[PATCH 1/2] mtd: parsers: trx: Allow to specify trx-magic in DT

[Hauke Mehrtens]

Buffalo uses a different TRX magic for every device, to be able to use
this trx parser, make it possible to specify the TRX magic in device
tree. If no TRX magic is specified in device tree, the standard value
will be used. This value should only be specified if a vendor chooses to
use a non standard TRX magic.

Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 .../bindings/mtd/partitions/brcm,trx.txt      |  5 +++++
 drivers/mtd/parsers/parser_trx.c              | 21 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt b/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt
index b677147ca4e1..715a18ca36bd 100644
--- a/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt
+++ b/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt
@@ -28,6 +28,11 @@ detected by a software parsing TRX header.
 Required properties:
 - compatible : (required) must be "brcm,trx"
 
+Optional properties:
+
+- trx-magic: TRX magic, if it is different from the default magic
+	     0x30524448 as a u32.
+
 Example:
 
 flash at 0 {
diff --git a/drivers/mtd/parsers/parser_trx.c b/drivers/mtd/parsers/parser_trx.c
index 8541182134d4..fd424587caa4 100644
--- a/drivers/mtd/parsers/parser_trx.c
+++ b/drivers/mtd/parsers/parser_trx.c
@@ -47,6 +47,24 @@ static const char *parser_trx_data_part_name(struct mtd_info *master,
 	return "rootfs";
 }
 
+static uint32_t parser_trx_get_magic(struct mtd_info *mtd)
+{
+	uint32_t trx_magic = TRX_MAGIC;
+	struct device_node *np;
+	int err;
+
+	np = mtd_get_of_node(mtd);
+	if (!np)
+		return trx_magic;
+
+	/* Get different magic from device tree if specified */
+	err = of_property_read_u32(np, "trx-magic", &trx_magic);
+	if (err != 0 && err != -EINVAL)
+		pr_err("failed to parse \"trx-magic\" DT attribute, use default: %d\n", err);
+
+	return trx_magic;
+}
+
 static int parser_trx_parse(struct mtd_info *mtd,
 			    const struct mtd_partition **pparts,
 			    struct mtd_part_parser_data *data)
@@ -56,6 +74,7 @@ static int parser_trx_parse(struct mtd_info *mtd,
 	struct trx_header trx;
 	size_t bytes_read;
 	uint8_t curr_part = 0, i = 0;
+	uint32_t trx_magic = parser_trx_get_magic(mtd);
 	int err;
 
 	parts = kcalloc(TRX_PARSER_MAX_PARTS, sizeof(struct mtd_partition),
@@ -70,7 +89,7 @@ static int parser_trx_parse(struct mtd_info *mtd,
 		return err;
 	}
 
-	if (trx.magic != TRX_MAGIC) {
+	if (trx.magic != trx_magic) {
 		kfree(parts);
 		return -ENOENT;
 	}
-- 
2.30.1