1 files changed, 376 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
new file mode 100644
index 0000000..9bb4f04
--- /dev/null
+++ b/arch/arm/mach-at91/pm.c
@@ -0,0 +1,376 @@
+/*
+ * arch/arm/mach-at91/pm.c
+ * AT91 Power Management
+ *
+ * Copyright (C) 2005 David Brownell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/suspend.h>
+#include <linux/sched.h>
+#include <linux/proc_fs.h>
+#include <linux/interrupt.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include <asm/irq.h>
+#include <asm/atomic.h>
+#include <asm/mach/time.h>
+#include <asm/mach/irq.h>
+
+#include <mach/at91_pmc.h>
+#include <mach/gpio.h>
+#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
+
+
+/*
+ * Show the reason for the previous system reset.
+ */
+#if defined(AT91_SHDWC)
+
+#include <mach/at91_rstc.h>
+#include <mach/at91_shdwc.h>
+
+static void __init show_reset_status(void)
+{
+	static char reset[] __initdata = "reset";
+
+	static char general[] __initdata = "general";
+	static char wakeup[] __initdata = "wakeup";
+	static char watchdog[] __initdata = "watchdog";
+	static char software[] __initdata = "software";
+	static char user[] __initdata = "user";
+	static char unknown[] __initdata = "unknown";
+
+	static char signal[] __initdata = "signal";
+	static char rtc[] __initdata = "rtc";
+	static char rtt[] __initdata = "rtt";
+	static char restore[] __initdata = "power-restored";
+
+	char *reason, *r2 = reset;
+	u32 reset_type, wake_type;
+
+	reset_type = at91_sys_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP;
+	wake_type = at91_sys_read(AT91_SHDW_SR);
+
+	switch (reset_type) {
+	case AT91_RSTC_RSTTYP_GENERAL:
+		reason = general;
+		break;
+	case AT91_RSTC_RSTTYP_WAKEUP:
+		/* board-specific code enabled the wakeup sources */
+		reason = wakeup;
+
+		/* "wakeup signal" */
+		if (wake_type & AT91_SHDW_WAKEUP0)
+			r2 = signal;
+		else {
+			r2 = reason;
+			if (wake_type & AT91_SHDW_RTTWK)	/* rtt wakeup */
+				reason = rtt;
+			else if (wake_type & AT91_SHDW_RTCWK)	/* rtc wakeup */
+				reason = rtc;
+			else if (wake_type == 0)	/* power-restored wakeup */
+				reason = restore;
+			else				/* unknown wakeup */
+				reason = unknown;
+		}
+		break;
+	case AT91_RSTC_RSTTYP_WATCHDOG:
+		reason = watchdog;
+		break;
+	case AT91_RSTC_RSTTYP_SOFTWARE:
+		reason = software;
+		break;
+	case AT91_RSTC_RSTTYP_USER:
+		reason = user;
+		break;
+	default:
+		reason = unknown;
+		break;
+	}
+	pr_info("AT91: Starting after %s %s\n", reason, r2);
+}
+#else
+static void __init show_reset_status(void) {}
+#endif
+
+
+static int at91_pm_valid_state(suspend_state_t state)
+{
+	switch (state) {
+		case PM_SUSPEND_ON:
+		case PM_SUSPEND_STANDBY:
+		case PM_SUSPEND_MEM:
+			return 1;
+
+		default:
+			return 0;
+	}
+}
+
+
+static suspend_state_t target_state;
+
+/*
+ * Called after processes are frozen, but before we shutdown devices.
+ */
+static int at91_pm_begin(suspend_state_t state)
+{
+	target_state = state;
+	return 0;
+}
+
+/*
+ * Verify that all the clocks are correct before entering
+ * slow-clock mode.
+ */
+static int at91_pm_verify_clocks(void)
+{
+	unsigned long scsr;
+	int i;
+
+	scsr = at91_sys_read(AT91_PMC_SCSR);
+
+	/* USB must not be using PLLB */
+	if (cpu_is_at91rm9200()) {
+		if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
+			pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
+			return 0;
+		}
+	} else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263() || cpu_is_at91sam9g20()) {
+		if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
+			pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
+			return 0;
+		}
+	} else if (cpu_is_at91cap9()) {
+		if ((scsr & AT91CAP9_PMC_UHP) != 0) {
+			pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n");
+			return 0;
+		}
+	}
+
+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
+	/* PCK0..PCK3 must be disabled, or configured to use clk32k */
+	for (i = 0; i < 4; i++) {
+		u32 css;
+
+		if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
+			continue;
+
+		css = at91_sys_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
+		if (css != AT91_PMC_CSS_SLOW) {
+			pr_debug("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
+			return 0;
+		}
+	}
+#endif
+
+	return 1;
+}
+
+/*
+ * Call this from platform driver suspend() to see how deeply to suspend.
+ * For example, some controllers (like OHCI) need one of the PLL clocks
+ * in order to act as a wakeup source, and those are not available when
+ * going into slow clock mode.
+ *
+ * REVISIT: generalize as clk_will_be_available(clk)?  Other platforms have
+ * the very same problem (but not using at91 main_clk), and it'd be better
+ * to add one generic API rather than lots of platform-specific ones.
+ */
+int at91_suspend_entering_slow_clock(void)
+{
+	return (target_state == PM_SUSPEND_MEM);
+}
+EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
+
+
+static void (*slow_clock)(void);
+
+#ifdef CONFIG_AT91_SLOW_CLOCK
+extern void at91_slow_clock(void);
+extern u32 at91_slow_clock_sz;
+#endif
+
+
+static int at91_pm_enter(suspend_state_t state)
+{
+	at91_gpio_suspend();
+	at91_irq_suspend();
+
+	pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
+			/* remember all the always-wake irqs */
+			(at91_sys_read(AT91_PMC_PCSR)
+					| (1 << AT91_ID_FIQ)
+					| (1 << AT91_ID_SYS)
+					| (at91_extern_irq))
+				& at91_sys_read(AT91_AIC_IMR),
+			state);
+
+	switch (state) {
+		/*
+		 * Suspend-to-RAM is like STANDBY plus slow clock mode, so
+		 * drivers must suspend more deeply:  only the master clock
+		 * controller may be using the main oscillator.
+		 */
+		case PM_SUSPEND_MEM:
+			/*
+			 * Ensure that clocks are in a valid state.
+			 */
+			if (!at91_pm_verify_clocks())
+				goto error;
+
+			/*
+			 * Enter slow clock mode by switching over to clk32k and
+			 * turning off the main oscillator; reverse on wakeup.
+			 */
+			if (slow_clock) {
+#ifdef CONFIG_AT91_SLOW_CLOCK
+				/* copy slow_clock handler to SRAM, and call it */
+				memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
+#endif
+				slow_clock();
+				break;
+			} else {
+				pr_info("AT91: PM - no slow clock mode enabled ...\n");
+				/* FALLTHROUGH leaving master clock alone */
+			}
+
+		/*
+		 * STANDBY mode has *all* drivers suspended; ignores irqs not
+		 * marked as 'wakeup' event sources; and reduces DRAM power.
+		 * But otherwise it's identical to PM_SUSPEND_ON:  cpu idle, and
+		 * nothing fancy done with main or cpu clocks.
+		 */
+		case PM_SUSPEND_STANDBY:
+			/*
+			 * NOTE: the Wait-for-Interrupt instruction needs to be
+			 * in icache so no SDRAM accesses are needed until the
+			 * wakeup IRQ occurs and self-refresh is terminated.
+			 */
+			asm("b 1f; .align 5; 1:");
+			asm("mcr p15, 0, r0, c7, c10, 4");	/* drain write buffer */
+			sdram_selfrefresh_enable();
+			asm("mcr p15, 0, r0, c7, c0, 4");	/* wait for interrupt */
+			sdram_selfrefresh_disable();
+			break;
+
+		case PM_SUSPEND_ON:
+			asm("mcr p15, 0, r0, c7, c0, 4");	/* wait for interrupt */
+			break;
+
+		default:
+			pr_debug("AT91: PM - bogus suspend state %d\n", state);
+			goto error;
+	}
+
+	pr_debug("AT91: PM - wakeup %08x\n",
+			at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR));
+
+error:
+	sdram_selfrefresh_disable();
+	target_state = PM_SUSPEND_ON;
+	at91_irq_resume();
+	at91_gpio_resume();
+	return 0;
+}
+
+/*
+ * Called right prior to thawing processes.
+ */
+static void at91_pm_end(void)
+{
+	target_state = PM_SUSPEND_ON;
+}
+
+
+static struct platform_suspend_ops at91_pm_ops ={
+	.valid	= at91_pm_valid_state,
+	.begin	= at91_pm_begin,
+	.enter	= at91_pm_enter,
+	.end	= at91_pm_end,
+};
+
+static int __init at91_pm_init(void)
+{
+#ifdef CONFIG_AT91_SLOW_CLOCK
+	slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
+#endif
+
+	pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
+
+#ifdef CONFIG_ARCH_AT91RM9200
+	/* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
+	at91_sys_write(AT91_SDRAMC_LPR, 0);
+#endif
+
+	suspend_set_ops(&at91_pm_ops);
+
+	show_reset_status();
+	return 0;
+}
+arch_initcall(at91_pm_init);