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>
24 #include <linux/atomic.h>
25 #include <asm/mach/time.h>
26 #include <asm/mach/irq.h>
28 #include <mach/at91_pmc.h>
35 * Show the reason for the previous system reset.
38 #include <mach/at91_rstc.h>
39 #include <mach/at91_shdwc.h>
41 static void __init show_reset_status(void)
43 static char reset[] __initdata = "reset";
45 static char general[] __initdata = "general";
46 static char wakeup[] __initdata = "wakeup";
47 static char watchdog[] __initdata = "watchdog";
48 static char software[] __initdata = "software";
49 static char user[] __initdata = "user";
50 static char unknown[] __initdata = "unknown";
52 static char signal[] __initdata = "signal";
53 static char rtc[] __initdata = "rtc";
54 static char rtt[] __initdata = "rtt";
55 static char restore[] __initdata = "power-restored";
57 char *reason, *r2 = reset;
58 u32 reset_type, wake_type;
60 if (!at91_shdwc_base || !at91_rstc_base)
63 reset_type = at91_rstc_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP;
64 wake_type = at91_shdwc_read(AT91_SHDW_SR);
67 case AT91_RSTC_RSTTYP_GENERAL:
70 case AT91_RSTC_RSTTYP_WAKEUP:
71 /* board-specific code enabled the wakeup sources */
75 if (wake_type & AT91_SHDW_WAKEUP0)
79 if (wake_type & AT91_SHDW_RTTWK) /* rtt wakeup */
81 else if (wake_type & AT91_SHDW_RTCWK) /* rtc wakeup */
83 else if (wake_type == 0) /* power-restored wakeup */
85 else /* unknown wakeup */
89 case AT91_RSTC_RSTTYP_WATCHDOG:
92 case AT91_RSTC_RSTTYP_SOFTWARE:
95 case AT91_RSTC_RSTTYP_USER:
102 pr_info("AT91: Starting after %s %s\n", reason, r2);
105 static int at91_pm_valid_state(suspend_state_t state)
109 case PM_SUSPEND_STANDBY:
119 static suspend_state_t target_state;
122 * Called after processes are frozen, but before we shutdown devices.
124 static int at91_pm_begin(suspend_state_t state)
126 target_state = state;
131 * Verify that all the clocks are correct before entering
134 static int at91_pm_verify_clocks(void)
139 scsr = at91_pmc_read(AT91_PMC_SCSR);
141 /* USB must not be using PLLB */
142 if (cpu_is_at91rm9200()) {
143 if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
144 pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
147 } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
148 || cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
149 if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
150 pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
155 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
156 /* PCK0..PCK3 must be disabled, or configured to use clk32k */
157 for (i = 0; i < 4; i++) {
160 if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
163 css = at91_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
164 if (css != AT91_PMC_CSS_SLOW) {
165 pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
175 * Call this from platform driver suspend() to see how deeply to suspend.
176 * For example, some controllers (like OHCI) need one of the PLL clocks
177 * in order to act as a wakeup source, and those are not available when
178 * going into slow clock mode.
180 * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have
181 * the very same problem (but not using at91 main_clk), and it'd be better
182 * to add one generic API rather than lots of platform-specific ones.
184 int at91_suspend_entering_slow_clock(void)
186 return (target_state == PM_SUSPEND_MEM);
188 EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
191 static void (*slow_clock)(void __iomem *pmc, void __iomem *ramc0,
192 void __iomem *ramc1, int memctrl);
194 #ifdef CONFIG_AT91_SLOW_CLOCK
195 extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0,
196 void __iomem *ramc1, int memctrl);
197 extern u32 at91_slow_clock_sz;
200 static int at91_pm_enter(suspend_state_t state)
205 pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
206 /* remember all the always-wake irqs */
207 (at91_pmc_read(AT91_PMC_PCSR)
211 & at91_aic_read(AT91_AIC_IMR),
216 * Suspend-to-RAM is like STANDBY plus slow clock mode, so
217 * drivers must suspend more deeply: only the master clock
218 * controller may be using the main oscillator.
222 * Ensure that clocks are in a valid state.
224 if (!at91_pm_verify_clocks())
228 * Enter slow clock mode by switching over to clk32k and
229 * turning off the main oscillator; reverse on wakeup.
232 int memctrl = AT91_MEMCTRL_SDRAMC;
234 if (cpu_is_at91rm9200())
235 memctrl = AT91_MEMCTRL_MC;
236 else if (cpu_is_at91sam9g45())
237 memctrl = AT91_MEMCTRL_DDRSDR;
238 #ifdef CONFIG_AT91_SLOW_CLOCK
239 /* copy slow_clock handler to SRAM, and call it */
240 memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
242 slow_clock(at91_pmc_base, at91_ramc_base[0],
243 at91_ramc_base[1], memctrl);
246 pr_info("AT91: PM - no slow clock mode enabled ...\n");
247 /* FALLTHROUGH leaving master clock alone */
251 * STANDBY mode has *all* drivers suspended; ignores irqs not
252 * marked as 'wakeup' event sources; and reduces DRAM power.
253 * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and
254 * nothing fancy done with main or cpu clocks.
256 case PM_SUSPEND_STANDBY:
258 * NOTE: the Wait-for-Interrupt instruction needs to be
259 * in icache so no SDRAM accesses are needed until the
260 * wakeup IRQ occurs and self-refresh is terminated.
261 * For ARM 926 based chips, this requirement is weaker
262 * as at91sam9 can access a RAM in self-refresh mode.
264 if (cpu_is_at91rm9200())
265 at91rm9200_standby();
266 else if (cpu_is_at91sam9g45())
267 at91sam9g45_standby();
277 pr_debug("AT91: PM - bogus suspend state %d\n", state);
281 pr_debug("AT91: PM - wakeup %08x\n",
282 at91_aic_read(AT91_AIC_IPR) & at91_aic_read(AT91_AIC_IMR));
285 target_state = PM_SUSPEND_ON;
292 * Called right prior to thawing processes.
294 static void at91_pm_end(void)
296 target_state = PM_SUSPEND_ON;
300 static const struct platform_suspend_ops at91_pm_ops = {
301 .valid = at91_pm_valid_state,
302 .begin = at91_pm_begin,
303 .enter = at91_pm_enter,
307 static int __init at91_pm_init(void)
309 #ifdef CONFIG_AT91_SLOW_CLOCK
310 slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
313 pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
315 /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
316 if (cpu_is_at91rm9200())
317 at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0);
319 suspend_set_ops(&at91_pm_ops);
324 arch_initcall(at91_pm_init);