/* A simple I2C slave for returning monitor EDID data via DDC.
*
* Copyright (c) 2011 Linaro Limited
* Written by Peter Maydell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/log.h"
#include "hw/i2c/i2c.h"
#include "hw/i2c/i2c-ddc.h"
#ifndef DEBUG_I2CDDC
#define DEBUG_I2CDDC 0
#endif
#define DPRINTF(fmt, ...) do { \
if (DEBUG_I2CDDC) { \
qemu_log("i2c-ddc: " fmt , ## __VA_ARGS__); \
} \
} while (0)
/* Structure defining a monitor's characteristics in a
* readable format: this should be passed to build_edid_blob()
* to convert it into the 128 byte binary EDID blob.
* Not all bits of the EDID are customisable here.
*/
struct EDIDData {
char manuf_id[3]; /* three upper case letters */
uint16_t product_id;
uint32_t serial_no;
uint8_t manuf_week;
int manuf_year;
uint8_t h_cm;
uint8_t v_cm;
uint8_t gamma;
char monitor_name[14];
char serial_no_string[14];
/* Range limits */
uint8_t vmin; /* Hz */
uint8_t vmax; /* Hz */
uint8_t hmin; /* kHz */
uint8_t hmax; /* kHz */
uint8_t pixclock; /* MHz / 10 */
uint8_t timing_data[18];
};
typedef struct EDIDData EDIDData;
/* EDID data for a simple LCD monitor */
static const EDIDData lcd_edid = {
/* The manuf_id ought really to be an assigned EISA ID */
.manuf_id = "QMU",
.product_id = 0,
.serial_no = 1,
.manuf_week = 1,
.manuf_year = 2011,
.h_cm = 40,
.v_cm = 30,
.gamma = 0x78,
.monitor_name = "QEMU monitor",
.serial_no_string = "1",
.vmin = 40,
.vmax = 120,
.hmin = 30,
.hmax = 100,
.pixclock = 18,
.timing_data = {
/* Borrowed from a 21" LCD */
0x48, 0x3f, 0x40, 0x30, 0x62, 0xb0, 0x32, 0x40, 0x40,
0xc0, 0x13, 0x00, 0x98, 0x32, 0x11, 0x00, 0x00, 0x1e
}
};
static uint8_t manuf_char_to_int(char c)
{
return (c - 'A') & 0x1f;
}
static void write_ascii_descriptor_block(uint8_t *descblob, uint8_t blocktype,
const char *string)
{
/* Write an EDID Descriptor Block of the "ascii string" type */
int i;
descblob[0] = descblob[1] = descblob[2] = descblob[4] = 0;
descblob[3] = blocktype;
/* The rest is 13 bytes of ASCII; if less then the rest must
* be filled with newline then spaces
*/
for (i = 5; i < 19; i++) {
descblob[i] = string[i - 5];
if (!descblob[i]) {
break;
}
}
if (i < 19) {
descblob[i++] = '\n';
}
for ( ; i < 19; i++) {
descblob[i] = ' ';
}
}
static void write_range_limits_descriptor(const EDIDData *edid,
uint8_t *descblob)
{
int i;
descblob[0] = descblob[1] = descblob[2] = descblob[4] = 0;
descblob[3] = 0xfd;
descblob[5] = edid->vmin;
descblob[6] = edid->vmax;
descblob[7] = edid->hmin;
descblob[8] = edid->hmax;
descblob[9] = edid->pixclock;
descblob[10] = 0;
descblob[11] = 0xa;
for (i = 12; i < 19; i++) {
descblob[i] = 0x20;
}
}
static void build_edid_blob(const EDIDData *edid, uint8_t *blob)
{
/* Write an EDID 1.3 format blob (128 bytes) based
* on the EDIDData structure.
*/
int i;
uint8_t cksum;
/* 00-07 : header */
blob[0] = blob[7] = 0;
for (i = 1 ; i < 7; i++) {
blob[i] = 0xff;
}
/* 08-09 : manufacturer ID */
blob[8] = (manuf_char_to_int(edid->manuf_id[0]) << 2)
| (manuf_char_to_int(edid->manuf_id[1]) >> 3);
blob[9] = (manuf_char_to_int(edid->manuf_id[1]) << 5)
| manuf_char_to_int(edid->manuf_id[2]);
/* 10-11 : product ID code */
blob[10] = edid->product_id;
blob[11] = edid->product_id >> 8;
blob[12] = edid->serial_no;
blob[13] = edid->serial_no >> 8;
blob[14] = edid->serial_no >> 16;
blob[15] = edid->serial_no >> 24;
/* 16 : week of manufacture */
blob[16] = edid->manuf_week;
/* 17 : year of manufacture - 1990 */
blob[17] = edid->manuf_year - 1990;
/* 18, 19 : EDID version and revision */
blob[18] = 1;
blob[19] = 3;
/* 20 - 24 : basic display parameters */
/* We are always a digital display */
blob[20] = 0x80;
/* 21, 22 : max h/v size in cm */
blob[21] = edid->h_cm;
blob[22] = edid->v_cm;
/* 23 : gamma (divide by 100 then add 1 for actual value) */
blob[23] = edid->gamma;
/* 24 feature support: no power management, RGB, preferred timing mode,
* standard colour space
*/
blob[24] = 0x0e;
/* 25 - 34 : chromaticity coordinates. These are the
* standard sRGB chromaticity values
*/
blob[25] = 0xee;
blob[26] = 0x91;
blob[27] = 0xa3;
blob[28] = 0x54;
blob[29] = 0x4c;
blob[30] = 0x99;
blob[31] = 0x26;
blob[32] = 0x0f;
blob[33] = 0x50;
blob[34] = 0x54;
/* 35, 36 : Established timings: claim to support everything */
blob[35] = blob[36] = 0xff;
/* 37 : manufacturer's reserved timing: none */
blob[37] = 0;
/* 38 - 53 : standard timing identification
* don't claim anything beyond what the 'established timings'
* already provide. Unused slots must be (0x1, 0x1)
*/
for (i = 38; i < 54; i++) {
blob[i] = 0x1;
}
/* 54 - 71 : descriptor block 1 : must be preferred timing data */
memcpy(blob + 54, edid->timing_data, 18);
/* 72 - 89, 90 - 107, 108 - 125 : descriptor block 2, 3, 4
* Order not important, but we must have a monitor name and a
* range limits descriptor.
*/
write_range_limits_descriptor(edid, blob + 72);
write_ascii_descriptor_block(blob + 90, 0xfc, edid->monitor_name);
write_ascii_descriptor_block(blob + 108, 0xff, edid->serial_no_string);
/* 126 : extension flag */
blob[126] = 0;
cksum = 0;
for (i = 0; i < 127; i++) {
cksum += blob[i];
}
/* 127 : checksum */
blob[127] = -cksum;
if (DEBUG_I2CDDC) {
qemu_hexdump((char *)blob, stdout, "", 128);
}
}
static void i2c_ddc_reset(DeviceState *ds)
{
I2CDDCState *s = I2CDDC(ds);
s->firstbyte = false;
s->reg = 0;
}
static int i2c_ddc_event(I2CSlave *i2c, enum i2c_event event)
{
I2CDDCState *s = I2CDDC(i2c);
if (event == I2C_START_SEND) {
s->firstbyte = true;
}
return 0;
}
static int i2c_ddc_rx(I2CSlave *i2c)
{
I2CDDCState *s = I2CDDC(i2c);
int value;
value = s->edid_blob[s->reg];
s->reg++;
return value;
}
static int i2c_ddc_tx(I2CSlave *i2c, uint8_t data)
{
I2CDDCState *s = I2CDDC(i2c);
if (s->firstbyte) {
s->reg = data;
s->firstbyte = false;
DPRINTF("[EDID] Written new pointer: %u\n", data);
return 0;
}
/* Ignore all writes */
s->reg++;
return 0;
}
static void i2c_ddc_init(Object *obj)
{
I2CDDCState *s = I2CDDC(obj);
build_edid_blob(&lcd_edid, s->edid_blob);
}
static const VMStateDescription vmstate_i2c_ddc = {
.name = TYPE_I2CDDC,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_BOOL(firstbyte, I2CDDCState),
VMSTATE_UINT8(reg, I2CDDCState),
VMSTATE_END_OF_LIST()
}
};
static void i2c_ddc_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
I2CSlaveClass *isc = I2C_SLAVE_CLASS(oc);
dc->reset = i2c_ddc_reset;
dc->vmsd = &vmstate_i2c_ddc;
isc->event = i2c_ddc_event;
isc->recv = i2c_ddc_rx;
isc->send = i2c_ddc_tx;
}
static TypeInfo i2c_ddc_info = {
.name = TYPE_I2CDDC,
.parent = TYPE_I2C_SLAVE,
.instance_size = sizeof(I2CDDCState),
.instance_init = i2c_ddc_init,
.class_init = i2c_ddc_class_init
};
static void ddc_register_devices(void)
{
type_register_static(&i2c_ddc_info);
}
type_init(ddc_register_devices);
