linux-kernel - [PATCH 2/2] nvmem: u-boot-env: reformat MAC in "ethaddr" cell when reading

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Message-Id: <20221127231035.17547-2-zajec5@gmail.com>
Date:   Mon, 28 Nov 2022 00:10:35 +0100
From:   Rafał Miłecki <zajec5@...il.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     Michael Walle <michael@...le.cc>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Shawn Guo <shawnguo@...nel.org>, linux-mtd@...ts.infradead.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, u-boot@...ts.denx.de,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: [PATCH 2/2] nvmem: u-boot-env: reformat MAC in "ethaddr" cell when reading

From: Rafał Miłecki <rafal@...ecki.pl>

NVMEM consumers expect MAC in a byte-based format (see e.g.
nvmem_get_mac_address()). U-Boot environment data stores all values in
ASCII form.

Add post processing callback detecting "ethaddr" reads and reformat data
as expected. This fixes Ethernet drivers reading MAC from NVMEM devices.

Signed-off-by: Rafał Miłecki <rafal@...ecki.pl>
---
 drivers/nvmem/u-boot-env.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c
index 2a87dda45188..d103a52e0008 100644
--- a/drivers/nvmem/u-boot-env.c
+++ b/drivers/nvmem/u-boot-env.c
@@ -4,6 +4,8 @@
  */
 
 #include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mtd/mtd.h>
@@ -70,6 +72,24 @@ static int u_boot_env_read(void *context, unsigned int offset, void *val,
 	return 0;
 }
 
+static int u_boot_env_cell_post_process(void *context, struct nvmem_cell_entry *cell,
+					const char *id, void *buf, size_t *len)
+{
+	struct u_boot_env *priv = context;
+
+	if (!strcmp(cell->name, "ethaddr")) {
+		u8 mac[ETH_ALEN];
+
+		if (mac_pton(buf, mac)) {
+			ether_addr_copy(buf, mac);
+			if (len)
+				*len = ETH_ALEN;
+		}
+	}
+
+	return 0;
+}
+
 static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
 				size_t data_offset, size_t data_len)
 {
@@ -179,6 +199,7 @@ static int u_boot_env_probe(struct platform_device *pdev)
 	struct nvmem_config config = {
 		.name = "u-boot-env",
 		.reg_read = u_boot_env_read,
+		.cell_post_process = u_boot_env_cell_post_process,
 	};
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
-- 
2.34.1