arch/powerpc/platforms/powermac/time.c

   1 /*
   2  * Support for periodic interrupts (100 per second) and for getting
   3  * the current time from the RTC on Power Macintoshes.
   4  *
   5  * We use the decrementer register for our periodic interrupts.
   6  *
   7  * Paul Mackerras       August 1996.
   8  * Copyright (C) 1996 Paul Mackerras.
   9  * Copyright (C) 2003-2005 Benjamin Herrenschmidt.
  10  *
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/kernel.h>
  15 #include <linux/param.h>
  16 #include <linux/string.h>
  17 #include <linux/mm.h>
  18 #include <linux/init.h>
  19 #include <linux/time.h>
  20 #include <linux/adb.h>
  21 #include <linux/cuda.h>
  22 #include <linux/pmu.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/hardirq.h>
  25 #include <linux/rtc.h>
  26
  27 #include <asm/sections.h>
  28 #include <asm/prom.h>
  29 #include <asm/system.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 static unsigned long from_rtc_time(struct rtc_time *tm)
  97 {
  98         return mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
  99                       tm->tm_hour, tm->tm_min, tm->tm_sec);
 100 }
 101
 102 #ifdef CONFIG_ADB_CUDA
 103 static unsigned long cuda_get_time(void)
 104 {
 105         struct adb_request req;
 106         unsigned int now;
 107
 108         if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
 109                 return 0;
 110         while (!req.complete)
 111                 cuda_poll();
 112         if (req.reply_len != 7)
 113                 printk(KERN_ERR "cuda_get_time: got %d byte reply\n",
 114                        req.reply_len);
 115         now = (req.reply[3] << 24) + (req.reply[4] << 16)
 116                 + (req.reply[5] << 8) + req.reply[6];
 117         return ((unsigned long)now) - RTC_OFFSET;
 118 }
 119
 120 #define cuda_get_rtc_time(tm)   to_rtc_time(cuda_get_time(), (tm))
 121
 122 static int cuda_set_rtc_time(struct rtc_time *tm)
 123 {
 124         unsigned int nowtime;
 125         struct adb_request req;
 126
 127         nowtime = from_rtc_time(tm) + RTC_OFFSET;
 128         if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
 129                          nowtime >> 24, nowtime >> 16, nowtime >> 8,
 130                          nowtime) < 0)
 131                 return -ENXIO;
 132         while (!req.complete)
 133                 cuda_poll();
 134         if ((req.reply_len != 3) && (req.reply_len != 7))
 135                 printk(KERN_ERR "cuda_set_rtc_time: got %d byte reply\n",
 136                        req.reply_len);
 137         return 0;
 138 }
 139
 140 #else
 141 #define cuda_get_time()         0
 142 #define cuda_get_rtc_time(tm)
 143 #define cuda_set_rtc_time(tm)   0
 144 #endif
 145
 146 #ifdef CONFIG_ADB_PMU
 147 static unsigned long pmu_get_time(void)
 148 {
 149         struct adb_request req;
 150         unsigned int now;
 151
 152         if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
 153                 return 0;
 154         pmu_wait_complete(&req);
 155         if (req.reply_len != 4)
 156                 printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n",
 157                        req.reply_len);
 158         now = (req.reply[0] << 24) + (req.reply[1] << 16)
 159                 + (req.reply[2] << 8) + req.reply[3];
 160         return ((unsigned long)now) - RTC_OFFSET;
 161 }
 162
 163 #define pmu_get_rtc_time(tm)    to_rtc_time(pmu_get_time(), (tm))
 164
 165 static int pmu_set_rtc_time(struct rtc_time *tm)
 166 {
 167         unsigned int nowtime;
 168         struct adb_request req;
 169
 170         nowtime = from_rtc_time(tm) + RTC_OFFSET;
 171         if (pmu_request(&req, NULL, 5, PMU_SET_RTC, nowtime >> 24,
 172                         nowtime >> 16, nowtime >> 8, nowtime) < 0)
 173                 return -ENXIO;
 174         pmu_wait_complete(&req);
 175         if (req.reply_len != 0)
 176                 printk(KERN_ERR "pmu_set_rtc_time: %d byte reply from PMU\n",
 177                        req.reply_len);
 178         return 0;
 179 }
 180
 181 #else
 182 #define pmu_get_time()          0
 183 #define pmu_get_rtc_time(tm)
 184 #define pmu_set_rtc_time(tm)    0
 185 #endif
 186
 187 #ifdef CONFIG_PMAC_SMU
 188 static unsigned long smu_get_time(void)
 189 {
 190         struct rtc_time tm;
 191
 192         if (smu_get_rtc_time(&tm, 1))
 193                 return 0;
 194         return from_rtc_time(&tm);
 195 }
 196
 197 #else
 198 #define smu_get_time()                  0
 199 #define smu_get_rtc_time(tm, spin)
 200 #define smu_set_rtc_time(tm, spin)      0
 201 #endif
 202
 203 /* Can't be __init, it's called when suspending and resuming */
 204 unsigned long pmac_get_boot_time(void)
 205 {
 206         /* Get the time from the RTC, used only at boot time */
 207         switch (sys_ctrler) {
 208         case SYS_CTRLER_CUDA:
 209                 return cuda_get_time();
 210         case SYS_CTRLER_PMU:
 211                 return pmu_get_time();
 212         case SYS_CTRLER_SMU:
 213                 return smu_get_time();
 214         default:
 215                 return 0;
 216         }
 217 }
 218
 219 void pmac_get_rtc_time(struct rtc_time *tm)
 220 {
 221         /* Get the time from the RTC, used only at boot time */
 222         switch (sys_ctrler) {
 223         case SYS_CTRLER_CUDA:
 224                 cuda_get_rtc_time(tm);
 225                 break;
 226         case SYS_CTRLER_PMU:
 227                 pmu_get_rtc_time(tm);
 228                 break;
 229         case SYS_CTRLER_SMU:
 230                 smu_get_rtc_time(tm, 1);
 231                 break;
 232         default:
 233                 ;
 234         }
 235 }
 236
 237 int pmac_set_rtc_time(struct rtc_time *tm)
 238 {
 239         switch (sys_ctrler) {
 240         case SYS_CTRLER_CUDA:
 241                 return cuda_set_rtc_time(tm);
 242         case SYS_CTRLER_PMU:
 243                 return pmu_set_rtc_time(tm);
 244         case SYS_CTRLER_SMU:
 245                 return smu_set_rtc_time(tm, 1);
 246         default:
 247                 return -ENODEV;
 248         }
 249 }
 250
 251 #ifdef CONFIG_PPC32
 252 /*
 253  * Calibrate the decrementer register using VIA timer 1.
 254  * This is used both on powermacs and CHRP machines.
 255  */
 256 int __init via_calibrate_decr(void)
 257 {
 258         struct device_node *vias;
 259         volatile unsigned char __iomem *via;
 260         int count = VIA_TIMER_FREQ_6 / 100;
 261         unsigned int dstart, dend;
 262         struct resource rsrc;
 263
 264         vias = of_find_node_by_name(NULL, "via-cuda");
 265         if (vias == 0)
 266                 vias = of_find_node_by_name(NULL, "via-pmu");
 267         if (vias == 0)
 268                 vias = of_find_node_by_name(NULL, "via");
 269         if (vias == 0 || of_address_to_resource(vias, 0, &rsrc))
 270                 return 0;
 271         via = ioremap(rsrc.start, rsrc.end - rsrc.start + 1);
 272         if (via == NULL) {
 273                 printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
 274                 return 0;
 275         }
 276
 277         /* set timer 1 for continuous interrupts */
 278         out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
 279         /* set the counter to a small value */
 280         out_8(&via[T1CH], 2);
 281         /* set the latch to `count' */
 282         out_8(&via[T1LL], count);
 283         out_8(&via[T1LH], count >> 8);
 284         /* wait until it hits 0 */
 285         while ((in_8(&via[IFR]) & T1_INT) == 0)
 286                 ;
 287         dstart = get_dec();
 288         /* clear the interrupt & wait until it hits 0 again */
 289         in_8(&via[T1CL]);
 290         while ((in_8(&via[IFR]) & T1_INT) == 0)
 291                 ;
 292         dend = get_dec();
 293
 294         ppc_tb_freq = (dstart - dend) * 100 / 6;
 295
 296         iounmap(via);
 297
 298         return 1;
 299 }
 300 #endif
 301
 302 /*
 303  * Query the OF and get the decr frequency.
 304  */
 305 void __init pmac_calibrate_decr(void)
 306 {
 307         generic_calibrate_decr();
 308
 309 #ifdef CONFIG_PPC32
 310         /* We assume MacRISC2 machines have correct device-tree
 311          * calibration. That's better since the VIA itself seems
 312          * to be slightly off. --BenH
 313          */
 314         if (!machine_is_compatible("MacRISC2") &&
 315             !machine_is_compatible("MacRISC3") &&
 316             !machine_is_compatible("MacRISC4"))
 317                 if (via_calibrate_decr())
 318                         return;
 319
 320         /* Special case: QuickSilver G4s seem to have a badly calibrated
 321          * timebase-frequency in OF, VIA is much better on these. We should
 322          * probably implement calibration based on the KL timer on these
 323          * machines anyway... -BenH
 324          */
 325         if (machine_is_compatible("PowerMac3,5"))
 326                 if (via_calibrate_decr())
 327                         return;
 328 #endif
 329 }