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1 | /* |
2 | * QEMU model of the LatticeMico32 timer block. | |
3 | * | |
4 | * Copyright (c) 2010 Michael Walle <[email protected]> | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
18 | * | |
19 | * | |
20 | * Specification available at: | |
21 | * http://www.latticesemi.com/documents/mico32timer.pdf | |
22 | */ | |
23 | ||
24 | #include "hw.h" | |
25 | #include "sysbus.h" | |
26 | #include "trace.h" | |
27 | #include "qemu-timer.h" | |
28 | #include "qemu-error.h" | |
29 | ||
30 | #define DEFAULT_FREQUENCY (50*1000000) | |
31 | ||
32 | enum { | |
33 | R_SR = 0, | |
34 | R_CR, | |
35 | R_PERIOD, | |
36 | R_SNAPSHOT, | |
37 | R_MAX | |
38 | }; | |
39 | ||
40 | enum { | |
41 | SR_TO = (1 << 0), | |
42 | SR_RUN = (1 << 1), | |
43 | }; | |
44 | ||
45 | enum { | |
46 | CR_ITO = (1 << 0), | |
47 | CR_CONT = (1 << 1), | |
48 | CR_START = (1 << 2), | |
49 | CR_STOP = (1 << 3), | |
50 | }; | |
51 | ||
52 | struct LM32TimerState { | |
53 | SysBusDevice busdev; | |
54 | ||
55 | QEMUBH *bh; | |
56 | ptimer_state *ptimer; | |
57 | ||
58 | qemu_irq irq; | |
59 | uint32_t freq_hz; | |
60 | ||
61 | uint32_t regs[R_MAX]; | |
62 | }; | |
63 | typedef struct LM32TimerState LM32TimerState; | |
64 | ||
65 | static void timer_update_irq(LM32TimerState *s) | |
66 | { | |
67 | int state = (s->regs[R_SR] & SR_TO) && (s->regs[R_CR] & CR_ITO); | |
68 | ||
69 | trace_lm32_timer_irq_state(state); | |
70 | qemu_set_irq(s->irq, state); | |
71 | } | |
72 | ||
73 | static uint32_t timer_read(void *opaque, target_phys_addr_t addr) | |
74 | { | |
75 | LM32TimerState *s = opaque; | |
76 | uint32_t r = 0; | |
77 | ||
78 | addr >>= 2; | |
79 | switch (addr) { | |
80 | case R_SR: | |
81 | case R_CR: | |
82 | case R_PERIOD: | |
83 | r = s->regs[addr]; | |
84 | break; | |
85 | case R_SNAPSHOT: | |
86 | r = (uint32_t)ptimer_get_count(s->ptimer); | |
87 | break; | |
88 | default: | |
dd3d6775 | 89 | error_report("lm32_timer: read access to unknown register 0x" |
ea7924dc MW |
90 | TARGET_FMT_plx, addr << 2); |
91 | break; | |
92 | } | |
93 | ||
94 | trace_lm32_timer_memory_read(addr << 2, r); | |
95 | return r; | |
96 | } | |
97 | ||
98 | static void timer_write(void *opaque, target_phys_addr_t addr, uint32_t value) | |
99 | { | |
100 | LM32TimerState *s = opaque; | |
101 | ||
102 | trace_lm32_timer_memory_write(addr, value); | |
103 | ||
104 | addr >>= 2; | |
105 | switch (addr) { | |
106 | case R_SR: | |
107 | s->regs[R_SR] &= ~SR_TO; | |
108 | break; | |
109 | case R_CR: | |
110 | s->regs[R_CR] = value; | |
111 | if (s->regs[R_CR] & CR_START) { | |
112 | ptimer_run(s->ptimer, 1); | |
113 | } | |
114 | if (s->regs[R_CR] & CR_STOP) { | |
115 | ptimer_stop(s->ptimer); | |
116 | } | |
117 | break; | |
118 | case R_PERIOD: | |
119 | s->regs[R_PERIOD] = value; | |
120 | ptimer_set_count(s->ptimer, value); | |
121 | break; | |
122 | case R_SNAPSHOT: | |
123 | error_report("lm32_timer: write access to read only register 0x" | |
124 | TARGET_FMT_plx, addr << 2); | |
125 | break; | |
126 | default: | |
dd3d6775 | 127 | error_report("lm32_timer: write access to unknown register 0x" |
ea7924dc MW |
128 | TARGET_FMT_plx, addr << 2); |
129 | break; | |
130 | } | |
131 | timer_update_irq(s); | |
132 | } | |
133 | ||
134 | static CPUReadMemoryFunc * const timer_read_fn[] = { | |
135 | NULL, | |
136 | NULL, | |
137 | &timer_read, | |
138 | }; | |
139 | ||
140 | static CPUWriteMemoryFunc * const timer_write_fn[] = { | |
141 | NULL, | |
142 | NULL, | |
143 | &timer_write, | |
144 | }; | |
145 | ||
146 | static void timer_hit(void *opaque) | |
147 | { | |
148 | LM32TimerState *s = opaque; | |
149 | ||
150 | trace_lm32_timer_hit(); | |
151 | ||
152 | s->regs[R_SR] |= SR_TO; | |
153 | ||
154 | if (s->regs[R_CR] & CR_CONT) { | |
155 | ptimer_set_count(s->ptimer, s->regs[R_PERIOD]); | |
156 | ptimer_run(s->ptimer, 1); | |
157 | } | |
158 | timer_update_irq(s); | |
159 | } | |
160 | ||
161 | static void timer_reset(DeviceState *d) | |
162 | { | |
163 | LM32TimerState *s = container_of(d, LM32TimerState, busdev.qdev); | |
164 | int i; | |
165 | ||
166 | for (i = 0; i < R_MAX; i++) { | |
167 | s->regs[i] = 0; | |
168 | } | |
169 | ptimer_stop(s->ptimer); | |
170 | } | |
171 | ||
172 | static int lm32_timer_init(SysBusDevice *dev) | |
173 | { | |
174 | LM32TimerState *s = FROM_SYSBUS(typeof(*s), dev); | |
175 | int timer_regs; | |
176 | ||
177 | sysbus_init_irq(dev, &s->irq); | |
178 | ||
179 | s->bh = qemu_bh_new(timer_hit, s); | |
180 | s->ptimer = ptimer_init(s->bh); | |
181 | ptimer_set_freq(s->ptimer, s->freq_hz); | |
182 | ||
183 | timer_regs = cpu_register_io_memory(timer_read_fn, timer_write_fn, s, | |
184 | DEVICE_NATIVE_ENDIAN); | |
185 | sysbus_init_mmio(dev, R_MAX * 4, timer_regs); | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | static const VMStateDescription vmstate_lm32_timer = { | |
191 | .name = "lm32-timer", | |
192 | .version_id = 1, | |
193 | .minimum_version_id = 1, | |
194 | .minimum_version_id_old = 1, | |
195 | .fields = (VMStateField[]) { | |
196 | VMSTATE_PTIMER(ptimer, LM32TimerState), | |
197 | VMSTATE_UINT32(freq_hz, LM32TimerState), | |
198 | VMSTATE_UINT32_ARRAY(regs, LM32TimerState, R_MAX), | |
199 | VMSTATE_END_OF_LIST() | |
200 | } | |
201 | }; | |
202 | ||
203 | static SysBusDeviceInfo lm32_timer_info = { | |
204 | .init = lm32_timer_init, | |
205 | .qdev.name = "lm32-timer", | |
206 | .qdev.size = sizeof(LM32TimerState), | |
207 | .qdev.vmsd = &vmstate_lm32_timer, | |
208 | .qdev.reset = timer_reset, | |
209 | .qdev.props = (Property[]) { | |
210 | DEFINE_PROP_UINT32( | |
211 | "frequency", LM32TimerState, freq_hz, DEFAULT_FREQUENCY | |
212 | ), | |
213 | DEFINE_PROP_END_OF_LIST(), | |
214 | } | |
215 | }; | |
216 | ||
217 | static void lm32_timer_register(void) | |
218 | { | |
219 | sysbus_register_withprop(&lm32_timer_info); | |
220 | } | |
221 | ||
222 | device_init(lm32_timer_register) |