/*
* 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>
#include <linux/device.h>
#define hdmi_log(fmt, ...) dev_printk(level, dev, fmt, ##__VA_ARGS__)
static u8 hdmi_infoframe_checksum(u8 *ptr, size_t size)
{
u8 csum = 0;
size_t i;
/* compute checksum */
for (i = 0; i < size; i++)
csum += ptr[i];
return 256 - csum;
}
static void hdmi_infoframe_set_checksum(void *buffer, size_t size)
{
u8 *ptr = buffer;
ptr[3] = hdmi_infoframe_checksum(buffer, size);
}
/**
* 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