1 /*
2 * QEMU ETRAX System Emulator
3 *
4 * Copyright (c) 2007 Edgar E. Iglesias, Axis Communications AB.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu/osdep.h"
26 #include "hw/irq.h"
27 #include "hw/qdev-properties.h"
28 #include "hw/sysbus.h"
29 #include "chardev/char-fe.h"
30 #include "qemu/log.h"
31 #include "qemu/module.h"
32
33 #define D(x)
34
35 #define RW_TR_CTRL (0x00 / 4)
36 #define RW_TR_DMA_EN (0x04 / 4)
37 #define RW_REC_CTRL (0x08 / 4)
38 #define RW_DOUT (0x1c / 4)
39 #define RS_STAT_DIN (0x20 / 4)
40 #define R_STAT_DIN (0x24 / 4)
41 #define RW_INTR_MASK (0x2c / 4)
42 #define RW_ACK_INTR (0x30 / 4)
43 #define R_INTR (0x34 / 4)
44 #define R_MASKED_INTR (0x38 / 4)
45 #define R_MAX (0x3c / 4)
46
47 #define STAT_DAV 16
48 #define STAT_TR_IDLE 22
49 #define STAT_TR_RDY 24
50
51 #define TYPE_ETRAX_FS_SERIAL "etraxfs,serial"
52 #define ETRAX_SERIAL(obj) \
53 OBJECT_CHECK(ETRAXSerial, (obj), TYPE_ETRAX_FS_SERIAL)
54
55 typedef struct ETRAXSerial {
56 SysBusDevice parent_obj;
57
58 MemoryRegion mmio;
59 CharBackend chr;
60 qemu_irq irq;
61
62 int pending_tx;
63
64 uint8_t rx_fifo[16];
65 unsigned int rx_fifo_pos;
66 unsigned int rx_fifo_len;
67
68 /* Control registers. */
69 uint32_t regs[R_MAX];
70 } ETRAXSerial;
71
ser_update_irq(ETRAXSerial * s)72 static void ser_update_irq(ETRAXSerial *s)
73 {
74
75 if (s->rx_fifo_len) {
76 s->regs[R_INTR] |= 8;
77 } else {
78 s->regs[R_INTR] &= ~8;
79 }
80
81 s->regs[R_MASKED_INTR] = s->regs[R_INTR] & s->regs[RW_INTR_MASK];
82 qemu_set_irq(s->irq, !!s->regs[R_MASKED_INTR]);
83 }
84
85 static uint64_t
ser_read(void * opaque,hwaddr addr,unsigned int size)86 ser_read(void *opaque, hwaddr addr, unsigned int size)
87 {
88 ETRAXSerial *s = opaque;
89 uint32_t r = 0;
90
91 addr >>= 2;
92 switch (addr)
93 {
94 case R_STAT_DIN:
95 r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
96 if (s->rx_fifo_len) {
97 r |= 1 << STAT_DAV;
98 }
99 r |= 1 << STAT_TR_RDY;
100 r |= 1 << STAT_TR_IDLE;
101 break;
102 case RS_STAT_DIN:
103 r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
104 if (s->rx_fifo_len) {
105 r |= 1 << STAT_DAV;
106 s->rx_fifo_len--;
107 }
108 r |= 1 << STAT_TR_RDY;
109 r |= 1 << STAT_TR_IDLE;
110 break;
111 default:
112 r = s->regs[addr];
113 D(qemu_log("%s " TARGET_FMT_plx "=%x\n", __func__, addr, r));
114 break;
115 }
116 return r;
117 }
118
119 static void
ser_write(void * opaque,hwaddr addr,uint64_t val64,unsigned int size)120 ser_write(void *opaque, hwaddr addr,
121 uint64_t val64, unsigned int size)
122 {
123 ETRAXSerial *s = opaque;
124 uint32_t value = val64;
125 unsigned char ch = val64;
126
127 D(qemu_log("%s " TARGET_FMT_plx "=%x\n", __func__, addr, value));
128 addr >>= 2;
129 switch (addr)
130 {
131 case RW_DOUT:
132 /* XXX this blocks entire thread. Rewrite to use
133 * qemu_chr_fe_write and background I/O callbacks */
134 qemu_chr_fe_write_all(&s->chr, &ch, 1);
135 s->regs[R_INTR] |= 3;
136 s->pending_tx = 1;
137 s->regs[addr] = value;
138 break;
139 case RW_ACK_INTR:
140 if (s->pending_tx) {
141 value &= ~1;
142 s->pending_tx = 0;
143 D(qemu_log("fixedup value=%x r_intr=%x\n",
144 value, s->regs[R_INTR]));
145 }
146 s->regs[addr] = value;
147 s->regs[R_INTR] &= ~value;
148 D(printf("r_intr=%x\n", s->regs[R_INTR]));
149 break;
150 default:
151 s->regs[addr] = value;
152 break;
153 }
154 ser_update_irq(s);
155 }
156
157 static const MemoryRegionOps ser_ops = {
158 .read = ser_read,
159 .write = ser_write,
160 .endianness = DEVICE_NATIVE_ENDIAN,
161 .valid = {
162 .min_access_size = 4,
163 .max_access_size = 4
164 }
165 };
166
167 static Property etraxfs_ser_properties[] = {
168 DEFINE_PROP_CHR("chardev", ETRAXSerial, chr),
169 DEFINE_PROP_END_OF_LIST(),
170 };
171
serial_receive(void * opaque,const uint8_t * buf,int size)172 static void serial_receive(void *opaque, const uint8_t *buf, int size)
173 {
174 ETRAXSerial *s = opaque;
175 int i;
176
177 /* Got a byte. */
178 if (s->rx_fifo_len >= 16) {
179 D(qemu_log("WARNING: UART dropped char.\n"));
180 return;
181 }
182
183 for (i = 0; i < size; i++) {
184 s->rx_fifo[s->rx_fifo_pos] = buf[i];
185 s->rx_fifo_pos++;
186 s->rx_fifo_pos &= 15;
187 s->rx_fifo_len++;
188 }
189
190 ser_update_irq(s);
191 }
192
serial_can_receive(void * opaque)193 static int serial_can_receive(void *opaque)
194 {
195 ETRAXSerial *s = opaque;
196
197 /* Is the receiver enabled? */
198 if (!(s->regs[RW_REC_CTRL] & (1 << 3))) {
199 return 0;
200 }
201
202 return sizeof(s->rx_fifo) - s->rx_fifo_len;
203 }
204
serial_event(void * opaque,int event)205 static void serial_event(void *opaque, int event)
206 {
207
208 }
209
etraxfs_ser_reset(DeviceState * d)210 static void etraxfs_ser_reset(DeviceState *d)
211 {
212 ETRAXSerial *s = ETRAX_SERIAL(d);
213
214 /* transmitter begins ready and idle. */
215 s->regs[RS_STAT_DIN] |= (1 << STAT_TR_RDY);
216 s->regs[RS_STAT_DIN] |= (1 << STAT_TR_IDLE);
217
218 s->regs[RW_REC_CTRL] = 0x10000;
219
220 }
221
etraxfs_ser_init(Object * obj)222 static void etraxfs_ser_init(Object *obj)
223 {
224 ETRAXSerial *s = ETRAX_SERIAL(obj);
225 SysBusDevice *dev = SYS_BUS_DEVICE(obj);
226
227 sysbus_init_irq(dev, &s->irq);
228 memory_region_init_io(&s->mmio, obj, &ser_ops, s,
229 "etraxfs-serial", R_MAX * 4);
230 sysbus_init_mmio(dev, &s->mmio);
231 }
232
etraxfs_ser_realize(DeviceState * dev,Error ** errp)233 static void etraxfs_ser_realize(DeviceState *dev, Error **errp)
234 {
235 ETRAXSerial *s = ETRAX_SERIAL(dev);
236
237 qemu_chr_fe_set_handlers(&s->chr,
238 serial_can_receive, serial_receive,
239 serial_event, NULL, s, NULL, true);
240 }
241
etraxfs_ser_class_init(ObjectClass * klass,void * data)242 static void etraxfs_ser_class_init(ObjectClass *klass, void *data)
243 {
244 DeviceClass *dc = DEVICE_CLASS(klass);
245
246 dc->reset = etraxfs_ser_reset;
247 dc->props = etraxfs_ser_properties;
248 dc->realize = etraxfs_ser_realize;
249 }
250
251 static const TypeInfo etraxfs_ser_info = {
252 .name = TYPE_ETRAX_FS_SERIAL,
253 .parent = TYPE_SYS_BUS_DEVICE,
254 .instance_size = sizeof(ETRAXSerial),
255 .instance_init = etraxfs_ser_init,
256 .class_init = etraxfs_ser_class_init,
257 };
258
etraxfs_serial_register_types(void)259 static void etraxfs_serial_register_types(void)
260 {
261 type_register_static(&etraxfs_ser_info);
262 }
263
264 type_init(etraxfs_serial_register_types)
265