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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 
pmac_time_init(void)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)
to_rtc_time(unsigned long now,struct rtc_time * tm)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)
from_rtc_time(struct rtc_time * tm)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
cuda_get_time(void)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 
cuda_set_rtc_time(struct rtc_time * tm)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
pmu_get_time(void)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 
pmu_set_rtc_time(struct rtc_time * tm)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
smu_get_time(void)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 */
pmac_get_boot_time(void)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 
pmac_get_rtc_time(struct rtc_time * tm)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 
pmac_set_rtc_time(struct rtc_time * tm)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  */
via_calibrate_decr(void)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, rsrc.end - rsrc.start + 1);
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  */
pmac_calibrate_decr(void)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 (!machine_is_compatible("MacRISC2") &&
321 	    !machine_is_compatible("MacRISC3") &&
322 	    !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 (machine_is_compatible("PowerMac3,5"))
332 		if (via_calibrate_decr())
333 			return;
334 #endif
335 }
336