[PATCH 4/4] nvmem: u-boot-env: post-process "ethaddr" env variable

Rafał Miłecki
2023-02-22T17:23:58Z

From: Rafał Miłecki <rafal@milecki.pl>

U-Boot environment variables are stored in ASCII format so "ethaddr"
requires parsing into binary to make it work with Ethernet interfaces.

This includes support for indexes to support #nvmem-cell-cells = <1>.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
drivers/nvmem/Kconfig | 1 +
drivers/nvmem/u-boot-env.c | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+)

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 189ea85bd67d..71322ea7cf53 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -346,6 +346,7 @@ config NVMEM_U_BOOT_ENV
tristate "U-Boot environment variables support"
depends on OF && MTD
select CRC32
+ select GENERIC_NET_UTILS
help
U-Boot stores its setup as environment variables. This driver adds
support for verifying & exporting such data. It also exposes variables
diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c
index 29b1d87a3c51..1f5d8aba98bf 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 +72,27 @@ static int u_boot_env_read(void *context, unsigned int offset, void *val,
return 0;
}

+static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,
+ unsigned int offset, void **data, size_t *bytes)
+{
+ u8 mac[ETH_ALEN];
+
+ if (*bytes != 3 * ETH_ALEN - 1)
+ return -EINVAL;
+
+ if (!mac_pton(*data, mac))
+ return -EINVAL;
+
+ if (index)
+ eth_addr_add(mac, index);
+
+ /* We need *smaller* buffer so don't bother to krealloc() */
+ ether_addr_copy(*data, mac);
+ *bytes = 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)
{
@@ -101,6 +124,8 @@ static int u_boot_env_add_cells(struct u_boot_env *priv, uint8_t *buf,
priv->cells[idx].offset = data_offset + value - data;
priv->cells[idx].bytes = strlen(value);
priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
+ if (!strcmp(var, "ethaddr"))
+ priv->cells[idx].read_post_process = u_boot_env_read_post_process_ethaddr;
}

if (WARN_ON(idx != priv->ncells))
--
2.34.1