hdmi.c

/*
 * Copyright (C) 2012 Avionic Design GmbH
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sub license,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/hdmi.h>
#include <linux/string.h>

static void hdmi_infoframe_checksum(void *buffer, size_t size)
{
	u8 *ptr = buffer;
	u8 csum = 0;
	size_t i;

	/* compute checksum */
	for (i = 0; i < size; i++)
		csum += ptr[i];

	ptr[3] = 256 - csum;
}

/**
 * hdmi_avi_infoframe_init() - initialize an HDMI AVI infoframe
 * @frame: HDMI AVI infoframe
 *
 * Returns 0 on success or a negative error code on failure.
 */
int hdmi_avi_infoframe_init(struct hdmi_avi_infoframe *frame)
{
	memset(frame, 0, sizeof(*frame));

	frame->type = HDMI_INFOFRAME_TYPE_AVI;
	frame->version = 2;
	frame->length = HDMI_AVI_INFOFRAME_SIZE;

	return 0;
}
EXPORT_SYMBOL(hdmi_avi_infoframe_init);

/**
 * hdmi_avi_infoframe_pack() - write HDMI AVI infoframe to binary buffer
 * @frame: HDMI AVI infoframe
 * @buffer: destination buffer
 * @size: size of buffer
 *
 * Packs the information contained in the @frame structure into a binary
 * representation that can be written into the corresponding controller
 * registers. Also computes the checksum as required by section 5.3.5 of
 * the HDMI 1.4 specification.
 *
 * Returns the number of bytes packed into the binary buffer or a negative
 * error code on failure.
 */
ssize_t hdmi_avi_infoframe_pack(struct hdmi_avi_infoframe *frame, void *buffer,
				size_t size)
{
	u8 *ptr = buffer;
	size_t length;

	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;

	if (size < length)
		return -ENOSPC;

	memset(buffer, 0, size);

	ptr[0] = frame->type;
	ptr[1] = frame->version;
	ptr[2] = frame->length;
	ptr[3] = 0; /* checksum */

	/* start infoframe payload */
	ptr += HDMI_INFOFRAME_HEADER_SIZE;

	ptr[0] = ((frame->colorspace & 0x3) << 5) | (frame->scan_mode & 0x3);

	/*
	 * Data byte 1, bit 4 has to be set if we provide the active format
	 * aspect ratio
	 */
	if (frame->active_aspect & 0xf)
		ptr[0] |= BIT(4);

	/* Bit 3 and 2 indicate if we transmit horizontal/vertical bar data */
	if (frame->top_bar || frame->bottom_bar)
		ptr[0] |= BIT(3);

	if (frame->left_bar || frame->right_bar)
		ptr[0] |= BIT(2);

	ptr[1] = ((frame->colorimetry & 0x3) << 6) |
		 ((frame->picture_aspect & 0x3) << 4) |
		 (frame->active_aspect & 0xf);

	ptr[2] = ((frame->extended_colorimetry & 0x7) << 4) |
		 ((frame->quantization_range & 0x3) << 2) |
		 (frame->nups & 0x3);

	if (frame->itc)
		ptr[2] |= BIT(7);

	ptr[3] = frame->video_code & 0x7f;

	ptr[4] = ((frame->ycc_quantization_range & 0x3) << 6) |
		 ((frame->content_type & 0x3) << 4) |
		 (frame->pixel_repeat & 0xf);

	ptr[5] = frame->top_bar & 0xff;
	ptr[6] = (frame->top_bar >> 8) & 0xff;
	ptr[7] = frame->bottom_bar & 0xff;
	ptr[8] = (frame->bottom_bar >> 8) & 0xff;
	ptr[9] = frame->left_bar & 0xff;
	ptr[10] = (frame->left_bar >> 8) & 0xff;
	ptr[11] = frame->right_bar & 0xff;
	ptr[12] = (frame->right_bar >> 8) & 0xff;

	hdmi_infoframe_checksum(buffer, length);

	return length;
}
EXPORT_SYMBOL(hdmi_avi_infoframe_pack);

/**
 * hdmi_spd_infoframe_init() - initialize an HDMI SPD infoframe
 * @frame: HDMI SPD infoframe
 * @vendor: vendor string
 * @product: product string
 *
 * Returns 0 on success or a negative error code on failure.
 */
int hdmi_spd_infoframe_init(struct hdmi_spd_infoframe *frame,
			    const char *vendor, const char *product)
{
	memset(frame, 0, sizeof(*frame));

	frame->type = HDMI_INFOFRAME_TYPE_SPD;
	frame->version = 1;
	frame->length = HDMI_SPD_INFOFRAME_SIZE;

	strncpy(frame->vendor, vendor, sizeof(frame->vendor));
	strncpy(frame->product, product, sizeof(frame->product));

	return 0;
}
EXPORT_SYMBOL(hdmi_spd_infoframe_init);

/**
 * hdmi_spd_infoframe_pack() - write HDMI SPD infoframe to binary buffer
 * @frame: HDMI SPD infoframe
 * @buffer: destination buffer
 * @size: size of buffer
 *
 * Packs the information contained in the @frame structure into a binary
 * representation that can be written into the corresponding controller
 * registers. Also computes the checksum as required by section 5.3.5 of
 * the HDMI 1.4 specification.
 *
 * Returns the number of bytes packed into the binary buffer or a negative
 * error code on failure.
 */
ssize_t hdmi_spd_infoframe_pack(struct hdmi_spd_infoframe *frame, void *buffer,
				size_t size)
{
	u8 *ptr = buffer;
	size_t length;

	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;

	if (size < length)
		return -ENOSPC;

	memset(buffer, 0, size);

	ptr[0] = frame->type;
	ptr[1] = frame->version;
	ptr[2] = frame->length;
	ptr[3] = 0; /* checksum */

	/* start infoframe payload */
	ptr += HDMI_INFOFRAME_HEADER_SIZE;

	memcpy(ptr, frame->vendor, sizeof(frame->vendor));
	memcpy(ptr + 8, frame->product, sizeof(frame->product));

	ptr[24] = frame->sdi;

	hdmi_infoframe_checksum(buffer, length);

	return length;
}
EXPORT_SYMBOL(hdmi_spd_infoframe_pack);

/**
 * hdmi_audio_infoframe_init() - initialize an HDMI audio infoframe
 * @frame: HDMI audio infoframe
 *
 * Returns 0 on success or a negative error code on failure.
 */
int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe *frame)
{
	memset(frame, 0, sizeof(*frame));

	frame->type = HDMI_INFOFRAME_TYPE_AUDIO;
	frame->version = 1;
	frame->length = HDMI_AUDIO_INFOFRAME_SIZE;

	return 0;
}
EXPORT_SYMBOL(hdmi_audio_infoframe_init);

/**
 * hdmi_audio_infoframe_pack() - write HDMI audio infoframe to binary buffer
 * @frame: HDMI audio infoframe
 * @buffer: destination buffer
 * @size: size of buffer
 *
 * Packs the information contained in the @frame structure into a binary
 * representation that can be written into the corresponding controller
 * registers. Also computes the checksum as required by section 5.3.5 of
 * the HDMI 1.4 specification.
 *
 * Returns the number of bytes packed into the binary buffer or a negative
 * error code on failure.
 */
ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
				  void *buffer, size_t size)
{
	unsigned char channels;
	u8 *ptr = buffer;
	size_t length;

	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;

	if (size < length)
		return -ENOSPC;

	memset(buffer, 0, size);

	if (frame->channels >= 2)
		channels = frame->channels - 1;
	else
		channels = 0;

	ptr[0] = frame->type;
	ptr[1] = frame->version;
	ptr[2] = frame->length;
	ptr[3] = 0; /* checksum */

	/* start infoframe payload */
	ptr += HDMI_INFOFRAME_HEADER_SIZE;

	ptr[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
	ptr[1] = ((frame->sample_frequency & 0x7) << 2) |
		 (frame->sample_size & 0x3);
	ptr[2] = frame->coding_type_ext & 0x1f;
	ptr[3] = frame->channel_allocation;
	ptr[4] = (frame->level_shift_value & 0xf) << 3;

	if (frame->downmix_inhibit)
		ptr[4] |= BIT(7);

	hdmi_infoframe_checksum(buffer, length);

	return length;
}
EXPORT_SYMBOL(hdmi_audio_infoframe_pack);

/**
 * hdmi_vendor_infoframe_init() - initialize an HDMI vendor infoframe
 * @frame: HDMI vendor infoframe
 *
 * Returns 0 on success or a negative error code on failure.
 */
int hdmi_vendor_infoframe_init(struct hdmi_vendor_infoframe *frame)
{
	memset(frame, 0, sizeof(*frame));

	frame->type = HDMI_INFOFRAME_TYPE_VENDOR;
	frame->version = 1;

	frame->oui = HDMI_IDENTIFIER;

	/*
	 * 0 is a valid value for s3d_struct, so we use a special "not set"
	 * value
	 */
	frame->s3d_struct = HDMI_3D_STRUCTURE_INVALID;

	return 0;
}
EXPORT_SYMBOL(hdmi_vendor_infoframe_init);

/**
 * hdmi_vendor_infoframe_pack() - write a HDMI vendor infoframe to binary buffer
 * @frame: HDMI infoframe
 * @buffer: destination buffer
 * @size: size of buffer
 *
 * Packs the information contained in the @frame structure into a binary
 * representation that can be written into the corresponding controller
 * registers. Also computes the checksum as required by section 5.3.5 of
 * the HDMI 1.4 specification.
 *
 * Returns the number of bytes packed into the binary buffer or a negative
 * error code on failure.
 */
ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
				 void *buffer, size_t size)
{
	u8 *ptr = buffer;
	size_t length;

	/* empty info frame */
	if (frame->vic == 0 && frame->s3d_struct == HDMI_3D_STRUCTURE_INVALID)
		return -EINVAL;

	/* only one of those can be supplied */
	if (frame->vic != 0 && frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID)
		return -EINVAL;

	/* for side by side (half) we also need to provide 3D_Ext_Data */
	if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
		frame->length = 6;
	else
		frame->length = 5;

	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;

	if (size < length)
		return -ENOSPC;

	memset(buffer, 0, size);

	ptr[0] = frame->type;
	ptr[1] = frame->version;
	ptr[2] = frame->length;
	ptr[3] = 0; /* checksum */

	/* HDMI OUI */
	ptr[4] = 0x03;
	ptr[5] = 0x0c;
	ptr[6] = 0x00;

	if (frame->vic) {
		ptr[7] = 0x1 << 5;	/* video format */
		ptr[8] = frame->vic;
	} else {
		ptr[7] = 0x2 << 5;	/* video format */
		ptr[8] = (frame->s3d_struct & 0xf) << 4;
		if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
			ptr[9] = (frame->s3d_ext_data & 0xf) << 4;
	}

	hdmi_infoframe_checksum(buffer, length);

	return length;
}
EXPORT_SYMBOL(hdmi_vendor_infoframe_pack);

/*
 * hdmi_vendor_any_infoframe_pack() - write a vendor infoframe to binary buffer
 */
static ssize_t
hdmi_vendor_any_infoframe_pack(union hdmi_vendor_any_infoframe *frame,
			   void *buffer, size_t size)
{
	/* we only know about HDMI vendor infoframes */
	if (frame->any.oui != HDMI_IDENTIFIER)
		return -EINVAL;

	return hdmi_vendor_infoframe_pack(&frame->hdmi, buffer, size);
}

/**
 * hdmi_infoframe_pack() - write a HDMI infoframe to binary buffer
 * @frame: HDMI infoframe
 * @buffer: destination buffer
 * @size: size of buffer
 *
 * Packs the information contained in the @frame structure into a binary
 * representation that can be written into the corresponding controller
 * registers. Also computes the checksum as required by section 5.3.5 of
 * the HDMI 1.4 specification.
 *
 * Returns the number of bytes packed into the binary buffer or a negative
 * error code on failure.
 */
ssize_t
hdmi_infoframe_pack(union hdmi_infoframe *frame, void *buffer, size_t size)
{
	ssize_t length;

	switch (frame->any.type) {
	case HDMI_INFOFRAME_TYPE_AVI:
		length = hdmi_avi_infoframe_pack(&frame->avi, buffer, size);
		break;
	case HDMI_INFOFRAME_TYPE_SPD:
		length = hdmi_spd_infoframe_pack(&frame->spd, buffer, size);
		break;
	case HDMI_INFOFRAME_TYPE_AUDIO:
		length = hdmi_audio_infoframe_pack(&frame->audio, buffer, size);
		break;
	case HDMI_INFOFRAME_TYPE_VENDOR:
		length = hdmi_vendor_any_infoframe_pack(&frame->vendor,
							buffer, size);
		break;
	default:
		WARN(1, "Bad infoframe type %d\n", frame->any.type);
		length = -EINVAL;
	}

	return length;
}
EXPORT_SYMBOL(hdmi_infoframe_pack);