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 #include <linux/of_address.h> 28 29 #include <asm/sections.h> 30 #include <asm/io.h> 31 #include <asm/machdep.h> 32 #include <asm/time.h> 33 #include <asm/nvram.h> 34 #include <asm/smu.h> 35 36 #include "pmac.h" 37 38 #undef DEBUG 39 40 #ifdef DEBUG 41 #define DBG(x...) printk(x) 42 #else 43 #define DBG(x...) 44 #endif 45 46 /* 47 * Calibrate the decrementer frequency with the VIA timer 1. 48 */ 49 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ 50 51 /* VIA registers */ 52 #define RS 0x200 /* skip between registers */ 53 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ 54 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ 55 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ 56 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ 57 #define ACR (11*RS) /* Auxiliary control register */ 58 #define IFR (13*RS) /* Interrupt flag register */ 59 60 /* Bits in ACR */ 61 #define T1MODE 0xc0 /* Timer 1 mode */ 62 #define T1MODE_CONT 0x40 /* continuous interrupts */ 63 64 /* Bits in IFR and IER */ 65 #define T1_INT 0x40 /* Timer 1 interrupt */ 66 67 long __init pmac_time_init(void) 68 { 69 s32 delta = 0; 70 #if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32) 71 int dst; 72 73 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; 74 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; 75 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); 76 if (delta & 0x00800000UL) 77 delta |= 0xFF000000UL; 78 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); 79 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, 80 dst ? "on" : "off"); 81 #endif 82 return delta; 83 } 84 85 #ifdef CONFIG_PMAC_SMU 86 static time64_t smu_get_time(void) 87 { 88 struct rtc_time tm; 89 90 if (smu_get_rtc_time(&tm, 1)) 91 return 0; 92 return rtc_tm_to_time64(&tm); 93 } 94 #endif 95 96 /* Can't be __init, it's called when suspending and resuming */ 97 time64_t pmac_get_boot_time(void) 98 { 99 /* Get the time from the RTC, used only at boot time */ 100 switch (sys_ctrler) { 101 #ifdef CONFIG_ADB_CUDA 102 case SYS_CTRLER_CUDA: 103 return cuda_get_time(); 104 #endif 105 #ifdef CONFIG_ADB_PMU 106 case SYS_CTRLER_PMU: 107 return pmu_get_time(); 108 #endif 109 #ifdef CONFIG_PMAC_SMU 110 case SYS_CTRLER_SMU: 111 return smu_get_time(); 112 #endif 113 default: 114 return 0; 115 } 116 } 117 118 void pmac_get_rtc_time(struct rtc_time *tm) 119 { 120 /* Get the time from the RTC, used only at boot time */ 121 switch (sys_ctrler) { 122 #ifdef CONFIG_ADB_CUDA 123 case SYS_CTRLER_CUDA: 124 rtc_time64_to_tm(cuda_get_time(), tm); 125 break; 126 #endif 127 #ifdef CONFIG_ADB_PMU 128 case SYS_CTRLER_PMU: 129 rtc_time64_to_tm(pmu_get_time(), tm); 130 break; 131 #endif 132 #ifdef CONFIG_PMAC_SMU 133 case SYS_CTRLER_SMU: 134 smu_get_rtc_time(tm, 1); 135 break; 136 #endif 137 default: 138 ; 139 } 140 } 141 142 int pmac_set_rtc_time(struct rtc_time *tm) 143 { 144 switch (sys_ctrler) { 145 #ifdef CONFIG_ADB_CUDA 146 case SYS_CTRLER_CUDA: 147 return cuda_set_rtc_time(tm); 148 #endif 149 #ifdef CONFIG_ADB_PMU 150 case SYS_CTRLER_PMU: 151 return pmu_set_rtc_time(tm); 152 #endif 153 #ifdef CONFIG_PMAC_SMU 154 case SYS_CTRLER_SMU: 155 return smu_set_rtc_time(tm, 1); 156 #endif 157 default: 158 return -ENODEV; 159 } 160 } 161 162 #ifdef CONFIG_PPC32 163 /* 164 * Calibrate the decrementer register using VIA timer 1. 165 * This is used both on powermacs and CHRP machines. 166 */ 167 static int __init via_calibrate_decr(void) 168 { 169 struct device_node *vias; 170 volatile unsigned char __iomem *via; 171 int count = VIA_TIMER_FREQ_6 / 100; 172 unsigned int dstart, dend; 173 struct resource rsrc; 174 175 vias = of_find_node_by_name(NULL, "via-cuda"); 176 if (vias == NULL) 177 vias = of_find_node_by_name(NULL, "via-pmu"); 178 if (vias == NULL) 179 vias = of_find_node_by_name(NULL, "via"); 180 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) { 181 of_node_put(vias); 182 return 0; 183 } 184 of_node_put(vias); 185 via = ioremap(rsrc.start, resource_size(&rsrc)); 186 if (via == NULL) { 187 printk(KERN_ERR "Failed to map VIA for timer calibration !\n"); 188 return 0; 189 } 190 191 /* set timer 1 for continuous interrupts */ 192 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); 193 /* set the counter to a small value */ 194 out_8(&via[T1CH], 2); 195 /* set the latch to `count' */ 196 out_8(&via[T1LL], count); 197 out_8(&via[T1LH], count >> 8); 198 /* wait until it hits 0 */ 199 while ((in_8(&via[IFR]) & T1_INT) == 0) 200 ; 201 dstart = get_dec(); 202 /* clear the interrupt & wait until it hits 0 again */ 203 in_8(&via[T1CL]); 204 while ((in_8(&via[IFR]) & T1_INT) == 0) 205 ; 206 dend = get_dec(); 207 208 ppc_tb_freq = (dstart - dend) * 100 / 6; 209 210 iounmap(via); 211 212 return 1; 213 } 214 #endif 215 216 /* 217 * Query the OF and get the decr frequency. 218 */ 219 void __init pmac_calibrate_decr(void) 220 { 221 generic_calibrate_decr(); 222 223 #ifdef CONFIG_PPC32 224 /* We assume MacRISC2 machines have correct device-tree 225 * calibration. That's better since the VIA itself seems 226 * to be slightly off. --BenH 227 */ 228 if (!of_machine_is_compatible("MacRISC2") && 229 !of_machine_is_compatible("MacRISC3") && 230 !of_machine_is_compatible("MacRISC4")) 231 if (via_calibrate_decr()) 232 return; 233 234 /* Special case: QuickSilver G4s seem to have a badly calibrated 235 * timebase-frequency in OF, VIA is much better on these. We should 236 * probably implement calibration based on the KL timer on these 237 * machines anyway... -BenH 238 */ 239 if (of_machine_is_compatible("PowerMac3,5")) 240 if (via_calibrate_decr()) 241 return; 242 #endif 243 } 244