309 lines
8.4 KiB
C
309 lines
8.4 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 "hw/i2c/i2c.h"
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#include "hw/i2c/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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/* Structure defining a monitor's characteristics in a
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* readable format: this should be passed to build_edid_blob()
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* to convert it into the 128 byte binary EDID blob.
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* Not all bits of the EDID are customisable here.
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*/
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struct EDIDData {
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char manuf_id[3]; /* three upper case letters */
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uint16_t product_id;
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uint32_t serial_no;
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uint8_t manuf_week;
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int manuf_year;
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uint8_t h_cm;
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uint8_t v_cm;
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uint8_t gamma;
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char monitor_name[14];
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char serial_no_string[14];
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/* Range limits */
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uint8_t vmin; /* Hz */
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uint8_t vmax; /* Hz */
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uint8_t hmin; /* kHz */
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uint8_t hmax; /* kHz */
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uint8_t pixclock; /* MHz / 10 */
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uint8_t timing_data[18];
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};
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typedef struct EDIDData EDIDData;
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/* EDID data for a simple LCD monitor */
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static const EDIDData lcd_edid = {
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/* The manuf_id ought really to be an assigned EISA ID */
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.manuf_id = "QMU",
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.product_id = 0,
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.serial_no = 1,
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.manuf_week = 1,
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.manuf_year = 2011,
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.h_cm = 40,
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.v_cm = 30,
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.gamma = 0x78,
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.monitor_name = "QEMU monitor",
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.serial_no_string = "1",
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.vmin = 40,
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.vmax = 120,
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.hmin = 30,
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.hmax = 100,
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.pixclock = 18,
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.timing_data = {
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/* Borrowed from a 21" LCD */
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0x48, 0x3f, 0x40, 0x30, 0x62, 0xb0, 0x32, 0x40, 0x40,
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0xc0, 0x13, 0x00, 0x98, 0x32, 0x11, 0x00, 0x00, 0x1e
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}
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};
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static uint8_t manuf_char_to_int(char c)
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{
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return (c - 'A') & 0x1f;
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}
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static void write_ascii_descriptor_block(uint8_t *descblob, uint8_t blocktype,
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const char *string)
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{
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/* Write an EDID Descriptor Block of the "ascii string" type */
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int i;
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descblob[0] = descblob[1] = descblob[2] = descblob[4] = 0;
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descblob[3] = blocktype;
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/* The rest is 13 bytes of ASCII; if less then the rest must
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* be filled with newline then spaces
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*/
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for (i = 5; i < 19; i++) {
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descblob[i] = string[i - 5];
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if (!descblob[i]) {
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break;
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}
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}
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if (i < 19) {
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descblob[i++] = '\n';
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}
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for ( ; i < 19; i++) {
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descblob[i] = ' ';
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}
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}
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static void write_range_limits_descriptor(const EDIDData *edid,
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uint8_t *descblob)
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{
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int i;
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descblob[0] = descblob[1] = descblob[2] = descblob[4] = 0;
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descblob[3] = 0xfd;
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descblob[5] = edid->vmin;
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descblob[6] = edid->vmax;
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descblob[7] = edid->hmin;
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descblob[8] = edid->hmax;
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descblob[9] = edid->pixclock;
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descblob[10] = 0;
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descblob[11] = 0xa;
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for (i = 12; i < 19; i++) {
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descblob[i] = 0x20;
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}
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}
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static void build_edid_blob(const EDIDData *edid, uint8_t *blob)
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{
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/* Write an EDID 1.3 format blob (128 bytes) based
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* on the EDIDData structure.
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*/
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int i;
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uint8_t cksum;
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/* 00-07 : header */
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blob[0] = blob[7] = 0;
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for (i = 1 ; i < 7; i++) {
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blob[i] = 0xff;
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}
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/* 08-09 : manufacturer ID */
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blob[8] = (manuf_char_to_int(edid->manuf_id[0]) << 2)
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| (manuf_char_to_int(edid->manuf_id[1]) >> 3);
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blob[9] = (manuf_char_to_int(edid->manuf_id[1]) << 5)
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| manuf_char_to_int(edid->manuf_id[2]);
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/* 10-11 : product ID code */
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blob[10] = edid->product_id;
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blob[11] = edid->product_id >> 8;
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blob[12] = edid->serial_no;
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blob[13] = edid->serial_no >> 8;
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blob[14] = edid->serial_no >> 16;
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blob[15] = edid->serial_no >> 24;
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/* 16 : week of manufacture */
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blob[16] = edid->manuf_week;
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/* 17 : year of manufacture - 1990 */
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blob[17] = edid->manuf_year - 1990;
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/* 18, 19 : EDID version and revision */
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blob[18] = 1;
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blob[19] = 3;
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/* 20 - 24 : basic display parameters */
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/* We are always a digital display */
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blob[20] = 0x80;
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/* 21, 22 : max h/v size in cm */
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blob[21] = edid->h_cm;
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blob[22] = edid->v_cm;
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/* 23 : gamma (divide by 100 then add 1 for actual value) */
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blob[23] = edid->gamma;
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/* 24 feature support: no power management, RGB, preferred timing mode,
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* standard colour space
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*/
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blob[24] = 0x0e;
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/* 25 - 34 : chromaticity coordinates. These are the
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* standard sRGB chromaticity values
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*/
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blob[25] = 0xee;
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blob[26] = 0x91;
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blob[27] = 0xa3;
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blob[28] = 0x54;
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blob[29] = 0x4c;
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blob[30] = 0x99;
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blob[31] = 0x26;
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blob[32] = 0x0f;
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blob[33] = 0x50;
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blob[34] = 0x54;
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/* 35, 36 : Established timings: claim to support everything */
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blob[35] = blob[36] = 0xff;
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/* 37 : manufacturer's reserved timing: none */
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blob[37] = 0;
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/* 38 - 53 : standard timing identification
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* don't claim anything beyond what the 'established timings'
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* already provide. Unused slots must be (0x1, 0x1)
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*/
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for (i = 38; i < 54; i++) {
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blob[i] = 0x1;
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}
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/* 54 - 71 : descriptor block 1 : must be preferred timing data */
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memcpy(blob + 54, edid->timing_data, 18);
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/* 72 - 89, 90 - 107, 108 - 125 : descriptor block 2, 3, 4
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* Order not important, but we must have a monitor name and a
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* range limits descriptor.
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*/
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write_range_limits_descriptor(edid, blob + 72);
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write_ascii_descriptor_block(blob + 90, 0xfc, edid->monitor_name);
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write_ascii_descriptor_block(blob + 108, 0xff, edid->serial_no_string);
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/* 126 : extension flag */
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blob[126] = 0;
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cksum = 0;
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for (i = 0; i < 127; i++) {
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cksum += blob[i];
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}
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/* 127 : checksum */
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blob[127] = -cksum;
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if (DEBUG_I2CDDC) {
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qemu_hexdump((char *)blob, stdout, "", 128);
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}
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}
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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 void 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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}
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static int 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];
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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 1;
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}
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/* Ignore all writes */
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s->reg++;
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return 1;
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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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build_edid_blob(&lcd_edid, s->edid_blob);
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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 = (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 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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dc->reset = i2c_ddc_reset;
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dc->vmsd = &vmstate_i2c_ddc;
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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 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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