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130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
/* A simple I2C slave for returning monitor EDID data via DDC.
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*
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* Copyright (c) 2011 Linaro Limited
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* Written by Peter Maydell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qemu/log.h"
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#include "qemu/module.h"
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#include "hw/i2c/i2c.h"
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#include "hw/qdev-properties.h"
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#include "migration/vmstate.h"
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#include "hw/display/i2c-ddc.h"
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#ifndef DEBUG_I2CDDC
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#define DEBUG_I2CDDC 0
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#endif
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#define DPRINTF(fmt, ...) do { \
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if (DEBUG_I2CDDC) { \
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qemu_log("i2c-ddc: " fmt , ## __VA_ARGS__); \
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} \
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} while (0)
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static void i2c_ddc_reset(DeviceState *ds)
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{
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I2CDDCState *s = I2CDDC(ds);
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s->firstbyte = false;
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s->reg = 0;
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}
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static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event)
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{
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I2CDDCState *s = I2CDDC(i2c);
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if (event == I2C_START_SEND) {
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s->firstbyte = true;
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}
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return 0;
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}
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static uint8_t i2c_ddc_rx(I2CSlave *i2c)
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{
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I2CDDCState *s = I2CDDC(i2c);
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int value;
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value = s->edid_blob[s->reg % sizeof(s->edid_blob)];
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s->reg++;
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return value;
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}
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static int i2c_ddc_tx(I2CSlave *i2c, uint8_t data)
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{
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I2CDDCState *s = I2CDDC(i2c);
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if (s->firstbyte) {
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s->reg = data;
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s->firstbyte = false;
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DPRINTF("[EDID] Written new pointer: %u\n", data);
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return 0;
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}
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/* Ignore all writes */
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s->reg++;
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return 0;
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}
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static void i2c_ddc_init(Object *obj)
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{
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I2CDDCState *s = I2CDDC(obj);
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qemu_edid_generate(s->edid_blob, sizeof(s->edid_blob), &s->edid_info);
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}
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static const VMStateDescription vmstate_i2c_ddc = {
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.name = TYPE_I2CDDC,
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.version_id = 1,
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.fields = (const VMStateField[]) {
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VMSTATE_BOOL(firstbyte, I2CDDCState),
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VMSTATE_UINT8(reg, I2CDDCState),
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VMSTATE_END_OF_LIST()
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}
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};
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static Property i2c_ddc_properties[] = {
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DEFINE_EDID_PROPERTIES(I2CDDCState, edid_info),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void i2c_ddc_class_init(ObjectClass *oc, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(oc);
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I2CSlaveClass *isc = I2C_SLAVE_CLASS(oc);
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device_class_set_legacy_reset(dc, i2c_ddc_reset);
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dc->vmsd = &vmstate_i2c_ddc;
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device_class_set_props(dc, i2c_ddc_properties);
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isc->event = i2c_ddc_event;
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isc->recv = i2c_ddc_rx;
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isc->send = i2c_ddc_tx;
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}
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static const TypeInfo i2c_ddc_info = {
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.name = TYPE_I2CDDC,
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.parent = TYPE_I2C_SLAVE,
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.instance_size = sizeof(I2CDDCState),
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.instance_init = i2c_ddc_init,
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.class_init = i2c_ddc_class_init
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};
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static void ddc_register_devices(void)
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{
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type_register_static(&i2c_ddc_info);
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}
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type_init(ddc_register_devices);
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