From dae4b9c16d218581bb759d4d8d1cbedae122b4c0 Mon Sep 17 00:00:00 2001
From: Praveen Chidambaram <pchidamb@codeaurora.org>
Date: Mon, 11 Mar 2013 14:50:06 -0600
Subject: [PATCH] Revert "msm: cpufreq: Remove cross-calling limitation"
This reverts commit be01a17afb6b6e85456217caa1ac11eb0b6674e1.
Re-introduce cross calling in cpufreq to prevent race conditions in the
hardware when changing PLLs.
A core could be in retention, while another core, could try and set the
frequency of the core in retention, causing a change in PLL and when the
core exits retention, the PLL mismatch could hang the SPM state machine.
Change-Id: I99b454a0f146652f2d8a369f79f6d35748160dcb
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>
---
arch/arm/mach-msm/cpufreq.c | 54 +++++++++++++++++++++++++++++++++++--
1 file changed, 52 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-msm/cpufreq.c b/arch/arm/mach-msm/cpufreq.c
index 9d9ea5cb3c9b..06627263e071 100644
--- a/arch/arm/mach-msm/cpufreq.c
+++ b/arch/arm/mach-msm/cpufreq.c
@@ -32,6 +32,17 @@
#include "acpuclock.h"
+struct cpufreq_work_struct {
+ struct work_struct work;
+ struct cpufreq_policy *policy;
+ struct completion complete;
+ int frequency;
+ int status;
+};
+
+static DEFINE_PER_CPU(struct cpufreq_work_struct, cpufreq_work);
+static struct workqueue_struct *msm_cpufreq_wq;
+
struct cpufreq_suspend_t {
struct mutex suspend_mutex;
int device_suspended;
@@ -78,6 +89,15 @@ static int set_cpu_freq(struct cpufreq_policy *policy, unsigned int new_freq)
return ret;
}
+static void set_cpu_work(struct work_struct *work)
+{
+ struct cpufreq_work_struct *cpu_work =
+ container_of(work, struct cpufreq_work_struct, work);
+
+ cpu_work->status = set_cpu_freq(cpu_work->policy, cpu_work->frequency);
+ complete(&cpu_work->complete);
+}
+
static int msm_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
@@ -86,11 +106,17 @@ static int msm_cpufreq_target(struct cpufreq_policy *policy,
int index;
struct cpufreq_frequency_table *table;
+ struct cpufreq_work_struct *cpu_work = NULL;
+ cpumask_var_t mask;
+
if (!cpu_active(policy->cpu)) {
pr_info("cpufreq: cpu %d is not active.\n", policy->cpu);
return -ENODEV;
}
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+ return -ENOMEM;
+
mutex_lock(&per_cpu(cpufreq_suspend, policy->cpu).suspend_mutex);
if (per_cpu(cpufreq_suspend, policy->cpu).device_suspended) {
@@ -112,9 +138,27 @@ static int msm_cpufreq_target(struct cpufreq_policy *policy,
policy->cpu, target_freq, relation,
policy->min, policy->max, table[index].frequency);
- ret = set_cpu_freq(policy, table[index].frequency);
+ cpu_work = &per_cpu(cpufreq_work, policy->cpu);
+ cpu_work->policy = policy;
+ cpu_work->frequency = table[index].frequency;
+ cpu_work->status = -ENODEV;
+
+ cpumask_clear(mask);
+ cpumask_set_cpu(policy->cpu, mask);
+ if (cpumask_equal(mask, ¤t->cpus_allowed)) {
+ ret = set_cpu_freq(cpu_work->policy, cpu_work->frequency);
+ goto done;
+ } else {
+ cancel_work_sync(&cpu_work->work);
+ INIT_COMPLETION(cpu_work->complete);
+ queue_work_on(policy->cpu, msm_cpufreq_wq, &cpu_work->work);
+ wait_for_completion(&cpu_work->complete);
+ }
+
+ ret = cpu_work->status;
done:
+ free_cpumask_var(mask);
mutex_unlock(&per_cpu(cpufreq_suspend, policy->cpu).suspend_mutex);
return ret;
}
@@ -197,6 +241,7 @@ static int __cpuinit msm_cpufreq_init(struct cpufreq_policy *policy)
int cur_freq;
int index;
struct cpufreq_frequency_table *table;
+ struct cpufreq_work_struct *cpu_work = NULL;
table = cpufreq_frequency_get_table(policy->cpu);
if (table == NULL)
@@ -225,7 +270,7 @@ static int __cpuinit msm_cpufreq_init(struct cpufreq_policy *policy)
CPUFREQ_RELATION_H, &index) &&
cpufreq_frequency_table_target(policy, table, cur_freq,
CPUFREQ_RELATION_L, &index)) {
- pr_info("%s: cpu%d at invalid freq: %d\n", __func__,
+ pr_info("cpufreq: cpu%d at invalid freq: %d\n",
policy->cpu, cur_freq);
return -EINVAL;
}
@@ -246,6 +291,10 @@ static int __cpuinit msm_cpufreq_init(struct cpufreq_policy *policy)
policy->cpuinfo.transition_latency =
acpuclk_get_switch_time() * NSEC_PER_USEC;
+ cpu_work = &per_cpu(cpufreq_work, policy->cpu);
+ INIT_WORK(&cpu_work->work, set_cpu_work);
+ init_completion(&cpu_work->complete);
+
return 0;
}
@@ -333,6 +382,7 @@ static int __init msm_cpufreq_register(void)
per_cpu(cpufreq_suspend, cpu).device_suspended = 0;
}
+ msm_cpufreq_wq = create_workqueue("msm-cpufreq");
register_hotcpu_notifier(&msm_cpufreq_cpu_notifier);
return cpufreq_register_driver(&msm_cpufreq_driver);
--
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