Thread (32 messages) 32 messages, 4 authors, 2019-11-25
STALE2413d REVIEWED: 1 (0M)
Revisions (5)
  1. v1 [diff vs current]
  2. v2 current
  3. v3 [diff vs current]
  4. v4 [diff vs current]
  5. v5 [diff vs current]

[PATCH v2 01/13] cpuidle: psci: Align psci_power_state count with idle state count

From: Ulf Hansson <hidden>
Date: 2019-10-29 16:44:47
Also in: linux-arm-msm, linux-pm
Subsystem: cpu idle time management framework, cpuidle driver - arm psci, the rest · Maintainers: "Rafael J. Wysocki", Daniel Lezcano, Lorenzo Pieralisi, Sudeep Holla, Ulf Hansson, Linus Torvalds

From: Sudeep Holla <redacted>

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 <redacted>
Signed-off-by: Sudeep Holla <redacted>
Reviewed-by: Ulf Hansson <redacted>
---

Changes in v2:
	- Added tags.

---
 drivers/cpuidle/cpuidle-psci.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
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


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