On Thu, 24 Oct 2019 at 17:18, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>
> Instead of allocating 'n-1' states in psci_power_state to manage 'n'
> idle states which include "ARM WFI" state, it would be simpler to have
> 1:1 mapping between psci_power_state and cpuidle driver states.
>
> ARM WFI state(i.e. idx == 0) is handled specially in the generic macro
> CPU_PM_CPU_IDLE_ENTER_PARAM and hence state[-1] is not possible. However
> for sake of code readability, it is better to have 1:1 mapping and not
> use [idx - 1] to access psci_power_state corresponding to driver cpuidle
> state for idx.
>
> psci_power_state[0] is default initialised to 0 and is never accessed
> while entering WFI state.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Reported-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> drivers/cpuidle/cpuidle-psci.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> Hi Ulf, Lorenzo,
>
> Just to avoid confusion, I thought I will just write this patch as I was
> about to make reference to this in my review.
As discussed with Lorenzo, I said I was going to adopt his review
comments, which means I already have a patch for this locally.
Nevermind this time, but I would appreciate if this kind of
bikeshedding can been avoided future wise.
Kind regards
Uffe
>
> Regards,
> Sudeep
>
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index f3c1a2396f98..361985f52ddd 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -30,7 +30,7 @@ static int psci_enter_idle_state(struct cpuidle_device *dev,
> u32 *state = __this_cpu_read(psci_power_state);
>
> return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
> - idx, state[idx - 1]);
> + idx, state[idx]);
> }
>
> static struct cpuidle_driver psci_idle_driver __initdata = {
> @@ -89,12 +89,14 @@ static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
> if (!count)
> return -ENODEV;
>
> + count++; /* Add WFI state too */
> psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
> if (!psci_states)
> return -ENOMEM;
>
> - for (i = 0; i < count; i++) {
> - state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
> + for (i = 1; i < count; i++) {
> + state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
> + i - 1);
> ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
> of_node_put(state_node);
>
> --
> 2.17.1
>
