diff options
Diffstat (limited to 'drivers/cpufreq/tegra-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/tegra-cpufreq.c | 146 |
1 files changed, 67 insertions, 79 deletions
diff --git a/drivers/cpufreq/tegra-cpufreq.c b/drivers/cpufreq/tegra-cpufreq.c index e652c1bd8d0..8084c7f7e20 100644 --- a/drivers/cpufreq/tegra-cpufreq.c +++ b/drivers/cpufreq/tegra-cpufreq.c @@ -26,7 +26,6 @@ #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> -#include <linux/suspend.h> static struct cpufreq_frequency_table freq_table[] = { { .frequency = 216000 }, @@ -46,49 +45,54 @@ static struct clk *cpu_clk; static struct clk *pll_x_clk; static struct clk *pll_p_clk; static struct clk *emc_clk; +static bool pll_x_prepared; -static DEFINE_MUTEX(tegra_cpu_lock); -static bool is_suspended; +static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy, + unsigned int index) +{ + unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000; + + /* + * Don't switch to intermediate freq if: + * - we are already at it, i.e. policy->cur == ifreq + * - index corresponds to ifreq + */ + if ((freq_table[index].frequency == ifreq) || (policy->cur == ifreq)) + return 0; + + return ifreq; +} -static int tegra_cpu_clk_set_rate(unsigned long rate) +static int tegra_target_intermediate(struct cpufreq_policy *policy, + unsigned int index) { int ret; /* * Take an extra reference to the main pll so it doesn't turn - * off when we move the cpu off of it + * off when we move the cpu off of it as enabling it again while we + * switch to it from tegra_target() would take additional time. + * + * When target-freq is equal to intermediate freq we don't need to + * switch to an intermediate freq and so this routine isn't called. + * Also, we wouldn't be using pll_x anymore and must not take extra + * reference to it, as it can be disabled now to save some power. */ clk_prepare_enable(pll_x_clk); ret = clk_set_parent(cpu_clk, pll_p_clk); - if (ret) { - pr_err("Failed to switch cpu to clock pll_p\n"); - goto out; - } - - if (rate == clk_get_rate(pll_p_clk)) - goto out; - - ret = clk_set_rate(pll_x_clk, rate); - if (ret) { - pr_err("Failed to change pll_x to %lu\n", rate); - goto out; - } - - ret = clk_set_parent(cpu_clk, pll_x_clk); - if (ret) { - pr_err("Failed to switch cpu to clock pll_x\n"); - goto out; - } + if (ret) + clk_disable_unprepare(pll_x_clk); + else + pll_x_prepared = true; -out: - clk_disable_unprepare(pll_x_clk); return ret; } -static int tegra_update_cpu_speed(struct cpufreq_policy *policy, - unsigned long rate) +static int tegra_target(struct cpufreq_policy *policy, unsigned int index) { + unsigned long rate = freq_table[index].frequency; + unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000; int ret = 0; /* @@ -102,52 +106,34 @@ static int tegra_update_cpu_speed(struct cpufreq_policy *policy, else clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */ - ret = tegra_cpu_clk_set_rate(rate * 1000); - if (ret) - pr_err("cpu-tegra: Failed to set cpu frequency to %lu kHz\n", - rate); - - return ret; -} - -static int tegra_target(struct cpufreq_policy *policy, unsigned int index) -{ - int ret = -EBUSY; - - mutex_lock(&tegra_cpu_lock); + /* + * target freq == pll_p, don't need to take extra reference to pll_x_clk + * as it isn't used anymore. + */ + if (rate == ifreq) + return clk_set_parent(cpu_clk, pll_p_clk); - if (!is_suspended) - ret = tegra_update_cpu_speed(policy, - freq_table[index].frequency); + ret = clk_set_rate(pll_x_clk, rate * 1000); + /* Restore to earlier frequency on error, i.e. pll_x */ + if (ret) + pr_err("Failed to change pll_x to %lu\n", rate); - mutex_unlock(&tegra_cpu_lock); - return ret; -} + ret = clk_set_parent(cpu_clk, pll_x_clk); + /* This shouldn't fail while changing or restoring */ + WARN_ON(ret); -static int tegra_pm_notify(struct notifier_block *nb, unsigned long event, - void *dummy) -{ - mutex_lock(&tegra_cpu_lock); - if (event == PM_SUSPEND_PREPARE) { - struct cpufreq_policy *policy = cpufreq_cpu_get(0); - is_suspended = true; - pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n", - freq_table[0].frequency); - if (clk_get_rate(cpu_clk) / 1000 != freq_table[0].frequency) - tegra_update_cpu_speed(policy, freq_table[0].frequency); - cpufreq_cpu_put(policy); - } else if (event == PM_POST_SUSPEND) { - is_suspended = false; + /* + * Drop count to pll_x clock only if we switched to intermediate freq + * earlier while transitioning to a target frequency. + */ + if (pll_x_prepared) { + clk_disable_unprepare(pll_x_clk); + pll_x_prepared = false; } - mutex_unlock(&tegra_cpu_lock); - return NOTIFY_OK; + return ret; } -static struct notifier_block tegra_cpu_pm_notifier = { - .notifier_call = tegra_pm_notify, -}; - static int tegra_cpu_init(struct cpufreq_policy *policy) { int ret; @@ -166,30 +152,32 @@ static int tegra_cpu_init(struct cpufreq_policy *policy) return ret; } - if (policy->cpu == 0) - register_pm_notifier(&tegra_cpu_pm_notifier); - policy->clk = cpu_clk; + policy->suspend_freq = freq_table[0].frequency; return 0; } static int tegra_cpu_exit(struct cpufreq_policy *policy) { - cpufreq_frequency_table_put_attr(policy->cpu); clk_disable_unprepare(cpu_clk); clk_disable_unprepare(emc_clk); return 0; } static struct cpufreq_driver tegra_cpufreq_driver = { - .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, - .verify = cpufreq_generic_frequency_table_verify, - .target_index = tegra_target, - .get = cpufreq_generic_get, - .init = tegra_cpu_init, - .exit = tegra_cpu_exit, - .name = "tegra", - .attr = cpufreq_generic_attr, + .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, + .verify = cpufreq_generic_frequency_table_verify, + .get_intermediate = tegra_get_intermediate, + .target_intermediate = tegra_target_intermediate, + .target_index = tegra_target, + .get = cpufreq_generic_get, + .init = tegra_cpu_init, + .exit = tegra_cpu_exit, + .name = "tegra", + .attr = cpufreq_generic_attr, +#ifdef CONFIG_PM + .suspend = cpufreq_generic_suspend, +#endif }; static int __init tegra_cpufreq_init(void) |