1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Support for periodic interrupts (100 per second) and for getting 4 * the current time from the RTC on Power Macintoshes. 5 * 6 * We use the decrementer register for our periodic interrupts. 7 * 8 * Paul Mackerras August 1996. 9 * Copyright (C) 1996 Paul Mackerras. 10 * Copyright (C) 2003-2005 Benjamin Herrenschmidt. 11 * 12 */ 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/io.h> 31 #include <asm/pgtable.h> 32 #include <asm/machdep.h> 33 #include <asm/time.h> 34 #include <asm/nvram.h> 35 #include <asm/smu.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 s32 delta = 0; 72 #ifdef CONFIG_NVRAM 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 #endif 84 return delta; 85 } 86 87 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) 88 static void to_rtc_time(unsigned long now, struct rtc_time *tm) 89 { 90 to_tm(now, tm); 91 tm->tm_year -= 1900; 92 tm->tm_mon -= 1; 93 } 94 #endif 95 96 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) || \ 97 defined(CONFIG_PMAC_SMU) 98 static unsigned long from_rtc_time(struct rtc_time *tm) 99 { 100 return mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday, 101 tm->tm_hour, tm->tm_min, tm->tm_sec); 102 } 103 #endif 104 105 #ifdef CONFIG_ADB_CUDA 106 static unsigned long cuda_get_time(void) 107 { 108 struct adb_request req; 109 unsigned int now; 110 111 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0) 112 return 0; 113 while (!req.complete) 114 cuda_poll(); 115 if (req.reply_len != 7) 116 printk(KERN_ERR "cuda_get_time: got %d byte reply\n", 117 req.reply_len); 118 now = (req.reply[3] << 24) + (req.reply[4] << 16) 119 + (req.reply[5] << 8) + req.reply[6]; 120 return ((unsigned long)now) - RTC_OFFSET; 121 } 122 123 #define cuda_get_rtc_time(tm) to_rtc_time(cuda_get_time(), (tm)) 124 125 static int cuda_set_rtc_time(struct rtc_time *tm) 126 { 127 unsigned int nowtime; 128 struct adb_request req; 129 130 nowtime = from_rtc_time(tm) + RTC_OFFSET; 131 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME, 132 nowtime >> 24, nowtime >> 16, nowtime >> 8, 133 nowtime) < 0) 134 return -ENXIO; 135 while (!req.complete) 136 cuda_poll(); 137 if ((req.reply_len != 3) && (req.reply_len != 7)) 138 printk(KERN_ERR "cuda_set_rtc_time: got %d byte reply\n", 139 req.reply_len); 140 return 0; 141 } 142 143 #else 144 #define cuda_get_time() 0 145 #define cuda_get_rtc_time(tm) 146 #define cuda_set_rtc_time(tm) 0 147 #endif 148 149 #ifdef CONFIG_ADB_PMU 150 static unsigned long pmu_get_time(void) 151 { 152 struct adb_request req; 153 unsigned int now; 154 155 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0) 156 return 0; 157 pmu_wait_complete(&req); 158 if (req.reply_len != 4) 159 printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n", 160 req.reply_len); 161 now = (req.reply[0] << 24) + (req.reply[1] << 16) 162 + (req.reply[2] << 8) + req.reply[3]; 163 return ((unsigned long)now) - RTC_OFFSET; 164 } 165 166 #define pmu_get_rtc_time(tm) to_rtc_time(pmu_get_time(), (tm)) 167 168 static int pmu_set_rtc_time(struct rtc_time *tm) 169 { 170 unsigned int nowtime; 171 struct adb_request req; 172 173 nowtime = from_rtc_time(tm) + RTC_OFFSET; 174 if (pmu_request(&req, NULL, 5, PMU_SET_RTC, nowtime >> 24, 175 nowtime >> 16, nowtime >> 8, nowtime) < 0) 176 return -ENXIO; 177 pmu_wait_complete(&req); 178 if (req.reply_len != 0) 179 printk(KERN_ERR "pmu_set_rtc_time: %d byte reply from PMU\n", 180 req.reply_len); 181 return 0; 182 } 183 184 #else 185 #define pmu_get_time() 0 186 #define pmu_get_rtc_time(tm) 187 #define pmu_set_rtc_time(tm) 0 188 #endif 189 190 #ifdef CONFIG_PMAC_SMU 191 static unsigned long smu_get_time(void) 192 { 193 struct rtc_time tm; 194 195 if (smu_get_rtc_time(&tm, 1)) 196 return 0; 197 return from_rtc_time(&tm); 198 } 199 200 #else 201 #define smu_get_time() 0 202 #define smu_get_rtc_time(tm, spin) 203 #define smu_set_rtc_time(tm, spin) 0 204 #endif 205 206 /* Can't be __init, it's called when suspending and resuming */ 207 unsigned long pmac_get_boot_time(void) 208 { 209 /* Get the time from the RTC, used only at boot time */ 210 switch (sys_ctrler) { 211 case SYS_CTRLER_CUDA: 212 return cuda_get_time(); 213 case SYS_CTRLER_PMU: 214 return pmu_get_time(); 215 case SYS_CTRLER_SMU: 216 return smu_get_time(); 217 default: 218 return 0; 219 } 220 } 221 222 void pmac_get_rtc_time(struct rtc_time *tm) 223 { 224 /* Get the time from the RTC, used only at boot time */ 225 switch (sys_ctrler) { 226 case SYS_CTRLER_CUDA: 227 cuda_get_rtc_time(tm); 228 break; 229 case SYS_CTRLER_PMU: 230 pmu_get_rtc_time(tm); 231 break; 232 case SYS_CTRLER_SMU: 233 smu_get_rtc_time(tm, 1); 234 break; 235 default: 236 ; 237 } 238 } 239 240 int pmac_set_rtc_time(struct rtc_time *tm) 241 { 242 switch (sys_ctrler) { 243 case SYS_CTRLER_CUDA: 244 return cuda_set_rtc_time(tm); 245 case SYS_CTRLER_PMU: 246 return pmu_set_rtc_time(tm); 247 case SYS_CTRLER_SMU: 248 return smu_set_rtc_time(tm, 1); 249 default: 250 return -ENODEV; 251 } 252 } 253 254 #ifdef CONFIG_PPC32 255 /* 256 * Calibrate the decrementer register using VIA timer 1. 257 * This is used both on powermacs and CHRP machines. 258 */ 259 int __init via_calibrate_decr(void) 260 { 261 struct device_node *vias; 262 volatile unsigned char __iomem *via; 263 int count = VIA_TIMER_FREQ_6 / 100; 264 unsigned int dstart, dend; 265 struct resource rsrc; 266 267 vias = of_find_node_by_name(NULL, "via-cuda"); 268 if (vias == NULL) 269 vias = of_find_node_by_name(NULL, "via-pmu"); 270 if (vias == NULL) 271 vias = of_find_node_by_name(NULL, "via"); 272 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) { 273 of_node_put(vias); 274 return 0; 275 } 276 of_node_put(vias); 277 via = ioremap(rsrc.start, resource_size(&rsrc)); 278 if (via == NULL) { 279 printk(KERN_ERR "Failed to map VIA for timer calibration !\n"); 280 return 0; 281 } 282 283 /* set timer 1 for continuous interrupts */ 284 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); 285 /* set the counter to a small value */ 286 out_8(&via[T1CH], 2); 287 /* set the latch to `count' */ 288 out_8(&via[T1LL], count); 289 out_8(&via[T1LH], count >> 8); 290 /* wait until it hits 0 */ 291 while ((in_8(&via[IFR]) & T1_INT) == 0) 292 ; 293 dstart = get_dec(); 294 /* clear the interrupt & wait until it hits 0 again */ 295 in_8(&via[T1CL]); 296 while ((in_8(&via[IFR]) & T1_INT) == 0) 297 ; 298 dend = get_dec(); 299 300 ppc_tb_freq = (dstart - dend) * 100 / 6; 301 302 iounmap(via); 303 304 return 1; 305 } 306 #endif 307 308 /* 309 * Query the OF and get the decr frequency. 310 */ 311 void __init pmac_calibrate_decr(void) 312 { 313 generic_calibrate_decr(); 314 315 #ifdef CONFIG_PPC32 316 /* We assume MacRISC2 machines have correct device-tree 317 * calibration. That's better since the VIA itself seems 318 * to be slightly off. --BenH 319 */ 320 if (!of_machine_is_compatible("MacRISC2") && 321 !of_machine_is_compatible("MacRISC3") && 322 !of_machine_is_compatible("MacRISC4")) 323 if (via_calibrate_decr()) 324 return; 325 326 /* Special case: QuickSilver G4s seem to have a badly calibrated 327 * timebase-frequency in OF, VIA is much better on these. We should 328 * probably implement calibration based on the KL timer on these 329 * machines anyway... -BenH 330 */ 331 if (of_machine_is_compatible("PowerMac3,5")) 332 if (via_calibrate_decr()) 333 return; 334 #endif 335 } 336