xref: /openbmc/qemu/hw/display/dpcd.c (revision 500eb6db)
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 "qemu/module.h"
32 #include "hw/misc/auxbus.h"
33 #include "hw/display/dpcd.h"
34 
35 #ifndef DEBUG_DPCD
36 #define DEBUG_DPCD 0
37 #endif
38 
39 #define DPRINTF(fmt, ...) do {                                                 \
40     if (DEBUG_DPCD) {                                                          \
41         qemu_log("dpcd: " fmt, ## __VA_ARGS__);                                \
42     }                                                                          \
43 } while (0)
44 
45 #define DPCD_READABLE_AREA                      0x600
46 
47 struct DPCDState {
48     /*< private >*/
49     AUXSlave parent_obj;
50 
51     /*< public >*/
52     /*
53      * The DCPD is 0x7FFFF length but read as 0 after offset 0x5FF.
54      */
55     uint8_t dpcd_info[DPCD_READABLE_AREA];
56 
57     MemoryRegion iomem;
58 };
59 
60 static uint64_t dpcd_read(void *opaque, hwaddr offset, unsigned size)
61 {
62     uint8_t ret;
63     DPCDState *e = DPCD(opaque);
64 
65     if (offset < DPCD_READABLE_AREA) {
66         ret = e->dpcd_info[offset];
67     } else {
68         qemu_log_mask(LOG_GUEST_ERROR, "dpcd: Bad offset 0x%" HWADDR_PRIX "\n",
69                                        offset);
70         ret = 0;
71     }
72 
73     DPRINTF("read 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", ret, offset);
74     return ret;
75 }
76 
77 static void dpcd_write(void *opaque, hwaddr offset, uint64_t value,
78                        unsigned size)
79 {
80     DPCDState *e = DPCD(opaque);
81 
82     DPRINTF("write 0x%" PRIX8 " @0x%" HWADDR_PRIX "\n", (uint8_t)value, offset);
83 
84     if (offset < DPCD_READABLE_AREA) {
85         e->dpcd_info[offset] = value;
86     } else {
87         qemu_log_mask(LOG_GUEST_ERROR, "dpcd: Bad offset 0x%" HWADDR_PRIX "\n",
88                                        offset);
89     }
90 }
91 
92 static const MemoryRegionOps aux_ops = {
93     .read = dpcd_read,
94     .write = dpcd_write,
95     .valid = {
96         .min_access_size = 1,
97         .max_access_size = 1,
98     },
99     .impl = {
100         .min_access_size = 1,
101         .max_access_size = 1,
102     },
103 };
104 
105 static void dpcd_reset(DeviceState *dev)
106 {
107     DPCDState *s = DPCD(dev);
108 
109     memset(&(s->dpcd_info), 0, sizeof(s->dpcd_info));
110 
111     s->dpcd_info[DPCD_REVISION] = DPCD_REV_1_0;
112     s->dpcd_info[DPCD_MAX_LINK_RATE] = DPCD_5_4GBPS;
113     s->dpcd_info[DPCD_MAX_LANE_COUNT] = DPCD_FOUR_LANES;
114     s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_0] = DPCD_EDID_PRESENT;
115     /* buffer size */
116     s->dpcd_info[DPCD_RECEIVE_PORT0_CAP_1] = 0xFF;
117 
118     s->dpcd_info[DPCD_LANE0_1_STATUS] = DPCD_LANE0_CR_DONE
119                                       | DPCD_LANE0_CHANNEL_EQ_DONE
120                                       | DPCD_LANE0_SYMBOL_LOCKED
121                                       | DPCD_LANE1_CR_DONE
122                                       | DPCD_LANE1_CHANNEL_EQ_DONE
123                                       | DPCD_LANE1_SYMBOL_LOCKED;
124     s->dpcd_info[DPCD_LANE2_3_STATUS] = DPCD_LANE2_CR_DONE
125                                       | DPCD_LANE2_CHANNEL_EQ_DONE
126                                       | DPCD_LANE2_SYMBOL_LOCKED
127                                       | DPCD_LANE3_CR_DONE
128                                       | DPCD_LANE3_CHANNEL_EQ_DONE
129                                       | DPCD_LANE3_SYMBOL_LOCKED;
130 
131     s->dpcd_info[DPCD_LANE_ALIGN_STATUS_UPDATED] = DPCD_INTERLANE_ALIGN_DONE;
132     s->dpcd_info[DPCD_SINK_STATUS] = DPCD_RECEIVE_PORT_0_STATUS;
133 }
134 
135 static void dpcd_init(Object *obj)
136 {
137     DPCDState *s = DPCD(obj);
138 
139     memory_region_init_io(&s->iomem, obj, &aux_ops, s, TYPE_DPCD, 0x7FFFF);
140     aux_init_mmio(AUX_SLAVE(obj), &s->iomem);
141 }
142 
143 static const VMStateDescription vmstate_dpcd = {
144     .name = TYPE_DPCD,
145     .version_id = 0,
146     .minimum_version_id = 0,
147     .fields = (VMStateField[]) {
148         VMSTATE_UINT8_ARRAY_V(dpcd_info, DPCDState, DPCD_READABLE_AREA, 0),
149         VMSTATE_END_OF_LIST()
150     }
151 };
152 
153 static void dpcd_class_init(ObjectClass *oc, void *data)
154 {
155     DeviceClass *dc = DEVICE_CLASS(oc);
156 
157     dc->reset = dpcd_reset;
158     dc->vmsd = &vmstate_dpcd;
159 }
160 
161 static const TypeInfo dpcd_info = {
162     .name          = TYPE_DPCD,
163     .parent        = TYPE_AUX_SLAVE,
164     .instance_size = sizeof(DPCDState),
165     .class_init    = dpcd_class_init,
166     .instance_init = dpcd_init,
167 };
168 
169 static void dpcd_register_types(void)
170 {
171     type_register_static(&dpcd_info);
172 }
173 
174 type_init(dpcd_register_types)
175