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 21 #include <asm/io.h> 22 #include <asm/irq.h> 23 #include <asm/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 33 #ifdef CONFIG_ARCH_AT91RM9200 34 #include <mach/at91rm9200_mc.h> 35 36 /* 37 * The AT91RM9200 goes into self-refresh mode with this command, and will 38 * terminate self-refresh automatically on the next SDRAM access. 39 */ 40 #define sdram_selfrefresh_enable() at91_sys_write(AT91_SDRAMC_SRR, 1) 41 #define sdram_selfrefresh_disable() do {} while (0) 42 43 #elif defined(CONFIG_ARCH_AT91CAP9) 44 #include <mach/at91cap9_ddrsdr.h> 45 46 static u32 saved_lpr; 47 48 static inline void sdram_selfrefresh_enable(void) 49 { 50 u32 lpr; 51 52 saved_lpr = at91_sys_read(AT91_DDRSDRC_LPR); 53 54 lpr = saved_lpr & ~AT91_DDRSDRC_LPCB; 55 at91_sys_write(AT91_DDRSDRC_LPR, lpr | AT91_DDRSDRC_LPCB_SELF_REFRESH); 56 } 57 58 #define sdram_selfrefresh_disable() at91_sys_write(AT91_DDRSDRC_LPR, saved_lpr) 59 60 #else 61 #include <mach/at91sam9_sdramc.h> 62 63 #ifdef CONFIG_ARCH_AT91SAM9263 64 /* 65 * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use; 66 * handle those cases both here and in the Suspend-To-RAM support. 67 */ 68 #define AT91_SDRAMC AT91_SDRAMC0 69 #warning Assuming EB1 SDRAM controller is *NOT* used 70 #endif 71 72 static u32 saved_lpr; 73 74 static inline void sdram_selfrefresh_enable(void) 75 { 76 u32 lpr; 77 78 saved_lpr = at91_sys_read(AT91_SDRAMC_LPR); 79 80 lpr = saved_lpr & ~AT91_SDRAMC_LPCB; 81 at91_sys_write(AT91_SDRAMC_LPR, lpr | AT91_SDRAMC_LPCB_SELF_REFRESH); 82 } 83 84 #define sdram_selfrefresh_disable() at91_sys_write(AT91_SDRAMC_LPR, saved_lpr) 85 86 #endif 87 88 89 /* 90 * Show the reason for the previous system reset. 91 */ 92 #if defined(AT91_SHDWC) 93 94 #include <mach/at91_rstc.h> 95 #include <mach/at91_shdwc.h> 96 97 static void __init show_reset_status(void) 98 { 99 static char reset[] __initdata = "reset"; 100 101 static char general[] __initdata = "general"; 102 static char wakeup[] __initdata = "wakeup"; 103 static char watchdog[] __initdata = "watchdog"; 104 static char software[] __initdata = "software"; 105 static char user[] __initdata = "user"; 106 static char unknown[] __initdata = "unknown"; 107 108 static char signal[] __initdata = "signal"; 109 static char rtc[] __initdata = "rtc"; 110 static char rtt[] __initdata = "rtt"; 111 static char restore[] __initdata = "power-restored"; 112 113 char *reason, *r2 = reset; 114 u32 reset_type, wake_type; 115 116 reset_type = at91_sys_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP; 117 wake_type = at91_sys_read(AT91_SHDW_SR); 118 119 switch (reset_type) { 120 case AT91_RSTC_RSTTYP_GENERAL: 121 reason = general; 122 break; 123 case AT91_RSTC_RSTTYP_WAKEUP: 124 /* board-specific code enabled the wakeup sources */ 125 reason = wakeup; 126 127 /* "wakeup signal" */ 128 if (wake_type & AT91_SHDW_WAKEUP0) 129 r2 = signal; 130 else { 131 r2 = reason; 132 if (wake_type & AT91_SHDW_RTTWK) /* rtt wakeup */ 133 reason = rtt; 134 else if (wake_type & AT91_SHDW_RTCWK) /* rtc wakeup */ 135 reason = rtc; 136 else if (wake_type == 0) /* power-restored wakeup */ 137 reason = restore; 138 else /* unknown wakeup */ 139 reason = unknown; 140 } 141 break; 142 case AT91_RSTC_RSTTYP_WATCHDOG: 143 reason = watchdog; 144 break; 145 case AT91_RSTC_RSTTYP_SOFTWARE: 146 reason = software; 147 break; 148 case AT91_RSTC_RSTTYP_USER: 149 reason = user; 150 break; 151 default: 152 reason = unknown; 153 break; 154 } 155 pr_info("AT91: Starting after %s %s\n", reason, r2); 156 } 157 #else 158 static void __init show_reset_status(void) {} 159 #endif 160 161 162 static int at91_pm_valid_state(suspend_state_t state) 163 { 164 switch (state) { 165 case PM_SUSPEND_ON: 166 case PM_SUSPEND_STANDBY: 167 case PM_SUSPEND_MEM: 168 return 1; 169 170 default: 171 return 0; 172 } 173 } 174 175 176 static suspend_state_t target_state; 177 178 /* 179 * Called after processes are frozen, but before we shutdown devices. 180 */ 181 static int at91_pm_begin(suspend_state_t state) 182 { 183 target_state = state; 184 return 0; 185 } 186 187 /* 188 * Verify that all the clocks are correct before entering 189 * slow-clock mode. 190 */ 191 static int at91_pm_verify_clocks(void) 192 { 193 unsigned long scsr; 194 int i; 195 196 scsr = at91_sys_read(AT91_PMC_SCSR); 197 198 /* USB must not be using PLLB */ 199 if (cpu_is_at91rm9200()) { 200 if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) { 201 pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n"); 202 return 0; 203 } 204 } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263() || cpu_is_at91sam9g20()) { 205 if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) { 206 pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n"); 207 return 0; 208 } 209 } else if (cpu_is_at91cap9()) { 210 if ((scsr & AT91CAP9_PMC_UHP) != 0) { 211 pr_debug("AT91: PM - Suspend-to-RAM with USB still active\n"); 212 return 0; 213 } 214 } 215 216 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS 217 /* PCK0..PCK3 must be disabled, or configured to use clk32k */ 218 for (i = 0; i < 4; i++) { 219 u32 css; 220 221 if ((scsr & (AT91_PMC_PCK0 << i)) == 0) 222 continue; 223 224 css = at91_sys_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS; 225 if (css != AT91_PMC_CSS_SLOW) { 226 pr_debug("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css); 227 return 0; 228 } 229 } 230 #endif 231 232 return 1; 233 } 234 235 /* 236 * Call this from platform driver suspend() to see how deeply to suspend. 237 * For example, some controllers (like OHCI) need one of the PLL clocks 238 * in order to act as a wakeup source, and those are not available when 239 * going into slow clock mode. 240 * 241 * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have 242 * the very same problem (but not using at91 main_clk), and it'd be better 243 * to add one generic API rather than lots of platform-specific ones. 244 */ 245 int at91_suspend_entering_slow_clock(void) 246 { 247 return (target_state == PM_SUSPEND_MEM); 248 } 249 EXPORT_SYMBOL(at91_suspend_entering_slow_clock); 250 251 252 static void (*slow_clock)(void); 253 254 #ifdef CONFIG_AT91_SLOW_CLOCK 255 extern void at91_slow_clock(void); 256 extern u32 at91_slow_clock_sz; 257 #endif 258 259 260 static int at91_pm_enter(suspend_state_t state) 261 { 262 at91_gpio_suspend(); 263 at91_irq_suspend(); 264 265 pr_debug("AT91: PM - wake mask %08x, pm state %d\n", 266 /* remember all the always-wake irqs */ 267 (at91_sys_read(AT91_PMC_PCSR) 268 | (1 << AT91_ID_FIQ) 269 | (1 << AT91_ID_SYS) 270 | (at91_extern_irq)) 271 & at91_sys_read(AT91_AIC_IMR), 272 state); 273 274 switch (state) { 275 /* 276 * Suspend-to-RAM is like STANDBY plus slow clock mode, so 277 * drivers must suspend more deeply: only the master clock 278 * controller may be using the main oscillator. 279 */ 280 case PM_SUSPEND_MEM: 281 /* 282 * Ensure that clocks are in a valid state. 283 */ 284 if (!at91_pm_verify_clocks()) 285 goto error; 286 287 /* 288 * Enter slow clock mode by switching over to clk32k and 289 * turning off the main oscillator; reverse on wakeup. 290 */ 291 if (slow_clock) { 292 #ifdef CONFIG_AT91_SLOW_CLOCK 293 /* copy slow_clock handler to SRAM, and call it */ 294 memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz); 295 #endif 296 slow_clock(); 297 break; 298 } else { 299 pr_info("AT91: PM - no slow clock mode enabled ...\n"); 300 /* FALLTHROUGH leaving master clock alone */ 301 } 302 303 /* 304 * STANDBY mode has *all* drivers suspended; ignores irqs not 305 * marked as 'wakeup' event sources; and reduces DRAM power. 306 * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and 307 * nothing fancy done with main or cpu clocks. 308 */ 309 case PM_SUSPEND_STANDBY: 310 /* 311 * NOTE: the Wait-for-Interrupt instruction needs to be 312 * in icache so no SDRAM accesses are needed until the 313 * wakeup IRQ occurs and self-refresh is terminated. 314 */ 315 asm("b 1f; .align 5; 1:"); 316 asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ 317 sdram_selfrefresh_enable(); 318 asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ 319 sdram_selfrefresh_disable(); 320 break; 321 322 case PM_SUSPEND_ON: 323 asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ 324 break; 325 326 default: 327 pr_debug("AT91: PM - bogus suspend state %d\n", state); 328 goto error; 329 } 330 331 pr_debug("AT91: PM - wakeup %08x\n", 332 at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR)); 333 334 error: 335 sdram_selfrefresh_disable(); 336 target_state = PM_SUSPEND_ON; 337 at91_irq_resume(); 338 at91_gpio_resume(); 339 return 0; 340 } 341 342 /* 343 * Called right prior to thawing processes. 344 */ 345 static void at91_pm_end(void) 346 { 347 target_state = PM_SUSPEND_ON; 348 } 349 350 351 static struct platform_suspend_ops at91_pm_ops ={ 352 .valid = at91_pm_valid_state, 353 .begin = at91_pm_begin, 354 .enter = at91_pm_enter, 355 .end = at91_pm_end, 356 }; 357 358 static int __init at91_pm_init(void) 359 { 360 #ifdef CONFIG_AT91_SLOW_CLOCK 361 slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz); 362 #endif 363 364 pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : "")); 365 366 #ifdef CONFIG_ARCH_AT91RM9200 367 /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */ 368 at91_sys_write(AT91_SDRAMC_LPR, 0); 369 #endif 370 371 suspend_set_ops(&at91_pm_ops); 372 373 show_reset_status(); 374 return 0; 375 } 376 arch_initcall(at91_pm_init); 377