cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag

Sometimes boot loaders set CPU frequency to a value outside of frequency table
present with cpufreq core. In such cases CPU might be unstable if it has to run
on that frequency for long duration of time and so its better to set it to a
frequency which is specified in frequency table.

On some systems we can't really say what frequency we're running at the moment
and so for these we shouldn't check if we are running at a frequency present in
frequency table. And so we really can't force this for all the cpufreq drivers.

Hence we are created another flag here: CPUFREQ_NEED_INITIAL_FREQ_CHECK that
will be marked by platforms which want to go for this check at boot time.

Initially this is done for all ARM platforms but others may follow if required.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/arm_big_little.c

@@ -488,7 +488,8 @@ static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 static struct cpufreq_driver bL_cpufreq_driver = {
 	.name			= "arm-big-little",
 	.flags			= CPUFREQ_STICKY |
-					CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
+					CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
+					CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify			= cpufreq_generic_frequency_table_verify,
 	.target_index		= bL_cpufreq_set_target,
 	.get			= bL_cpufreq_get_rate,

drivers/cpufreq/davinci-cpufreq.c

@@ -126,7 +126,7 @@ static int davinci_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver davinci_driver = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= davinci_verify_speed,
 	.target_index	= davinci_target,
 	.get		= davinci_getspeed,

drivers/cpufreq/dbx500-cpufreq.c

@@ -48,7 +48,8 @@ static int dbx500_cpufreq_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver dbx500_cpufreq_driver = {
-	.flags  = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS,
+	.flags  = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS |
+			CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = dbx500_cpufreq_target,
 	.get    = dbx500_cpufreq_getspeed,

drivers/cpufreq/exynos-cpufreq.c

@@ -218,7 +218,7 @@ static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver exynos_driver = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= exynos_target,
 	.get		= exynos_getspeed,

drivers/cpufreq/exynos5440-cpufreq.c

@@ -312,7 +312,8 @@ static int exynos_cpufreq_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver exynos_driver = {
-	.flags		= CPUFREQ_STICKY | CPUFREQ_ASYNC_NOTIFICATION,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_ASYNC_NOTIFICATION |
+				CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= exynos_target,
 	.get		= exynos_getspeed,

drivers/cpufreq/imx6q-cpufreq.c

@@ -143,6 +143,7 @@ static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver imx6q_cpufreq_driver = {
+	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = imx6q_set_target,
 	.get = imx6q_get_speed,

drivers/cpufreq/integrator-cpufreq.c

@@ -190,6 +190,7 @@ static int integrator_cpufreq_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver integrator_driver = {
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= integrator_verify_policy,
 	.target		= integrator_set_target,
 	.get		= integrator_get,

drivers/cpufreq/kirkwood-cpufreq.c

@@ -97,6 +97,7 @@ static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver kirkwood_cpufreq_driver = {
+	.flags	= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.get	= kirkwood_cpufreq_get_cpu_frequency,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = kirkwood_cpufreq_target,

drivers/cpufreq/omap-cpufreq.c

@@ -162,7 +162,7 @@ static int omap_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver omap_driver = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= omap_target,
 	.get		= omap_getspeed,

drivers/cpufreq/pxa2xx-cpufreq.c

@@ -423,6 +423,7 @@ static int pxa_cpufreq_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver pxa_cpufreq_driver = {
+	.flags	= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = pxa_set_target,
 	.init	= pxa_cpufreq_init,

drivers/cpufreq/pxa3xx-cpufreq.c

@@ -201,6 +201,7 @@ static int pxa3xx_cpufreq_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver pxa3xx_cpufreq_driver = {
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= pxa3xx_cpufreq_set,
 	.init		= pxa3xx_cpufreq_init,

drivers/cpufreq/s3c2416-cpufreq.c

@@ -481,7 +481,7 @@ static int __init s3c2416_cpufreq_driver_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver s3c2416_cpufreq_driver = {
-	.flags          = 0,
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= s3c2416_cpufreq_set_target,
 	.get		= s3c2416_cpufreq_get_speed,

drivers/cpufreq/s3c24xx-cpufreq.c

@@ -448,7 +448,7 @@ static int s3c_cpufreq_resume(struct cpufreq_policy *policy)
 #endif
 
 static struct cpufreq_driver s3c24xx_driver = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.target		= s3c_cpufreq_target,
 	.get		= s3c_cpufreq_get,
 	.init		= s3c_cpufreq_init,

drivers/cpufreq/s3c64xx-cpufreq.c

@@ -226,7 +226,7 @@ static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver s3c64xx_cpufreq_driver = {
-	.flags          = 0,
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= s3c64xx_cpufreq_set_target,
 	.get		= s3c64xx_cpufreq_get_speed,

drivers/cpufreq/s5pv210-cpufreq.c

@@ -560,7 +560,7 @@ static int s5pv210_cpufreq_reboot_notifier_event(struct notifier_block *this,
 }
 
 static struct cpufreq_driver s5pv210_driver = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= s5pv210_target,
 	.get		= s5pv210_getspeed,

drivers/cpufreq/sa1100-cpufreq.c

@@ -201,7 +201,7 @@ static int __init sa1100_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver sa1100_driver __refdata = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= sa1100_target,
 	.get		= sa11x0_getspeed,

drivers/cpufreq/sa1110-cpufreq.c

@@ -312,7 +312,7 @@ static int __init sa1110_cpu_init(struct cpufreq_policy *policy)
 /* sa1110_driver needs __refdata because it must remain after init registers
  * it with cpufreq_register_driver() */
 static struct cpufreq_driver sa1110_driver __refdata = {
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= sa1110_target,
 	.get		= sa11x0_getspeed,

drivers/cpufreq/spear-cpufreq.c

@@ -162,7 +162,7 @@ static int spear_cpufreq_init(struct cpufreq_policy *policy)
 
 static struct cpufreq_driver spear_cpufreq_driver = {
 	.name		= "cpufreq-spear",
-	.flags		= CPUFREQ_STICKY,
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= spear_cpufreq_target,
 	.get		= spear_cpufreq_get,

drivers/cpufreq/tegra-cpufreq.c

@@ -214,6 +214,7 @@ static int tegra_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver tegra_cpufreq_driver = {
+	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= tegra_target,
 	.get		= tegra_getspeed,

include/linux/cpufreq.h

@@ -252,6 +252,15 @@ struct cpufreq_driver {
  */
 #define CPUFREQ_ASYNC_NOTIFICATION  (1 << 4)
 
+/*
+ * Set by drivers which want cpufreq core to check if CPU is running at a
+ * frequency present in freq-table exposed by the driver. For these drivers if
+ * CPU is found running at an out of table freq, we will try to set it to a freq
+ * from the table. And if that fails, we will stop further boot process by
+ * issuing a BUG_ON().
+ */
+#define CPUFREQ_NEED_INITIAL_FREQ_CHECK	(1 << 5)
+
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);