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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-12-09 17:14:38 +1100 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-12-09 17:14:38 +1100 |
commit | bcd6acd51f3d4d1ada201e9bc5c40a31d6d80c71 (patch) | |
tree | 2f6dffd2d3e4dd67355a224de7e7a960335a92fd /arch/arm/mach-at91/cpuidle.c | |
parent | 11c34c7deaeeebcee342cbc35e1bb2a6711b2431 (diff) | |
parent | 3ff6a468b45b5dfeb0e903e56f4eb27d34b2437c (diff) | |
download | op-kernel-dev-bcd6acd51f3d4d1ada201e9bc5c40a31d6d80c71.zip op-kernel-dev-bcd6acd51f3d4d1ada201e9bc5c40a31d6d80c71.tar.gz |
Merge commit 'origin/master' into next
Conflicts:
include/linux/kvm.h
Diffstat (limited to 'arch/arm/mach-at91/cpuidle.c')
-rw-r--r-- | arch/arm/mach-at91/cpuidle.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/cpuidle.c b/arch/arm/mach-at91/cpuidle.c new file mode 100644 index 0000000..1cfeac1 --- /dev/null +++ b/arch/arm/mach-at91/cpuidle.c @@ -0,0 +1,94 @@ +/* + * based on arch/arm/mach-kirkwood/cpuidle.c + * + * CPU idle support for AT91 SoC + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * The cpu idle uses wait-for-interrupt and RAM self refresh in order + * to implement two idle states - + * #1 wait-for-interrupt + * #2 wait-for-interrupt and RAM self refresh + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/cpuidle.h> +#include <asm/proc-fns.h> +#include <linux/io.h> + +#include "pm.h" + +#define AT91_MAX_STATES 2 + +static DEFINE_PER_CPU(struct cpuidle_device, at91_cpuidle_device); + +static struct cpuidle_driver at91_idle_driver = { + .name = "at91_idle", + .owner = THIS_MODULE, +}; + +/* Actual code that puts the SoC in different idle states */ +static int at91_enter_idle(struct cpuidle_device *dev, + struct cpuidle_state *state) +{ + struct timeval before, after; + int idle_time; + u32 saved_lpr; + + local_irq_disable(); + do_gettimeofday(&before); + if (state == &dev->states[0]) + /* Wait for interrupt state */ + cpu_do_idle(); + else if (state == &dev->states[1]) { + asm("b 1f; .align 5; 1:"); + asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ + saved_lpr = sdram_selfrefresh_enable(); + cpu_do_idle(); + sdram_selfrefresh_disable(saved_lpr); + } + do_gettimeofday(&after); + local_irq_enable(); + idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + + (after.tv_usec - before.tv_usec); + return idle_time; +} + +/* Initialize CPU idle by registering the idle states */ +static int at91_init_cpuidle(void) +{ + struct cpuidle_device *device; + + cpuidle_register_driver(&at91_idle_driver); + + device = &per_cpu(at91_cpuidle_device, smp_processor_id()); + device->state_count = AT91_MAX_STATES; + + /* Wait for interrupt state */ + device->states[0].enter = at91_enter_idle; + device->states[0].exit_latency = 1; + device->states[0].target_residency = 10000; + device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; + strcpy(device->states[0].name, "WFI"); + strcpy(device->states[0].desc, "Wait for interrupt"); + + /* Wait for interrupt and RAM self refresh state */ + device->states[1].enter = at91_enter_idle; + device->states[1].exit_latency = 10; + device->states[1].target_residency = 10000; + device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; + strcpy(device->states[1].name, "RAM_SR"); + strcpy(device->states[1].desc, "WFI and RAM Self Refresh"); + + if (cpuidle_register_device(device)) { + printk(KERN_ERR "at91_init_cpuidle: Failed registering\n"); + return -EIO; + } + return 0; +} + +device_initcall(at91_init_cpuidle); |