1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Support for periodic interrupts (100 per second) and for getting
4 * the current time from the RTC on Power Macintoshes.
5 *
6 * We use the decrementer register for our periodic interrupts.
7 *
8 * Paul Mackerras August 1996.
9 * Copyright (C) 1996 Paul Mackerras.
10 * Copyright (C) 2003-2005 Benjamin Herrenschmidt.
11 *
12 */
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>
18 #include <linux/mm.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>
27 #include <linux/of_address.h>
28
29 #include <asm/early_ioremap.h>
30 #include <asm/sections.h>
31 #include <asm/machdep.h>
32 #include <asm/time.h>
33 #include <asm/nvram.h>
34 #include <asm/smu.h>
35
36 #include "pmac.h"
37
38 #undef DEBUG
39
40 #ifdef DEBUG
41 #define DBG(x...) printk(x)
42 #else
43 #define DBG(x...)
44 #endif
45
46 /*
47 * Calibrate the decrementer frequency with the VIA timer 1.
48 */
49 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */
50
51 /* VIA registers */
52 #define RS 0x200 /* skip between registers */
53 #define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
54 #define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
55 #define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
56 #define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
57 #define ACR (11*RS) /* Auxiliary control register */
58 #define IFR (13*RS) /* Interrupt flag register */
59
60 /* Bits in ACR */
61 #define T1MODE 0xc0 /* Timer 1 mode */
62 #define T1MODE_CONT 0x40 /* continuous interrupts */
63
64 /* Bits in IFR and IER */
65 #define T1_INT 0x40 /* Timer 1 interrupt */
66
67 long __init pmac_time_init(void)
68 {
69 s32 delta = 0;
70 #if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32)
71 int dst;
72
73 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
74 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
75 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
76 if (delta & 0x00800000UL)
77 delta |= 0xFF000000UL;
78 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
79 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
80 dst ? "on" : "off");
81 #endif
82 return delta;
83 }
84
85 #ifdef CONFIG_PMAC_SMU
86 static time64_t smu_get_time(void)
87 {
88 struct rtc_time tm;
89
90 if (smu_get_rtc_time(&tm, 1))
91 return 0;
92 return rtc_tm_to_time64(&tm);
93 }
94 #endif
95
96 /* Can't be __init, it's called when suspending and resuming */
97 time64_t pmac_get_boot_time(void)
98 {
99 /* Get the time from the RTC, used only at boot time */
100 switch (sys_ctrler) {
101 #ifdef CONFIG_ADB_CUDA
102 case SYS_CTRLER_CUDA:
103 return cuda_get_time();
104 #endif
105 #ifdef CONFIG_ADB_PMU
106 case SYS_CTRLER_PMU:
107 return pmu_get_time();
108 #endif
109 #ifdef CONFIG_PMAC_SMU
110 case SYS_CTRLER_SMU:
111 return smu_get_time();
112 #endif
113 default:
114 return 0;
115 }
116 }
117
118 void pmac_get_rtc_time(struct rtc_time *tm)
119 {
120 /* Get the time from the RTC, used only at boot time */
121 switch (sys_ctrler) {
122 #ifdef CONFIG_ADB_CUDA
123 case SYS_CTRLER_CUDA:
124 rtc_time64_to_tm(cuda_get_time(), tm);
125 break;
126 #endif
127 #ifdef CONFIG_ADB_PMU
128 case SYS_CTRLER_PMU:
129 rtc_time64_to_tm(pmu_get_time(), tm);
130 break;
131 #endif
132 #ifdef CONFIG_PMAC_SMU
133 case SYS_CTRLER_SMU:
134 smu_get_rtc_time(tm, 1);
135 break;
136 #endif
137 default:
138 ;
139 }
140 }
141
142 int pmac_set_rtc_time(struct rtc_time *tm)
143 {
144 switch (sys_ctrler) {
145 #ifdef CONFIG_ADB_CUDA
146 case SYS_CTRLER_CUDA:
147 return cuda_set_rtc_time(tm);
148 #endif
149 #ifdef CONFIG_ADB_PMU
150 case SYS_CTRLER_PMU:
151 return pmu_set_rtc_time(tm);
152 #endif
153 #ifdef CONFIG_PMAC_SMU
154 case SYS_CTRLER_SMU:
155 return smu_set_rtc_time(tm, 1);
156 #endif
157 default:
158 return -ENODEV;
159 }
160 }
161
162 #ifdef CONFIG_PPC32
163 /*
164 * Calibrate the decrementer register using VIA timer 1.
165 * This is used both on powermacs and CHRP machines.
166 */
167 static int __init via_calibrate_decr(void)
168 {
169 struct device_node *vias;
170 volatile unsigned char __iomem *via;
171 int count = VIA_TIMER_FREQ_6 / 100;
172 unsigned int dstart, dend;
173 struct resource rsrc;
174
175 vias = of_find_node_by_name(NULL, "via-cuda");
176 if (vias == NULL)
177 vias = of_find_node_by_name(NULL, "via-pmu");
178 if (vias == NULL)
179 vias = of_find_node_by_name(NULL, "via");
180 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) {
181 of_node_put(vias);
182 return 0;
183 }
184 of_node_put(vias);
185 via = early_ioremap(rsrc.start, resource_size(&rsrc));
186 if (via == NULL) {
187 printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
188 return 0;
189 }
190
191 /* set timer 1 for continuous interrupts */
192 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
193 /* set the counter to a small value */
194 out_8(&via[T1CH], 2);
195 /* set the latch to `count' */
196 out_8(&via[T1LL], count);
197 out_8(&via[T1LH], count >> 8);
198 /* wait until it hits 0 */
199 while ((in_8(&via[IFR]) & T1_INT) == 0)
200 ;
201 dstart = get_dec();
202 /* clear the interrupt & wait until it hits 0 again */
203 in_8(&via[T1CL]);
204 while ((in_8(&via[IFR]) & T1_INT) == 0)
205 ;
206 dend = get_dec();
207
208 ppc_tb_freq = (dstart - dend) * 100 / 6;
209
210 early_iounmap((void *)via, resource_size(&rsrc));
211
212 return 1;
213 }
214 #endif
215
216 /*
217 * Query the OF and get the decr frequency.
218 */
219 void __init pmac_calibrate_decr(void)
220 {
221 generic_calibrate_decr();
222
223 #ifdef CONFIG_PPC32
224 /* We assume MacRISC2 machines have correct device-tree
225 * calibration. That's better since the VIA itself seems
226 * to be slightly off. --BenH
227 */
228 if (!of_machine_is_compatible("MacRISC2") &&
229 !of_machine_is_compatible("MacRISC3") &&
230 !of_machine_is_compatible("MacRISC4"))
231 if (via_calibrate_decr())
232 return;
233
234 /* Special case: QuickSilver G4s seem to have a badly calibrated
235 * timebase-frequency in OF, VIA is much better on these. We should
236 * probably implement calibration based on the KL timer on these
237 * machines anyway... -BenH
238 */
239 if (of_machine_is_compatible("PowerMac3,5"))
240 if (via_calibrate_decr())
241 return;
242 #endif
243 }
244
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