aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-at91/pm.c
blob: a5cfe866c9ddf2915f12d50c6eccb814b961fb29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
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 <asm/io.h>
#include <asm/irq.h>
#include <asm/atomic.h>
#include <asm/mach/time.h>
#include <asm/mach/irq.h>

#include <asm/arch/at91_pmc.h>
#include <asm/arch/gpio.h>
#include <asm/arch/cpu.h>

#include "generic.h"

#ifdef CONFIG_ARCH_AT91RM9200
#include <asm/arch/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 <asm/arch/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 <asm/arch/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 <asm/arch/at91_rstc.h>
#include <asm/arch/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);