd_parser() and of_mtd_match_mtd_parser() helpers
[RFC PATCH 6/7] RFC: mtd: partitions: enable of_match_table matching

V1: Put helpers in mtdpart.c instead of drivers/of/of_mtd.c
    Merge helpers into a single of_mtd_match_mtd_parser
V3: Add a simple comment to note we will need the best match in the future
V4: Rework new functions to pick parser with the best match
    Move new code in parse_mtd_partitions up so it has precedence over flash
    driver defaults and MTD defaults
---
 drivers/mtd/mtdpart.c          | 65 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/mtd/partitions.h |  1 +
 2 files changed, 66 insertions(+)

Comments

Jonas Gorski June 28, 2017, 9:19 p.m.
Hi,

On 25 June 2017 at 01:10, Rafał Miłecki <zajec5@gmail.com> wrote:
> From: Brian Norris <computersforpeace@gmail.com>
>
> Partition parsers can now provide an of_match_table to enable
> flash<-->parser matching via device tree.
>
> This support is currently limited to built-in parsers as it uses
> request_module() and friends. This should be sufficient for most cases
> though as compiling parsers as modules isn't a common choice.
>
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

I gave this and Rafał's recent patches a spin and split out
bcm63xxpart's imagetag parsing into its own parser as a partition
parser assigned to the imagetag partition, then added an
of_match_table to bcm63xxpart, and it worked beautifully:

[    1.111302] m25p80 spi1.0: s25fl129p1 (16384 Kbytes)
[    1.117222] bcm63xxpart: Partition 0 is CFE offset 0 and length 10000
[    1.127313] bcm63xxpart: Partition 1 is nvram offset ff0000 and length 10000
[    1.134604] bcm63xxpart: Partition 2 is linux offset 10000 and length fe0000
[    1.141927] 3 bcm63xxpart partitions found on MTD device spi1.0
[    1.148032] Creating 3 MTD partitions on "spi1.0":
[    1.152945] 0x000000000000-0x000000010000 : "CFE"
[    1.161004] 0x000000ff0000-0x000001000000 : "nvram"
[    1.169777] 0x000000010000-0x000000ff0000 : "linux"
[    1.179489] parser_bcm63xx_imagetag: rootfs: CFE image tag found at
0x0 with version 6, board type 96328avng
[    1.189671] parser_bcm63xx_imagetag: Partition 0 is kernel offset
100 and length 151f52
[    1.197902] parser_bcm63xx_imagetag: Partition 1 is rootfs offset
152052 and length e8dfae
[    1.206405] parser_bcm63xx_imagetag: Spare partition is offset
350004 and length c8fffc
[    1.214738] 2 bcm63xx-imagetag partitions found on MTD device linux
[    1.221201] Creating 2 MTD partitions on "linux":
[    1.226032] 0x000000000100-0x000000152052 : "kernel"
[    1.234445] 0x000000152052-0x000000fe0000 : "rootfs"

Things I did:
1) having just the compatible for bcm63xxpart: bcm63xxpart was used.
2) bcm63xxpart, then fixed-partitions as two compatible strings:
bcm63xxpart was used.
3) fixed-partitons, then bcm63xxpart: ofpart was used.
4) non-existent compatible, then fixed-partitons: ofpart was used.

then I ran out of ideas to test.

I guess this might be enough for a

Tested-by: Jonas Gorski <jonas.gorski@gmail.com>


Regards
Jonas

Patch hide | download patch | download mbox

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 2ad9493703f9..239d5e6e62ed 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -30,6 +30,7 @@ 
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
 #include <linux/err.h>
+#include <linux/of.h>
 
 #include "mtdcore.h"
 
@@ -885,6 +886,60 @@  static int mtd_part_do_parse(struct mtd_part_parser *parser,
 	return ret;
 }
 
+static int of_mtd_match_mtd_parser(struct mtd_info *mtd,
+				   struct mtd_part_parser *parser)
+{
+	const struct of_device_id *matches;
+	struct device_node *np;
+	int score = 0;
+
+	matches = parser->of_match_table;
+	if (!matches)
+		return false;
+
+	np = mtd_get_of_node(mtd);
+	np = of_get_child_by_name(np, "partitions");
+	if (!np)
+		return false;
+
+	for (; matches->name[0] || matches->type[0] || matches->compatible[0];
+	     matches++) {
+		if (!matches->compatible[0])
+			continue;
+		score = max(score,
+			    of_device_is_compatible(np, matches->compatible));
+	}
+
+	of_node_put(np);
+
+	return score;
+}
+
+static struct mtd_part_parser *mtd_part_get_parser_by_of(struct mtd_info *mtd)
+{
+	struct mtd_part_parser *p, *ret = NULL;
+	struct mtd_part_parser *best_parser = NULL;
+	int best_score = 0;
+
+	spin_lock(&part_parser_lock);
+
+	list_for_each_entry(p, &part_parsers, list) {
+		int score = of_mtd_match_mtd_parser(mtd, p);
+
+		if (score > best_score) {
+			best_score = score;
+			best_parser = p;
+		}
+	}
+
+	if (best_parser && try_module_get(best_parser->owner))
+		ret = best_parser;
+
+	spin_unlock(&part_parser_lock);
+
+	return ret;
+}
+
 /**
  * parse_mtd_partitions - parse MTD partitions
  * @master: the master partition (describes whole MTD device)
@@ -913,6 +968,16 @@  int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
 	struct mtd_part_parser *parser;
 	int ret, err = 0;
 
+	parser = mtd_part_get_parser_by_of(master);
+	if (parser) {
+		ret = mtd_part_do_parse(parser, master, pparts, data);
+		if (ret > 0)
+			return 0;
+		mtd_part_parser_put(parser);
+		if (ret < 0)
+			err = ret;
+	}
+
 	if (!types)
 		types = default_mtd_part_types;
 
diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
index c4beb70dacbd..11cb0c50cd84 100644
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -77,6 +77,7 @@  struct mtd_part_parser {
 	struct list_head list;
 	struct module *owner;
 	const char *name;
+	const struct of_device_id *of_match_table;
 	int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
 			struct mtd_part_parser_data *);
 	void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);