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.
9 * Copyright (C) 2003-2005 Benjamin Herrenschmidt.
12 #include <linux/config.h>
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>
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>
28 #include <asm/sections.h>
30 #include <asm/system.h>
32 #include <asm/pgtable.h>
33 #include <asm/machdep.h>
35 #include <asm/nvram.h>
40 #define DBG(x...) printk(x)
45 /* Apparently the RTC stores seconds since 1 Jan 1904 */
46 #define RTC_OFFSET 2082844800
49 * Calibrate the decrementer frequency with the VIA timer 1.
51 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */
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 */
63 #define T1MODE 0xc0 /* Timer 1 mode */
64 #define T1MODE_CONT 0x40 /* continuous interrupts */
66 /* Bits in IFR and IER */
67 #define T1_INT 0x40 /* Timer 1 interrupt */
69 long __init pmac_time_init(void)
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,
89 unsigned long pmac_get_boot_time(void)
91 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
92 struct adb_request req;
96 /* Get the time from the RTC */
98 #ifdef CONFIG_ADB_CUDA
100 if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
102 while (!req.complete)
104 if (req.reply_len != 7)
105 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
107 now = (req.reply[3] << 24) + (req.reply[4] << 16)
108 + (req.reply[5] << 8) + req.reply[6];
109 return now - RTC_OFFSET;
110 #endif /* CONFIG_ADB_CUDA */
111 #ifdef CONFIG_ADB_PMU
113 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
115 while (!req.complete)
117 if (req.reply_len != 4)
118 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
120 now = (req.reply[0] << 24) + (req.reply[1] << 16)
121 + (req.reply[2] << 8) + req.reply[3];
122 return now - RTC_OFFSET;
123 #endif /* CONFIG_ADB_PMU */
129 void pmac_get_rtc_time(struct rtc_time *tm)
133 now = pmac_get_boot_time();
136 tm->tm_mon -= 1; /* month is 0-based */
139 int pmac_set_rtc_time(struct rtc_time *tm)
141 unsigned long nowtime;
142 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
143 struct adb_request req;
146 nowtime = mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
147 tm->tm_hour, tm->tm_min, tm->tm_sec);
148 nowtime += RTC_OFFSET;
150 switch (sys_ctrler) {
151 #ifdef CONFIG_ADB_CUDA
152 case SYS_CTRLER_CUDA:
153 if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
154 nowtime >> 24, nowtime >> 16, nowtime >> 8,
157 while (!req.complete)
159 if ((req.reply_len != 3) && (req.reply_len != 7))
160 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
163 #endif /* CONFIG_ADB_CUDA */
164 #ifdef CONFIG_ADB_PMU
166 if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
167 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
169 while (!req.complete)
171 if (req.reply_len != 0)
172 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
175 #endif /* CONFIG_ADB_PMU */
182 * Calibrate the decrementer register using VIA timer 1.
183 * This is used both on powermacs and CHRP machines.
186 via_calibrate_decr(void)
188 struct device_node *vias;
189 volatile unsigned char __iomem *via;
190 int count = VIA_TIMER_FREQ_6 / 100;
191 unsigned int dstart, dend;
193 vias = find_devices("via-cuda");
195 vias = find_devices("via-pmu");
197 vias = find_devices("via");
198 if (vias == 0 || vias->n_addrs == 0)
200 via = ioremap(vias->addrs[0].address, vias->addrs[0].size);
202 /* set timer 1 for continuous interrupts */
203 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
204 /* set the counter to a small value */
205 out_8(&via[T1CH], 2);
206 /* set the latch to `count' */
207 out_8(&via[T1LL], count);
208 out_8(&via[T1LH], count >> 8);
209 /* wait until it hits 0 */
210 while ((in_8(&via[IFR]) & T1_INT) == 0)
213 /* clear the interrupt & wait until it hits 0 again */
215 while ((in_8(&via[IFR]) & T1_INT) == 0)
219 ppc_tb_freq = (dstart - dend) * 100 / 6;
220 tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
222 printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %lu (%u ticks)\n",
223 tb_ticks_per_jiffy, dstart - dend);
232 * Reset the time after a sleep.
235 time_sleep_notify(struct pmu_sleep_notifier *self, int when)
237 static unsigned long time_diff;
243 case PBOOK_SLEEP_NOW:
245 seq = read_seqbegin_irqsave(&xtime_lock, flags);
246 time_diff = xtime.tv_sec - pmac_get_boot_time();
247 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
250 tv.tv_sec = pmac_get_boot_time() + time_diff;
252 do_settimeofday(&tv);
255 return PBOOK_SLEEP_OK;
258 static struct pmu_sleep_notifier time_sleep_notifier = {
259 time_sleep_notify, SLEEP_LEVEL_MISC,
261 #endif /* CONFIG_PM */
264 * Query the OF and get the decr frequency.
265 * This was taken from the pmac time_init() when merging the prep/pmac
269 pmac_calibrate_decr(void)
271 struct device_node *cpu;
272 unsigned int freq, *fp;
275 pmu_register_sleep_notifier(&time_sleep_notifier);
276 #endif /* CONFIG_PM */
278 /* We assume MacRISC2 machines have correct device-tree
279 * calibration. That's better since the VIA itself seems
280 * to be slightly off. --BenH
282 if (!machine_is_compatible("MacRISC2") &&
283 !machine_is_compatible("MacRISC3") &&
284 !machine_is_compatible("MacRISC4"))
285 if (via_calibrate_decr())
288 /* Special case: QuickSilver G4s seem to have a badly calibrated
289 * timebase-frequency in OF, VIA is much better on these. We should
290 * probably implement calibration based on the KL timer on these
291 * machines anyway... -BenH
293 if (machine_is_compatible("PowerMac3,5"))
294 if (via_calibrate_decr())
297 * The cpu node should have a timebase-frequency property
298 * to tell us the rate at which the decrementer counts.
300 cpu = find_type_devices("cpu");
302 panic("can't find cpu node in time_init");
303 fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL);
305 panic("can't get cpu timebase frequency");
307 printk("time_init: decrementer frequency = %u.%.6u MHz\n",
308 freq/1000000, freq%1000000);