diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mach-at91/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/mach-at91/cpuidle.c | 94 | ||||
| -rw-r--r-- | arch/arm/mach-at91/pm.c | 62 | ||||
| -rw-r--r-- | arch/arm/mach-at91/pm.h | 67 |
4 files changed, 166 insertions, 58 deletions
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile index ada440a..f9e12bb 100644 --- a/arch/arm/mach-at91/Makefile +++ b/arch/arm/mach-at91/Makefile @@ -77,6 +77,7 @@ obj-y += leds.o # Power Management obj-$(CONFIG_PM) += pm.o obj-$(CONFIG_AT91_SLOW_CLOCK) += pm_slowclock.o +obj-$(CONFIG_CPU_IDLE) += cpuidle.o ifeq ($(CONFIG_PM_DEBUG),y) CFLAGS_pm.o += -DDEBUG 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); diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 4028724..6156689 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -29,62 +29,7 @@ #include <mach/cpu.h> #include "generic.h" - -#ifdef CONFIG_ARCH_AT91RM9200 -#include <mach/at91rm9200_mc.h> - -/* - * The AT91RM9200 goes into self-refresh mode with this command, and will - * terminate self-refresh automatically on the next SDRAM access. - */ -#define sdram_selfrefresh_enable() at91_sys_write(AT91_SDRAMC_SRR, 1) -#define sdram_selfrefresh_disable() do {} while (0) - -#elif defined(CONFIG_ARCH_AT91CAP9) -#include <mach/at91cap9_ddrsdr.h> - -static u32 saved_lpr; - -static inline void sdram_selfrefresh_enable(void) -{ - u32 lpr; - - saved_lpr = at91_sys_read(AT91_DDRSDRC_LPR); - - lpr = saved_lpr & ~AT91_DDRSDRC_LPCB; - at91_sys_write(AT91_DDRSDRC_LPR, lpr | AT91_DDRSDRC_LPCB_SELF_REFRESH); -} - -#define sdram_selfrefresh_disable() at91_sys_write(AT91_DDRSDRC_LPR, saved_lpr) - -#else -#include <mach/at91sam9_sdramc.h> - -#ifdef CONFIG_ARCH_AT91SAM9263 -/* - * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use; - * handle those cases both here and in the Suspend-To-RAM support. - */ -#define AT91_SDRAMC AT91_SDRAMC0 -#warning Assuming EB1 SDRAM controller is *NOT* used -#endif - -static u32 saved_lpr; - -static inline void sdram_selfrefresh_enable(void) -{ - u32 lpr; - - saved_lpr = at91_sys_read(AT91_SDRAMC_LPR); - - lpr = saved_lpr & ~AT91_SDRAMC_LPCB; - at91_sys_write(AT91_SDRAMC_LPR, lpr | AT91_SDRAMC_LPCB_SELF_REFRESH); -} - -#define sdram_selfrefresh_disable() at91_sys_write(AT91_SDRAMC_LPR, saved_lpr) - -#endif - +#include "pm.h" /* * Show the reason for the previous system reset. @@ -260,6 +205,7 @@ extern u32 at91_slow_clock_sz; static int at91_pm_enter(suspend_state_t state) { + u32 saved_lpr; at91_gpio_suspend(); at91_irq_suspend(); @@ -315,9 +261,9 @@ static int at91_pm_enter(suspend_state_t state) */ asm("b 1f; .align 5; 1:"); asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ - sdram_selfrefresh_enable(); + saved_lpr = sdram_selfrefresh_enable(); asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ - sdram_selfrefresh_disable(); + sdram_selfrefresh_disable(saved_lpr); break; case PM_SUSPEND_ON: diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h new file mode 100644 index 0000000..08322c4 --- /dev/null +++ b/arch/arm/mach-at91/pm.h @@ -0,0 +1,67 @@ +#ifdef CONFIG_ARCH_AT91RM9200 +#include <mach/at91rm9200_mc.h> + +/* + * The AT91RM9200 goes into self-refresh mode with this command, and will + * terminate self-refresh automatically on the next SDRAM access. + * + * Self-refresh mode is exited as soon as a memory access is made, but we don't + * know for sure when that happens. However, we need to restore the low-power + * mode if it was enabled before going idle. Restoring low-power mode while + * still in self-refresh is "not recommended", but seems to work. + */ + +static inline u32 sdram_selfrefresh_enable(void) +{ + u32 saved_lpr = at91_sys_read(AT91_SDRAMC_LPR); + + at91_sys_write(AT91_SDRAMC_LPR, 0); + at91_sys_write(AT91_SDRAMC_SRR, 1); + return saved_lpr; +} + +#define sdram_selfrefresh_disable(saved_lpr) at91_sys_write(AT91_SDRAMC_LPR, saved_lpr) + +#elif defined(CONFIG_ARCH_AT91CAP9) +#include <mach/at91cap9_ddrsdr.h> + + +static inline u32 sdram_selfrefresh_enable(void) +{ + u32 saved_lpr, lpr; + + saved_lpr = at91_sys_read(AT91_DDRSDRC_LPR); + + lpr = saved_lpr & ~AT91_DDRSDRC_LPCB; + at91_sys_write(AT91_DDRSDRC_LPR, lpr | AT91_DDRSDRC_LPCB_SELF_REFRESH); + return saved_lpr; +} + +#define sdram_selfrefresh_disable(saved_lpr) at91_sys_write(AT91_DDRSDRC_LPR, saved_lpr) + +#else +#include <mach/at91sam9_sdramc.h> + +#ifdef CONFIG_ARCH_AT91SAM9263 +/* + * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use; + * handle those cases both here and in the Suspend-To-RAM support. + */ +#define AT91_SDRAMC AT91_SDRAMC0 +#warning Assuming EB1 SDRAM controller is *NOT* used +#endif + +static inline u32 sdram_selfrefresh_enable(void) +{ + u32 saved_lpr, lpr; + + saved_lpr = at91_sys_read(AT91_SDRAMC_LPR); + + lpr = saved_lpr & ~AT91_SDRAMC_LPCB; + at91_sys_write(AT91_SDRAMC_LPR, lpr | AT91_SDRAMC_LPCB_SELF_REFRESH); + return saved_lpr; +} + +#define sdram_selfrefresh_disable(saved_lpr) at91_sys_write(AT91_SDRAMC_LPR, saved_lpr) + +#endif |
