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 --- V4->V5: - Inverted flag, moved to CPUFREQ_NEED_INITIAL_FREQ_CHECK instead of CPUFREQ_SKIP_INITIAL_FREQ_CHECK and so this patch does it now for all the ARM drivers. - Flag and its usage expression changed in 2/2 as well..
drivers/cpufreq/arm_big_little.c | 3 ++- drivers/cpufreq/davinci-cpufreq.c | 2 +- drivers/cpufreq/dbx500-cpufreq.c | 3 ++- drivers/cpufreq/exynos-cpufreq.c | 2 +- drivers/cpufreq/exynos5440-cpufreq.c | 3 ++- drivers/cpufreq/imx6q-cpufreq.c | 1 + drivers/cpufreq/integrator-cpufreq.c | 1 + drivers/cpufreq/kirkwood-cpufreq.c | 1 + drivers/cpufreq/omap-cpufreq.c | 2 +- drivers/cpufreq/pxa2xx-cpufreq.c | 1 + drivers/cpufreq/pxa3xx-cpufreq.c | 1 + drivers/cpufreq/s3c2416-cpufreq.c | 2 +- drivers/cpufreq/s3c24xx-cpufreq.c | 2 +- drivers/cpufreq/s3c64xx-cpufreq.c | 2 +- drivers/cpufreq/s5pv210-cpufreq.c | 2 +- drivers/cpufreq/sa1100-cpufreq.c | 2 +- drivers/cpufreq/sa1110-cpufreq.c | 2 +- drivers/cpufreq/spear-cpufreq.c | 2 +- drivers/cpufreq/tegra-cpufreq.c | 1 + include/linux/cpufreq.h | 9 +++++++++ 20 files changed, 31 insertions(+), 13 deletions(-)
diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c index 5519933..72f87e9 100644 --- a/drivers/cpufreq/arm_big_little.c +++ b/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, diff --git a/drivers/cpufreq/davinci-cpufreq.c b/drivers/cpufreq/davinci-cpufreq.c index 5e8a854..04f3390 100644 --- a/drivers/cpufreq/davinci-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/dbx500-cpufreq.c b/drivers/cpufreq/dbx500-cpufreq.c index 0e67ab9..21d9898 100644 --- a/drivers/cpufreq/dbx500-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/exynos-cpufreq.c b/drivers/cpufreq/exynos-cpufreq.c index f3c2287..85e67dc 100644 --- a/drivers/cpufreq/exynos-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c index 76bef8b..ffe6fae 100644 --- a/drivers/cpufreq/exynos5440-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c index 4b3f18e..530ce9a 100644 --- a/drivers/cpufreq/imx6q-cpufreq.c +++ b/drivers/cpufreq/imx6q-cpufreq.c @@ -138,6 +138,7 @@ 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, diff --git a/drivers/cpufreq/integrator-cpufreq.c b/drivers/cpufreq/integrator-cpufreq.c index 7d8ab000d..0e27844 100644 --- a/drivers/cpufreq/integrator-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/kirkwood-cpufreq.c b/drivers/cpufreq/kirkwood-cpufreq.c index 0767a4e..eb7abe3 100644 --- a/drivers/cpufreq/kirkwood-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c index a0acd0b..5de1e5f 100644 --- a/drivers/cpufreq/omap-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/pxa2xx-cpufreq.c b/drivers/cpufreq/pxa2xx-cpufreq.c index 0a0f436..a9195a8 100644 --- a/drivers/cpufreq/pxa2xx-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/pxa3xx-cpufreq.c b/drivers/cpufreq/pxa3xx-cpufreq.c index 9384004..3785687 100644 --- a/drivers/cpufreq/pxa3xx-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/s3c2416-cpufreq.c b/drivers/cpufreq/s3c2416-cpufreq.c index 8d904a0..826b8be 100644 --- a/drivers/cpufreq/s3c2416-cpufreq.c +++ b/drivers/cpufreq/s3c2416-cpufreq.c @@ -481,7 +481,7 @@ err_hclk: }
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, diff --git a/drivers/cpufreq/s3c24xx-cpufreq.c b/drivers/cpufreq/s3c24xx-cpufreq.c index 4850882..d38e50f 100644 --- a/drivers/cpufreq/s3c24xx-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/s3c64xx-cpufreq.c b/drivers/cpufreq/s3c64xx-cpufreq.c index 67e302e..8435f45 100644 --- a/drivers/cpufreq/s3c64xx-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c index e3973da..ccd548c 100644 --- a/drivers/cpufreq/s5pv210-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/sa1100-cpufreq.c b/drivers/cpufreq/sa1100-cpufreq.c index 623da74..728eab7 100644 --- a/drivers/cpufreq/sa1100-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/sa1110-cpufreq.c b/drivers/cpufreq/sa1110-cpufreq.c index 2c2b2e6..5463767 100644 --- a/drivers/cpufreq/sa1110-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/spear-cpufreq.c b/drivers/cpufreq/spear-cpufreq.c index 45ea4c0..c7525fe 100644 --- a/drivers/cpufreq/spear-cpufreq.c +++ b/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, diff --git a/drivers/cpufreq/tegra-cpufreq.c b/drivers/cpufreq/tegra-cpufreq.c index b7309c3..01b5578 100644 --- a/drivers/cpufreq/tegra-cpufreq.c +++ b/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, diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index ee5fe9d..bfb62cb 100644 --- a/include/linux/cpufreq.h +++ b/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);
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 freq-table. This also makes cpufreq stats inconsistent as cpufreq-stats would fail to register because current frequency of CPU isn't found in freq-table.
Because we don't want this change to effect boot process badly, we go for the next freq which is >= policy->cur ('cur' must be set by now, otherwise we will end up setting freq to lowest of the table as 'cur' is initialized to zero).
In case current frequency doesn't match any frequency from freq-table, we throw warnings to user, so that user can get this fixed in their bootloaders or freq-tables.
Reported-by: Carlos Hernandez ceh@ti.com Reported-and-tested-by: Nishanth Menon nm@ti.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/cpufreq.c | 40 ++++++++++++++++++++++++++++++++++++++++ drivers/cpufreq/freq_table.c | 22 ++++++++++++++++++++++ include/linux/cpufreq.h | 2 ++ 3 files changed, 64 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 606224a..15a962e 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1042,6 +1042,46 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, } }
+ /* + * 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 + * freq-table. This also makes cpufreq stats inconsistent as + * cpufreq-stats would fail to register because current frequency of CPU + * isn't found in freq-table. + * + * Because we don't want this change to effect boot process badly, we go + * for the next freq which is >= policy->cur ('cur' must be set by now, + * otherwise we will end up setting freq to lowest of the table as 'cur' + * is initialized to zero). + * + * We are passing target-freq as "policy->cur - 1" otherwise + * __cpufreq_driver_target() would simply fail, as policy->cur will be + * equal to target-freq. + */ + if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK) + && has_target()) { + /* Are we running at unknown frequency ? */ + ret = cpufreq_frequency_table_get_index(policy, policy->cur); + if (ret == -EINVAL) { + /* Warn user and fix it */ + pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n", + __func__, policy->cpu, policy->cur); + ret = __cpufreq_driver_target(policy, policy->cur - 1, + CPUFREQ_RELATION_L); + + /* + * Reaching here after boot in a few seconds may not + * mean that system will remain stable at "unknown" + * frequency for longer duration. Hence, a BUG_ON(). + */ + BUG_ON(ret); + pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n", + __func__, policy->cpu, policy->cur); + } + } + /* related cpus should atleast have policy->cpus */ cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index 3458d27..a8ac042 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -178,7 +178,29 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
+int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy, + unsigned int freq) +{ + struct cpufreq_frequency_table *table; + int i; + + table = cpufreq_frequency_get_table(policy->cpu); + if (unlikely(!table)) { + pr_debug("%s: Unable to find frequency table\n", __func__); + return -ENOENT; + } + + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { + if (table[i].frequency == freq) + return i; + } + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index); + static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table); + /** * show_available_freqs - show available frequencies for the specified CPU */ diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index bfb62cb..115ceb4 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -456,6 +456,8 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation, unsigned int *index); +int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy, + unsigned int freq);
void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy); ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
linaro-kernel@lists.linaro.org
-
Viresh Kumar