/*
 * Copyright (c) 2011 Jan Vesely
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/** @addtogroup drvaudiosb16
 * @{
 */
/** @file
 * @brief DSP helper functions implementation
 */

#include <libarch/ddi.h>

#include "dma.h"
#include "dma_controller.h"
#include "ddf_log.h"
#include "dsp_commands.h"
#include "dsp.h"


#ifndef DSP_RETRY_COUNT
#define DSP_RETRY_COUNT 100
#endif

#define DSP_RESET_RESPONSE 0xaa

static inline int sb_dsp_read(sb_dsp_t *dsp, uint8_t *data)
{
	assert(data);
	assert(dsp);
	uint8_t status;
	size_t attempts = DSP_RETRY_COUNT;
	do {
		status = pio_read_8(&dsp->regs->dsp_read_status);
	} while (--attempts && ((status & DSP_READ_READY) == 0));

	if ((status & DSP_READ_READY) == 0)
		return EIO;

	*data = pio_read_8(&dsp->regs->dsp_data_read);
	return EOK;
}
/*----------------------------------------------------------------------------*/
static inline int sb_dsp_write(sb_dsp_t *dsp, uint8_t data)
{
	assert(dsp);
	uint8_t status;
	size_t attempts = DSP_RETRY_COUNT;
	do {
		status = pio_read_8(&dsp->regs->dsp_write);
	} while (--attempts && ((status & DSP_WRITE_BUSY) != 0));

	if ((status & DSP_WRITE_BUSY))
		return EIO;

	pio_write_8(&dsp->regs->dsp_write, data);
	return EOK;
}
/*----------------------------------------------------------------------------*/
static inline void sb_dsp_reset(sb_dsp_t *dsp)
{
	assert(dsp);
	/* Reset DSP, see Chapter 2 of Sound Blaster HW programming guide */
	pio_write_8(&dsp->regs->dsp_reset, 1);
	udelay(3); /* Keep reset for 3 us */
	pio_write_8(&dsp->regs->dsp_reset, 0);
}
/*----------------------------------------------------------------------------*/
int sb_dsp_init(sb_dsp_t *dsp, sb16_regs_t *regs)
{
	assert(dsp);
	dsp->regs = regs;
	sb_dsp_reset(dsp);
	/* "DSP takes about 100 microseconds to initialize itself" */
	udelay(100);
	uint8_t response;
	const int ret = sb_dsp_read(dsp, &response);
	if (ret != EOK) {
		ddf_log_error("Failed to read DSP reset response value.\n");
		return ret;
	}
	if (response != DSP_RESET_RESPONSE) {
		ddf_log_error("Invalid DSP reset response: %x.\n", response);
		return EIO;
	}

	/* Get DSP version number */
	sb_dsp_write(dsp, DSP_VERSION);
	sb_dsp_read(dsp, &dsp->version.major);
	sb_dsp_read(dsp, &dsp->version.minor);
	return EOK;
}
/*----------------------------------------------------------------------------*/
int sb_dsp_play_direct(sb_dsp_t *dsp, const uint8_t *data, size_t size,
    unsigned sampling_rate, unsigned channels, unsigned bit_depth)
{
	assert(dsp);
	if (channels != 1 || bit_depth != 8)
		return EIO;
	/* In microseconds */
	const unsigned wait_period = 1000000 / sampling_rate;
	while (size--) {
		pio_write_8(&dsp->regs->dsp_write, DIRECT_8B_OUTPUT);
		pio_write_8(&dsp->regs->dsp_write, *data++);
		udelay(wait_period);
	}
	return EOK;
}
/**
 * @}
 */