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 "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 typedef struct sii9022_state sii9022_state;
  40 DECLARE_INSTANCE_CHECKER(sii9022_state, SII9022,
  41                          TYPE_SII9022)
  42
  43 struct sii9022_state {
  44     I2CSlave parent_obj;
  45     uint8_t ptr;
  46     bool addr_byte;
  47     bool ddc_req;
  48     bool ddc_skip_finish;
  49     bool ddc;
  50 };
  51
  52 static const VMStateDescription vmstate_sii9022 = {
  53     .name = "sii9022",
  54     .version_id = 1,
  55     .minimum_version_id = 1,
  56     .fields = (VMStateField[]) {
  57         VMSTATE_I2C_SLAVE(parent_obj, sii9022_state),
  58         VMSTATE_UINT8(ptr, sii9022_state),
  59         VMSTATE_BOOL(addr_byte, sii9022_state),
  60         VMSTATE_BOOL(ddc_req, sii9022_state),
  61         VMSTATE_BOOL(ddc_skip_finish, sii9022_state),
  62         VMSTATE_BOOL(ddc, sii9022_state),
  63         VMSTATE_END_OF_LIST()
  64     }
  65 };
  66
  67 static int sii9022_event(I2CSlave *i2c, enum i2c_event event)
  68 {
  69     sii9022_state *s = SII9022(i2c);
  70
  71     switch (event) {
  72     case I2C_START_SEND:
  73         s->addr_byte = true;
  74         break;
  75     case I2C_START_RECV:
  76         break;
  77     case I2C_FINISH:
  78         break;
  79     case I2C_NACK:
  80         break;
  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)