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 #include "pmac.h" 38 39 #undef DEBUG 40 41 #ifdef DEBUG 42 #define DBG(x...) printk(x) 43 #else 44 #define DBG(x...) 45 #endif 46 47 /* 48 * Offset between Unix time (1970-based) and Mac time (1904-based). Cuda and PMU 49 * times wrap in 2040. If we need to handle later times, the read_time functions 50 * need to be changed to interpret wrapped times as post-2040. 51 */ 52 #define RTC_OFFSET 2082844800 53 54 /* 55 * Calibrate the decrementer frequency with the VIA timer 1. 56 */ 57 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ 58 59 /* VIA registers */ 60 #define RS 0x200 /* skip between registers */ 61 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ 62 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ 63 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ 64 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ 65 #define ACR (11*RS) /* Auxiliary control register */ 66 #define IFR (13*RS) /* Interrupt flag register */ 67 68 /* Bits in ACR */ 69 #define T1MODE 0xc0 /* Timer 1 mode */ 70 #define T1MODE_CONT 0x40 /* continuous interrupts */ 71 72 /* Bits in IFR and IER */ 73 #define T1_INT 0x40 /* Timer 1 interrupt */ 74 75 long __init pmac_time_init(void) 76 { 77 s32 delta = 0; 78 #ifdef CONFIG_NVRAM 79 int dst; 80 81 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; 82 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; 83 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); 84 if (delta & 0x00800000UL) 85 delta |= 0xFF000000UL; 86 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); 87 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, 88 dst ? "on" : "off"); 89 #endif 90 return delta; 91 } 92 93 #ifdef CONFIG_ADB_CUDA 94 static time64_t cuda_get_time(void) 95 { 96 struct adb_request req; 97 time64_t now; 98 99 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0) 100 return 0; 101 while (!req.complete) 102 cuda_poll(); 103 if (req.reply_len != 7) 104 printk(KERN_ERR "cuda_get_time: got %d byte reply\n", 105 req.reply_len); 106 now = (u32)((req.reply[3] << 24) + (req.reply[4] << 16) + 107 (req.reply[5] << 8) + req.reply[6]); 108 /* it's either after year 2040, or the RTC has gone backwards */ 109 WARN_ON(now < RTC_OFFSET); 110 111 return now - RTC_OFFSET; 112 } 113 114 #define cuda_get_rtc_time(tm) rtc_time64_to_tm(cuda_get_time(), (tm)) 115 116 static int cuda_set_rtc_time(struct rtc_time *tm) 117 { 118 u32 nowtime; 119 struct adb_request req; 120 121 nowtime = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET); 122 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME, 123 nowtime >> 24, nowtime >> 16, nowtime >> 8, 124 nowtime) < 0) 125 return -ENXIO; 126 while (!req.complete) 127 cuda_poll(); 128 if ((req.reply_len != 3) && (req.reply_len != 7)) 129 printk(KERN_ERR "cuda_set_rtc_time: got %d byte reply\n", 130 req.reply_len); 131 return 0; 132 } 133 134 #else 135 #define cuda_get_time() 0 136 #define cuda_get_rtc_time(tm) 137 #define cuda_set_rtc_time(tm) 0 138 #endif 139 140 #ifdef CONFIG_ADB_PMU 141 static time64_t pmu_get_time(void) 142 { 143 struct adb_request req; 144 time64_t now; 145 146 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0) 147 return 0; 148 pmu_wait_complete(&req); 149 if (req.reply_len != 4) 150 printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n", 151 req.reply_len); 152 now = (u32)((req.reply[0] << 24) + (req.reply[1] << 16) + 153 (req.reply[2] << 8) + req.reply[3]); 154 155 /* it's either after year 2040, or the RTC has gone backwards */ 156 WARN_ON(now < RTC_OFFSET); 157 158 return now - RTC_OFFSET; 159 } 160 161 #define pmu_get_rtc_time(tm) rtc_time64_to_tm(pmu_get_time(), (tm)) 162 163 static int pmu_set_rtc_time(struct rtc_time *tm) 164 { 165 u32 nowtime; 166 struct adb_request req; 167 168 nowtime = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET); 169 if (pmu_request(&req, NULL, 5, PMU_SET_RTC, nowtime >> 24, 170 nowtime >> 16, nowtime >> 8, nowtime) < 0) 171 return -ENXIO; 172 pmu_wait_complete(&req); 173 if (req.reply_len != 0) 174 printk(KERN_ERR "pmu_set_rtc_time: %d byte reply from PMU\n", 175 req.reply_len); 176 return 0; 177 } 178 179 #else 180 #define pmu_get_time() 0 181 #define pmu_get_rtc_time(tm) 182 #define pmu_set_rtc_time(tm) 0 183 #endif 184 185 #ifdef CONFIG_PMAC_SMU 186 static time64_t smu_get_time(void) 187 { 188 struct rtc_time tm; 189 190 if (smu_get_rtc_time(&tm, 1)) 191 return 0; 192 return rtc_tm_to_time64(&tm); 193 } 194 195 #else 196 #define smu_get_time() 0 197 #define smu_get_rtc_time(tm, spin) 198 #define smu_set_rtc_time(tm, spin) 0 199 #endif 200 201 /* Can't be __init, it's called when suspending and resuming */ 202 time64_t pmac_get_boot_time(void) 203 { 204 /* Get the time from the RTC, used only at boot time */ 205 switch (sys_ctrler) { 206 case SYS_CTRLER_CUDA: 207 return cuda_get_time(); 208 case SYS_CTRLER_PMU: 209 return pmu_get_time(); 210 case SYS_CTRLER_SMU: 211 return smu_get_time(); 212 default: 213 return 0; 214 } 215 } 216 217 void pmac_get_rtc_time(struct rtc_time *tm) 218 { 219 /* Get the time from the RTC, used only at boot time */ 220 switch (sys_ctrler) { 221 case SYS_CTRLER_CUDA: 222 cuda_get_rtc_time(tm); 223 break; 224 case SYS_CTRLER_PMU: 225 pmu_get_rtc_time(tm); 226 break; 227 case SYS_CTRLER_SMU: 228 smu_get_rtc_time(tm, 1); 229 break; 230 default: 231 ; 232 } 233 } 234 235 int pmac_set_rtc_time(struct rtc_time *tm) 236 { 237 switch (sys_ctrler) { 238 case SYS_CTRLER_CUDA: 239 return cuda_set_rtc_time(tm); 240 case SYS_CTRLER_PMU: 241 return pmu_set_rtc_time(tm); 242 case SYS_CTRLER_SMU: 243 return smu_set_rtc_time(tm, 1); 244 default: 245 return -ENODEV; 246 } 247 } 248 249 #ifdef CONFIG_PPC32 250 /* 251 * Calibrate the decrementer register using VIA timer 1. 252 * This is used both on powermacs and CHRP machines. 253 */ 254 static int __init via_calibrate_decr(void) 255 { 256 struct device_node *vias; 257 volatile unsigned char __iomem *via; 258 int count = VIA_TIMER_FREQ_6 / 100; 259 unsigned int dstart, dend; 260 struct resource rsrc; 261 262 vias = of_find_node_by_name(NULL, "via-cuda"); 263 if (vias == NULL) 264 vias = of_find_node_by_name(NULL, "via-pmu"); 265 if (vias == NULL) 266 vias = of_find_node_by_name(NULL, "via"); 267 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) { 268 of_node_put(vias); 269 return 0; 270 } 271 of_node_put(vias); 272 via = ioremap(rsrc.start, resource_size(&rsrc)); 273 if (via == NULL) { 274 printk(KERN_ERR "Failed to map VIA for timer calibration !\n"); 275 return 0; 276 } 277 278 /* set timer 1 for continuous interrupts */ 279 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); 280 /* set the counter to a small value */ 281 out_8(&via[T1CH], 2); 282 /* set the latch to `count' */ 283 out_8(&via[T1LL], count); 284 out_8(&via[T1LH], count >> 8); 285 /* wait until it hits 0 */ 286 while ((in_8(&via[IFR]) & T1_INT) == 0) 287 ; 288 dstart = get_dec(); 289 /* clear the interrupt & wait until it hits 0 again */ 290 in_8(&via[T1CL]); 291 while ((in_8(&via[IFR]) & T1_INT) == 0) 292 ; 293 dend = get_dec(); 294 295 ppc_tb_freq = (dstart - dend) * 100 / 6; 296 297 iounmap(via); 298 299 return 1; 300 } 301 #endif 302 303 /* 304 * Query the OF and get the decr frequency. 305 */ 306 void __init pmac_calibrate_decr(void) 307 { 308 generic_calibrate_decr(); 309 310 #ifdef CONFIG_PPC32 311 /* We assume MacRISC2 machines have correct device-tree 312 * calibration. That's better since the VIA itself seems 313 * to be slightly off. --BenH 314 */ 315 if (!of_machine_is_compatible("MacRISC2") && 316 !of_machine_is_compatible("MacRISC3") && 317 !of_machine_is_compatible("MacRISC4")) 318 if (via_calibrate_decr()) 319 return; 320 321 /* Special case: QuickSilver G4s seem to have a badly calibrated 322 * timebase-frequency in OF, VIA is much better on these. We should 323 * probably implement calibration based on the KL timer on these 324 * machines anyway... -BenH 325 */ 326 if (of_machine_is_compatible("PowerMac3,5")) 327 if (via_calibrate_decr()) 328 return; 329 #endif 330 } 331