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author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-08-02 16:52:48 (GMT) |
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committer | Nicolas Pitre <nico@fluxnic.net> | 2012-01-20 23:55:11 (GMT) |
commit | 1b7f72fc395d3d2b498fee5ecfb9e46497f55cdd (patch) | |
tree | 8fefa3bde9652f8acb8bda177f3b38149d53a0be /arch/arm/mach-ebsa110/core.c | |
parent | 71e256c54d67f55536bae184bb579c682714a95a (diff) | |
download | linux-1b7f72fc395d3d2b498fee5ecfb9e46497f55cdd.tar.xz |
ARM: mach-ebsa110: move special idle code out of line
... and hook it to arm_pm_idle.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Diffstat (limited to 'arch/arm/mach-ebsa110/core.c')
-rw-r--r-- | arch/arm/mach-ebsa110/core.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/mach-ebsa110/core.c b/arch/arm/mach-ebsa110/core.c index 294aad0..804c912 100644 --- a/arch/arm/mach-ebsa110/core.c +++ b/arch/arm/mach-ebsa110/core.c @@ -271,8 +271,33 @@ static struct platform_device *ebsa110_devices[] = { &am79c961_device, }; +/* + * EBSA110 idling methodology: + * + * We can not execute the "wait for interrupt" instruction since that + * will stop our MCLK signal (which provides the clock for the glue + * logic, and therefore the timer interrupt). + * + * Instead, we spin, polling the IRQ_STAT register for the occurrence + * of any interrupt with core clock down to the memory clock. + */ +static void ebsa110_idle(void) +{ + const char *irq_stat = (char *)0xff000000; + + /* disable clock switching */ + asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc"); + + /* wait for an interrupt to occur */ + while (!*irq_stat); + + /* enable clock switching */ + asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc"); +} + static int __init ebsa110_init(void) { + arm_pm_idle = ebsa110_idle; return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices)); } |