1. 根目录:
2. sound
3. pci
4. echoaudio
5. darla24_dsp.c

/***************************************************************************

   Copyright Echo Digital Audio Corporation (c) 1998 - 2004
   All rights reserved
   www.echoaudio.com

   This file is part of Echo Digital Audio's generic driver library.

   Echo Digital Audio's generic driver library is free software;
   you can redistribute it and/or modify it under the terms of
   the GNU General Public License 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston,
   MA  02111-1307, USA.

   *************************************************************************

 Translation from C++ and adaptation for use in ALSA-Driver
 were made by Giuliano Pochini <pochini@shiny.it>

****************************************************************************/


static int init_hw(struct echoaudio *chip, u16 device_id, u16 subdevice_id)
{
	int err;

	DE_INIT(("init_hw() - Darla24\n"));
	if (snd_BUG_ON((subdevice_id & 0xfff0) != DARLA24))
		return -ENODEV;

	if ((err = init_dsp_comm_page(chip))) {
		DE_INIT(("init_hw - could not initialize DSP comm page\n"));
		return err;
	}

	chip->device_id = device_id;
	chip->subdevice_id = subdevice_id;
	chip->bad_board = TRUE;
	chip->dsp_code_to_load = FW_DARLA24_DSP;
	/* Since this card has no ASIC, mark it as loaded so everything
	   works OK */
	chip->asic_loaded = TRUE;
	chip->input_clock_types = ECHO_CLOCK_BIT_INTERNAL |
		ECHO_CLOCK_BIT_ESYNC;

	if ((err = load_firmware(chip)) < 0)
		return err;
	chip->bad_board = FALSE;

	DE_INIT(("init_hw done\n"));
	return err;
}



static int set_mixer_defaults(struct echoaudio *chip)
{
	return init_line_levels(chip);
}



static u32 detect_input_clocks(const struct echoaudio *chip)
{
	u32 clocks_from_dsp, clock_bits;

	/* Map the DSP clock detect bits to the generic driver clock
	   detect bits */
	clocks_from_dsp = le32_to_cpu(chip->comm_page->status_clocks);

	clock_bits = ECHO_CLOCK_BIT_INTERNAL;

	if (clocks_from_dsp & GLDM_CLOCK_DETECT_BIT_ESYNC)
		clock_bits |= ECHO_CLOCK_BIT_ESYNC;

	return clock_bits;
}



/* The Darla24 has no ASIC. Just do nothing */
static int load_asic(struct echoaudio *chip)
{
	return 0;
}



static int set_sample_rate(struct echoaudio *chip, u32 rate)
{
	u8 clock;

	switch (rate) {
	case 96000:
		clock = GD24_96000;
		break;
	case 88200:
		clock = GD24_88200;
		break;
	case 48000:
		clock = GD24_48000;
		break;
	case 44100:
		clock = GD24_44100;
		break;
	case 32000:
		clock = GD24_32000;
		break;
	case 22050:
		clock = GD24_22050;
		break;
	case 16000:
		clock = GD24_16000;
		break;
	case 11025:
		clock = GD24_11025;
		break;
	case 8000:
		clock = GD24_8000;
		break;
	default:
		DE_ACT(("set_sample_rate: Error, invalid sample rate %d\n",
			rate));
		return -EINVAL;
	}

	if (wait_handshake(chip))
		return -EIO;

	DE_ACT(("set_sample_rate: %d clock %d\n", rate, clock));
	chip->sample_rate = rate;

	/* Override the sample rate if this card is set to Echo sync. */
	if (chip->input_clock == ECHO_CLOCK_ESYNC)
		clock = GD24_EXT_SYNC;

	chip->comm_page->sample_rate = cpu_to_le32(rate);	/* ignored by the DSP ? */
	chip->comm_page->gd_clock_state = clock;
	clear_handshake(chip);
	return send_vector(chip, DSP_VC_SET_GD_AUDIO_STATE);
}



static int set_input_clock(struct echoaudio *chip, u16 clock)
{
	if (snd_BUG_ON(clock != ECHO_CLOCK_INTERNAL &&
		       clock != ECHO_CLOCK_ESYNC))
		return -EINVAL;
	chip->input_clock = clock;
	return set_sample_rate(chip, chip->sample_rate);
}