2 * arch/arm/mach-at91/pm.c
3 * AT91 Power Management
5 * Copyright (C) 2005 David Brownell
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
13 #include <linux/gpio.h>
14 #include <linux/suspend.h>
15 #include <linux/sched.h>
16 #include <linux/proc_fs.h>
17 #include <linux/interrupt.h>
18 #include <linux/sysfs.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
22 #include <linux/clk/at91_pmc.h>
25 #include <linux/atomic.h>
26 #include <asm/mach/time.h>
27 #include <asm/mach/irq.h>
30 #include <mach/hardware.h>
37 static void (*at91_pm_standby)(void);
39 static int at91_pm_valid_state(suspend_state_t state)
43 case PM_SUSPEND_STANDBY:
53 static suspend_state_t target_state;
56 * Called after processes are frozen, but before we shutdown devices.
58 static int at91_pm_begin(suspend_state_t state)
65 * Verify that all the clocks are correct before entering
68 static int at91_pm_verify_clocks(void)
73 scsr = at91_pmc_read(AT91_PMC_SCSR);
75 /* USB must not be using PLLB */
76 if (cpu_is_at91rm9200()) {
77 if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
78 pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
81 } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
82 || cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
83 if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
84 pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
89 /* PCK0..PCK3 must be disabled, or configured to use clk32k */
90 for (i = 0; i < 4; i++) {
93 if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
96 css = at91_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
97 if (css != AT91_PMC_CSS_SLOW) {
98 pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
107 * Call this from platform driver suspend() to see how deeply to suspend.
108 * For example, some controllers (like OHCI) need one of the PLL clocks
109 * in order to act as a wakeup source, and those are not available when
110 * going into slow clock mode.
112 * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have
113 * the very same problem (but not using at91 main_clk), and it'd be better
114 * to add one generic API rather than lots of platform-specific ones.
116 int at91_suspend_entering_slow_clock(void)
118 return (target_state == PM_SUSPEND_MEM);
120 EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
123 static void (*slow_clock)(void __iomem *pmc, void __iomem *ramc0,
124 void __iomem *ramc1, int memctrl);
126 #ifdef CONFIG_AT91_SLOW_CLOCK
127 extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0,
128 void __iomem *ramc1, int memctrl);
129 extern u32 at91_slow_clock_sz;
132 static int at91_pm_enter(suspend_state_t state)
134 if (of_have_populated_dt())
135 at91_pinctrl_gpio_suspend();
139 if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base) {
142 pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
143 /* remember all the always-wake irqs */
144 (at91_pmc_read(AT91_PMC_PCSR)
147 | (at91_get_extern_irq()))
148 & at91_aic_read(AT91_AIC_IMR),
154 * Suspend-to-RAM is like STANDBY plus slow clock mode, so
155 * drivers must suspend more deeply: only the master clock
156 * controller may be using the main oscillator.
160 * Ensure that clocks are in a valid state.
162 if (!at91_pm_verify_clocks())
166 * Enter slow clock mode by switching over to clk32k and
167 * turning off the main oscillator; reverse on wakeup.
170 int memctrl = AT91_MEMCTRL_SDRAMC;
172 if (cpu_is_at91rm9200())
173 memctrl = AT91_MEMCTRL_MC;
174 else if (cpu_is_at91sam9g45())
175 memctrl = AT91_MEMCTRL_DDRSDR;
176 #ifdef CONFIG_AT91_SLOW_CLOCK
177 /* copy slow_clock handler to SRAM, and call it */
178 memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
180 slow_clock(at91_pmc_base, at91_ramc_base[0],
181 at91_ramc_base[1], memctrl);
184 pr_info("AT91: PM - no slow clock mode enabled ...\n");
185 /* FALLTHROUGH leaving master clock alone */
189 * STANDBY mode has *all* drivers suspended; ignores irqs not
190 * marked as 'wakeup' event sources; and reduces DRAM power.
191 * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
192 * nothing fancy done with main or cpu clocks.
194 case PM_SUSPEND_STANDBY:
196 * NOTE: the Wait-for-Interrupt instruction needs to be
197 * in icache so no SDRAM accesses are needed until the
198 * wakeup IRQ occurs and self-refresh is terminated.
199 * For ARM 926 based chips, this requirement is weaker
200 * as at91sam9 can access a RAM in self-refresh mode.
211 pr_debug("AT91: PM - bogus suspend state %d\n", state);
215 if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base)
216 pr_debug("AT91: PM - wakeup %08x\n",
217 at91_aic_read(AT91_AIC_IPR) &
218 at91_aic_read(AT91_AIC_IMR));
221 target_state = PM_SUSPEND_ON;
223 if (IS_ENABLED(CONFIG_OLD_IRQ_AT91) && at91_aic_base)
226 if (of_have_populated_dt())
227 at91_pinctrl_gpio_resume();
234 * Called right prior to thawing processes.
236 static void at91_pm_end(void)
238 target_state = PM_SUSPEND_ON;
242 static const struct platform_suspend_ops at91_pm_ops = {
243 .valid = at91_pm_valid_state,
244 .begin = at91_pm_begin,
245 .enter = at91_pm_enter,
249 static struct platform_device at91_cpuidle_device = {
250 .name = "cpuidle-at91",
253 void at91_pm_set_standby(void (*at91_standby)(void))
256 at91_cpuidle_device.dev.platform_data = at91_standby;
257 at91_pm_standby = at91_standby;
261 static int __init at91_pm_init(void)
263 #ifdef CONFIG_AT91_SLOW_CLOCK
264 slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
267 pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
269 /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
270 if (cpu_is_at91rm9200())
271 at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0);
273 if (at91_cpuidle_device.dev.platform_data)
274 platform_device_register(&at91_cpuidle_device);
276 suspend_set_ops(&at91_pm_ops);
280 arch_initcall(at91_pm_init);