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 * Calibrate the decrementer frequency with the VIA timer 1. 49 */ 50 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ 51 52 /* VIA registers */ 53 #define RS 0x200 /* skip between registers */ 54 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ 55 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ 56 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ 57 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ 58 #define ACR (11*RS) /* Auxiliary control register */ 59 #define IFR (13*RS) /* Interrupt flag register */ 60 61 /* Bits in ACR */ 62 #define T1MODE 0xc0 /* Timer 1 mode */ 63 #define T1MODE_CONT 0x40 /* continuous interrupts */ 64 65 /* Bits in IFR and IER */ 66 #define T1_INT 0x40 /* Timer 1 interrupt */ 67 68 long __init pmac_time_init(void) 69 { 70 s32 delta = 0; 71 #ifdef CONFIG_NVRAM 72 int dst; 73 74 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; 75 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; 76 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); 77 if (delta & 0x00800000UL) 78 delta |= 0xFF000000UL; 79 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); 80 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, 81 dst ? "on" : "off"); 82 #endif 83 return delta; 84 } 85 86 #ifdef CONFIG_PMAC_SMU 87 static time64_t smu_get_time(void) 88 { 89 struct rtc_time tm; 90 91 if (smu_get_rtc_time(&tm, 1)) 92 return 0; 93 return rtc_tm_to_time64(&tm); 94 } 95 #endif 96 97 /* Can't be __init, it's called when suspending and resuming */ 98 time64_t pmac_get_boot_time(void) 99 { 100 /* Get the time from the RTC, used only at boot time */ 101 switch (sys_ctrler) { 102 #ifdef CONFIG_ADB_CUDA 103 case SYS_CTRLER_CUDA: 104 return cuda_get_time(); 105 #endif 106 #ifdef CONFIG_ADB_PMU 107 case SYS_CTRLER_PMU: 108 return pmu_get_time(); 109 #endif 110 #ifdef CONFIG_PMAC_SMU 111 case SYS_CTRLER_SMU: 112 return smu_get_time(); 113 #endif 114 default: 115 return 0; 116 } 117 } 118 119 void pmac_get_rtc_time(struct rtc_time *tm) 120 { 121 /* Get the time from the RTC, used only at boot time */ 122 switch (sys_ctrler) { 123 #ifdef CONFIG_ADB_CUDA 124 case SYS_CTRLER_CUDA: 125 rtc_time64_to_tm(cuda_get_time(), tm); 126 break; 127 #endif 128 #ifdef CONFIG_ADB_PMU 129 case SYS_CTRLER_PMU: 130 rtc_time64_to_tm(pmu_get_time(), tm); 131 break; 132 #endif 133 #ifdef CONFIG_PMAC_SMU 134 case SYS_CTRLER_SMU: 135 smu_get_rtc_time(tm, 1); 136 break; 137 #endif 138 default: 139 ; 140 } 141 } 142 143 int pmac_set_rtc_time(struct rtc_time *tm) 144 { 145 switch (sys_ctrler) { 146 #ifdef CONFIG_ADB_CUDA 147 case SYS_CTRLER_CUDA: 148 return cuda_set_rtc_time(tm); 149 #endif 150 #ifdef CONFIG_ADB_PMU 151 case SYS_CTRLER_PMU: 152 return pmu_set_rtc_time(tm); 153 #endif 154 #ifdef CONFIG_PMAC_SMU 155 case SYS_CTRLER_SMU: 156 return smu_set_rtc_time(tm, 1); 157 #endif 158 default: 159 return -ENODEV; 160 } 161 } 162 163 #ifdef CONFIG_PPC32 164 /* 165 * Calibrate the decrementer register using VIA timer 1. 166 * This is used both on powermacs and CHRP machines. 167 */ 168 static int __init via_calibrate_decr(void) 169 { 170 struct device_node *vias; 171 volatile unsigned char __iomem *via; 172 int count = VIA_TIMER_FREQ_6 / 100; 173 unsigned int dstart, dend; 174 struct resource rsrc; 175 176 vias = of_find_node_by_name(NULL, "via-cuda"); 177 if (vias == NULL) 178 vias = of_find_node_by_name(NULL, "via-pmu"); 179 if (vias == NULL) 180 vias = of_find_node_by_name(NULL, "via"); 181 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) { 182 of_node_put(vias); 183 return 0; 184 } 185 of_node_put(vias); 186 via = ioremap(rsrc.start, resource_size(&rsrc)); 187 if (via == NULL) { 188 printk(KERN_ERR "Failed to map VIA for timer calibration !\n"); 189 return 0; 190 } 191 192 /* set timer 1 for continuous interrupts */ 193 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); 194 /* set the counter to a small value */ 195 out_8(&via[T1CH], 2); 196 /* set the latch to `count' */ 197 out_8(&via[T1LL], count); 198 out_8(&via[T1LH], count >> 8); 199 /* wait until it hits 0 */ 200 while ((in_8(&via[IFR]) & T1_INT) == 0) 201 ; 202 dstart = get_dec(); 203 /* clear the interrupt & wait until it hits 0 again */ 204 in_8(&via[T1CL]); 205 while ((in_8(&via[IFR]) & T1_INT) == 0) 206 ; 207 dend = get_dec(); 208 209 ppc_tb_freq = (dstart - dend) * 100 / 6; 210 211 iounmap(via); 212 213 return 1; 214 } 215 #endif 216 217 /* 218 * Query the OF and get the decr frequency. 219 */ 220 void __init pmac_calibrate_decr(void) 221 { 222 generic_calibrate_decr(); 223 224 #ifdef CONFIG_PPC32 225 /* We assume MacRISC2 machines have correct device-tree 226 * calibration. That's better since the VIA itself seems 227 * to be slightly off. --BenH 228 */ 229 if (!of_machine_is_compatible("MacRISC2") && 230 !of_machine_is_compatible("MacRISC3") && 231 !of_machine_is_compatible("MacRISC4")) 232 if (via_calibrate_decr()) 233 return; 234 235 /* Special case: QuickSilver G4s seem to have a badly calibrated 236 * timebase-frequency in OF, VIA is much better on these. We should 237 * probably implement calibration based on the KL timer on these 238 * machines anyway... -BenH 239 */ 240 if (of_machine_is_compatible("PowerMac3,5")) 241 if (via_calibrate_decr()) 242 return; 243 #endif 244 } 245