1 /* 2 * Support for periodic interrupts (100 per second) and for getting 3 * the current time from the RTC on Power Macintoshes. 4 * 5 * We use the decrementer register for our periodic interrupts. 6 * 7 * Paul Mackerras August 1996. 8 * Copyright (C) 1996 Paul Mackerras. 9 * Copyright (C) 2003-2005 Benjamin Herrenschmidt. 10 * 11 */ 12 #include <linux/config.h> 13 #include <linux/errno.h> 14 #include <linux/sched.h> 15 #include <linux/kernel.h> 16 #include <linux/param.h> 17 #include <linux/string.h> 18 #include <linux/mm.h> 19 #include <linux/init.h> 20 #include <linux/time.h> 21 #include <linux/adb.h> 22 #include <linux/cuda.h> 23 #include <linux/pmu.h> 24 #include <linux/interrupt.h> 25 #include <linux/hardirq.h> 26 #include <linux/rtc.h> 27 28 #include <asm/sections.h> 29 #include <asm/prom.h> 30 #include <asm/system.h> 31 #include <asm/io.h> 32 #include <asm/pgtable.h> 33 #include <asm/machdep.h> 34 #include <asm/time.h> 35 #include <asm/nvram.h> 36 37 #undef DEBUG 38 39 #ifdef DEBUG 40 #define DBG(x...) printk(x) 41 #else 42 #define DBG(x...) 43 #endif 44 45 /* Apparently the RTC stores seconds since 1 Jan 1904 */ 46 #define RTC_OFFSET 2082844800 47 48 /* 49 * Calibrate the decrementer frequency with the VIA timer 1. 50 */ 51 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ 52 53 /* VIA registers */ 54 #define RS 0x200 /* skip between registers */ 55 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ 56 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ 57 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ 58 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ 59 #define ACR (11*RS) /* Auxiliary control register */ 60 #define IFR (13*RS) /* Interrupt flag register */ 61 62 /* Bits in ACR */ 63 #define T1MODE 0xc0 /* Timer 1 mode */ 64 #define T1MODE_CONT 0x40 /* continuous interrupts */ 65 66 /* Bits in IFR and IER */ 67 #define T1_INT 0x40 /* Timer 1 interrupt */ 68 69 long __init pmac_time_init(void) 70 { 71 #ifdef CONFIG_NVRAM 72 s32 delta = 0; 73 int dst; 74 75 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; 76 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; 77 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); 78 if (delta & 0x00800000UL) 79 delta |= 0xFF000000UL; 80 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); 81 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, 82 dst ? "on" : "off"); 83 return delta; 84 #else 85 return 0; 86 #endif 87 } 88 89 unsigned long pmac_get_boot_time(void) 90 { 91 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) 92 struct adb_request req; 93 unsigned long now; 94 #endif 95 96 /* Get the time from the RTC */ 97 switch (sys_ctrler) { 98 #ifdef CONFIG_ADB_CUDA 99 case SYS_CTRLER_CUDA: 100 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0) 101 return 0; 102 while (!req.complete) 103 cuda_poll(); 104 if (req.reply_len != 7) 105 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", 106 req.reply_len); 107 now = (req.reply[3] << 24) + (req.reply[4] << 16) 108 + (req.reply[5] << 8) + req.reply[6]; 109 return now - RTC_OFFSET; 110 #endif /* CONFIG_ADB_CUDA */ 111 #ifdef CONFIG_ADB_PMU 112 case SYS_CTRLER_PMU: 113 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0) 114 return 0; 115 while (!req.complete) 116 pmu_poll(); 117 if (req.reply_len != 4) 118 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n", 119 req.reply_len); 120 now = (req.reply[0] << 24) + (req.reply[1] << 16) 121 + (req.reply[2] << 8) + req.reply[3]; 122 return now - RTC_OFFSET; 123 #endif /* CONFIG_ADB_PMU */ 124 default: ; 125 } 126 return 0; 127 } 128 129 void pmac_get_rtc_time(struct rtc_time *tm) 130 { 131 unsigned long now; 132 133 now = pmac_get_boot_time(); 134 to_tm(now, tm); 135 tm->tm_year -= 1900; 136 tm->tm_mon -= 1; /* month is 0-based */ 137 } 138 139 int pmac_set_rtc_time(struct rtc_time *tm) 140 { 141 unsigned long nowtime; 142 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) 143 struct adb_request req; 144 #endif 145 146 nowtime = mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday, 147 tm->tm_hour, tm->tm_min, tm->tm_sec); 148 nowtime += RTC_OFFSET; 149 150 switch (sys_ctrler) { 151 #ifdef CONFIG_ADB_CUDA 152 case SYS_CTRLER_CUDA: 153 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME, 154 nowtime >> 24, nowtime >> 16, nowtime >> 8, 155 nowtime) < 0) 156 return 0; 157 while (!req.complete) 158 cuda_poll(); 159 if ((req.reply_len != 3) && (req.reply_len != 7)) 160 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n", 161 req.reply_len); 162 return 1; 163 #endif /* CONFIG_ADB_CUDA */ 164 #ifdef CONFIG_ADB_PMU 165 case SYS_CTRLER_PMU: 166 if (pmu_request(&req, NULL, 5, PMU_SET_RTC, 167 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0) 168 return 0; 169 while (!req.complete) 170 pmu_poll(); 171 if (req.reply_len != 0) 172 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n", 173 req.reply_len); 174 return 1; 175 #endif /* CONFIG_ADB_PMU */ 176 default: 177 return 0; 178 } 179 } 180 181 /* 182 * Calibrate the decrementer register using VIA timer 1. 183 * This is used both on powermacs and CHRP machines. 184 */ 185 int __init 186 via_calibrate_decr(void) 187 { 188 struct device_node *vias; 189 volatile unsigned char __iomem *via; 190 int count = VIA_TIMER_FREQ_6 / 100; 191 unsigned int dstart, dend; 192 193 vias = find_devices("via-cuda"); 194 if (vias == 0) 195 vias = find_devices("via-pmu"); 196 if (vias == 0) 197 vias = find_devices("via"); 198 if (vias == 0 || vias->n_addrs == 0) 199 return 0; 200 via = ioremap(vias->addrs[0].address, vias->addrs[0].size); 201 202 /* set timer 1 for continuous interrupts */ 203 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); 204 /* set the counter to a small value */ 205 out_8(&via[T1CH], 2); 206 /* set the latch to `count' */ 207 out_8(&via[T1LL], count); 208 out_8(&via[T1LH], count >> 8); 209 /* wait until it hits 0 */ 210 while ((in_8(&via[IFR]) & T1_INT) == 0) 211 ; 212 dstart = get_dec(); 213 /* clear the interrupt & wait until it hits 0 again */ 214 in_8(&via[T1CL]); 215 while ((in_8(&via[IFR]) & T1_INT) == 0) 216 ; 217 dend = get_dec(); 218 219 ppc_tb_freq = (dstart - dend) * 100 / 6; 220 tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100); 221 222 printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %lu (%u ticks)\n", 223 tb_ticks_per_jiffy, dstart - dend); 224 225 iounmap(via); 226 227 return 1; 228 } 229 230 #ifdef CONFIG_PM 231 /* 232 * Reset the time after a sleep. 233 */ 234 static int 235 time_sleep_notify(struct pmu_sleep_notifier *self, int when) 236 { 237 static unsigned long time_diff; 238 unsigned long flags; 239 unsigned long seq; 240 struct timespec tv; 241 242 switch (when) { 243 case PBOOK_SLEEP_NOW: 244 do { 245 seq = read_seqbegin_irqsave(&xtime_lock, flags); 246 time_diff = xtime.tv_sec - pmac_get_boot_time(); 247 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); 248 break; 249 case PBOOK_WAKE: 250 tv.tv_sec = pmac_get_boot_time() + time_diff; 251 tv.tv_nsec = 0; 252 do_settimeofday(&tv); 253 break; 254 } 255 return PBOOK_SLEEP_OK; 256 } 257 258 static struct pmu_sleep_notifier time_sleep_notifier = { 259 time_sleep_notify, SLEEP_LEVEL_MISC, 260 }; 261 #endif /* CONFIG_PM */ 262 263 /* 264 * Query the OF and get the decr frequency. 265 * This was taken from the pmac time_init() when merging the prep/pmac 266 * time functions. 267 */ 268 void __init 269 pmac_calibrate_decr(void) 270 { 271 struct device_node *cpu; 272 unsigned int freq, *fp; 273 274 #ifdef CONFIG_PM 275 pmu_register_sleep_notifier(&time_sleep_notifier); 276 #endif /* CONFIG_PM */ 277 278 /* We assume MacRISC2 machines have correct device-tree 279 * calibration. That's better since the VIA itself seems 280 * to be slightly off. --BenH 281 */ 282 if (!machine_is_compatible("MacRISC2") && 283 !machine_is_compatible("MacRISC3") && 284 !machine_is_compatible("MacRISC4")) 285 if (via_calibrate_decr()) 286 return; 287 288 /* Special case: QuickSilver G4s seem to have a badly calibrated 289 * timebase-frequency in OF, VIA is much better on these. We should 290 * probably implement calibration based on the KL timer on these 291 * machines anyway... -BenH 292 */ 293 if (machine_is_compatible("PowerMac3,5")) 294 if (via_calibrate_decr()) 295 return; 296 /* 297 * The cpu node should have a timebase-frequency property 298 * to tell us the rate at which the decrementer counts. 299 */ 300 cpu = find_type_devices("cpu"); 301 if (cpu == 0) 302 panic("can't find cpu node in time_init"); 303 fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL); 304 if (fp == 0) 305 panic("can't get cpu timebase frequency"); 306 freq = *fp; 307 printk("time_init: decrementer frequency = %u.%.6u MHz\n", 308 freq/1000000, freq%1000000); 309 ppc_tb_freq = freq; 310 } 311