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authorVitja Makarov <vitja.makarov@gmail.com>2008-05-07 11:41:26 +0800
committerBryan Wu <cooloney@kernel.org>2008-05-07 11:41:26 +0800
commit1bfb4b21c7c39295f5535c139f796df1d51ec009 (patch)
tree5c5a58a83c5f1d5d1ff984e8f073a16416fa8abb /arch/blackfin/mach-common
parent14b03204c8060d036b04cbb18bbd6f6f311f4fed (diff)
[Blackfin] arch: Support for CPU_FREQ and NOHZ
Singed-off-by: Vitja Makarov <vitja.makarov@gmail.com>
Diffstat (limited to 'arch/blackfin/mach-common')
-rw-r--r--arch/blackfin/mach-common/cpufreq.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/arch/blackfin/mach-common/cpufreq.c b/arch/blackfin/mach-common/cpufreq.c
index dd1515e4094..75cdad291e8 100644
--- a/arch/blackfin/mach-common/cpufreq.c
+++ b/arch/blackfin/mach-common/cpufreq.c
@@ -62,6 +62,14 @@ static struct bfin_dpm_state {
unsigned int tscale; /* change the divider on the core timer interrupt */
} dpm_state_table[3];
+/*
+ normalized to maximum frequncy offset for CYCLES,
+ used in time-ts cycles clock source, but could be used
+ somewhere also.
+ */
+unsigned long long __bfin_cycles_off;
+unsigned int __bfin_cycles_mod;
+
/**************************************************************************/
static unsigned int bfin_getfreq(unsigned int cpu)
@@ -80,6 +88,7 @@ static int bfin_target(struct cpufreq_policy *policy,
unsigned int index, plldiv, tscale;
unsigned long flags, cclk_hz;
struct cpufreq_freqs freqs;
+ cycles_t cycles;
if (cpufreq_frequency_table_target(policy, bfin_freq_table,
target_freq, relation, &index))
@@ -101,8 +110,14 @@ static int bfin_target(struct cpufreq_policy *policy,
bfin_write_PLL_DIV(plldiv);
/* we have to adjust the core timer, because it is using cclk */
bfin_write_TSCALE(tscale);
+ cycles = get_cycles();
SSYNC();
+ cycles += 10; /* ~10 cycles we loose after get_cycles() */
+ __bfin_cycles_off += (cycles << __bfin_cycles_mod) - (cycles << index);
+ __bfin_cycles_mod = index;
local_irq_restore(flags);
+ /* TODO: just test case for cycles clock source, remove later */
+ pr_debug("cpufreq: done\n");
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
@@ -119,15 +134,6 @@ static int __init __bfin_cpu_init(struct cpufreq_policy *policy)
unsigned long cclk, sclk, csel, min_cclk;
int index;
-#ifdef CONFIG_CYCLES_CLOCKSOURCE
-/*
- * Clocksource CYCLES is still CONTINUOUS but not longer with a constant tick rate in case we enable
- * CPU frequency scaling, since CYCLES runs off Core Clock.
- */
- printk(KERN_WARNING "CPU frequency scaling not supported: Clocksource not suitable\n"
- return -ENODEV;
-#endif
-
if (policy->cpu != 0)
return -EINVAL;