Re: [PATCH] net: dsa: fix filling rtable from OF description

[Pavel Nakonechny <pavel.nakonechny@skitlab.ru>]

Hi Andrew

В письме от 4 апреля 2015 18:38:14 пользователь Andrew Lunn написал:
> There is the code after applying your patch:
> 
> static int dsa_of_setup_routing_table(struct dsa_platform_data *pd,
>                                         struct dsa_chip_data *cd,
>                                         int chip_index, int port_index,
>                                         struct device_node *link)
> {
>         const __be32 *reg;
>         int link_sw_addr;
>         struct device_node *parent_sw;
>         int len;
> 
>         parent_sw = of_get_parent(link);
>         if (!parent_sw)
>                 return -EINVAL;
> 
> link is the phandle to the port in other switch. parent_sw is then the
> switch property.
yep

>         reg = of_get_property(parent_sw, "reg", &len);
>         if (!reg || (len != sizeof(*reg) * 2))
>                 return -EINVAL;
> 
> So now you get the reg property. This is documented as:
> 
> - reg                   : Describes the switch address on the MII bus
Yes, but read further in the entry example:
"reg = <16 0>;	/* MDIO address 16, switch 0 in tree */"


>         link_sw_addr = be32_to_cpup(reg + 1);
Now we extract switch number (" + 1"), but not switch MDIO address.

> 
>         if (link_sw_addr >= pd->nr_chips)
>                 return -EINVAL;
> 
> This is now not making much sense.
> 
> Looking up the MII bus address seems wrong. You want the chip number,
> not its address.
Yes, you are right that its wrong to take MII address, but this code is taking 
switch number, not its address. I can agree that this is silly, but it is not 
my code originally and patch fixes other thing.