# 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
--- /dev/null
+/*
+ * 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);
#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.
static int at91_pm_enter(suspend_state_t state)
{
+ u32 saved_lpr;
at91_gpio_suspend();
at91_irq_suspend();
*/
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:
--- /dev/null
+#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
projects / cascardo / linux.git / commitdiff