arch/powerpc/platforms/powermac/time.c

   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 }