/* * 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/gpio.h> #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 <linux/atomic.h> #include <asm/mach/time.h> #include <asm/mach/irq.h> #include <mach/at91_pmc.h> #include <mach/cpu.h> #include "at91_aic.h" #include "generic.h" #include "pm.h" /* * Show the reason for the previous system reset. */ #include "at91_rstc.h" #include "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; if (!at91_shdwc_base || !at91_rstc_base) return; reset_type = at91_rstc_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP; wake_type = at91_shdwc_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); } 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_pmc_read(AT91_PMC_SCSR); /* USB must not be using PLLB */ if (cpu_is_at91rm9200()) { if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) { pr_err("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() || cpu_is_at91sam9g10()) { if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) { pr_err("AT91: PM - Suspend-to-RAM with USB still active\n"); return 0; } } if (!IS_ENABLED(CONFIG_AT91_PROGRAMMABLE_CLOCKS)) return 1; /* 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_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS; if (css != AT91_PMC_CSS_SLOW) { pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css); return 0; } } 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 __iomem *pmc, void __iomem *ramc0, void __iomem *ramc1, int memctrl); #ifdef CONFIG_AT91_SLOW_CLOCK extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0, void __iomem *ramc1, int memctrl); 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_pmc_read(AT91_PMC_PCSR) | (1 << AT91_ID_FIQ) | (1 << AT91_ID_SYS) | (at91_extern_irq)) & at91_aic_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) { int memctrl = AT91_MEMCTRL_SDRAMC; if (cpu_is_at91rm9200()) memctrl = AT91_MEMCTRL_MC; else if (cpu_is_at91sam9g45()) memctrl = AT91_MEMCTRL_DDRSDR; #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(at91_pmc_base, at91_ramc_base[0], at91_ramc_base[1], memctrl); 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. * For ARM 926 based chips, this requirement is weaker * as at91sam9 can access a RAM in self-refresh mode. */ if (cpu_is_at91rm9200()) at91rm9200_standby(); else if (cpu_is_at91sam9g45()) at91sam9g45_standby(); else at91sam9_standby(); break; case PM_SUSPEND_ON: cpu_do_idle(); break; default: pr_debug("AT91: PM - bogus suspend state %d\n", state); goto error; } pr_debug("AT91: PM - wakeup %08x\n", at91_aic_read(AT91_AIC_IPR) & at91_aic_read(AT91_AIC_IMR)); error: 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 const 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)" : "")); /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */ if (cpu_is_at91rm9200()) at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0); suspend_set_ops(&at91_pm_ops); show_reset_status(); return 0; } arch_initcall(at91_pm_init);