hw/display/sii9022.c

   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 "hw/display/i2c-ddc.h"
  20 #include "trace.h"
  21
  22 #define SII9022_SYS_CTRL_DATA 0x1a
  23 #define SII9022_SYS_CTRL_PWR_DWN 0x10
  24 #define SII9022_SYS_CTRL_AV_MUTE 0x08
  25 #define SII9022_SYS_CTRL_DDC_BUS_REQ 0x04
  26 #define SII9022_SYS_CTRL_DDC_BUS_GRTD 0x02
  27 #define SII9022_SYS_CTRL_OUTPUT_MODE 0x01
  28 #define SII9022_SYS_CTRL_OUTPUT_HDMI 1
  29 #define SII9022_SYS_CTRL_OUTPUT_DVI 0
  30 #define SII9022_REG_CHIPID 0x1b
  31 #define SII9022_INT_ENABLE 0x3c
  32 #define SII9022_INT_STATUS 0x3d
  33 #define SII9022_INT_STATUS_HOTPLUG 0x01;
  34 #define SII9022_INT_STATUS_PLUGGED 0x04;
  35
  36 #define TYPE_SII9022 "sii9022"
  37 #define SII9022(obj) OBJECT_CHECK(sii9022_state, (obj), TYPE_SII9022)
  38
  39 typedef struct sii9022_state {
  40     I2CSlave parent_obj;
  41     uint8_t ptr;
  42     bool addr_byte;
  43     bool ddc_req;
  44     bool ddc_skip_finish;
  45     bool ddc;
  46 } sii9022_state;
  47
  48 static const VMStateDescription vmstate_sii9022 = {
  49     .name = "sii9022",
  50     .version_id = 1,
  51     .minimum_version_id = 1,
  52     .fields = (VMStateField[]) {
  53         VMSTATE_I2C_SLAVE(parent_obj, sii9022_state),
  54         VMSTATE_UINT8(ptr, sii9022_state),
  55         VMSTATE_BOOL(addr_byte, sii9022_state),
  56         VMSTATE_BOOL(ddc_req, sii9022_state),
  57         VMSTATE_BOOL(ddc_skip_finish, sii9022_state),
  58         VMSTATE_BOOL(ddc, sii9022_state),
  59         VMSTATE_END_OF_LIST()
  60     }
  61 };
  62
  63 static int sii9022_event(I2CSlave *i2c, enum i2c_event event)
  64 {
  65     sii9022_state *s = SII9022(i2c);
  66
  67     switch (event) {
  68     case I2C_START_SEND:
  69         s->addr_byte = true;
  70         break;
  71     case I2C_START_RECV:
  72         break;
  73     case I2C_FINISH:
  74         break;
  75     case I2C_NACK:
  76         break;
  77     }
  78
  79     return 0;
  80 }
  81
  82 static uint8_t sii9022_rx(I2CSlave *i2c)
  83 {
  84     sii9022_state *s = SII9022(i2c);
  85     uint8_t res = 0x00;
  86
  87     switch (s->ptr) {
  88     case SII9022_SYS_CTRL_DATA:
  89         if (s->ddc_req) {
  90             /* Acknowledge DDC bus request */
  91             res = SII9022_SYS_CTRL_DDC_BUS_GRTD | SII9022_SYS_CTRL_DDC_BUS_REQ;
  92         }
  93         break;
  94     case SII9022_REG_CHIPID:
  95         res = 0xb0;
  96         break;
  97     case SII9022_INT_STATUS:
  98         /* Something is cold-plugged in, no interrupts */
  99         res = SII9022_INT_STATUS_PLUGGED;
 100         break;
 101     default:
 102         break;
 103     }
 104
 105     trace_sii9022_read_reg(s->ptr, res);
 106     s->ptr++;
 107
 108     return res;
 109 }
 110
 111 static int sii9022_tx(I2CSlave *i2c, uint8_t data)
 112 {
 113     sii9022_state *s = SII9022(i2c);
 114
 115     if (s->addr_byte) {
 116         s->ptr = data;
 117         s->addr_byte = false;
 118         return 0;
 119     }
 120
 121     switch (s->ptr) {
 122     case SII9022_SYS_CTRL_DATA:
 123         if (data & SII9022_SYS_CTRL_DDC_BUS_REQ) {
 124             s->ddc_req = true;
 125             if (data & SII9022_SYS_CTRL_DDC_BUS_GRTD) {
 126                 s->ddc = true;
 127                 /* Skip this finish since we just switched to DDC */
 128                 s->ddc_skip_finish = true;
 129                 trace_sii9022_switch_mode("DDC");
 130             }
 131         } else {
 132             s->ddc_req = false;
 133             s->ddc = false;
 134             trace_sii9022_switch_mode("normal");
 135         }
 136         break;
 137     default:
 138         break;
 139     }
 140
 141     trace_sii9022_write_reg(s->ptr, data);
 142     s->ptr++;
 143
 144     return 0;
 145 }
 146
 147 static void sii9022_reset(DeviceState *dev)
 148 {
 149     sii9022_state *s = SII9022(dev);
 150
 151     s->ptr = 0;
 152     s->addr_byte = false;
 153     s->ddc_req = false;
 154     s->ddc_skip_finish = false;
 155     s->ddc = false;
 156 }
 157
 158 static void sii9022_realize(DeviceState *dev, Error **errp)
 159 {
 160     I2CBus *bus;
 161
 162     bus = I2C_BUS(qdev_get_parent_bus(dev));
 163     i2c_create_slave(bus, TYPE_I2CDDC, 0x50);
 164 }
 165
 166 static void sii9022_class_init(ObjectClass *klass, void *data)
 167 {
 168     DeviceClass *dc = DEVICE_CLASS(klass);
 169     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 170
 171     k->event = sii9022_event;
 172     k->recv = sii9022_rx;
 173     k->send = sii9022_tx;
 174     dc->reset = sii9022_reset;
 175     dc->realize = sii9022_realize;
 176     dc->vmsd = &vmstate_sii9022;
 177 }
 178
 179 static const TypeInfo sii9022_info = {
 180     .name          = TYPE_SII9022,
 181     .parent        = TYPE_I2C_SLAVE,
 182     .instance_size = sizeof(sii9022_state),
 183     .class_init    = sii9022_class_init,
 184 };
 185
 186 static void sii9022_register_types(void)
 187 {
 188     type_register_static(&sii9022_info);
 189 }
 190
 191 type_init(sii9022_register_types)