cpuidle: psci: Align psci_power_state count with idle state count

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.

Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index f3c1a2396f989e29a9251106484d762ccca97aec..361985f52ddd1b9c8120a785071100b18a83102f 100644 (file)
--- 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);