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

Hello Tony,

On 28-10-16 17:52, Tony Lindgren wrote:

* Jeroen Hofstee [off-list ref] [161028 08:33]:

quoted

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 ];
};