Re: [PATCH v2 05/10] boards: enclustra-sa2: read MAC address from EEPROM

[Sascha Hauer <s.hauer@pengutronix.de>]

On Thu, Sep 25, 2025 at 01:59:12PM +0200, David Picard wrote:
> Signed-off-by: David Picard <david.picard@clermont.in2p3.fr>
> 
> ---
> v1 --> v2:
>   - Use the atsha204a driver to read the MAC address instead of
>     board-specific code.
> ---
> ---
>  arch/arm/boards/enclustra-sa2/board.c          | 74 +++++++++++++++++++++++++-
>  arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi | 16 +++++-
>  2 files changed, 87 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/boards/enclustra-sa2/board.c b/arch/arm/boards/enclustra-sa2/board.c
> index d3117e9a1058738ea541f45b28c6a95184331554..4c2b44252d84c78ed8de5754051d0bf194ce8d02 100644
> --- a/arch/arm/boards/enclustra-sa2/board.c
> +++ b/arch/arm/boards/enclustra-sa2/board.c
> @@ -12,6 +12,12 @@
>  #include <fcntl.h>
>  #include <fs.h>
>  #include <mach/socfpga/cyclone5-regs.h>
> +#include <net.h>
> +#include <linux/nvmem-consumer.h>
> +
> +/** Enclustra's MAC address vendor prefix is 20:B0:F7 */
> +#define ENCLUSTRA_PREFIX            (0x20b0f7)
> +#define MAC_ADDR_NUM_BYTES          (6)
>  
>  /*
>   * Ethernet PHY: Microchip/Micrel KSZ9031RNX
> @@ -21,14 +27,78 @@ static int phy_fixup(struct phy_device *dev)
>  	return 0;
>  }
>  
> +/*
> + * Read the MAC address via the atsha204a driver.
> + *
> + * Set two consecutive MAC addresses, as specified by the manufacturer.
> + */
> +static void set_mac_addr(void)
> +{
> +	uint8_t hwaddr[MAC_ADDR_NUM_BYTES] = { 0, 0, 0, 0, 0, 0 };
> +	uint32_t hwaddr_prefix;
> +	u8 *data = NULL;
> +	static const char * const aliases[] = { "ethernet0" };
> +	struct device_node *np, *root;
> +	/* Fallback MAC addresses, used if we can't read from EEPROM: */
> +	const uint8_t enclustra_ethaddr_fallback1[] = { 0x20, 0xB0, 0xF7, 0x01,
> +													0x02, 0x03 };
> +	const uint8_t enclustra_ethaddr_fallback2[] = { 0x20, 0xB0, 0xF7, 0x01,
> +													0x02, 0x04 };

Please no fallback addresses. Just skip setting these and barebox will
use a random MAC.

> +
> +	root = of_get_root_node();
> +
> +	for (int i = 0; i < ARRAY_SIZE(aliases); i++) {
> +		const char *alias = aliases[i];
> +		np = of_find_node_by_alias(root, alias);
> +		if (!np) {
> +			pr_warn("%s() >> ERROR: can't find alias %s\n", __func__, alias);
> +			continue;
> +		}
> +		data = nvmem_cell_get_and_read(np, "mac-address", MAC_ADDR_NUM_BYTES);
> +		if (IS_ERR(data)) {
> +			pr_warn("%s() >> ERROR: can't read NVMEM cell\n", __func__);
> +			data = NULL;
> +		}
> +	}

You shouldn't need this. of_get_mac_addr_nvmem() called by the net layer
during startup should handle this for you.

> +	if (!data)
> +		goto fallback_addr;
> +
> +	memcpy(hwaddr, data, MAC_ADDR_NUM_BYTES);
> +
> +	debug("MAC address: %02x:%02x:%02x:%02x:%02x:%02x\n",
> +		  hwaddr[0], hwaddr[1], hwaddr[2],
> +		  hwaddr[3], hwaddr[4], hwaddr[5]);
> +
> +	/* check vendor prefix and set the environment variable */
> +	hwaddr_prefix = (hwaddr[0] << 16) | (hwaddr[1] << 8) | (hwaddr[2]);
> +	if (hwaddr_prefix == ENCLUSTRA_PREFIX) {
> +		eth_register_ethaddr(0, hwaddr);
> +		hwaddr[5]++;    /* calculate 2nd, consecutive MAC address */
> +		eth_register_ethaddr(1, hwaddr);
> +	} else {
> +		printf("%s() >> ERROR: invalid MAC address vendor prefix,"
> +			   "using fallback addresses\n", __func__);
> +		goto fallback_addr;
> +	}

Not sure what to do about the consecutive MAC address. There seems to be
beginning support for this in fixed-cell.yaml, but I can't find an
implementation for it.

> diff --git a/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi b/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
> index fa80b7c63d28d17a24d63ac3ee87531ad320ddb1..55d54d289c81fa4a6d46123bcb93c5fc483485e4 100644
> --- a/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
> +++ b/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
> @@ -76,6 +76,19 @@ atsha204a: atsha204a@64 {
>  		status = "okay";
>  		compatible = "atmel,atsha204a";
>  		reg = <0x64>;
> +
> +		nvmem-layout {
> +		compatible = "fixed-layout";
> +		#address-cells = <1>;
> +		#size-cells = <1>;

Indentation wrong here.

> +
> +			mac_address_0: mac@10 {
> +				compatible = "mac-base";
> +				reg = <0x10 0x6>;
> +				nvmem-cell-cells = <1>;

must be #nvmem-cell-cells#

Sascha

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