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| author | Pavel Pisa <ppisa@pikron.com> | 2007-01-12 09:57:22 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-01-24 11:59:56 +0000 |
| commit | 5225cd8079484ed27cd52040e8584616d1ef1e2c (patch) | |
| tree | b0e13402a8845e996ec4b4b7e043786cbe78d3cf /arch/arm/mach-imx | |
| parent | 3ea163e44c041b9e1d7314998dfbfd4fbc6eea20 (diff) | |
| download | linux-5225cd8079484ed27cd52040e8584616d1ef1e2c.tar.gz linux-5225cd8079484ed27cd52040e8584616d1ef1e2c.tar.bz2 linux-5225cd8079484ed27cd52040e8584616d1ef1e2c.zip | |
[ARM] 4092/1: i.MX/MX1 CPU Frequency scaling latency definition
The transition latency has to be defined and reasonably
small to allow on-demand and conservative governors.
The value has been defined according to manual.
The imx_set_target() protected against seen out of range
requests now.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-imx')
| -rw-r--r-- | arch/arm/mach-imx/cpufreq.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/arm/mach-imx/cpufreq.c b/arch/arm/mach-imx/cpufreq.c index ac5f99895660..4f66e90db74f 100644 --- a/arch/arm/mach-imx/cpufreq.c +++ b/arch/arm/mach-imx/cpufreq.c @@ -184,6 +184,17 @@ static int imx_set_target(struct cpufreq_policy *policy, long sysclk; unsigned int bclk_div = 1; + /* + * Some governors do not respects CPU and policy lower limits + * which leads to bad things (division by zero etc), ensure + * that such things do not happen. + */ + if(target_freq < policy->cpuinfo.min_freq) + target_freq = policy->cpuinfo.min_freq; + + if(target_freq < policy->min) + target_freq = policy->min; + freq = target_freq * 1000; pr_debug(KERN_DEBUG "imx: requested frequency %ld Hz, mpctl0 at boot 0x%08x\n", @@ -258,7 +269,8 @@ static int __init imx_cpufreq_driver_init(struct cpufreq_policy *policy) policy->governor = CPUFREQ_DEFAULT_GOVERNOR; policy->cpuinfo.min_freq = 8000; policy->cpuinfo.max_freq = 200000; - policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + /* Manual states, that PLL stabilizes in two CLK32 periods */ + policy->cpuinfo.transition_latency = 4 * 1000000000LL / CLK32; return 0; } |