1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
|
/*
* BCM2835 (Raspberry Pi / Pi 2) Aux block (mini UART and SPI).
* Copyright (c) 2015, Microsoft
* Written by Andrew Baumann
* Based on pl011.c, copyright terms below:
*
* Arm PrimeCell PL011 UART
*
* Copyright (c) 2006 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the GPL.
*
* At present only the core UART functions (data path for tx/rx) are
* implemented. The following features/registers are unimplemented:
* - Line/modem control
* - Scratch register
* - Extra control
* - Baudrate
* - SPI interfaces
*/
#include "qemu/osdep.h"
#include "hw/char/bcm2835_aux.h"
#include "hw/irq.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-properties-system.h"
#include "migration/vmstate.h"
#include "qemu/log.h"
#include "qemu/module.h"
#define AUX_IRQ 0x0
#define AUX_ENABLES 0x4
#define AUX_MU_IO_REG 0x40
#define AUX_MU_IER_REG 0x44
#define AUX_MU_IIR_REG 0x48
#define AUX_MU_LCR_REG 0x4c
#define AUX_MU_MCR_REG 0x50
#define AUX_MU_LSR_REG 0x54
#define AUX_MU_MSR_REG 0x58
#define AUX_MU_SCRATCH 0x5c
#define AUX_MU_CNTL_REG 0x60
#define AUX_MU_STAT_REG 0x64
#define AUX_MU_BAUD_REG 0x68
/* bits in IER/IIR registers */
#define RX_INT 0x1
#define TX_INT 0x2
static void bcm2835_aux_update(BCM2835AuxState *s)
{
/* signal an interrupt if either:
* 1. rx interrupt is enabled and we have a non-empty rx fifo, or
* 2. the tx interrupt is enabled (since we instantly drain the tx fifo)
*/
s->iir = 0;
if ((s->ier & RX_INT) && s->read_count != 0) {
s->iir |= RX_INT;
}
if (s->ier & TX_INT) {
s->iir |= TX_INT;
}
qemu_set_irq(s->irq, s->iir != 0);
}
static uint64_t bcm2835_aux_read(void *opaque, hwaddr offset, unsigned size)
{
BCM2835AuxState *s = opaque;
uint32_t c, res;
switch (offset) {
case AUX_IRQ:
return s->iir != 0;
case AUX_ENABLES:
return 1; /* mini UART permanently enabled */
case AUX_MU_IO_REG:
/* "DLAB bit set means access baudrate register" is NYI */
c = s->read_fifo[s->read_pos];
if (s->read_count > 0) {
s->read_count--;
if (++s->read_pos == BCM2835_AUX_RX_FIFO_LEN) {
s->read_pos = 0;
}
}
qemu_chr_fe_accept_input(&s->chr);
bcm2835_aux_update(s);
return c;
case AUX_MU_IER_REG:
/* "DLAB bit set means access baudrate register" is NYI */
return 0xc0 | s->ier; /* FIFO enables always read 1 */
case AUX_MU_IIR_REG:
res = 0xc0; /* FIFO enables */
/* The spec is unclear on what happens when both tx and rx
* interrupts are active, besides that this cannot occur. At
* present, we choose to prioritise the rx interrupt, since
* the tx fifo is always empty. */
if (s->read_count != 0) {
res |= 0x4;
} else {
res |= 0x2;
}
if (s->iir == 0) {
res |= 0x1;
}
return res;
case AUX_MU_LCR_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_LCR_REG unsupported\n", __func__);
return 0;
case AUX_MU_MCR_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_MCR_REG unsupported\n", __func__);
return 0;
case AUX_MU_LSR_REG:
res = 0x60; /* tx idle, empty */
if (s->read_count != 0) {
res |= 0x1;
}
return res;
case AUX_MU_MSR_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_MSR_REG unsupported\n", __func__);
return 0;
case AUX_MU_SCRATCH:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_SCRATCH unsupported\n", __func__);
return 0;
case AUX_MU_CNTL_REG:
return 0x3; /* tx, rx enabled */
case AUX_MU_STAT_REG:
res = 0x30e; /* space in the output buffer, empty tx fifo, idle tx/rx */
if (s->read_count > 0) {
res |= 0x1; /* data in input buffer */
assert(s->read_count <= BCM2835_AUX_RX_FIFO_LEN);
res |= ((uint32_t)s->read_count) << 16; /* rx fifo fill level */
}
return res;
case AUX_MU_BAUD_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_BAUD_REG unsupported\n", __func__);
return 0;
default:
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
__func__, offset);
return 0;
}
}
static void bcm2835_aux_write(void *opaque, hwaddr offset, uint64_t value,
unsigned size)
{
BCM2835AuxState *s = opaque;
unsigned char ch;
switch (offset) {
case AUX_ENABLES:
if (value != 1) {
qemu_log_mask(LOG_UNIMP, "%s: unsupported attempt to enable SPI"
" or disable UART: 0x%"PRIx64"\n",
__func__, value);
}
break;
case AUX_MU_IO_REG:
/* "DLAB bit set means access baudrate register" is NYI */
ch = value;
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_fe_write_all(&s->chr, &ch, 1);
break;
case AUX_MU_IER_REG:
/* "DLAB bit set means access baudrate register" is NYI */
s->ier = value & (TX_INT | RX_INT);
bcm2835_aux_update(s);
break;
case AUX_MU_IIR_REG:
if (value & 0x2) {
s->read_count = 0;
}
break;
case AUX_MU_LCR_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_LCR_REG unsupported\n", __func__);
break;
case AUX_MU_MCR_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_MCR_REG unsupported\n", __func__);
break;
case AUX_MU_SCRATCH:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_SCRATCH unsupported\n", __func__);
break;
case AUX_MU_CNTL_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_CNTL_REG unsupported\n", __func__);
break;
case AUX_MU_BAUD_REG:
qemu_log_mask(LOG_UNIMP, "%s: AUX_MU_BAUD_REG unsupported\n", __func__);
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
__func__, offset);
}
bcm2835_aux_update(s);
}
static int bcm2835_aux_can_receive(void *opaque)
{
BCM2835AuxState *s = opaque;
return s->read_count < BCM2835_AUX_RX_FIFO_LEN;
}
static void bcm2835_aux_put_fifo(void *opaque, uint8_t value)
{
BCM2835AuxState *s = opaque;
int slot;
slot = s->read_pos + s->read_count;
if (slot >= BCM2835_AUX_RX_FIFO_LEN) {
slot -= BCM2835_AUX_RX_FIFO_LEN;
}
s->read_fifo[slot] = value;
s->read_count++;
if (s->read_count == BCM2835_AUX_RX_FIFO_LEN) {
/* buffer full */
}
bcm2835_aux_update(s);
}
static void bcm2835_aux_receive(void *opaque, const uint8_t *buf, int size)
{
bcm2835_aux_put_fifo(opaque, *buf);
}
static const MemoryRegionOps bcm2835_aux_ops = {
.read = bcm2835_aux_read,
.write = bcm2835_aux_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.impl.min_access_size = 4,
.impl.max_access_size = 4,
.valid.min_access_size = 1,
.valid.max_access_size = 4,
};
static const VMStateDescription vmstate_bcm2835_aux = {
.name = TYPE_BCM2835_AUX,
.version_id = 1,
.minimum_version_id = 1,
.fields = (const VMStateField[]) {
VMSTATE_UINT8_ARRAY(read_fifo, BCM2835AuxState,
BCM2835_AUX_RX_FIFO_LEN),
VMSTATE_UINT8(read_pos, BCM2835AuxState),
VMSTATE_UINT8(read_count, BCM2835AuxState),
VMSTATE_UINT8(ier, BCM2835AuxState),
VMSTATE_UINT8(iir, BCM2835AuxState),
VMSTATE_END_OF_LIST()
}
};
static void bcm2835_aux_init(Object *obj)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
BCM2835AuxState *s = BCM2835_AUX(obj);
memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_aux_ops, s,
TYPE_BCM2835_AUX, 0x100);
sysbus_init_mmio(sbd, &s->iomem);
sysbus_init_irq(sbd, &s->irq);
}
static void bcm2835_aux_realize(DeviceState *dev, Error **errp)
{
BCM2835AuxState *s = BCM2835_AUX(dev);
qemu_chr_fe_set_handlers(&s->chr, bcm2835_aux_can_receive,
bcm2835_aux_receive, NULL, NULL, s, NULL, true);
}
static const Property bcm2835_aux_props[] = {
DEFINE_PROP_CHR("chardev", BCM2835AuxState, chr),
};
static void bcm2835_aux_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
dc->realize = bcm2835_aux_realize;
dc->vmsd = &vmstate_bcm2835_aux;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
device_class_set_props(dc, bcm2835_aux_props);
}
static const TypeInfo bcm2835_aux_info = {
.name = TYPE_BCM2835_AUX,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(BCM2835AuxState),
.instance_init = bcm2835_aux_init,
.class_init = bcm2835_aux_class_init,
};
static void bcm2835_aux_register_types(void)
{
type_register_static(&bcm2835_aux_info);
}
type_init(bcm2835_aux_register_types)
|