Re: [RFC PATCH 01/11] driver/core: cpu: initialize of_node in cpu'sdevice struture

[Viresh Kumar]

On 15 July 2013 15:52,  <Sudeep.KarkadaNagesha@xxxxxxx> wrote:
> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx>
>
> CPUs are also registered as devices but the of_node in these cpu
> devices are not initialized. Currently different drivers requiring
> to access cpu device node are parsing the nodes themselves and
> initialising the of_node in cpu device.
>
> The of_node in all the cpu devices properly needs to be initialized

s/properly /

> properly and at one place. The best place to update this is CPU
> subsystem driver when registering the cpu devices.
>
> This patch introduces a new function arch_of_get_cpu_node and uses it
> to assign of_node. The definition of this function can be overridden
> by architecture specific implementation.
>
> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx>
> ---
>  drivers/base/cpu.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index a16d20e..4b3047a 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -28,6 +28,24 @@ static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
>         return 0;
>  }
>
> +/**
> + * arch_of_get_cpu_node - Get device node associated with the given logical CPU
> + * @cpu: CPU number(logical index) for which device node is required
> + *
> + * The only purpose of this function is to retrieve the device node for the
> + * given logical CPU index. It should be used to intialise the of_node in
> + * cpu device. Once of_node in cpu device is populated, all the further
> + * references can use that instead.
> + *
> + * CPU logical to physical index mapping is architecure specific and is built
> + * before booting secondary cores. Hence this function is marked __weak and
> + * can be overridden by architecture specific implementation.
> + */
> +struct device_node * __weak arch_of_get_cpu_node(int cpu)
> +{
> +       return NULL;
> +}
> +
>  #ifdef CONFIG_HOTPLUG_CPU
>  static void change_cpu_under_node(struct cpu *cpu,
>                         unsigned int from_nid, unsigned int to_nid)
> @@ -289,6 +307,7 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
>         cpu->dev.release = cpu_device_release;
>         cpu->dev.offline_disabled = !cpu->hotpluggable;
>         cpu->dev.offline = !cpu_online(num);
> +       cpu->dev.of_node = arch_of_get_cpu_node(num);
>  #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
>         cpu->dev.bus->uevent = arch_cpu_uevent;
>  #endif
> --
> 1.8.1.2
>
>
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