1 /*
2 * ColdFire UART emulation.
3 *
4 * Copyright (c) 2007 CodeSourcery.
5 *
6 * This code is licensed under the GPL
7 */
8
9 #include "qemu/osdep.h"
10 #include "hw/irq.h"
11 #include "hw/sysbus.h"
12 #include "qemu/module.h"
13 #include "qapi/error.h"
14 #include "hw/m68k/mcf.h"
15 #include "hw/qdev-properties.h"
16 #include "hw/qdev-properties-system.h"
17 #include "chardev/char-fe.h"
18 #include "qom/object.h"
19
20 struct mcf_uart_state {
21 SysBusDevice parent_obj;
22
23 MemoryRegion iomem;
24 uint8_t mr[2];
25 uint8_t sr;
26 uint8_t isr;
27 uint8_t imr;
28 uint8_t bg1;
29 uint8_t bg2;
30 uint8_t fifo[4];
31 uint8_t tb;
32 int current_mr;
33 int fifo_len;
34 int tx_enabled;
35 int rx_enabled;
36 qemu_irq irq;
37 CharBackend chr;
38 };
39
40 #define TYPE_MCF_UART "mcf-uart"
OBJECT_DECLARE_SIMPLE_TYPE(mcf_uart_state,MCF_UART)41 OBJECT_DECLARE_SIMPLE_TYPE(mcf_uart_state, MCF_UART)
42
43 /* UART Status Register bits. */
44 #define MCF_UART_RxRDY 0x01
45 #define MCF_UART_FFULL 0x02
46 #define MCF_UART_TxRDY 0x04
47 #define MCF_UART_TxEMP 0x08
48 #define MCF_UART_OE 0x10
49 #define MCF_UART_PE 0x20
50 #define MCF_UART_FE 0x40
51 #define MCF_UART_RB 0x80
52
53 /* Interrupt flags. */
54 #define MCF_UART_TxINT 0x01
55 #define MCF_UART_RxINT 0x02
56 #define MCF_UART_DBINT 0x04
57 #define MCF_UART_COSINT 0x80
58
59 /* UMR1 flags. */
60 #define MCF_UART_BC0 0x01
61 #define MCF_UART_BC1 0x02
62 #define MCF_UART_PT 0x04
63 #define MCF_UART_PM0 0x08
64 #define MCF_UART_PM1 0x10
65 #define MCF_UART_ERR 0x20
66 #define MCF_UART_RxIRQ 0x40
67 #define MCF_UART_RxRTS 0x80
68
69 static void mcf_uart_update(mcf_uart_state *s)
70 {
71 s->isr &= ~(MCF_UART_TxINT | MCF_UART_RxINT);
72 if (s->sr & MCF_UART_TxRDY)
73 s->isr |= MCF_UART_TxINT;
74 if ((s->sr & ((s->mr[0] & MCF_UART_RxIRQ)
75 ? MCF_UART_FFULL : MCF_UART_RxRDY)) != 0)
76 s->isr |= MCF_UART_RxINT;
77
78 qemu_set_irq(s->irq, (s->isr & s->imr) != 0);
79 }
80
mcf_uart_read(void * opaque,hwaddr addr,unsigned size)81 uint64_t mcf_uart_read(void *opaque, hwaddr addr,
82 unsigned size)
83 {
84 mcf_uart_state *s = (mcf_uart_state *)opaque;
85 switch (addr & 0x3f) {
86 case 0x00:
87 return s->mr[s->current_mr];
88 case 0x04:
89 return s->sr;
90 case 0x0c:
91 {
92 uint8_t val;
93 int i;
94
95 if (s->fifo_len == 0)
96 return 0;
97
98 val = s->fifo[0];
99 s->fifo_len--;
100 for (i = 0; i < s->fifo_len; i++)
101 s->fifo[i] = s->fifo[i + 1];
102 s->sr &= ~MCF_UART_FFULL;
103 if (s->fifo_len == 0)
104 s->sr &= ~MCF_UART_RxRDY;
105 mcf_uart_update(s);
106 qemu_chr_fe_accept_input(&s->chr);
107 return val;
108 }
109 case 0x10:
110 /* TODO: Implement IPCR. */
111 return 0;
112 case 0x14:
113 return s->isr;
114 case 0x18:
115 return s->bg1;
116 case 0x1c:
117 return s->bg2;
118 default:
119 return 0;
120 }
121 }
122
123 /* Update TxRDY flag and set data if present and enabled. */
mcf_uart_do_tx(mcf_uart_state * s)124 static void mcf_uart_do_tx(mcf_uart_state *s)
125 {
126 if (s->tx_enabled && (s->sr & MCF_UART_TxEMP) == 0) {
127 /* XXX this blocks entire thread. Rewrite to use
128 * qemu_chr_fe_write and background I/O callbacks */
129 qemu_chr_fe_write_all(&s->chr, (unsigned char *)&s->tb, 1);
130 s->sr |= MCF_UART_TxEMP;
131 }
132 if (s->tx_enabled) {
133 s->sr |= MCF_UART_TxRDY;
134 } else {
135 s->sr &= ~MCF_UART_TxRDY;
136 }
137 }
138
mcf_do_command(mcf_uart_state * s,uint8_t cmd)139 static void mcf_do_command(mcf_uart_state *s, uint8_t cmd)
140 {
141 /* Misc command. */
142 switch ((cmd >> 4) & 7) {
143 case 0: /* No-op. */
144 break;
145 case 1: /* Reset mode register pointer. */
146 s->current_mr = 0;
147 break;
148 case 2: /* Reset receiver. */
149 s->rx_enabled = 0;
150 s->fifo_len = 0;
151 s->sr &= ~(MCF_UART_RxRDY | MCF_UART_FFULL);
152 break;
153 case 3: /* Reset transmitter. */
154 s->tx_enabled = 0;
155 s->sr |= MCF_UART_TxEMP;
156 s->sr &= ~MCF_UART_TxRDY;
157 break;
158 case 4: /* Reset error status. */
159 break;
160 case 5: /* Reset break-change interrupt. */
161 s->isr &= ~MCF_UART_DBINT;
162 break;
163 case 6: /* Start break. */
164 case 7: /* Stop break. */
165 break;
166 }
167
168 /* Transmitter command. */
169 switch ((cmd >> 2) & 3) {
170 case 0: /* No-op. */
171 break;
172 case 1: /* Enable. */
173 s->tx_enabled = 1;
174 mcf_uart_do_tx(s);
175 break;
176 case 2: /* Disable. */
177 s->tx_enabled = 0;
178 mcf_uart_do_tx(s);
179 break;
180 case 3: /* Reserved. */
181 fprintf(stderr, "mcf_uart: Bad TX command\n");
182 break;
183 }
184
185 /* Receiver command. */
186 switch (cmd & 3) {
187 case 0: /* No-op. */
188 break;
189 case 1: /* Enable. */
190 s->rx_enabled = 1;
191 break;
192 case 2:
193 s->rx_enabled = 0;
194 break;
195 case 3: /* Reserved. */
196 fprintf(stderr, "mcf_uart: Bad RX command\n");
197 break;
198 }
199 }
200
mcf_uart_write(void * opaque,hwaddr addr,uint64_t val,unsigned size)201 void mcf_uart_write(void *opaque, hwaddr addr,
202 uint64_t val, unsigned size)
203 {
204 mcf_uart_state *s = (mcf_uart_state *)opaque;
205 switch (addr & 0x3f) {
206 case 0x00:
207 s->mr[s->current_mr] = val;
208 s->current_mr = 1;
209 break;
210 case 0x04:
211 /* CSR is ignored. */
212 break;
213 case 0x08: /* Command Register. */
214 mcf_do_command(s, val);
215 break;
216 case 0x0c: /* Transmit Buffer. */
217 s->sr &= ~MCF_UART_TxEMP;
218 s->tb = val;
219 mcf_uart_do_tx(s);
220 break;
221 case 0x10:
222 /* ACR is ignored. */
223 break;
224 case 0x14:
225 s->imr = val;
226 break;
227 default:
228 break;
229 }
230 mcf_uart_update(s);
231 }
232
mcf_uart_reset(DeviceState * dev)233 static void mcf_uart_reset(DeviceState *dev)
234 {
235 mcf_uart_state *s = MCF_UART(dev);
236
237 s->fifo_len = 0;
238 s->mr[0] = 0;
239 s->mr[1] = 0;
240 s->sr = MCF_UART_TxEMP;
241 s->tx_enabled = 0;
242 s->rx_enabled = 0;
243 s->isr = 0;
244 s->imr = 0;
245 }
246
mcf_uart_push_byte(mcf_uart_state * s,uint8_t data)247 static void mcf_uart_push_byte(mcf_uart_state *s, uint8_t data)
248 {
249 /* Break events overwrite the last byte if the fifo is full. */
250 if (s->fifo_len == 4)
251 s->fifo_len--;
252
253 s->fifo[s->fifo_len] = data;
254 s->fifo_len++;
255 s->sr |= MCF_UART_RxRDY;
256 if (s->fifo_len == 4)
257 s->sr |= MCF_UART_FFULL;
258
259 mcf_uart_update(s);
260 }
261
mcf_uart_event(void * opaque,QEMUChrEvent event)262 static void mcf_uart_event(void *opaque, QEMUChrEvent event)
263 {
264 mcf_uart_state *s = (mcf_uart_state *)opaque;
265
266 switch (event) {
267 case CHR_EVENT_BREAK:
268 s->isr |= MCF_UART_DBINT;
269 mcf_uart_push_byte(s, 0);
270 break;
271 default:
272 break;
273 }
274 }
275
mcf_uart_can_receive(void * opaque)276 static int mcf_uart_can_receive(void *opaque)
277 {
278 mcf_uart_state *s = (mcf_uart_state *)opaque;
279
280 return s->rx_enabled && (s->sr & MCF_UART_FFULL) == 0;
281 }
282
mcf_uart_receive(void * opaque,const uint8_t * buf,int size)283 static void mcf_uart_receive(void *opaque, const uint8_t *buf, int size)
284 {
285 mcf_uart_state *s = (mcf_uart_state *)opaque;
286
287 mcf_uart_push_byte(s, buf[0]);
288 }
289
290 static const MemoryRegionOps mcf_uart_ops = {
291 .read = mcf_uart_read,
292 .write = mcf_uart_write,
293 .endianness = DEVICE_NATIVE_ENDIAN,
294 };
295
mcf_uart_instance_init(Object * obj)296 static void mcf_uart_instance_init(Object *obj)
297 {
298 SysBusDevice *dev = SYS_BUS_DEVICE(obj);
299 mcf_uart_state *s = MCF_UART(dev);
300
301 memory_region_init_io(&s->iomem, obj, &mcf_uart_ops, s, "uart", 0x40);
302 sysbus_init_mmio(dev, &s->iomem);
303
304 sysbus_init_irq(dev, &s->irq);
305 }
306
mcf_uart_realize(DeviceState * dev,Error ** errp)307 static void mcf_uart_realize(DeviceState *dev, Error **errp)
308 {
309 mcf_uart_state *s = MCF_UART(dev);
310
311 qemu_chr_fe_set_handlers(&s->chr, mcf_uart_can_receive, mcf_uart_receive,
312 mcf_uart_event, NULL, s, NULL, true);
313 }
314
315 static Property mcf_uart_properties[] = {
316 DEFINE_PROP_CHR("chardev", mcf_uart_state, chr),
317 DEFINE_PROP_END_OF_LIST(),
318 };
319
mcf_uart_class_init(ObjectClass * oc,void * data)320 static void mcf_uart_class_init(ObjectClass *oc, void *data)
321 {
322 DeviceClass *dc = DEVICE_CLASS(oc);
323
324 dc->realize = mcf_uart_realize;
325 dc->reset = mcf_uart_reset;
326 device_class_set_props(dc, mcf_uart_properties);
327 set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
328 }
329
330 static const TypeInfo mcf_uart_info = {
331 .name = TYPE_MCF_UART,
332 .parent = TYPE_SYS_BUS_DEVICE,
333 .instance_size = sizeof(mcf_uart_state),
334 .instance_init = mcf_uart_instance_init,
335 .class_init = mcf_uart_class_init,
336 };
337
mcf_uart_register(void)338 static void mcf_uart_register(void)
339 {
340 type_register_static(&mcf_uart_info);
341 }
342
type_init(mcf_uart_register)343 type_init(mcf_uart_register)
344
345 DeviceState *mcf_uart_create(qemu_irq irq, Chardev *chrdrv)
346 {
347 DeviceState *dev;
348
349 dev = qdev_new(TYPE_MCF_UART);
350 if (chrdrv) {
351 qdev_prop_set_chr(dev, "chardev", chrdrv);
352 }
353 sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
354 sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, irq);
355
356 return dev;
357 }
358
mcf_uart_create_mmap(hwaddr base,qemu_irq irq,Chardev * chrdrv)359 DeviceState *mcf_uart_create_mmap(hwaddr base, qemu_irq irq, Chardev *chrdrv)
360 {
361 DeviceState *dev;
362
363 dev = mcf_uart_create(irq, chrdrv);
364 sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
365
366 return dev;
367 }
368