Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20220121...
[qemu.git] / hw / char / xilinx_uartlite.c
1 /*
2 * QEMU model of Xilinx uartlite.
3 *
4 * Copyright (c) 2009 Edgar E. Iglesias.
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 "qemu/log.h"
27 #include "hw/irq.h"
28 #include "hw/qdev-properties.h"
29 #include "hw/qdev-properties-system.h"
30 #include "hw/sysbus.h"
31 #include "qemu/module.h"
32 #include "chardev/char-fe.h"
33 #include "qom/object.h"
34
35 #define DUART(x)
36
37 #define R_RX 0
38 #define R_TX 1
39 #define R_STATUS 2
40 #define R_CTRL 3
41 #define R_MAX 4
42
43 #define STATUS_RXVALID 0x01
44 #define STATUS_RXFULL 0x02
45 #define STATUS_TXEMPTY 0x04
46 #define STATUS_TXFULL 0x08
47 #define STATUS_IE 0x10
48 #define STATUS_OVERRUN 0x20
49 #define STATUS_FRAME 0x40
50 #define STATUS_PARITY 0x80
51
52 #define CONTROL_RST_TX 0x01
53 #define CONTROL_RST_RX 0x02
54 #define CONTROL_IE 0x10
55
56 #define TYPE_XILINX_UARTLITE "xlnx.xps-uartlite"
57 OBJECT_DECLARE_SIMPLE_TYPE(XilinxUARTLite, XILINX_UARTLITE)
58
59 struct XilinxUARTLite {
60 SysBusDevice parent_obj;
61
62 MemoryRegion mmio;
63 CharBackend chr;
64 qemu_irq irq;
65
66 uint8_t rx_fifo[8];
67 unsigned int rx_fifo_pos;
68 unsigned int rx_fifo_len;
69
70 uint32_t regs[R_MAX];
71 };
72
73 static void uart_update_irq(XilinxUARTLite *s)
74 {
75 unsigned int irq;
76
77 if (s->rx_fifo_len)
78 s->regs[R_STATUS] |= STATUS_IE;
79
80 irq = (s->regs[R_STATUS] & STATUS_IE) && (s->regs[R_CTRL] & CONTROL_IE);
81 qemu_set_irq(s->irq, irq);
82 }
83
84 static void uart_update_status(XilinxUARTLite *s)
85 {
86 uint32_t r;
87
88 r = s->regs[R_STATUS];
89 r &= ~7;
90 r |= 1 << 2; /* Tx fifo is always empty. We are fast :) */
91 r |= (s->rx_fifo_len == sizeof (s->rx_fifo)) << 1;
92 r |= (!!s->rx_fifo_len);
93 s->regs[R_STATUS] = r;
94 }
95
96 static void xilinx_uartlite_reset(DeviceState *dev)
97 {
98 uart_update_status(XILINX_UARTLITE(dev));
99 }
100
101 static uint64_t
102 uart_read(void *opaque, hwaddr addr, unsigned int size)
103 {
104 XilinxUARTLite *s = opaque;
105 uint32_t r = 0;
106 addr >>= 2;
107 switch (addr)
108 {
109 case R_RX:
110 r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 7];
111 if (s->rx_fifo_len)
112 s->rx_fifo_len--;
113 uart_update_status(s);
114 uart_update_irq(s);
115 qemu_chr_fe_accept_input(&s->chr);
116 break;
117
118 default:
119 if (addr < ARRAY_SIZE(s->regs))
120 r = s->regs[addr];
121 DUART(qemu_log("%s addr=%x v=%x\n", __func__, addr, r));
122 break;
123 }
124 return r;
125 }
126
127 static void
128 uart_write(void *opaque, hwaddr addr,
129 uint64_t val64, unsigned int size)
130 {
131 XilinxUARTLite *s = opaque;
132 uint32_t value = val64;
133 unsigned char ch = value;
134
135 addr >>= 2;
136 switch (addr)
137 {
138 case R_STATUS:
139 qemu_log_mask(LOG_GUEST_ERROR, "%s: write to UART STATUS\n",
140 __func__);
141 break;
142
143 case R_CTRL:
144 if (value & CONTROL_RST_RX) {
145 s->rx_fifo_pos = 0;
146 s->rx_fifo_len = 0;
147 }
148 s->regs[addr] = value;
149 break;
150
151 case R_TX:
152 /* XXX this blocks entire thread. Rewrite to use
153 * qemu_chr_fe_write and background I/O callbacks */
154 qemu_chr_fe_write_all(&s->chr, &ch, 1);
155 s->regs[addr] = value;
156
157 /* hax. */
158 s->regs[R_STATUS] |= STATUS_IE;
159 break;
160
161 default:
162 DUART(printf("%s addr=%x v=%x\n", __func__, addr, value));
163 if (addr < ARRAY_SIZE(s->regs))
164 s->regs[addr] = value;
165 break;
166 }
167 uart_update_status(s);
168 uart_update_irq(s);
169 }
170
171 static const MemoryRegionOps uart_ops = {
172 .read = uart_read,
173 .write = uart_write,
174 .endianness = DEVICE_NATIVE_ENDIAN,
175 .valid = {
176 .min_access_size = 1,
177 .max_access_size = 4
178 }
179 };
180
181 static Property xilinx_uartlite_properties[] = {
182 DEFINE_PROP_CHR("chardev", XilinxUARTLite, chr),
183 DEFINE_PROP_END_OF_LIST(),
184 };
185
186 static void uart_rx(void *opaque, const uint8_t *buf, int size)
187 {
188 XilinxUARTLite *s = opaque;
189
190 /* Got a byte. */
191 if (s->rx_fifo_len >= 8) {
192 printf("WARNING: UART dropped char.\n");
193 return;
194 }
195 s->rx_fifo[s->rx_fifo_pos] = *buf;
196 s->rx_fifo_pos++;
197 s->rx_fifo_pos &= 0x7;
198 s->rx_fifo_len++;
199
200 uart_update_status(s);
201 uart_update_irq(s);
202 }
203
204 static int uart_can_rx(void *opaque)
205 {
206 XilinxUARTLite *s = opaque;
207
208 return s->rx_fifo_len < sizeof(s->rx_fifo);
209 }
210
211 static void uart_event(void *opaque, QEMUChrEvent event)
212 {
213
214 }
215
216 static void xilinx_uartlite_realize(DeviceState *dev, Error **errp)
217 {
218 XilinxUARTLite *s = XILINX_UARTLITE(dev);
219
220 qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
221 uart_event, NULL, s, NULL, true);
222 }
223
224 static void xilinx_uartlite_init(Object *obj)
225 {
226 XilinxUARTLite *s = XILINX_UARTLITE(obj);
227
228 sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
229
230 memory_region_init_io(&s->mmio, obj, &uart_ops, s,
231 "xlnx.xps-uartlite", R_MAX * 4);
232 sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
233 }
234
235 static void xilinx_uartlite_class_init(ObjectClass *klass, void *data)
236 {
237 DeviceClass *dc = DEVICE_CLASS(klass);
238
239 dc->reset = xilinx_uartlite_reset;
240 dc->realize = xilinx_uartlite_realize;
241 device_class_set_props(dc, xilinx_uartlite_properties);
242 }
243
244 static const TypeInfo xilinx_uartlite_info = {
245 .name = TYPE_XILINX_UARTLITE,
246 .parent = TYPE_SYS_BUS_DEVICE,
247 .instance_size = sizeof(XilinxUARTLite),
248 .instance_init = xilinx_uartlite_init,
249 .class_init = xilinx_uartlite_class_init,
250 };
251
252 static void xilinx_uart_register_types(void)
253 {
254 type_register_static(&xilinx_uartlite_info);
255 }
256
257 type_init(xilinx_uart_register_types)