Re: [PATCH 06/13] cpuidle: psci: Simplify OF parsing of CPU idle state nodes

On Thu, 24 Oct 2019 at 17:36, Sudeep Holla [off-list ref] wrote:

On Thu, Oct 10, 2019 at 01:39:30PM +0200, Ulf Hansson wrote:

quoted

Iterating through the idle state nodes in DT, to find out the number of
states that needs to be allocated is unnecessary, as it has already been
done from dt_init_idle_driver(). Therefore, drop the iteration and use the
number we already have at hand.

Signed-off-by: Ulf Hansson <redacted>
---
 drivers/cpuidle/cpuidle-psci.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2e91c8d6c211..1195a1056139 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c

@@ -73,28 +73,22 @@ static int __init psci_dt_parse_state_node(struct device_node *np, u32 *state)
      return 0;
 }

-static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
+static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node,
+                             unsigned int state_nodes, int cpu)

[super nit] Too much in the beginning of the patch to not notice this ;)
May need some '(' alignment here and other places in general.

I was trying to find a consistent way of doing it, according to the
existing code, but I failed. :-)

Two cases exist where calls/functions crosses one line, one use solely
tabs and the other uses tab+whitespace to align "exactly". You are
saying that you prefer the latter? If so, I can adopt to that.

quoted

 {
-     int i, ret = 0, count = 0;
+     int i, ret = 0;
      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(state_nodes, sizeof(*psci_states), GFP_KERNEL);
      if (!psci_states)
              return -ENOMEM;

-     for (i = 0; i < count; i++) {
+     for (i = 0; i < state_nodes; i++) {
              state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);

Can we move above to use of_get_cpu_state_node ? Since it also handles
domain-idle-states.

quoted

+             if (!state_node)
+                     break;
+
              ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
              of_node_put(state_node);

@@ -104,6 +98,11 @@ static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
              pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
      }

+     if (i != 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;

@@ -113,7 +112,7 @@ static int __init psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
      return ret;
 }

-static __init int psci_cpu_init_idle(unsigned int cpu)
+static __init int psci_cpu_init_idle(unsigned int cpu, unsigned int state_nodes)

Does it make sense to rename it as state_count or something similar ?

Let me check to see if it makes sense to change it. Rebasing on top of
your recently submitted patch, might tell better.

And it may need + 1 once we add wfi also as entry as suggested by
Lorenzo.

Yep.

Kind regards
Uffe

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