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Diffstat (limited to 'hw/i2c/i2c-ddc.c')
| -rw-r--r-- | hw/i2c/i2c-ddc.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/hw/i2c/i2c-ddc.c b/hw/i2c/i2c-ddc.c new file mode 100644 index 0000000000..1227212934 --- /dev/null +++ b/hw/i2c/i2c-ddc.c @@ -0,0 +1,308 @@ +/* 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/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 void i2c_ddc_event(I2CSlave *i2c, enum i2c_event event) +{ + I2CDDCState *s = I2CDDC(i2c); + + if (event == I2C_START_SEND) { + s->firstbyte = true; + } +} + +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 1; + } + + /* Ignore all writes */ + s->reg++; + return 1; +} + +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); |