hw/i2c/i2c-ddc.c - qemu - Git at Google

 /* 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);
	/* 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);