280 lines
6.8 KiB
C
280 lines
6.8 KiB
C
/*
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* arch/arm/mach-at91/pm.c
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* AT91 Power Management
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*
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* Copyright (C) 2005 David Brownell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/gpio.h>
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#include <linux/suspend.h>
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#include <linux/sched.h>
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#include <linux/proc_fs.h>
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#include <linux/interrupt.h>
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#include <linux/sysfs.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/clk/at91_pmc.h>
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#include <asm/irq.h>
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#include <linux/atomic.h>
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#include <asm/mach/time.h>
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#include <asm/mach/irq.h>
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#include <mach/cpu.h>
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#include <mach/hardware.h>
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#include "at91_aic.h"
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#include "generic.h"
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#include "pm.h"
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#include "gpio.h"
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static void (*at91_pm_standby)(void);
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static int at91_pm_valid_state(suspend_state_t state)
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{
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switch (state) {
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case PM_SUSPEND_ON:
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case PM_SUSPEND_STANDBY:
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case PM_SUSPEND_MEM:
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return 1;
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default:
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return 0;
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}
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}
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static suspend_state_t target_state;
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/*
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* Called after processes are frozen, but before we shutdown devices.
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*/
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static int at91_pm_begin(suspend_state_t state)
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{
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target_state = state;
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return 0;
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}
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/*
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* Verify that all the clocks are correct before entering
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* slow-clock mode.
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*/
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static int at91_pm_verify_clocks(void)
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{
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unsigned long scsr;
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int i;
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scsr = at91_pmc_read(AT91_PMC_SCSR);
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/* USB must not be using PLLB */
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if (cpu_is_at91rm9200()) {
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if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
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pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
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return 0;
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}
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} else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
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|| cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
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if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
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pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
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return 0;
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}
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}
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/* PCK0..PCK3 must be disabled, or configured to use clk32k */
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for (i = 0; i < 4; i++) {
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u32 css;
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if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
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continue;
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css = at91_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
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if (css != AT91_PMC_CSS_SLOW) {
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pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
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return 0;
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}
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}
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return 1;
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}
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/*
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* Call this from platform driver suspend() to see how deeply to suspend.
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* For example, some controllers (like OHCI) need one of the PLL clocks
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* in order to act as a wakeup source, and those are not available when
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* going into slow clock mode.
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*
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* REVISIT: generalize as clk_will_be_available(clk)? Other platforms have
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* the very same problem (but not using at91 main_clk), and it'd be better
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* to add one generic API rather than lots of platform-specific ones.
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*/
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int at91_suspend_entering_slow_clock(void)
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{
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return (target_state == PM_SUSPEND_MEM);
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}
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EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
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static void (*slow_clock)(void __iomem *pmc, void __iomem *ramc0,
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void __iomem *ramc1, int memctrl);
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#ifdef CONFIG_AT91_SLOW_CLOCK
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extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0,
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void __iomem *ramc1, int memctrl);
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extern u32 at91_slow_clock_sz;
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#endif
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static int at91_pm_enter(suspend_state_t state)
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{
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if (of_have_populated_dt())
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at91_pinctrl_gpio_suspend();
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else
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at91_gpio_suspend();
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if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base) {
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at91_irq_suspend();
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pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
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/* remember all the always-wake irqs */
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(at91_pmc_read(AT91_PMC_PCSR)
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| (1 << AT91_ID_FIQ)
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| (1 << AT91_ID_SYS)
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| (at91_get_extern_irq()))
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& at91_aic_read(AT91_AIC_IMR),
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state);
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}
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switch (state) {
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/*
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* Suspend-to-RAM is like STANDBY plus slow clock mode, so
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* drivers must suspend more deeply: only the master clock
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* controller may be using the main oscillator.
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*/
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case PM_SUSPEND_MEM:
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/*
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* Ensure that clocks are in a valid state.
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*/
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if (!at91_pm_verify_clocks())
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goto error;
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/*
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* Enter slow clock mode by switching over to clk32k and
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* turning off the main oscillator; reverse on wakeup.
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*/
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if (slow_clock) {
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int memctrl = AT91_MEMCTRL_SDRAMC;
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if (cpu_is_at91rm9200())
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memctrl = AT91_MEMCTRL_MC;
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else if (cpu_is_at91sam9g45())
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memctrl = AT91_MEMCTRL_DDRSDR;
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#ifdef CONFIG_AT91_SLOW_CLOCK
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/* copy slow_clock handler to SRAM, and call it */
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memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
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#endif
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slow_clock(at91_pmc_base, at91_ramc_base[0],
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at91_ramc_base[1], memctrl);
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break;
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} else {
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pr_info("AT91: PM - no slow clock mode enabled ...\n");
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/* FALLTHROUGH leaving master clock alone */
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}
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/*
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* STANDBY mode has *all* drivers suspended; ignores irqs not
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* marked as 'wakeup' event sources; and reduces DRAM power.
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* But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
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* nothing fancy done with main or cpu clocks.
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*/
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case PM_SUSPEND_STANDBY:
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/*
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* NOTE: the Wait-for-Interrupt instruction needs to be
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* in icache so no SDRAM accesses are needed until the
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* wakeup IRQ occurs and self-refresh is terminated.
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* For ARM 926 based chips, this requirement is weaker
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* as at91sam9 can access a RAM in self-refresh mode.
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*/
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if (at91_pm_standby)
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at91_pm_standby();
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break;
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case PM_SUSPEND_ON:
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cpu_do_idle();
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break;
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default:
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pr_debug("AT91: PM - bogus suspend state %d\n", state);
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goto error;
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}
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if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base)
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pr_debug("AT91: PM - wakeup %08x\n",
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at91_aic_read(AT91_AIC_IPR) &
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at91_aic_read(AT91_AIC_IMR));
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error:
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target_state = PM_SUSPEND_ON;
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if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base)
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at91_irq_resume();
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if (of_have_populated_dt())
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at91_pinctrl_gpio_resume();
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else
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at91_gpio_resume();
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return 0;
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}
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/*
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* Called right prior to thawing processes.
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*/
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static void at91_pm_end(void)
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{
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target_state = PM_SUSPEND_ON;
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}
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static const struct platform_suspend_ops at91_pm_ops = {
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.valid = at91_pm_valid_state,
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.begin = at91_pm_begin,
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.enter = at91_pm_enter,
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.end = at91_pm_end,
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};
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static struct platform_device at91_cpuidle_device = {
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.name = "cpuidle-at91",
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};
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void at91_pm_set_standby(void (*at91_standby)(void))
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{
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if (at91_standby) {
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at91_cpuidle_device.dev.platform_data = at91_standby;
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at91_pm_standby = at91_standby;
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}
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}
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static int __init at91_pm_init(void)
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{
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#ifdef CONFIG_AT91_SLOW_CLOCK
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slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
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#endif
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pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
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/* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
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if (cpu_is_at91rm9200())
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at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0);
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if (at91_cpuidle_device.dev.platform_data)
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platform_device_register(&at91_cpuidle_device);
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suspend_set_ops(&at91_pm_ops);
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return 0;
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}
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arch_initcall(at91_pm_init);
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