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

[Rafał Miłecki]

From: Rafał Miłecki <rafal at milecki.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 at milecki.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