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