Re: [PATCH v2] net: cpsw: fix obtaining mac address for am3517

[Jeroen Hofstee]

Hello Tony,

On 28-10-16 17:52, Tony Lindgren wrote:
> * Jeroen Hofstee <jhofstee@xxxxxxxxxxxxxxxxx> [161028 08:33]:
> > Commit b6745f6e4e63 ("drivers: net: cpsw: davinci_emac: move reading mac
> > id to common file") did not only move the code for an am3517, it also
> > added the slave parameter, resulting in an invalid (all zero) mac address
> > being returned for an am3517, since it only has a single emac and the slave
> > parameter is pointing to the second. So simply always read the first and
> > valid mac-address for a ti,am3517-emac.
> And others davinci_emac.c users can have more than one. So is the
> reason the slave parameter points to the second instance because
> of the location in the hardware?

Sort of, the slave parameter gets determined by the fact if there is one
or two register range(s) associated with the davinci_emac. In davinci_emac.c

    res_ctrl = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    ...
    rc = davinci_emac_try_get_mac(pdev, res_ctrl ? 0 : 1,
                          priv->mac_addr);

So it there are two ranges, the slave param becomes 0. It there is only 
one, it
will be 1. Since the am3517 only has a single regs entry it ends up with 
slave 1,
while there is only a single davinci_emac.

Regards,
Jeroen

arch/arm/boot/dts/dm816x.dtsi
-----------------------------
eth0: ethernet@4a100000 {
    compatible = "ti,dm816-emac";
    ti,hwmods = "emac0";
    reg = <0x4a100000 0x800
           0x4a100900 0x3700>;
    clocks = <&sysclk24_ck>;
    syscon = <&scm_conf>;
    ti,davinci-ctrl-reg-offset = <0>;
    ti,davinci-ctrl-mod-reg-offset = <0x900>;
    ti,davinci-ctrl-ram-offset = <0x2000>;
    ti,davinci-ctrl-ram-size = <0x2000>;
    interrupts = <40 41 42 43>;
    phy-handle = <&phy0>;
};

eth1: ethernet@4a120000 {
    compatible = "ti,dm816-emac";
    ti,hwmods = "emac1";
    reg = <0x4a120000 0x4000>;
    clocks = <&sysclk24_ck>;
    syscon = <&scm_conf>;
    ti,davinci-ctrl-reg-offset = <0>;
    ti,davinci-ctrl-mod-reg-offset = <0x900>;
    ti,davinci-ctrl-ram-offset = <0x2000>;
    ti,davinci-ctrl-ram-size = <0x2000>;
    interrupts = <44 45 46 47>;
    phy-handle = <&phy1>;
};

arch/arm/boot/dts/am3517.dtsi
-------------------------------
davinci_emac: ethernet@0x5c000000 {
    compatible = "ti,am3517-emac";
    ti,hwmods = "davinci_emac";
    status = "disabled";
    reg = <0x5c000000 0x30000>;
    interrupts = <67 68 69 70>;
    syscon = <&scm_conf>;
    ti,davinci-ctrl-reg-offset = <0x10000>;
    ti,davinci-ctrl-mod-reg-offset = <0>;
    ti,davinci-ctrl-ram-offset = <0x20000>;
    ti,davinci-ctrl-ram-size = <0x2000>;
    ti,davinci-rmii-en = /bits/ 8 <1>;
    local-mac-address = [ 00 00 00 00 00 00 ];
};