Re: [PATCH 1/3] net: Add a CONFIG_NET_BOARD_ETHADDR

On 3/14/24 3:43 PM, Detlev Casanova wrote:

On some boards, a MAC address is set based on the CPU ID or other information. This is usually done in the misc_init_r() function.

This becomes a problem for net devices that are probed after the call to misc_init_r(), for example, when the ethernet is on a PCI port, which needs to be enumerated.

In this case, misc_init_r() will set the ethaddr variable, then, when the ethernet device is probed, if it has a ROM address, u-boot will warn about a MAC address mismatch and use the misc_init_r() address instead of the one in ROM.

The operating system later will most likely use the ROM MAC address, which can be confusing.

To avoid that, this commit introduces a CONFIG_NET_BOARD_ETHADDR that allows board files to implement a function to set an ethaddr in the environment, that will only be called when necessary. The logic is now:

• If there is there an ethaddr env var, use it.
• If not, if there is a DT MAC address, use it.
• If not, if there is a ROM MAC address, use it.
• If not, if CONFIG_NET_BOARD_ETHADDR, call board_gen_ethaddr() and use it.
• If not, if CONFIG_NET_RANDOM_ETHADDR, generate random MAC
• If not, fail with No valid MAC address found

Signed-off-by: Detlev Casanova detlev.casanova@collabora.com

net/Kconfig | 7 +++++++ net/eth-uclass.c | 17 +++++++++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/net/Kconfig b/net/Kconfig index 5dff6336293..6dd333ddb9e 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -54,6 +54,13 @@ config NET_RANDOM_ETHADDR generated. It will be saved to the appropriate environment variable, too.

+config NET_BOARD_ETHADDR

• bool "Board specific ethaddr if unset"
• help

•  Allow a board function to set a specific Ethernet address that can
  

•  be, e.g., based on the CPU ID. If set, this will be tried before
  

•  setting a random address (if set).
  

• config NETCONSOLE bool "NetConsole support" help

diff --git a/net/eth-uclass.c b/net/eth-uclass.c index 3d0ec91dfa4..f194df8512a 100644 --- a/net/eth-uclass.c +++ b/net/eth-uclass.c @@ -56,6 +56,12 @@ __weak int board_interface_eth_init(struct udevice *dev, return 0; }

+/* board-specific MAC Address generation. */ +__weak int board_gen_ethaddr(int dev_num, u8 *mac_addr) +{

• return 0;

+}

• static struct eth_uclass_priv *eth_get_uclass_priv(void) { struct uclass *uc;

@@ -563,13 +569,20 @@ static int eth_post_probe(struct udevice *dev) if (!eth_dev_get_mac_address(dev, pdata->enetaddr) || !is_valid_ethaddr(pdata->enetaddr)) { /* Check if the device has a MAC address in ROM */

• int ret = -1;
  

  if (eth_get_ops(dev)->read_rom_hwaddr) {

• 	int ret;
  

• ret = eth_get_ops(dev)->read_rom_hwaddr(dev);
  if (!ret)
  	source = "ROM";
  

  }

• if (IS_ENABLED(CONFIG_NET_BOARD_ETHADDR) && ret) {
  

• 	board_gen_ethaddr(dev_seq(dev), pdata->enetaddr);
  

You do need to pass in the udevice *dev directly, otherwise this DM uclass patch would behave like non-DM code.

I'd personally just create a __weak board_gen_ethaddr() function here and let boards override it, without new Kconfig symbol.