2 * Support for periodic interrupts (100 per second) and for getting
3 * the current time from the RTC on Power Macintoshes.
5 * We use the decrementer register for our periodic interrupts.
7 * Paul Mackerras August 1996.
8 * Copyright (C) 1996 Paul Mackerras.
10 #include <linux/config.h>
11 #include <linux/errno.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/param.h>
15 #include <linux/string.h>
17 #include <linux/init.h>
18 #include <linux/time.h>
19 #include <linux/adb.h>
20 #include <linux/cuda.h>
21 #include <linux/pmu.h>
22 #include <linux/hardirq.h>
24 #include <asm/sections.h>
26 #include <asm/system.h>
28 #include <asm/pgtable.h>
29 #include <asm/machdep.h>
31 #include <asm/nvram.h>
33 /* Apparently the RTC stores seconds since 1 Jan 1904 */
34 #define RTC_OFFSET 2082844800
37 * Calibrate the decrementer frequency with the VIA timer 1.
39 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */
42 #define RS 0x200 /* skip between registers */
43 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
44 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
45 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
46 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
47 #define ACR (11*RS) /* Auxiliary control register */
48 #define IFR (13*RS) /* Interrupt flag register */
51 #define T1MODE 0xc0 /* Timer 1 mode */
52 #define T1MODE_CONT 0x40 /* continuous interrupts */
54 /* Bits in IFR and IER */
55 #define T1_INT 0x40 /* Timer 1 interrupt */
57 extern struct timezone sys_tz;
66 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
67 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
68 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
69 if (delta & 0x00800000UL)
70 delta |= 0xFF000000UL;
71 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
72 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
80 unsigned long pmac_get_boot_time(void)
82 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
83 struct adb_request req;
87 /* Get the time from the RTC */
89 #ifdef CONFIG_ADB_CUDA
91 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
95 if (req.reply_len != 7)
96 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
98 now = (req.reply[3] << 24) + (req.reply[4] << 16)
99 + (req.reply[5] << 8) + req.reply[6];
100 return now - RTC_OFFSET;
101 #endif /* CONFIG_ADB_CUDA */
102 #ifdef CONFIG_ADB_PMU
104 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
106 while (!req.complete)
108 if (req.reply_len != 4)
109 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
111 now = (req.reply[0] << 24) + (req.reply[1] << 16)
112 + (req.reply[2] << 8) + req.reply[3];
113 return now - RTC_OFFSET;
114 #endif /* CONFIG_ADB_PMU */
120 void pmac_get_rtc_time(struct rtc_time *tm)
124 now = pmac_get_boot_time();
127 tm->tm_mon -= 1; /* month is 0-based */
130 int pmac_set_rtc_time(struct rtc_time *tm)
132 unsigned long nowtime;
133 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
134 struct adb_request req;
137 nowtime = mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
138 tm->tm_hour, tm->tm_min, tm->tm_sec);
139 nowtime += RTC_OFFSET;
141 switch (sys_ctrler) {
142 #ifdef CONFIG_ADB_CUDA
143 case SYS_CTRLER_CUDA:
144 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
145 nowtime >> 24, nowtime >> 16, nowtime >> 8,
148 while (!req.complete)
150 if ((req.reply_len != 3) && (req.reply_len != 7))
151 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
154 #endif /* CONFIG_ADB_CUDA */
155 #ifdef CONFIG_ADB_PMU
157 if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
158 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
160 while (!req.complete)
162 if (req.reply_len != 0)
163 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
166 #endif /* CONFIG_ADB_PMU */
173 * Calibrate the decrementer register using VIA timer 1.
174 * This is used both on powermacs and CHRP machines.
177 via_calibrate_decr(void)
179 struct device_node *vias;
180 volatile unsigned char __iomem *via;
181 int count = VIA_TIMER_FREQ_6 / 100;
182 unsigned int dstart, dend;
184 vias = find_devices("via-cuda");
186 vias = find_devices("via-pmu");
188 vias = find_devices("via");
189 if (vias == 0 || vias->n_addrs == 0)
191 via = ioremap(vias->addrs[0].address, vias->addrs[0].size);
193 /* set timer 1 for continuous interrupts */
194 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
195 /* set the counter to a small value */
196 out_8(&via[T1CH], 2);
197 /* set the latch to `count' */
198 out_8(&via[T1LL], count);
199 out_8(&via[T1LH], count >> 8);
200 /* wait until it hits 0 */
201 while ((in_8(&via[IFR]) & T1_INT) == 0)
204 /* clear the interrupt & wait until it hits 0 again */
206 while ((in_8(&via[IFR]) & T1_INT) == 0)
210 tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
211 tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);
213 printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",
214 tb_ticks_per_jiffy, dstart - dend);
223 * Reset the time after a sleep.
226 time_sleep_notify(struct pmu_sleep_notifier *self, int when)
228 static unsigned long time_diff;
233 case PBOOK_SLEEP_NOW:
235 seq = read_seqbegin_irqsave(&xtime_lock, flags);
236 time_diff = xtime.tv_sec - pmac_get_boot_time();
237 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
240 write_seqlock_irqsave(&xtime_lock, flags);
241 xtime.tv_sec = pmac_get_rtc_time() + time_diff;
243 last_rtc_update = xtime.tv_sec;
244 write_sequnlock_irqrestore(&xtime_lock, flags);
247 return PBOOK_SLEEP_OK;
250 static struct pmu_sleep_notifier time_sleep_notifier = {
251 time_sleep_notify, SLEEP_LEVEL_MISC,
253 #endif /* CONFIG_PM */
256 * Query the OF and get the decr frequency.
257 * This was taken from the pmac time_init() when merging the prep/pmac
261 pmac_calibrate_decr(void)
263 struct device_node *cpu;
264 unsigned int freq, *fp;
267 pmu_register_sleep_notifier(&time_sleep_notifier);
268 #endif /* CONFIG_PM */
270 /* We assume MacRISC2 machines have correct device-tree
271 * calibration. That's better since the VIA itself seems
272 * to be slightly off. --BenH
274 if (!machine_is_compatible("MacRISC2") &&
275 !machine_is_compatible("MacRISC3") &&
276 !machine_is_compatible("MacRISC4"))
277 if (via_calibrate_decr())
280 /* Special case: QuickSilver G4s seem to have a badly calibrated
281 * timebase-frequency in OF, VIA is much better on these. We should
282 * probably implement calibration based on the KL timer on these
283 * machines anyway... -BenH
285 if (machine_is_compatible("PowerMac3,5"))
286 if (via_calibrate_decr())
289 * The cpu node should have a timebase-frequency property
290 * to tell us the rate at which the decrementer counts.
292 cpu = find_type_devices("cpu");
294 panic("can't find cpu node in time_init");
295 fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL);
297 panic("can't get cpu timebase frequency");
299 printk("time_init: decrementer frequency = %u.%.6u MHz\n",
300 freq/1000000, freq%1000000);
301 tb_ticks_per_jiffy = freq / HZ;
302 tb_to_us = mulhwu_scale_factor(freq, 1000000);