xref: /openbmc/qemu/hw/display/sii9022.c (revision d044b7c3)
1 /*
2  * Silicon Image SiI9022
3  *
4  * This is a pretty hollow emulation: all we do is acknowledge that we
5  * exist (chip ID) and confirm that we get switched over into DDC mode
6  * so the emulated host can proceed to read out EDID data. All subsequent
7  * set-up of connectors etc will be acknowledged and ignored.
8  *
9  * Copyright (C) 2018 Linus Walleij
10  *
11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
12  * See the COPYING file in the top-level directory.
13  * SPDX-License-Identifier: GPL-2.0-or-later
14  */
15 
16 #include "qemu/osdep.h"
17 #include "qemu/module.h"
18 #include "hw/i2c/i2c.h"
19 #include "migration/vmstate.h"
20 #include "hw/display/i2c-ddc.h"
21 #include "trace.h"
22 #include "qom/object.h"
23 
24 #define SII9022_SYS_CTRL_DATA 0x1a
25 #define SII9022_SYS_CTRL_PWR_DWN 0x10
26 #define SII9022_SYS_CTRL_AV_MUTE 0x08
27 #define SII9022_SYS_CTRL_DDC_BUS_REQ 0x04
28 #define SII9022_SYS_CTRL_DDC_BUS_GRTD 0x02
29 #define SII9022_SYS_CTRL_OUTPUT_MODE 0x01
30 #define SII9022_SYS_CTRL_OUTPUT_HDMI 1
31 #define SII9022_SYS_CTRL_OUTPUT_DVI 0
32 #define SII9022_REG_CHIPID 0x1b
33 #define SII9022_INT_ENABLE 0x3c
34 #define SII9022_INT_STATUS 0x3d
35 #define SII9022_INT_STATUS_HOTPLUG 0x01;
36 #define SII9022_INT_STATUS_PLUGGED 0x04;
37 
38 #define TYPE_SII9022 "sii9022"
39 OBJECT_DECLARE_SIMPLE_TYPE(sii9022_state, SII9022)
40 
41 struct sii9022_state {
42     I2CSlave parent_obj;
43     uint8_t ptr;
44     bool addr_byte;
45     bool ddc_req;
46     bool ddc_skip_finish;
47     bool ddc;
48 };
49 
50 static const VMStateDescription vmstate_sii9022 = {
51     .name = "sii9022",
52     .version_id = 1,
53     .minimum_version_id = 1,
54     .fields = (VMStateField[]) {
55         VMSTATE_I2C_SLAVE(parent_obj, sii9022_state),
56         VMSTATE_UINT8(ptr, sii9022_state),
57         VMSTATE_BOOL(addr_byte, sii9022_state),
58         VMSTATE_BOOL(ddc_req, sii9022_state),
59         VMSTATE_BOOL(ddc_skip_finish, sii9022_state),
60         VMSTATE_BOOL(ddc, sii9022_state),
61         VMSTATE_END_OF_LIST()
62     }
63 };
64 
65 static int sii9022_event(I2CSlave *i2c, enum i2c_event event)
66 {
67     sii9022_state *s = SII9022(i2c);
68 
69     switch (event) {
70     case I2C_START_SEND:
71         s->addr_byte = true;
72         break;
73     case I2C_START_RECV:
74         break;
75     case I2C_FINISH:
76         break;
77     case I2C_NACK:
78         break;
79     default:
80         return -1;
81     }
82 
83     return 0;
84 }
85 
86 static uint8_t sii9022_rx(I2CSlave *i2c)
87 {
88     sii9022_state *s = SII9022(i2c);
89     uint8_t res = 0x00;
90 
91     switch (s->ptr) {
92     case SII9022_SYS_CTRL_DATA:
93         if (s->ddc_req) {
94             /* Acknowledge DDC bus request */
95             res = SII9022_SYS_CTRL_DDC_BUS_GRTD | SII9022_SYS_CTRL_DDC_BUS_REQ;
96         }
97         break;
98     case SII9022_REG_CHIPID:
99         res = 0xb0;
100         break;
101     case SII9022_INT_STATUS:
102         /* Something is cold-plugged in, no interrupts */
103         res = SII9022_INT_STATUS_PLUGGED;
104         break;
105     default:
106         break;
107     }
108 
109     trace_sii9022_read_reg(s->ptr, res);
110     s->ptr++;
111 
112     return res;
113 }
114 
115 static int sii9022_tx(I2CSlave *i2c, uint8_t data)
116 {
117     sii9022_state *s = SII9022(i2c);
118 
119     if (s->addr_byte) {
120         s->ptr = data;
121         s->addr_byte = false;
122         return 0;
123     }
124 
125     switch (s->ptr) {
126     case SII9022_SYS_CTRL_DATA:
127         if (data & SII9022_SYS_CTRL_DDC_BUS_REQ) {
128             s->ddc_req = true;
129             if (data & SII9022_SYS_CTRL_DDC_BUS_GRTD) {
130                 s->ddc = true;
131                 /* Skip this finish since we just switched to DDC */
132                 s->ddc_skip_finish = true;
133                 trace_sii9022_switch_mode("DDC");
134             }
135         } else {
136             s->ddc_req = false;
137             s->ddc = false;
138             trace_sii9022_switch_mode("normal");
139         }
140         break;
141     default:
142         break;
143     }
144 
145     trace_sii9022_write_reg(s->ptr, data);
146     s->ptr++;
147 
148     return 0;
149 }
150 
151 static void sii9022_reset(DeviceState *dev)
152 {
153     sii9022_state *s = SII9022(dev);
154 
155     s->ptr = 0;
156     s->addr_byte = false;
157     s->ddc_req = false;
158     s->ddc_skip_finish = false;
159     s->ddc = false;
160 }
161 
162 static void sii9022_realize(DeviceState *dev, Error **errp)
163 {
164     I2CBus *bus;
165 
166     bus = I2C_BUS(qdev_get_parent_bus(dev));
167     i2c_slave_create_simple(bus, TYPE_I2CDDC, 0x50);
168 }
169 
170 static void sii9022_class_init(ObjectClass *klass, void *data)
171 {
172     DeviceClass *dc = DEVICE_CLASS(klass);
173     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
174 
175     k->event = sii9022_event;
176     k->recv = sii9022_rx;
177     k->send = sii9022_tx;
178     dc->reset = sii9022_reset;
179     dc->realize = sii9022_realize;
180     dc->vmsd = &vmstate_sii9022;
181 }
182 
183 static const TypeInfo sii9022_info = {
184     .name          = TYPE_SII9022,
185     .parent        = TYPE_I2C_SLAVE,
186     .instance_size = sizeof(sii9022_state),
187     .class_init    = sii9022_class_init,
188 };
189 
190 static void sii9022_register_types(void)
191 {
192     type_register_static(&sii9022_info);
193 }
194 
195 type_init(sii9022_register_types)
196