[CPUFREQ] S5PV210: Lock a mutex while changing the cpu frequency

Without this lock the call to change the frequency for suspend could
switch to a new frequency while another thread was still changing the
cpu voltage.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
index 79b1b4ec8e3c..7fba356d2729 100644
--- a/drivers/cpufreq/s5pv210-cpufreq.c
+++ b/drivers/cpufreq/s5pv210-cpufreq.c
@@ -26,6 +26,7 @@ static struct clk *cpu_clk;
 static struct clk *dmc0_clk;
 static struct clk *dmc1_clk;
 static struct cpufreq_freqs freqs;
+static DEFINE_MUTEX(set_freq_lock);
 
 /* APLL M,P,S values for 1G/800Mhz */
 #define APLL_VAL_1000   ((1 << 31) | (125 << 16) | (3 << 8) | 1)
@@ -199,6 +200,8 @@ static int s5pv210_target(struct cpufreq_policy *policy,
         int arm_volt, int_volt;
         int ret = 0;
 
+        mutex_lock(&set_freq_lock);
+
         if (relation & ENABLE_FURTHER_CPUFREQ)
                 no_cpufreq_access = false;
 
@@ -207,7 +210,8 @@ static int s5pv210_target(struct cpufreq_policy *policy,
                 pr_err("%s:%d denied access to %s as it is disabled"
                                 "temporarily\n", __FILE__, __LINE__, __func__);
 #endif
-                return -EINVAL;
+                ret = -EINVAL;
+                goto exit;
         }
 
         if (relation & DISABLE_FURTHER_CPUFREQ)
@@ -218,19 +222,23 @@ static int s5pv210_target(struct cpufreq_policy *policy,
         freqs.old = s5pv210_getspeed(0);
 
         if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
-                                           target_freq, relation, &index))
-                return -EINVAL;
+                                           target_freq, relation, &index)) {
+                ret = -EINVAL;
+                goto exit;
+        }
 
         freqs.new = s5pv210_freq_table[index].frequency;
         freqs.cpu = 0;
 
         if (freqs.new == freqs.old)
-                return 0;
+                goto exit;
 
         /* Finding current running level index */
         if (cpufreq_frequency_table_target(policy, s5pv210_freq_table,
-                                           freqs.old, relation, &priv_index))
-                return -EINVAL;
+                                           freqs.old, relation, &priv_index)) {
+                ret = -EINVAL;
+                goto exit;
+        }
 
         arm_volt = dvs_conf[index].arm_volt;
         int_volt = dvs_conf[index].int_volt;
@@ -239,12 +247,12 @@ static int s5pv210_target(struct cpufreq_policy *policy,
                 ret = regulator_set_voltage(arm_regulator,
                                 arm_volt, arm_volt_max);
                 if (ret)
-                        return ret;
+                        goto exit;
 
                 ret = regulator_set_voltage(int_regulator,
                                 int_volt, int_volt_max);
                 if (ret)
-                        return ret;
+                        goto exit;
         }
 
         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
@@ -471,7 +479,9 @@ static int s5pv210_target(struct cpufreq_policy *policy,
 
         printk(KERN_DEBUG "Perf changed[L%d]\n", index);
 
-        return 0;
+exit:
+        mutex_unlock(&set_freq_lock);
+        return ret;
 }
 
 #ifdef CONFIG_PM