atomic: use <linux/atomic.h>
[linux-2.6.git] / arch / arm / mach-at91 / pm.c
1 /*
2  * arch/arm/mach-at91/pm.c
3  * AT91 Power Management
4  *
5  * Copyright (C) 2005 David Brownell
6  *
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.
11  */
12
13 #include <linux/suspend.h>
14 #include <linux/sched.h>
15 #include <linux/proc_fs.h>
16 #include <linux/interrupt.h>
17 #include <linux/sysfs.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/io.h>
21
22 #include <asm/irq.h>
23 #include <linux/atomic.h>
24 #include <asm/mach/time.h>
25 #include <asm/mach/irq.h>
26
27 #include <mach/at91_pmc.h>
28 #include <mach/gpio.h>
29 #include <mach/cpu.h>
30
31 #include "generic.h"
32 #include "pm.h"
33
34 /*
35  * Show the reason for the previous system reset.
36  */
37 #if defined(AT91_SHDWC)
38
39 #include <mach/at91_rstc.h>
40 #include <mach/at91_shdwc.h>
41
42 static void __init show_reset_status(void)
43 {
44         static char reset[] __initdata = "reset";
45
46         static char general[] __initdata = "general";
47         static char wakeup[] __initdata = "wakeup";
48         static char watchdog[] __initdata = "watchdog";
49         static char software[] __initdata = "software";
50         static char user[] __initdata = "user";
51         static char unknown[] __initdata = "unknown";
52
53         static char signal[] __initdata = "signal";
54         static char rtc[] __initdata = "rtc";
55         static char rtt[] __initdata = "rtt";
56         static char restore[] __initdata = "power-restored";
57
58         char *reason, *r2 = reset;
59         u32 reset_type, wake_type;
60
61         reset_type = at91_sys_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP;
62         wake_type = at91_sys_read(AT91_SHDW_SR);
63
64         switch (reset_type) {
65         case AT91_RSTC_RSTTYP_GENERAL:
66                 reason = general;
67                 break;
68         case AT91_RSTC_RSTTYP_WAKEUP:
69                 /* board-specific code enabled the wakeup sources */
70                 reason = wakeup;
71
72                 /* "wakeup signal" */
73                 if (wake_type & AT91_SHDW_WAKEUP0)
74                         r2 = signal;
75                 else {
76                         r2 = reason;
77                         if (wake_type & AT91_SHDW_RTTWK)        /* rtt wakeup */
78                                 reason = rtt;
79                         else if (wake_type & AT91_SHDW_RTCWK)   /* rtc wakeup */
80                                 reason = rtc;
81                         else if (wake_type == 0)        /* power-restored wakeup */
82                                 reason = restore;
83                         else                            /* unknown wakeup */
84                                 reason = unknown;
85                 }
86                 break;
87         case AT91_RSTC_RSTTYP_WATCHDOG:
88                 reason = watchdog;
89                 break;
90         case AT91_RSTC_RSTTYP_SOFTWARE:
91                 reason = software;
92                 break;
93         case AT91_RSTC_RSTTYP_USER:
94                 reason = user;
95                 break;
96         default:
97                 reason = unknown;
98                 break;
99         }
100         pr_info("AT91: Starting after %s %s\n", reason, r2);
101 }
102 #else
103 static void __init show_reset_status(void) {}
104 #endif
105
106
107 static int at91_pm_valid_state(suspend_state_t state)
108 {
109         switch (state) {
110                 case PM_SUSPEND_ON:
111                 case PM_SUSPEND_STANDBY:
112                 case PM_SUSPEND_MEM:
113                         return 1;
114
115                 default:
116                         return 0;
117         }
118 }
119
120
121 static suspend_state_t target_state;
122
123 /*
124  * Called after processes are frozen, but before we shutdown devices.
125  */
126 static int at91_pm_begin(suspend_state_t state)
127 {
128         target_state = state;
129         return 0;
130 }
131
132 /*
133  * Verify that all the clocks are correct before entering
134  * slow-clock mode.
135  */
136 static int at91_pm_verify_clocks(void)
137 {
138         unsigned long scsr;
139         int i;
140
141         scsr = at91_sys_read(AT91_PMC_SCSR);
142
143         /* USB must not be using PLLB */
144         if (cpu_is_at91rm9200()) {
145                 if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
146                         pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
147                         return 0;
148                 }
149         } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
150                         || cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
151                 if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
152                         pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
153                         return 0;
154                 }
155         } else if (cpu_is_at91cap9()) {
156                 if ((scsr & AT91CAP9_PMC_UHP) != 0) {
157                         pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
158                         return 0;
159                 }
160         }
161
162 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
163         /* PCK0..PCK3 must be disabled, or configured to use clk32k */
164         for (i = 0; i < 4; i++) {
165                 u32 css;
166
167                 if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
168                         continue;
169
170                 css = at91_sys_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
171                 if (css != AT91_PMC_CSS_SLOW) {
172                         pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
173                         return 0;
174                 }
175         }
176 #endif
177
178         return 1;
179 }
180
181 /*
182  * Call this from platform driver suspend() to see how deeply to suspend.
183  * For example, some controllers (like OHCI) need one of the PLL clocks
184  * in order to act as a wakeup source, and those are not available when
185  * going into slow clock mode.
186  *
187  * REVISIT: generalize as clk_will_be_available(clk)?  Other platforms have
188  * the very same problem (but not using at91 main_clk), and it'd be better
189  * to add one generic API rather than lots of platform-specific ones.
190  */
191 int at91_suspend_entering_slow_clock(void)
192 {
193         return (target_state == PM_SUSPEND_MEM);
194 }
195 EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
196
197
198 static void (*slow_clock)(void);
199
200 #ifdef CONFIG_AT91_SLOW_CLOCK
201 extern void at91_slow_clock(void);
202 extern u32 at91_slow_clock_sz;
203 #endif
204
205
206 static int at91_pm_enter(suspend_state_t state)
207 {
208         u32 saved_lpr;
209         at91_gpio_suspend();
210         at91_irq_suspend();
211
212         pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
213                         /* remember all the always-wake irqs */
214                         (at91_sys_read(AT91_PMC_PCSR)
215                                         | (1 << AT91_ID_FIQ)
216                                         | (1 << AT91_ID_SYS)
217                                         | (at91_extern_irq))
218                                 & at91_sys_read(AT91_AIC_IMR),
219                         state);
220
221         switch (state) {
222                 /*
223                  * Suspend-to-RAM is like STANDBY plus slow clock mode, so
224                  * drivers must suspend more deeply:  only the master clock
225                  * controller may be using the main oscillator.
226                  */
227                 case PM_SUSPEND_MEM:
228                         /*
229                          * Ensure that clocks are in a valid state.
230                          */
231                         if (!at91_pm_verify_clocks())
232                                 goto error;
233
234                         /*
235                          * Enter slow clock mode by switching over to clk32k and
236                          * turning off the main oscillator; reverse on wakeup.
237                          */
238                         if (slow_clock) {
239 #ifdef CONFIG_AT91_SLOW_CLOCK
240                                 /* copy slow_clock handler to SRAM, and call it */
241                                 memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
242 #endif
243                                 slow_clock();
244                                 break;
245                         } else {
246                                 pr_info("AT91: PM - no slow clock mode enabled ...\n");
247                                 /* FALLTHROUGH leaving master clock alone */
248                         }
249
250                 /*
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.
255                  */
256                 case PM_SUSPEND_STANDBY:
257                         /*
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.
263                          */
264                         asm volatile (  "mov r0, #0\n\t"
265                                         "b 1f\n\t"
266                                         ".align 5\n\t"
267                                         "1: mcr p15, 0, r0, c7, c10, 4\n\t"
268                                         : /* no output */
269                                         : /* no input */
270                                         : "r0");
271                         saved_lpr = sdram_selfrefresh_enable();
272                         wait_for_interrupt_enable();
273                         sdram_selfrefresh_disable(saved_lpr);
274                         break;
275
276                 case PM_SUSPEND_ON:
277                         cpu_do_idle();
278                         break;
279
280                 default:
281                         pr_debug("AT91: PM - bogus suspend state %d\n", state);
282                         goto error;
283         }
284
285         pr_debug("AT91: PM - wakeup %08x\n",
286                         at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR));
287
288 error:
289         target_state = PM_SUSPEND_ON;
290         at91_irq_resume();
291         at91_gpio_resume();
292         return 0;
293 }
294
295 /*
296  * Called right prior to thawing processes.
297  */
298 static void at91_pm_end(void)
299 {
300         target_state = PM_SUSPEND_ON;
301 }
302
303
304 static const struct platform_suspend_ops at91_pm_ops = {
305         .valid  = at91_pm_valid_state,
306         .begin  = at91_pm_begin,
307         .enter  = at91_pm_enter,
308         .end    = at91_pm_end,
309 };
310
311 static int __init at91_pm_init(void)
312 {
313 #ifdef CONFIG_AT91_SLOW_CLOCK
314         slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
315 #endif
316
317         pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
318
319 #ifdef CONFIG_ARCH_AT91RM9200
320         /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
321         at91_sys_write(AT91_SDRAMC_LPR, 0);
322 #endif
323
324         suspend_set_ops(&at91_pm_ops);
325
326         show_reset_status();
327         return 0;
328 }
329 arch_initcall(at91_pm_init);