Subject: [RFC PATCH v2 3/4] powerpc: refactor of_get_cpu_node to support other architectures

From: [email-masked] (Benjamin Herrenschmidt)
Date: Sat, 17 Aug 2013 08:13:06 +1000

On Fri, 2013-08-16 at 18:39 +0100, Sudeep KarkadaNagesha wrote:
> +static bool __of_find_n_match_cpu_property(struct device_node *cpun,
> +                       const char *prop_name, int cpu, unsigned int
> *thread)
> +{
> +       const __be32 *cell;
> +       int ac, prop_len, tid;
> +       u64 hwid;
> +
> +       ac = of_n_addr_cells(cpun);
> +       cell = of_get_property(cpun, prop_name, &prop_len);
> +       if (!cell)
> +               return false;
> +       prop_len /= sizeof(*cell);
> +       for (tid = 0; tid < prop_len; tid++) {
> +               hwid = of_read_number(cell, ac);
> +               if (arch_match_cpu_phys_id(cpu, hwid)) {
> +                       if (thread)
> +                               *thread = tid;
> +                       return true;
> +               }
> +               cell += ac;
> +       }
> +       return false;
> +}

The only problem I can see here is if "ac" is not 1, that will not work
for the ibm,ppc-interrupt-server#s case. IE. The latter is always 1 cell
per entry, only "reg" depends on #address-cells.

However that's only a theorical problem since on ppc #address-cells of
/cpus is always 1...

Cheers,
Ben.