diff options
author | Kevin Hilman <khilman@mvista.com> | 2009-01-27 19:13:38 -0700 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-02-08 17:50:28 +0000 |
commit | aeec299011da8c3f07a47fe5d988f0eafda53906 (patch) | |
tree | 8661476adf90325972e5feab723f1272ab04fc6b /arch/arm/plat-omap/cpu-omap.c | |
parent | ae8578c0194695bd37435249dfed720769a6bbf3 (diff) | |
download | linux-aeec299011da8c3f07a47fe5d988f0eafda53906.tar.bz2 |
[ARM] OMAP2: Implement CPUfreq frequency table based on PRCM table
This patch adds a CPUfreq frequency-table implementation for OMAP2 by
walking the PRCM rate-table for available entries and adding them to a
CPUfreq table.
CPUfreq can then be used to manage switching between all the available
entries in the PRCM rate table. Either use the CPUfreq sysfs
interface directly, (see Section 3 of Documentation/cpu-freq/user-guide.txt)
or use the cpufrequtils package:
http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufrequtils.html
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Updated to try to use cpufreq_table if it exists.
linux-omap source commit is 77ce544fa48deb7a2003f454624e3ca10d37ab87.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-omap/cpu-omap.c')
-rw-r--r-- | arch/arm/plat-omap/cpu-omap.c | 57 |
1 files changed, 53 insertions, 4 deletions
diff --git a/arch/arm/plat-omap/cpu-omap.c b/arch/arm/plat-omap/cpu-omap.c index b2690242a390..843e8af64066 100644 --- a/arch/arm/plat-omap/cpu-omap.c +++ b/arch/arm/plat-omap/cpu-omap.c @@ -23,10 +23,13 @@ #include <linux/io.h> #include <mach/hardware.h> +#include <mach/clock.h> #include <asm/system.h> #define VERY_HI_RATE 900000000 +static struct cpufreq_frequency_table *freq_table; + #ifdef CONFIG_ARCH_OMAP1 #define MPU_CLK "mpu" #else @@ -39,6 +42,9 @@ static struct clk *mpu_clk; int omap_verify_speed(struct cpufreq_policy *policy) { + if (freq_table) + return cpufreq_frequency_table_verify(policy, freq_table); + if (policy->cpu) return -EINVAL; @@ -70,12 +76,26 @@ static int omap_target(struct cpufreq_policy *policy, struct cpufreq_freqs freqs; int ret = 0; + /* Ensure desired rate is within allowed range. Some govenors + * (ondemand) will just pass target_freq=0 to get the minimum. */ + if (target_freq < policy->cpuinfo.min_freq) + target_freq = policy->cpuinfo.min_freq; + if (target_freq > policy->cpuinfo.max_freq) + target_freq = policy->cpuinfo.max_freq; + freqs.old = omap_getspeed(0); freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; freqs.cpu = 0; + if (freqs.old == freqs.new) + return ret; + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); - ret = clk_set_rate(mpu_clk, target_freq * 1000); +#ifdef CONFIG_CPU_FREQ_DEBUG + printk(KERN_DEBUG "cpufreq-omap: transition: %u --> %u\n", + freqs.old, freqs.new); +#endif + ret = clk_set_rate(mpu_clk, freqs.new * 1000); cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); return ret; @@ -83,16 +103,31 @@ static int omap_target(struct cpufreq_policy *policy, static int __init omap_cpu_init(struct cpufreq_policy *policy) { + int result = 0; + mpu_clk = clk_get(NULL, MPU_CLK); if (IS_ERR(mpu_clk)) return PTR_ERR(mpu_clk); if (policy->cpu != 0) return -EINVAL; + policy->cur = policy->min = policy->max = omap_getspeed(0); - policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; - policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, VERY_HI_RATE) / 1000; - policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + + clk_init_cpufreq_table(&freq_table); + if (freq_table) { + result = cpufreq_frequency_table_cpuinfo(policy, freq_table); + if (!result) + cpufreq_frequency_table_get_attr(freq_table, + policy->cpu); + } else { + policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; + policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, + VERY_HI_RATE) / 1000; + } + + /* FIXME: what's the actual transition time? */ + policy->cpuinfo.transition_latency = 10 * 1000 * 1000; return 0; } @@ -103,6 +138,11 @@ static int omap_cpu_exit(struct cpufreq_policy *policy) return 0; } +static struct freq_attr *omap_cpufreq_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + static struct cpufreq_driver omap_driver = { .flags = CPUFREQ_STICKY, .verify = omap_verify_speed, @@ -111,6 +151,7 @@ static struct cpufreq_driver omap_driver = { .init = omap_cpu_init, .exit = omap_cpu_exit, .name = "omap", + .attr = omap_cpufreq_attr, }; static int __init omap_cpufreq_init(void) @@ -119,3 +160,11 @@ static int __init omap_cpufreq_init(void) } arch_initcall(omap_cpufreq_init); + +/* + * if ever we want to remove this, upon cleanup call: + * + * cpufreq_unregister_driver() + * cpufreq_frequency_table_put_attr() + */ + |