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/io.h>
30 #include <asm/pgtable.h>
31 #include <asm/machdep.h>
32 #include <asm/time.h>
33 #include <asm/nvram.h>
34 #include <asm/smu.h>
35 
36 #undef DEBUG
37 
38 #ifdef DEBUG
39 #define DBG(x...) printk(x)
40 #else
41 #define DBG(x...)
42 #endif
43 
44 /* Apparently the RTC stores seconds since 1 Jan 1904 */
45 #define RTC_OFFSET	2082844800
46 
47 /*
48  * Calibrate the decrementer frequency with the VIA timer 1.
49  */
50 #define VIA_TIMER_FREQ_6	4700000	/* time 1 frequency * 6 */
51 
52 /* VIA registers */
53 #define RS		0x200		/* skip between registers */
54 #define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
55 #define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
56 #define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
57 #define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
58 #define ACR		(11*RS)		/* Auxiliary control register */
59 #define IFR		(13*RS)		/* Interrupt flag register */
60 
61 /* Bits in ACR */
62 #define T1MODE		0xc0		/* Timer 1 mode */
63 #define T1MODE_CONT	0x40		/*  continuous interrupts */
64 
65 /* Bits in IFR and IER */
66 #define T1_INT		0x40		/* Timer 1 interrupt */
67 
pmac_time_init(void)68 long __init pmac_time_init(void)
69 {
70 	s32 delta = 0;
71 #ifdef CONFIG_NVRAM
72 	int dst;
73 
74 	delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
75 	delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
76 	delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
77 	if (delta & 0x00800000UL)
78 		delta |= 0xFF000000UL;
79 	dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
80 	printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
81 		dst ? "on" : "off");
82 #endif
83 	return delta;
84 }
85 
86 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
to_rtc_time(unsigned long now,struct rtc_time * tm)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 #endif
94 
95 #if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU) || \
96     defined(CONFIG_PMAC_SMU)
from_rtc_time(struct rtc_time * tm)97 static unsigned long from_rtc_time(struct rtc_time *tm)
98 {
99 	return mktime(tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
100 		      tm->tm_hour, tm->tm_min, tm->tm_sec);
101 }
102 #endif
103 
104 #ifdef CONFIG_ADB_CUDA
cuda_get_time(void)105 static unsigned long cuda_get_time(void)
106 {
107 	struct adb_request req;
108 	unsigned int now;
109 
110 	if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
111 		return 0;
112 	while (!req.complete)
113 		cuda_poll();
114 	if (req.reply_len != 7)
115 		printk(KERN_ERR "cuda_get_time: got %d byte reply\n",
116 		       req.reply_len);
117 	now = (req.reply[3] << 24) + (req.reply[4] << 16)
118 		+ (req.reply[5] << 8) + req.reply[6];
119 	return ((unsigned long)now) - RTC_OFFSET;
120 }
121 
122 #define cuda_get_rtc_time(tm)	to_rtc_time(cuda_get_time(), (tm))
123 
cuda_set_rtc_time(struct rtc_time * tm)124 static int cuda_set_rtc_time(struct rtc_time *tm)
125 {
126 	unsigned int nowtime;
127 	struct adb_request req;
128 
129 	nowtime = from_rtc_time(tm) + RTC_OFFSET;
130 	if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
131 			 nowtime >> 24, nowtime >> 16, nowtime >> 8,
132 			 nowtime) < 0)
133 		return -ENXIO;
134 	while (!req.complete)
135 		cuda_poll();
136 	if ((req.reply_len != 3) && (req.reply_len != 7))
137 		printk(KERN_ERR "cuda_set_rtc_time: got %d byte reply\n",
138 		       req.reply_len);
139 	return 0;
140 }
141 
142 #else
143 #define cuda_get_time()		0
144 #define cuda_get_rtc_time(tm)
145 #define cuda_set_rtc_time(tm)	0
146 #endif
147 
148 #ifdef CONFIG_ADB_PMU
pmu_get_time(void)149 static unsigned long pmu_get_time(void)
150 {
151 	struct adb_request req;
152 	unsigned int now;
153 
154 	if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
155 		return 0;
156 	pmu_wait_complete(&req);
157 	if (req.reply_len != 4)
158 		printk(KERN_ERR "pmu_get_time: got %d byte reply from PMU\n",
159 		       req.reply_len);
160 	now = (req.reply[0] << 24) + (req.reply[1] << 16)
161 		+ (req.reply[2] << 8) + req.reply[3];
162 	return ((unsigned long)now) - RTC_OFFSET;
163 }
164 
165 #define pmu_get_rtc_time(tm)	to_rtc_time(pmu_get_time(), (tm))
166 
pmu_set_rtc_time(struct rtc_time * tm)167 static int pmu_set_rtc_time(struct rtc_time *tm)
168 {
169 	unsigned int nowtime;
170 	struct adb_request req;
171 
172 	nowtime = from_rtc_time(tm) + RTC_OFFSET;
173 	if (pmu_request(&req, NULL, 5, PMU_SET_RTC, nowtime >> 24,
174 			nowtime >> 16, nowtime >> 8, nowtime) < 0)
175 		return -ENXIO;
176 	pmu_wait_complete(&req);
177 	if (req.reply_len != 0)
178 		printk(KERN_ERR "pmu_set_rtc_time: %d byte reply from PMU\n",
179 		       req.reply_len);
180 	return 0;
181 }
182 
183 #else
184 #define pmu_get_time()		0
185 #define pmu_get_rtc_time(tm)
186 #define pmu_set_rtc_time(tm)	0
187 #endif
188 
189 #ifdef CONFIG_PMAC_SMU
smu_get_time(void)190 static unsigned long smu_get_time(void)
191 {
192 	struct rtc_time tm;
193 
194 	if (smu_get_rtc_time(&tm, 1))
195 		return 0;
196 	return from_rtc_time(&tm);
197 }
198 
199 #else
200 #define smu_get_time()			0
201 #define smu_get_rtc_time(tm, spin)
202 #define smu_set_rtc_time(tm, spin)	0
203 #endif
204 
205 /* Can't be __init, it's called when suspending and resuming */
pmac_get_boot_time(void)206 unsigned long pmac_get_boot_time(void)
207 {
208 	/* Get the time from the RTC, used only at boot time */
209 	switch (sys_ctrler) {
210 	case SYS_CTRLER_CUDA:
211 		return cuda_get_time();
212 	case SYS_CTRLER_PMU:
213 		return pmu_get_time();
214 	case SYS_CTRLER_SMU:
215 		return smu_get_time();
216 	default:
217 		return 0;
218 	}
219 }
220 
pmac_get_rtc_time(struct rtc_time * tm)221 void pmac_get_rtc_time(struct rtc_time *tm)
222 {
223 	/* Get the time from the RTC, used only at boot time */
224 	switch (sys_ctrler) {
225 	case SYS_CTRLER_CUDA:
226 		cuda_get_rtc_time(tm);
227 		break;
228 	case SYS_CTRLER_PMU:
229 		pmu_get_rtc_time(tm);
230 		break;
231 	case SYS_CTRLER_SMU:
232 		smu_get_rtc_time(tm, 1);
233 		break;
234 	default:
235 		;
236 	}
237 }
238 
pmac_set_rtc_time(struct rtc_time * tm)239 int pmac_set_rtc_time(struct rtc_time *tm)
240 {
241 	switch (sys_ctrler) {
242 	case SYS_CTRLER_CUDA:
243 		return cuda_set_rtc_time(tm);
244 	case SYS_CTRLER_PMU:
245 		return pmu_set_rtc_time(tm);
246 	case SYS_CTRLER_SMU:
247 		return smu_set_rtc_time(tm, 1);
248 	default:
249 		return -ENODEV;
250 	}
251 }
252 
253 #ifdef CONFIG_PPC32
254 /*
255  * Calibrate the decrementer register using VIA timer 1.
256  * This is used both on powermacs and CHRP machines.
257  */
via_calibrate_decr(void)258 int __init via_calibrate_decr(void)
259 {
260 	struct device_node *vias;
261 	volatile unsigned char __iomem *via;
262 	int count = VIA_TIMER_FREQ_6 / 100;
263 	unsigned int dstart, dend;
264 	struct resource rsrc;
265 
266 	vias = of_find_node_by_name(NULL, "via-cuda");
267 	if (vias == NULL)
268 		vias = of_find_node_by_name(NULL, "via-pmu");
269 	if (vias == NULL)
270 		vias = of_find_node_by_name(NULL, "via");
271 	if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) {
272 	        of_node_put(vias);
273 		return 0;
274 	}
275 	of_node_put(vias);
276 	via = ioremap(rsrc.start, resource_size(&rsrc));
277 	if (via == NULL) {
278 		printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
279 		return 0;
280 	}
281 
282 	/* set timer 1 for continuous interrupts */
283 	out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
284 	/* set the counter to a small value */
285 	out_8(&via[T1CH], 2);
286 	/* set the latch to `count' */
287 	out_8(&via[T1LL], count);
288 	out_8(&via[T1LH], count >> 8);
289 	/* wait until it hits 0 */
290 	while ((in_8(&via[IFR]) & T1_INT) == 0)
291 		;
292 	dstart = get_dec();
293 	/* clear the interrupt & wait until it hits 0 again */
294 	in_8(&via[T1CL]);
295 	while ((in_8(&via[IFR]) & T1_INT) == 0)
296 		;
297 	dend = get_dec();
298 
299 	ppc_tb_freq = (dstart - dend) * 100 / 6;
300 
301 	iounmap(via);
302 
303 	return 1;
304 }
305 #endif
306 
307 /*
308  * Query the OF and get the decr frequency.
309  */
pmac_calibrate_decr(void)310 void __init pmac_calibrate_decr(void)
311 {
312 	generic_calibrate_decr();
313 
314 #ifdef CONFIG_PPC32
315 	/* We assume MacRISC2 machines have correct device-tree
316 	 * calibration. That's better since the VIA itself seems
317 	 * to be slightly off. --BenH
318 	 */
319 	if (!of_machine_is_compatible("MacRISC2") &&
320 	    !of_machine_is_compatible("MacRISC3") &&
321 	    !of_machine_is_compatible("MacRISC4"))
322 		if (via_calibrate_decr())
323 			return;
324 
325 	/* Special case: QuickSilver G4s seem to have a badly calibrated
326 	 * timebase-frequency in OF, VIA is much better on these. We should
327 	 * probably implement calibration based on the KL timer on these
328 	 * machines anyway... -BenH
329 	 */
330 	if (of_machine_is_compatible("PowerMac3,5"))
331 		if (via_calibrate_decr())
332 			return;
333 #endif
334 }
335