Re: [PATCH V2 1/9] uclass: cpu: Add new API to get udevice for current CPU

[Simon Glass]

Hi Peng,

On Fri, 1 May 2020 at 07:22, Peng Fan <peng....@nxp.com> wrote:
>
> When running on SoC with multiple clusters, the boot CPU may
> not be fixed, saying booting from cluster A or cluster B.
> Add a API that can return the udevice for current boot CPU.
> Cpu driver needs to implement is_current_cpu interface for this
> feature, otherwise the API only returns the first udevice in
> cpu uclass.
>
> Signed-off-by: Peng Fan <peng....@nxp.com>
> Signed-off-by: Ye Li <ye...@nxp.com>
> ---
>
> V2:
>  Per Simon's comment,
>   - Add cpu_is_current
>   - use uclass_foreach_dev_probe
>   - Update code comment
>
>  drivers/cpu/cpu-uclass.c | 34 ++++++++++++++++++++++++++++++++++
>  include/cpu.h            | 23 +++++++++++++++++++++++
>  2 files changed, 57 insertions(+)
>

Reviewed-by: Simon Glass <s...@chromium.org>


> diff --git a/drivers/cpu/cpu-uclass.c b/drivers/cpu/cpu-uclass.c
> index 457f77b7c8..33d38a0fde 100644
> --- a/drivers/cpu/cpu-uclass.c
> +++ b/drivers/cpu/cpu-uclass.c
> @@ -10,6 +10,7 @@
>  #include <errno.h>
>  #include <dm/lists.h>
>  #include <dm/root.h>
> +#include <linux/err.h>
>
>  int cpu_probe_all(void)
>  {
> @@ -34,6 +35,39 @@ int cpu_probe_all(void)
>         return 0;
>  }
>
> +int cpu_is_current(struct udevice *cpu)
> +{
> +       struct cpu_ops *ops = cpu_get_ops(cpu);
> +
> +       if (ops && ops->is_current) {
> +               if (ops->is_current(cpu))
> +                       return 1;

return 0 here I think

Also you should not check 'ops'.


> +       }
> +
> +       return -ENOSYS;
> +}
> +
> +struct udevice *cpu_get_current_dev(void)
> +{
> +       struct udevice *cpu;
> +       int ret;
> +
> +       uclass_foreach_dev_probe(UCLASS_CPU, cpu) {
> +               if (cpu_is_current(cpu) > 0)
> +                       return cpu;
> +       }
> +
> +       /* If can't find current cpu device, use the first dev instead */
> +       ret = uclass_first_device_err(UCLASS_CPU, &cpu);
> +       if (ret) {
> +               debug("%s: Could not get CPU device (err = %d)\n",
> +                     __func__, ret);
> +               return NULL;
> +       }
> +
> +       return cpu;
> +}
> +
>  int cpu_get_desc(struct udevice *dev, char *buf, int size)
>  {
>         struct cpu_ops *ops = cpu_get_ops(dev);
> diff --git a/include/cpu.h b/include/cpu.h
> index 6b1b6b37b3..2f283fe244 100644
> --- a/include/cpu.h
> +++ b/include/cpu.h
> @@ -89,6 +89,15 @@ struct cpu_ops {
>          * @return 0 if OK, -ENOSPC if buffer is too small, other -ve on error
>          */
>         int (*get_vendor)(struct udevice *dev, char *buf, int size);
> +
> +       /**
> +        * is_current() - Check if the CPU that U-Boot is currently running 
> from
> +        *
> +        * @dev:        Device to check (UCLASS_CPU)
> +        * @return 1 if the CPU that U-Boot is currently running from, 0
> +        *         if not.
> +        */
> +       int (*is_current)(struct udevice *dev);
>  };
>
>  #define cpu_get_ops(dev)        ((struct cpu_ops *)(dev)->driver->ops)
> @@ -137,4 +146,18 @@ int cpu_get_vendor(struct udevice *dev, char *buf, int 
> size);
>   */
>  int cpu_probe_all(void);
>
> +/**
> + * cpu_is_current() - Check if the CPU that U-Boot is currently running from
> + *
> + * Return: 1 if yes, - 0 if not
> + */
> +int cpu_is_current(struct udevice *cpu);
> +
> +/**
> + * cpu_get_current_dev() - Get CPU udevice for current CPU
> + *
> + * Return: udevice if OK, - NULL on error
> + */
> +struct udevice *cpu_get_current_dev(void);
> +
>  #endif
> --
> 2.16.4
>