[PATCH 04/10] fdt_support: Implement fdt_ethernet_set_macaddr()

[Sean Anderson]

On 8/26/21 5:42 PM, Alexandru Gagniuc wrote:
> Oftentimes we have MAC address information stored in a ROM or OTP. The
> way to add that to the FDT would be through the u-boot environment,
> and then fdt_fixup_ethernet(). This is not very useful in SPL.
>
> It would be more helpful to be able to "set interface x to MAC y".
> This is where fdt_ethernet_set_macaddr() comes in. It is similar in
> function to fdt_fixup_ethernet(), but only updates one interface,
> without using the u-boot env, and without string processing.

Have you considered adopting the nvmem-cells property for ethernet
controllers (added in Linux commit 0e839df92cf3 ("net: ethernet: provide
nvmem_get_mac_address()"))?

--Sean

> Signed-off-by: Alexandru Gagniuc <mr.nuke.me at gmail.com>
> ---
>   common/fdt_support.c  | 30 ++++++++++++++++++++++++++++++
>   include/fdt_support.h | 17 +++++++++++++++++
>   2 files changed, 47 insertions(+)
>
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 4341d84bd5..c4cbd4060e 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -592,6 +592,36 @@ void fdt_fixup_ethernet(void *fdt)
>   	}
>   }
>
> +int fdt_ethernet_set_macaddr(void *fdt, int ethnum, const uint8_t *mac_addr)
> +{
> +	const char *path, *name;
> +	int prop, aliases_node;
> +	char eth_name[16] = "ethernet";
> +
> +	aliases_node = fdt_path_offset(fdt, "/aliases");
> +	if (aliases_node < 0)
> +		return aliases_node;
> +
> +	if (ethnum >= 0)
> +		sprintf(eth_name, "ethernet%d", ethnum);
> +
> +	fdt_for_each_property_offset(prop, fdt, aliases_node) {
> +		path = fdt_getprop_by_offset(fdt, prop, &name, NULL);
> +		if (!strcmp(name, eth_name))
> +			break;
> +
> +		path = NULL;
> +	}
> +
> +	if (!path)
> +		return -FDT_ERR_NOTFOUND;
> +
> +	do_fixup_by_path(fdt, path, "mac-address", mac_addr, 6, 0);
> +	do_fixup_by_path(fdt, path, "local-mac-address", mac_addr, 6, 1);
> +
> +	return 0;
> +}
> +
>   int fdt_record_loadable(void *blob, u32 index, const char *name,
>   			uintptr_t load_addr, u32 size, uintptr_t entry_point,
>   			const char *type, const char *os, const char *arch)
> diff --git a/include/fdt_support.h b/include/fdt_support.h
> index f6f46bb8e9..3f0bcb5a00 100644
> --- a/include/fdt_support.h
> +++ b/include/fdt_support.h
> @@ -119,6 +119,23 @@ static inline int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[],
>   #endif
>
>   void fdt_fixup_ethernet(void *fdt);
> +
> +/**
> + * Set the "mac-address" and "local-mac-address" of ethernet node
> + * The ethernet node is located from the "/aliases" section of the fdt. When
> + * 'ethnum' is positive, then the name is matched exactly, e.g "ethernet0".
> + * When ethnum is negative, the first ethernet alias is updated.
> + * Unlike fdt_fixup_ethernet(), this function only updates one ethernet node,
> + * and soes not use the "ethaddr" from the u-boot environment. This is useful,
> + * for example, in SPL, when the environment is not initialized or available.
> + *
> + * @param fdt		FDT blob to update
> + * @param ethnum	Ethernet device index, or negative for any ethernet
> + * @param mac_addr	Pointer to 6-byte array containing the MAC address
> + *
> + * @return 0 if ok, or -FDT_ERR_... on error
> + */
> +int fdt_ethernet_set_macaddr(void *fdt, int ethnum, const uint8_t *mac_addr);
>   int fdt_find_and_setprop(void *fdt, const char *node, const char *prop,
>   			 const void *val, int len, int create);
>   void fdt_fixup_qe_firmware(void *fdt);
>