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/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>
  21 #include <linux/io.h>
  22 #include <linux/clk/at91_pmc.h>
  23
  24 #include <asm/irq.h>
  25 #include <linux/atomic.h>
  26 #include <asm/mach/time.h>
  27 #include <asm/mach/irq.h>
  28
  29 #include <mach/cpu.h>
  30 #include <mach/hardware.h>
  31
  32 #include "at91_aic.h"
  33 #include "generic.h"
  34 #include "pm.h"
  35 #include "gpio.h"
  36
  37 /*
  38  * Show the reason for the previous system reset.
  39  */
  40
  41 #include "at91_rstc.h"
  42 #include "at91_shdwc.h"
  43
  44 static void (*at91_pm_standby)(void);
  45
  46 static void __init show_reset_status(void)
  47 {
  48         static char reset[] __initdata = "reset";
  49
  50         static char general[] __initdata = "general";
  51         static char wakeup[] __initdata = "wakeup";
  52         static char watchdog[] __initdata = "watchdog";
  53         static char software[] __initdata = "software";
  54         static char user[] __initdata = "user";
  55         static char unknown[] __initdata = "unknown";
  56
  57         static char signal[] __initdata = "signal";
  58         static char rtc[] __initdata = "rtc";
  59         static char rtt[] __initdata = "rtt";
  60         static char restore[] __initdata = "power-restored";
  61
  62         char *reason, *r2 = reset;
  63         u32 reset_type, wake_type;
  64
  65         if (!at91_shdwc_base || !at91_rstc_base)
  66                 return;
  67
  68         reset_type = at91_rstc_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP;
  69         wake_type = at91_shdwc_read(AT91_SHDW_SR);
  70
  71         switch (reset_type) {
  72         case AT91_RSTC_RSTTYP_GENERAL:
  73                 reason = general;
  74                 break;
  75         case AT91_RSTC_RSTTYP_WAKEUP:
  76                 /* board-specific code enabled the wakeup sources */
  77                 reason = wakeup;
  78
  79                 /* "wakeup signal" */
  80                 if (wake_type & AT91_SHDW_WAKEUP0)
  81                         r2 = signal;
  82                 else {
  83                         r2 = reason;
  84                         if (wake_type & AT91_SHDW_RTTWK)        /* rtt wakeup */
  85                                 reason = rtt;
  86                         else if (wake_type & AT91_SHDW_RTCWK)   /* rtc wakeup */
  87                                 reason = rtc;
  88                         else if (wake_type == 0)        /* power-restored wakeup */
  89                                 reason = restore;
  90                         else                            /* unknown wakeup */
  91                                 reason = unknown;
  92                 }
  93                 break;
  94         case AT91_RSTC_RSTTYP_WATCHDOG:
  95                 reason = watchdog;
  96                 break;
  97         case AT91_RSTC_RSTTYP_SOFTWARE:
  98                 reason = software;
  99                 break;
 100         case AT91_RSTC_RSTTYP_USER:
 101                 reason = user;
 102                 break;
 103         default:
 104                 reason = unknown;
 105                 break;
 106         }
 107         pr_info("AT91: Starting after %s %s\n", reason, r2);
 108 }
 109
 110 static int at91_pm_valid_state(suspend_state_t state)
 111 {
 112         switch (state) {
 113                 case PM_SUSPEND_ON:
 114                 case PM_SUSPEND_STANDBY:
 115                 case PM_SUSPEND_MEM:
 116                         return 1;
 117
 118                 default:
 119                         return 0;
 120         }
 121 }
 122
 123
 124 static suspend_state_t target_state;
 125
 126 /*
 127  * Called after processes are frozen, but before we shutdown devices.
 128  */
 129 static int at91_pm_begin(suspend_state_t state)
 130 {
 131         target_state = state;
 132         return 0;
 133 }
 134
 135 /*
 136  * Verify that all the clocks are correct before entering
 137  * slow-clock mode.
 138  */
 139 static int at91_pm_verify_clocks(void)
 140 {
 141         unsigned long scsr;
 142         int i;
 143
 144         scsr = at91_pmc_read(AT91_PMC_SCSR);
 145
 146         /* USB must not be using PLLB */
 147         if (cpu_is_at91rm9200()) {
 148                 if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
 149                         pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
 150                         return 0;
 151                 }
 152         } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
 153                         || cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
 154                 if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
 155                         pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
 156                         return 0;
 157                 }
 158         }
 159
 160         /* PCK0..PCK3 must be disabled, or configured to use clk32k */
 161         for (i = 0; i < 4; i++) {
 162                 u32 css;
 163
 164                 if ((scsr & (AT91_PMC_PCK0 << i)) == 0)
 165                         continue;
 166
 167                 css = at91_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS;
 168                 if (css != AT91_PMC_CSS_SLOW) {
 169                         pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css);
 170                         return 0;
 171                 }
 172         }
 173
 174         return 1;
 175 }
 176
 177 /*
 178  * Call this from platform driver suspend() to see how deeply to suspend.
 179  * For example, some controllers (like OHCI) need one of the PLL clocks
 180  * in order to act as a wakeup source, and those are not available when
 181  * going into slow clock mode.
 182  *
 183  * REVISIT: generalize as clk_will_be_available(clk)?  Other platforms have
 184  * the very same problem (but not using at91 main_clk), and it'd be better
 185  * to add one generic API rather than lots of platform-specific ones.
 186  */
 187 int at91_suspend_entering_slow_clock(void)
 188 {
 189         return (target_state == PM_SUSPEND_MEM);
 190 }
 191 EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
 192
 193
 194 static void (*slow_clock)(void __iomem *pmc, void __iomem *ramc0,
 195                           void __iomem *ramc1, int memctrl);
 196
 197 #ifdef CONFIG_AT91_SLOW_CLOCK
 198 extern void at91_slow_clock(void __iomem *pmc, void __iomem *ramc0,
 199                             void __iomem *ramc1, int memctrl);
 200 extern u32 at91_slow_clock_sz;
 201 #endif
 202
 203 static int at91_pm_enter(suspend_state_t state)
 204 {
 205         if (of_have_populated_dt())
 206                 at91_pinctrl_gpio_suspend();
 207         else
 208                 at91_gpio_suspend();
 209         at91_irq_suspend();
 210
 211         pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
 212                         /* remember all the always-wake irqs */
 213                         (at91_pmc_read(AT91_PMC_PCSR)
 214                                         | (1 << AT91_ID_FIQ)
 215                                         | (1 << AT91_ID_SYS)
 216                                         | (at91_get_extern_irq()))
 217                                 & at91_aic_read(AT91_AIC_IMR),
 218                         state);
 219
 220         switch (state) {
 221                 /*
 222                  * Suspend-to-RAM is like STANDBY plus slow clock mode, so
 223                  * drivers must suspend more deeply:  only the master clock
 224                  * controller may be using the main oscillator.
 225                  */
 226                 case PM_SUSPEND_MEM:
 227                         /*
 228                          * Ensure that clocks are in a valid state.
 229                          */
 230                         if (!at91_pm_verify_clocks())
 231                                 goto error;
 232
 233                         /*
 234                          * Enter slow clock mode by switching over to clk32k and
 235                          * turning off the main oscillator; reverse on wakeup.
 236                          */
 237                         if (slow_clock) {
 238                                 int memctrl = AT91_MEMCTRL_SDRAMC;
 239
 240                                 if (cpu_is_at91rm9200())
 241                                         memctrl = AT91_MEMCTRL_MC;
 242                                 else if (cpu_is_at91sam9g45())
 243                                         memctrl = AT91_MEMCTRL_DDRSDR;
 244 #ifdef CONFIG_AT91_SLOW_CLOCK
 245                                 /* copy slow_clock handler to SRAM, and call it */
 246                                 memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
 247 #endif
 248                                 slow_clock(at91_pmc_base, at91_ramc_base[0],
 249                                            at91_ramc_base[1], memctrl);
 250                                 break;
 251                         } else {
 252                                 pr_info("AT91: PM - no slow clock mode enabled ...\n");
 253                                 /* FALLTHROUGH leaving master clock alone */
 254                         }
 255
 256                 /*
 257                  * STANDBY mode has *all* drivers suspended; ignores irqs not
 258                  * marked as 'wakeup' event sources; and reduces DRAM power.
 259                  * But otherwise it's identical to PM_SUSPEND_ON:  cpu idle, and
 260                  * nothing fancy done with main or cpu clocks.
 261                  */
 262                 case PM_SUSPEND_STANDBY:
 263                         /*
 264                          * NOTE: the Wait-for-Interrupt instruction needs to be
 265                          * in icache so no SDRAM accesses are needed until the
 266                          * wakeup IRQ occurs and self-refresh is terminated.
 267                          * For ARM 926 based chips, this requirement is weaker
 268                          * as at91sam9 can access a RAM in self-refresh mode.
 269                          */
 270                         if (at91_pm_standby)
 271                                 at91_pm_standby();
 272                         break;
 273
 274                 case PM_SUSPEND_ON:
 275                         cpu_do_idle();
 276                         break;
 277
 278                 default:
 279                         pr_debug("AT91: PM - bogus suspend state %d\n", state);
 280                         goto error;
 281         }
 282
 283         pr_debug("AT91: PM - wakeup %08x\n",
 284                         at91_aic_read(AT91_AIC_IPR) & at91_aic_read(AT91_AIC_IMR));
 285
 286 error:
 287         target_state = PM_SUSPEND_ON;
 288         at91_irq_resume();
 289         if (of_have_populated_dt())
 290                 at91_pinctrl_gpio_resume();
 291         else
 292                 at91_gpio_resume();
 293         return 0;
 294 }
 295
 296 /*
 297  * Called right prior to thawing processes.
 298  */
 299 static void at91_pm_end(void)
 300 {
 301         target_state = PM_SUSPEND_ON;
 302 }
 303
 304
 305 static const struct platform_suspend_ops at91_pm_ops = {
 306         .valid  = at91_pm_valid_state,
 307         .begin  = at91_pm_begin,
 308         .enter  = at91_pm_enter,
 309         .end    = at91_pm_end,
 310 };
 311
 312 static struct platform_device at91_cpuidle_device = {
 313         .name = "cpuidle-at91",
 314 };
 315
 316 void at91_pm_set_standby(void (*at91_standby)(void))
 317 {
 318         if (at91_standby) {
 319                 at91_cpuidle_device.dev.platform_data = at91_standby;
 320                 at91_pm_standby = at91_standby;
 321         }
 322 }
 323
 324 static int __init at91_pm_init(void)
 325 {
 326 #ifdef CONFIG_AT91_SLOW_CLOCK
 327         slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
 328 #endif
 329
 330         pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
 331
 332         /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
 333         if (cpu_is_at91rm9200())
 334                 at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0);
 335
 336         if (at91_cpuidle_device.dev.platform_data)
 337                 platform_device_register(&at91_cpuidle_device);
 338
 339         suspend_set_ops(&at91_pm_ops);
 340
 341         show_reset_status();
 342         return 0;
 343 }
 344 arch_initcall(at91_pm_init);