On Thu, 28 Feb 2019 at 16:40, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote:
>
> On 28/02/2019 14:59, Ulf Hansson wrote:
> > Instead of iterating through all the state nodes in DT, to find out how
> > many states that needs to be allocated, let's use the number already known
> > by the cpuidle driver. In this way we can drop the iteration altogether.
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > ---
> > drivers/firmware/psci/psci.c | 25 ++++++++++++-------------
> > 1 file changed, 12 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> > index d50b46a0528f..cbfc936d251c 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -290,26 +290,20 @@ static int psci_dt_parse_state_node(struct device_node *np, u32 *state)
> > static int psci_dt_cpu_init_idle(struct cpuidle_driver *drv,
> > struct device_node *cpu_node, int cpu)
> > {
> > - int i, ret = 0, count = 0;
> > + int i, ret = 0, num_state_nodes = drv->state_count - 1;
>
> why -1 ?
Because of the WFI state. The cpuidle-arm driver always carries this
state at index 0, which also is never used in
psci_cpu_suspend_enter(), where the similar is taken into account.
It's a bit of magic, so perhaps someone should post a patch that
documents this a bit better in the code, wherever it makes sense.
>
> > u32 *psci_states;
> > struct device_node *state_node;
> >
> > - /* Count idle states */
> > - while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
> > - count))) {
> > - count++;
> > - of_node_put(state_node);
> > - }
> > -
> > - if (!count)
> > - return -ENODEV;
> > -
> > - psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
> > + psci_states = kcalloc(num_state_nodes, sizeof(*psci_states),
> > + GFP_KERNEL);
> > if (!psci_states)
> > return -ENOMEM;
> >
> > - for (i = 0; i < count; i++) {
> > + for (i = 0; i < num_state_nodes; i++) {
> > state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
> > + if (!state_node)
> > + break;
> > +
> > ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
> > of_node_put(state_node);
> >
> > @@ -319,6 +313,11 @@ static int psci_dt_cpu_init_idle(struct cpuidle_driver *drv,
> > pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
> > }
> >
> > + if (i != num_state_nodes) {
> > + ret = -ENODEV;
> > + goto free_mem;
> > + }
> > +
> > /* Idle states parsed correctly, initialize per-cpu pointer */
> > per_cpu(psci_power_state, cpu) = psci_states;
> > return 0;
> >
Again, thanks a lot for reviewing!
Kind regards
Uffe
