xref: /openbmc/qemu/hw/display/dpcd.c (revision dc5bd18f)
1 /*
2  * dpcd.c
3  *
4  *  Copyright (C) 2015 : GreenSocs Ltd
5  *      http://www.greensocs.com/ , email: info@greensocs.com
6  *
7  *  Developed by :
8  *  Frederic Konrad   <fred.konrad@greensocs.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation, either version 2 of the License, or
13  * (at your option)any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License along
21  * with this program; if not, see <http://www.gnu.org/licenses/>.
22  *
23  */
24 
25 /*
26  * This is a simple AUX slave which emulates a connected screen.
27  */
28 
29 #include "qemu/osdep.h"
30 #include "qemu/log.h"
31 #include "hw/misc/auxbus.h"
32 #include "hw/display/dpcd.h"
33 
34 #ifndef DEBUG_DPCD
35 #define DEBUG_DPCD 0
36 #endif
37 
38 #define DPRINTF(fmt, ...) do {                                                 \
39     if (DEBUG_DPCD) {                                                          \
40         qemu_log("dpcd: " fmt, ## __VA_ARGS__);                                \
41     }                                                                          \
42 } while (0)
43 
44 #define DPCD_READABLE_AREA                      0x600
45 
46 struct DPCDState {
47     /*< private >*/
48     AUXSlave parent_obj;
49 
50     /*< public >*/
51     /*
52      * The DCPD is 0x7FFFF length but read as 0 after offset 0x5FF.
53      */
54     uint8_t dpcd_info[DPCD_READABLE_AREA];
55 
56     MemoryRegion iomem;
57 };
58 
59 static uint64_t dpcd_read(void *opaque, hwaddr offset, unsigned size)
60 {
61     uint8_t ret;
62     DPCDState *e = DPCD(opaque);
63 
64     if (offset < DPCD_READABLE_AREA) {
65         ret = e->dpcd_info[offset];
66     } else {
67         qemu_log_mask(LOG_GUEST_ERROR, "dpcd: Bad offset 0x%" HWADDR_PRIX "\n",
68                                        offset);
69         ret = 0;
70     }
71 
72     DPRINTF("read 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", ret, offset);
73     return ret;
74 }
75 
76 static void dpcd_write(void *opaque, hwaddr offset, uint64_t value,
77                        unsigned size)
78 {
79     DPCDState *e = DPCD(opaque);
80 
81     DPRINTF("write 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", (uint8_t)value, offset);
82 
83     if (offset < DPCD_READABLE_AREA) {
84         e->dpcd_info[offset] = value;
85     } else {
86         qemu_log_mask(LOG_GUEST_ERROR, "dpcd: Bad offset 0x%" HWADDR_PRIX "\n",
87                                        offset);
88     }
89 }
90 
91 static const MemoryRegionOps aux_ops = {
92     .read = dpcd_read,
93     .write = dpcd_write,
94     .valid = {
95         .min_access_size = 1,
96         .max_access_size = 1,
97     },
98     .impl = {
99         .min_access_size = 1,
100         .max_access_size = 1,
101     },
102 };
103 
104 static void dpcd_reset(DeviceState *dev)
105 {
106     DPCDState *s = DPCD(dev);
107 
108     memset(&(s->dpcd_info), 0, sizeof(s->dpcd_info));
109 
110     s->dpcd_info[DPCD_REVISION] = DPCD_REV_1_0;
111     s->dpcd_info[DPCD_MAX_LINK_RATE] = DPCD_5_4GBPS;
112     s->dpcd_info[DPCD_MAX_LANE_COUNT] = DPCD_FOUR_LANES;
113     s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_0] = DPCD_EDID_PRESENT;
114     /* buffer size */
115     s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_1] = 0xFF;
116 
117     s->dpcd_info[DPCD_LANE0_1_STATUS] = DPCD_LANE0_CR_DONE
118                                       | DPCD_LANE0_CHANNEL_EQ_DONE
119                                       | DPCD_LANE0_SYMBOL_LOCKED
120                                       | DPCD_LANE1_CR_DONE
121                                       | DPCD_LANE1_CHANNEL_EQ_DONE
122                                       | DPCD_LANE1_SYMBOL_LOCKED;
123     s->dpcd_info[DPCD_LANE2_3_STATUS] = DPCD_LANE2_CR_DONE
124                                       | DPCD_LANE2_CHANNEL_EQ_DONE
125                                       | DPCD_LANE2_SYMBOL_LOCKED
126                                       | DPCD_LANE3_CR_DONE
127                                       | DPCD_LANE3_CHANNEL_EQ_DONE
128                                       | DPCD_LANE3_SYMBOL_LOCKED;
129 
130     s->dpcd_info[DPCD_LANE_ALIGN_STATUS_UPDATED] = DPCD_INTERLANE_ALIGN_DONE;
131     s->dpcd_info[DPCD_SINK_STATUS] = DPCD_RECEIVE_PORT_0_STATUS;
132 }
133 
134 static void dpcd_init(Object *obj)
135 {
136     DPCDState *s = DPCD(obj);
137 
138     memory_region_init_io(&s->iomem, obj, &aux_ops, s, TYPE_DPCD, 0x7FFFF);
139     aux_init_mmio(AUX_SLAVE(obj), &s->iomem);
140 }
141 
142 static const VMStateDescription vmstate_dpcd = {
143     .name = TYPE_DPCD,
144     .version_id = 0,
145     .minimum_version_id = 0,
146     .fields = (VMStateField[]) {
147         VMSTATE_UINT8_ARRAY_V(dpcd_info, DPCDState, DPCD_READABLE_AREA, 0),
148         VMSTATE_END_OF_LIST()
149     }
150 };
151 
152 static void dpcd_class_init(ObjectClass *oc, void *data)
153 {
154     DeviceClass *dc = DEVICE_CLASS(oc);
155 
156     dc->reset = dpcd_reset;
157     dc->vmsd = &vmstate_dpcd;
158 }
159 
160 static const TypeInfo dpcd_info = {
161     .name          = TYPE_DPCD,
162     .parent        = TYPE_AUX_SLAVE,
163     .instance_size = sizeof(DPCDState),
164     .class_init    = dpcd_class_init,
165     .instance_init = dpcd_init,
166 };
167 
168 static void dpcd_register_types(void)
169 {
170     type_register_static(&dpcd_info);
171 }
172 
173 type_init(dpcd_register_types)
174