[U-Boot] [PATCH 3/3] arm: at91: ether: Prepare for mach-types.h changes

Reinhard Meyer
2011-05-01T19:38:11Z

Dear Igor Grinberg,

> at91 ethernet module used machine_is_cbs337() macro for board specific
> Linux compatibility issue.
> Use compile time defines instead.
>
> Signed-off-by: Igor Grinberg<grinberg@compulab.co.il>
> ---
> arch/arm/cpu/arm920t/at91rm9200/ether.c | 18 +++++++++---------
> 1 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/cpu/arm920t/at91rm9200/ether.c b/arch/arm/cpu/arm920t/at91rm9200/ether.c
> index e1cdeba..4aeb883 100644
> --- a/arch/arm/cpu/arm920t/at91rm9200/ether.c
> +++ b/arch/arm/cpu/arm920t/at91rm9200/ether.c
> @@ -201,15 +201,15 @@ int eth_init (bd_t * bd)
> * that MicroMonitor behavior so we avoid needing to make such OS code
> * care about which bootloader was used.
> */
> - if (machine_is_csb337()) {
> - p_mac->EMAC_SA2H = (enetaddr[0]<< 8) | (enetaddr[1]);
> - p_mac->EMAC_SA2L = (enetaddr[2]<< 24) | (enetaddr[3]<< 16)
> - | (enetaddr[4]<< 8) | (enetaddr[5]);
> - } else {
> - p_mac->EMAC_SA2L = (enetaddr[3]<< 24) | (enetaddr[2]<< 16)
> - | (enetaddr[1]<< 8) | (enetaddr[0]);
> - p_mac->EMAC_SA2H = (enetaddr[5]<< 8) | (enetaddr[4]);
> - }
> +#ifdef CONFIG_MACH_CSB337
> + p_mac->EMAC_SA2H = (enetaddr[0]<< 8) | (enetaddr[1]);
> + p_mac->EMAC_SA2L = (enetaddr[2]<< 24) | (enetaddr[3]<< 16)
> + | (enetaddr[4]<< 8) | (enetaddr[5]);
> +#else
> + p_mac->EMAC_SA2L = (enetaddr[3]<< 24) | (enetaddr[2]<< 16)
> + | (enetaddr[1]<< 8) | (enetaddr[0]);
> + p_mac->EMAC_SA2H = (enetaddr[5]<< 8) | (enetaddr[4]);
> +#endif
>
> p_mac->EMAC_RBQP = (long) (&rbfdt[0]);
> p_mac->EMAC_RSR&= ~(AT91C_EMAC_RSR_OVR | AT91C_EMAC_REC | AT91C_EMAC_BNA);

There is nothing wrong with your patch itself, but it let me to take a closer look at the
reasoning of why there is a machine dependency. The full code at this section is:

eth_getenv_enetaddr("ethaddr", enetaddr);

/* The CSB337 originally used a version of the MicroMonitor bootloader
* which saved Ethernet addresses in the "wrong" order. Operating
* systems (like Linux) know this, and apply a workaround. Replicate
* that MicroMonitor behavior so we avoid needing to make such OS code
* care about which bootloader was used.
*/
if (machine_is_csb337()) {
p_mac->EMAC_SA2H = (enetaddr[0] << 8) | (enetaddr[1]);
p_mac->EMAC_SA2L = (enetaddr[2] << 24) | (enetaddr[3] << 16)
| (enetaddr[4] << 8) | (enetaddr[5]);
} else {
p_mac->EMAC_SA2L = (enetaddr[3] << 24) | (enetaddr[2] << 16)
| (enetaddr[1] << 8) | (enetaddr[0]);
p_mac->EMAC_SA2H = (enetaddr[5] << 8) | (enetaddr[4]);
}

So, for the sake of a(nother) broken bootloader and a workaround in Linux we
store the MAC address in the wrong order? What if U-Boot itself is used to make
LAN accesses?

Apart from that, it feels entirely wrong to do so. Fix the kernel to NOT do a
workaround instead should be the better approach.

Any opinions by Ben or Wolfgang on this?

Best Regards,
Reinhard