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
28 #include <asm/sections.h>
29 #include <asm/prom.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 #include "pmac.h"
38
39 #undef DEBUG
40
41 #ifdef DEBUG
42 #define DBG(x...) printk(x)
43 #else
44 #define DBG(x...)
45 #endif
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 #if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32)
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 #ifdef CONFIG_PMAC_SMU
smu_get_time(void)87 static time64_t smu_get_time(void)
88 {
89 struct rtc_time tm;
90
91 if (smu_get_rtc_time(&tm, 1))
92 return 0;
93 return rtc_tm_to_time64(&tm);
94 }
95 #endif
96
97 /* Can't be __init, it's called when suspending and resuming */
pmac_get_boot_time(void)98 time64_t pmac_get_boot_time(void)
99 {
100 /* Get the time from the RTC, used only at boot time */
101 switch (sys_ctrler) {
102 #ifdef CONFIG_ADB_CUDA
103 case SYS_CTRLER_CUDA:
104 return cuda_get_time();
105 #endif
106 #ifdef CONFIG_ADB_PMU
107 case SYS_CTRLER_PMU:
108 return pmu_get_time();
109 #endif
110 #ifdef CONFIG_PMAC_SMU
111 case SYS_CTRLER_SMU:
112 return smu_get_time();
113 #endif
114 default:
115 return 0;
116 }
117 }
118
pmac_get_rtc_time(struct rtc_time * tm)119 void pmac_get_rtc_time(struct rtc_time *tm)
120 {
121 /* Get the time from the RTC, used only at boot time */
122 switch (sys_ctrler) {
123 #ifdef CONFIG_ADB_CUDA
124 case SYS_CTRLER_CUDA:
125 rtc_time64_to_tm(cuda_get_time(), tm);
126 break;
127 #endif
128 #ifdef CONFIG_ADB_PMU
129 case SYS_CTRLER_PMU:
130 rtc_time64_to_tm(pmu_get_time(), tm);
131 break;
132 #endif
133 #ifdef CONFIG_PMAC_SMU
134 case SYS_CTRLER_SMU:
135 smu_get_rtc_time(tm, 1);
136 break;
137 #endif
138 default:
139 ;
140 }
141 }
142
pmac_set_rtc_time(struct rtc_time * tm)143 int pmac_set_rtc_time(struct rtc_time *tm)
144 {
145 switch (sys_ctrler) {
146 #ifdef CONFIG_ADB_CUDA
147 case SYS_CTRLER_CUDA:
148 return cuda_set_rtc_time(tm);
149 #endif
150 #ifdef CONFIG_ADB_PMU
151 case SYS_CTRLER_PMU:
152 return pmu_set_rtc_time(tm);
153 #endif
154 #ifdef CONFIG_PMAC_SMU
155 case SYS_CTRLER_SMU:
156 return smu_set_rtc_time(tm, 1);
157 #endif
158 default:
159 return -ENODEV;
160 }
161 }
162
163 #ifdef CONFIG_PPC32
164 /*
165 * Calibrate the decrementer register using VIA timer 1.
166 * This is used both on powermacs and CHRP machines.
167 */
via_calibrate_decr(void)168 static int __init via_calibrate_decr(void)
169 {
170 struct device_node *vias;
171 volatile unsigned char __iomem *via;
172 int count = VIA_TIMER_FREQ_6 / 100;
173 unsigned int dstart, dend;
174 struct resource rsrc;
175
176 vias = of_find_node_by_name(NULL, "via-cuda");
177 if (vias == NULL)
178 vias = of_find_node_by_name(NULL, "via-pmu");
179 if (vias == NULL)
180 vias = of_find_node_by_name(NULL, "via");
181 if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) {
182 of_node_put(vias);
183 return 0;
184 }
185 of_node_put(vias);
186 via = ioremap(rsrc.start, resource_size(&rsrc));
187 if (via == NULL) {
188 printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
189 return 0;
190 }
191
192 /* set timer 1 for continuous interrupts */
193 out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
194 /* set the counter to a small value */
195 out_8(&via[T1CH], 2);
196 /* set the latch to `count' */
197 out_8(&via[T1LL], count);
198 out_8(&via[T1LH], count >> 8);
199 /* wait until it hits 0 */
200 while ((in_8(&via[IFR]) & T1_INT) == 0)
201 ;
202 dstart = get_dec();
203 /* clear the interrupt & wait until it hits 0 again */
204 in_8(&via[T1CL]);
205 while ((in_8(&via[IFR]) & T1_INT) == 0)
206 ;
207 dend = get_dec();
208
209 ppc_tb_freq = (dstart - dend) * 100 / 6;
210
211 iounmap(via);
212
213 return 1;
214 }
215 #endif
216
217 /*
218 * Query the OF and get the decr frequency.
219 */
pmac_calibrate_decr(void)220 void __init pmac_calibrate_decr(void)
221 {
222 generic_calibrate_decr();
223
224 #ifdef CONFIG_PPC32
225 /* We assume MacRISC2 machines have correct device-tree
226 * calibration. That's better since the VIA itself seems
227 * to be slightly off. --BenH
228 */
229 if (!of_machine_is_compatible("MacRISC2") &&
230 !of_machine_is_compatible("MacRISC3") &&
231 !of_machine_is_compatible("MacRISC4"))
232 if (via_calibrate_decr())
233 return;
234
235 /* Special case: QuickSilver G4s seem to have a badly calibrated
236 * timebase-frequency in OF, VIA is much better on these. We should
237 * probably implement calibration based on the KL timer on these
238 * machines anyway... -BenH
239 */
240 if (of_machine_is_compatible("PowerMac3,5"))
241 if (via_calibrate_decr())
242 return;
243 #endif
244 }
245
