Subject: [RFC PATCH 02/11] ARM: DT/kernel: define ARM specific arch_of_get_cpu_node

From: [email-masked] (Rob Herring)
Date: Mon, 15 Jul 2013 14:10:59 -0500

On 07/15/2013 05:22 AM, Sudeep.KarkadaNagesha at arm.com wrote:
> From: Sudeep KarkadaNagesha <[email-masked]>
> 
> CPU subsystem now provides architecture specific hook to retrieve the
> of_node. Most of the cpu DT node parsing and initialisation is contained
> in devtree.c. It's better to contain all CPU device node parsing there.
> 
> arch_of_get_cpu_node is mainly used to assign cpu->of_node when CPUs get
> registered. This patch overrides the defination of the same. It can also
> act as the helper function in pre-SMP/early initialisation stages to
> retrieve CPU device node pointers in logical ordering.
> 
> This mainly helps to avoid replication of the code doing CPU node parsing
> and physical(MPIDR) to logical mapping.
> 
> Signed-off-by: Sudeep KarkadaNagesha <[email-masked]>

[snip]

> +struct device_node * __init arch_of_get_cpu_node(int cpu)
> +{
> +	struct device_node *cpun, *cpus;
> +	const u32 *cell;
> +	u64 hwid;
> +	int ac;
> +
> +	cpus = of_find_node_by_path("/cpus");
> +	if (WARN(!cpus, "Missing cpus node, bailing out\n"))
> +		return NULL;
> +
> +	if (WARN_ON(of_property_read_u32(cpus, "#address-cells", &ac)))
> +		ac = of_n_addr_cells(cpus);
> +
> +	for_each_child_of_node(cpus, cpun) {
> +		if (of_node_cmp(cpun->type, "cpu"))
> +			continue;
> +		cell = of_get_property(cpun, "reg", NULL);
> +		if (WARN(!cell, "%s: missing reg property\n", cpun->full_name))
> +			continue;
> +
> +		hwid = of_read_number(cell, ac);
> +		if ((hwid & MPIDR_HWID_BITMASK) == cpu_logical_map(cpu))

Most of this function is not ARM specific, so it would be nice if we
could shrink the arch specific part down to just this match. A default
match of reg == logical cpu number might be useful.

The powermac cpufreq driver could probably also be converted
(arch/powerpc/platforms/powermac/cpufreq_64.c).

Other than that, this series looks good to me.

Rob