[PATCH RFC v3 5/6] drivers: cpuidle: CPU idle ARM64 driver

Lorenzo Pieralisi lorenzo.pieralisi at arm.com
Fri May 9 02:40:15 PDT 2014


On Fri, May 09, 2014 at 01:48:38AM +0100, Sebastian Capella wrote:
> Quoting Lorenzo Pieralisi (2014-05-06 11:04:42)
> > diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c
> > new file mode 100644
> > index 0000000..fef1fad
> > --- /dev/null
> > +++ b/drivers/cpuidle/cpuidle-arm64.c
> > @@ -0,0 +1,161 @@
> ...
> > +/*
> 
> Is this intended to be kernel-docs?  If so, should maybe use the /** and
> () after the function below.  Otherwise, should you remove the @ in the
> argument list below?

Changes done according to kernel-docs.

> > + * arm_enter_idle_state - Programs CPU to enter the specified state
> > + *
> > + * @dev: cpuidle device
> > + * @drv: cpuidle driver
> > + * @idx: state index
> > + *
> > + * Called from the CPUidle framework to program the device to the
> > + * specified target state selected by the governor.
> > + */
> > +static int arm_enter_idle_state(struct cpuidle_device *dev,
> > +                               struct cpuidle_driver *drv, int idx)
> 
> ...
> 
> > +static int __init arm64_idle_init(void)
> > +{
> > +       int i, ret;
> > +       const char *entry_method;
> > +       struct device_node *idle_states_node;
> > +       const struct cpu_suspend_ops *suspend_init;
> > +       struct cpuidle_driver *drv = &arm64_idle_driver;
> > +
> > +       idle_states_node = of_find_node_by_path("/cpus/idle-states");
> > +       if (!idle_states_node)
> > +               return -ENOENT;
> > +
> > +       if (of_property_read_string(idle_states_node, "entry-method",
> > +                                   &entry_method)) {
> > +               pr_warn(" * %s missing entry-method property\n",
> > +                           idle_states_node->full_name);
> > +               of_node_put(idle_states_node);
> > +               return -EOPNOTSUPP;
> > +       }
> > +
> > +       suspend_init = get_suspend_ops(entry_method);
> > +       if (!suspend_init) {
> > +               pr_warn("Missing suspend initializer\n");
> > +               of_node_put(idle_states_node);
> > +               return -EOPNOTSUPP;
> > +       }
> > +
> > +       /*
> > +        * State at index 0 is standby wfi and considered standard
> > +        * on all ARM platforms. If in some platforms simple wfi
> > +        * can't be used as "state 0", DT bindings must be implemented
> > +        * to work around this issue and allow installing a special
> > +        * handler for idle state index 0.
> > +        */
> > +       drv->states[0].exit_latency = 1;
> > +       drv->states[0].target_residency = 1;
> > +       drv->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
> > +       strncpy(drv->states[0].name, "ARM WFI", CPUIDLE_NAME_LEN);
> > +       strncpy(drv->states[0].desc, "ARM WFI", CPUIDLE_DESC_LEN);
> > +
> > +       drv->cpumask = (struct cpumask *) cpu_possible_mask;
> > +       /*
> > +        * Start at index 1, request idle state nodes to be filled
> > +        */
> > +       ret = of_init_idle_driver(drv, state_nodes, 1, true);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (suspend_init->init_fn(drv, state_nodes))
> > +               return -EOPNOTSUPP;
> > +
> > +       for (i = 0; i < drv->state_count; i++)
> > +               drv->states[i].enter = arm_enter_idle_state;
> 
> Is this missing an of_node_put(idle_states_node)?

Yes, good catch, patched.

Thanks !
Lorenzo




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