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 static void to_rtc_time(unsigned long now, struct rtc_time *tm)
  88 {
  89         to_tm(now, tm);
  90         tm->tm_year -= 1900;
  91         tm->tm_mon -= 1;
  92 }
  93
  94 static unsigned long from_rtc_time(struct rtc_time *tm)
  95 {
  96         return mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
  97                       tm->tm_hour, tm->tm_min, tm->tm_sec);
  98 }
  99
 100 #ifdef CONFIG_ADB_CUDA
 101 static unsigned long cuda_get_time(void)
 102 {
 103         struct adb_request req;
 104         unsigned int now;
 105
 106         if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
 107                 return 0;
 108         while (!req.complete)
 109                 cuda_poll();
 110         if (req.reply_len != 7)
 111                 printk(KERN_ERR "cuda_get_time: got %d byte reply\n",
 112                        req.reply_len);
 113         now = (req.reply[3] << 24) + (req.reply[4] << 16)
 114                 + (req.reply[5] << 8) + req.reply[6];
 115         return ((unsigned long)now) - RTC_OFFSET;
 116 }
 117
 118 #define cuda_get_rtc_time(tm)   to_rtc_time(cuda_get_time(), (tm))
 119
 120 static int cuda_set_rtc_time(struct rtc_time *tm)
 121 {
 122         unsigned int nowtime;
 123         struct adb_request req;
 124
 125         nowtime = from_rtc_time(tm) + RTC_OFFSET;
 126         if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
 127                          nowtime >> 24, nowtime >> 16, nowtime >> 8,
 128                          nowtime) < 0)
 129                 return -ENXIO;
 130         while (!req.complete)
 131                 cuda_poll();
 132         if ((req.reply_len != 3) && (req.reply_len != 7))
 133                 printk(KERN_ERR "cuda_set_rtc_time: got %d byte reply\n",
 134                        req.reply_len);
 135         return 0;
 136 }
 137
 138 #else
 139 #define cuda_get_time()         0
 140 #define cuda_get_rtc_time(tm)
 141 #define cuda_set_rtc_time(tm)   0
 142 #endif
 143
 144 #ifdef CONFIG_ADB_PMU
 145 static unsigned long pmu_get_time(void)
 146 {
 147         struct adb_request req;
 148         unsigned int now;
 149
 150         if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
 151                 return 0;
 152         pmu_wait_complete(&req);
 153         if (req.reply_len != 4)
 154                 printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n",
 155                        req.reply_len);
 156         now = (req.reply[0] << 24) + (req.reply[1] << 16)
 157                 + (req.reply[2] << 8) + req.reply[3];
 158         return ((unsigned long)now) - RTC_OFFSET;
 159 }
 160
 161 #define pmu_get_rtc_time(tm)    to_rtc_time(pmu_get_time(), (tm))
 162
 163 static int pmu_set_rtc_time(struct rtc_time *tm)
 164 {
 165         unsigned int nowtime;
 166         struct adb_request req;
 167
 168         nowtime = from_rtc_time(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 unsigned long smu_get_time(void)
 187 {
 188         struct rtc_time tm;
 189
 190         if (smu_get_rtc_time(&tm, 1))
 191                 return 0;
 192         return from_rtc_time(&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 unsigned long 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 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 == 0)
 264                 vias = of_find_node_by_name(NULL, "via-pmu");
 265         if (vias == 0)
 266                 vias = of_find_node_by_name(NULL, "via");
 267         if (vias == 0 || of_address_to_resource(vias, 0, &rsrc))
 268                 return 0;
 269         via = ioremap(rsrc.start, rsrc.end - rsrc.start + 1);
 270         if (via == NULL) {
 271                 printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
 272                 return 0;
 273         }
 274
 275         /* set timer 1 for continuous interrupts */
 276         out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
 277         /* set the counter to a small value */
 278         out_8(&via[T1CH], 2);
 279         /* set the latch to `count' */
 280         out_8(&via[T1LL], count);
 281         out_8(&via[T1LH], count >> 8);
 282         /* wait until it hits 0 */
 283         while ((in_8(&via[IFR]) & T1_INT) == 0)
 284                 ;
 285         dstart = get_dec();
 286         /* clear the interrupt & wait until it hits 0 again */
 287         in_8(&via[T1CL]);
 288         while ((in_8(&via[IFR]) & T1_INT) == 0)
 289                 ;
 290         dend = get_dec();
 291
 292         ppc_tb_freq = (dstart - dend) * 100 / 6;
 293
 294         iounmap(via);
 295
 296         return 1;
 297 }
 298 #endif
 299
 300 /*
 301  * Query the OF and get the decr frequency.
 302  */
 303 void __init pmac_calibrate_decr(void)
 304 {
 305         generic_calibrate_decr();
 306
 307 #ifdef CONFIG_PPC32
 308         /* We assume MacRISC2 machines have correct device-tree
 309          * calibration. That's better since the VIA itself seems
 310          * to be slightly off. --BenH
 311          */
 312         if (!machine_is_compatible("MacRISC2") &&
 313             !machine_is_compatible("MacRISC3") &&
 314             !machine_is_compatible("MacRISC4"))
 315                 if (via_calibrate_decr())
 316                         return;
 317
 318         /* Special case: QuickSilver G4s seem to have a badly calibrated
 319          * timebase-frequency in OF, VIA is much better on these. We should
 320          * probably implement calibration based on the KL timer on these
 321          * machines anyway... -BenH
 322          */
 323         if (machine_is_compatible("PowerMac3,5"))
 324                 if (via_calibrate_decr())
 325                         return;
 326 #endif
 327 }