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.
/* Some vector commands involve the DSP reading or writing data to and from the comm page; if you send one of these commands to the DSP, it will complete the command and then write a non-zero value to the Handshake field in the
comm page. This function waits for the handshake to show up. */ staticint wait_handshake(struct echoaudio *chip)
{ int i;
/* Wait up to 20ms for the handshake from the DSP */ for (i = 0; i < HANDSHAKE_TIMEOUT; i++) { /* Look for the handshake value */
barrier(); if (chip->comm_page->handshake) { return 0;
}
udelay(1);
}
dev_err(chip->card->dev, "wait_handshake(): Timeout waiting for DSP\n"); return -EBUSY;
}
/* Much of the interaction between the DSP and the driver is done via vector commands; send_vector writes a vector command to the DSP. Typically, this causes the DSP to read or write fields in the comm page.
PCI posting is not required thanks to the handshake logic. */ staticint send_vector(struct echoaudio *chip, u32 command)
{ int i;
wmb(); /* Flush all pending writes before sending the command */
/* Wait up to 100ms for the "vector busy" bit to be off */ for (i = 0; i < VECTOR_BUSY_TIMEOUT; i++) { if (!(get_dsp_register(chip, CHI32_VECTOR_REG) &
CHI32_VECTOR_BUSY)) {
set_dsp_register(chip, CHI32_VECTOR_REG, command); /*if (i) DE_ACT(("send_vector time: %d\n", i));*/ return 0;
}
udelay(1);
}
dev_err(chip->card->dev, "timeout on send_vector\n"); return -EBUSY;
}
/* write_dsp writes a 32-bit value to the DSP; this is used almost
exclusively for loading the DSP. */ staticint write_dsp(struct echoaudio *chip, u32 data)
{
u32 status, i;
for (i = 0; i < 10000000; i++) { /* timeout = 10s */
status = get_dsp_register(chip, CHI32_STATUS_REG); if ((status & CHI32_STATUS_HOST_WRITE_EMPTY) != 0) {
set_dsp_register(chip, CHI32_DATA_REG, data);
wmb(); /* write it immediately */ return 0;
}
udelay(1);
cond_resched();
}
chip->bad_board = true; /* Set true until DSP re-loaded */
dev_dbg(chip->card->dev, "write_dsp: Set bad_board to true\n"); return -EIO;
}
/* read_dsp reads a 32-bit value from the DSP; this is used almost
exclusively for loading the DSP and checking the status of the ASIC. */ staticint read_dsp(struct echoaudio *chip, u32 *data)
{
u32 status, i;
for (i = 0; i < READ_DSP_TIMEOUT; i++) {
status = get_dsp_register(chip, CHI32_STATUS_REG); if ((status & CHI32_STATUS_HOST_READ_FULL) != 0) {
*data = get_dsp_register(chip, CHI32_DATA_REG); return 0;
}
udelay(1);
cond_resched();
}
chip->bad_board = true; /* Set true until DSP re-loaded */
dev_err(chip->card->dev, "read_dsp: Set bad_board to true\n"); return -EIO;
}
/* This function is used to read back the serial number from the DSP; this is triggered by the SET_COMMPAGE_ADDR command. Only some early Echogals products have serial numbers in the ROM; the serial number is not used, but you still need to do this as
part of the DSP load process. */ staticint read_sn(struct echoaudio *chip)
{ int i;
u32 sn[6];
for (i = 0; i < 5; i++) { if (read_dsp(chip, &sn[i])) {
dev_err(chip->card->dev, "Failed to read serial number\n"); return -EIO;
}
}
dev_dbg(chip->card->dev, "Read serial number %08x %08x %08x %08x %08x\n",
sn[0], sn[1], sn[2], sn[3], sn[4]); return 0;
}
#ifndef ECHOCARD_HAS_ASIC /* This card has no ASIC, just return ok */ staticinlineint check_asic_status(struct echoaudio *chip)
{
chip->asic_loaded = true; return 0;
}
#endif/* !ECHOCARD_HAS_ASIC */
#ifdef ECHOCARD_HAS_ASIC
/* Load ASIC code - done after the DSP is loaded */ staticint load_asic_generic(struct echoaudio *chip, u32 cmd, short asic)
{ conststruct firmware *fw; int err;
u32 i, size;
u8 *code;
err = get_firmware(&fw, chip, asic); if (err < 0) {
dev_warn(chip->card->dev, "Firmware not found !\n"); return err;
}
code = (u8 *)fw->data;
size = fw->size;
/* Send the "Here comes the ASIC" command */ if (write_dsp(chip, cmd) < 0) goto la_error;
/* Write length of ASIC file in bytes */ if (write_dsp(chip, size) < 0) goto la_error;
for (i = 0; i < size; i++) { if (write_dsp(chip, code[i]) < 0) goto la_error;
}
free_firmware(fw, chip); return 0;
la_error:
dev_err(chip->card->dev, "failed on write_dsp\n");
free_firmware(fw, chip); return -EIO;
}
#endif/* ECHOCARD_HAS_ASIC */
#ifdef DSP_56361
/* Install the resident loader for 56361 DSPs; The resident loader is on the EPROM on the board for 56301 DSP. The resident loader is a tiny little
program that is used to load the real DSP code. */ staticint install_resident_loader(struct echoaudio *chip)
{
u32 address; int index, words, i;
u16 *code;
u32 status; conststruct firmware *fw;
/* 56361 cards only! This check is required by the old 56301-based
Mona and Gina24 */ if (chip->device_id != DEVICE_ID_56361) return 0;
/* Look to see if the resident loader is present. If the resident
loader is already installed, host flag 5 will be on. */
status = get_dsp_register(chip, CHI32_STATUS_REG); if (status & CHI32_STATUS_REG_HF5) {
dev_dbg(chip->card->dev, "Resident loader already installed; status is 0x%x\n",
status); return 0;
}
i = get_firmware(&fw, chip, FW_361_LOADER); if (i < 0) {
dev_warn(chip->card->dev, "Firmware not found !\n"); return i;
}
/* The DSP code is an array of 16 bit words. The array is divided up into sections. The first word of each section is the size in words, followed by the section type. Since DSP addresses and data are 24 bits wide, they each take up two 16 bit words in the array. This is a lot like the other loader loop, but it's not a loop, you
don't write the memory type, and you don't write a zero at the end. */
/* Set DSP format bits for 24 bit mode */
set_dsp_register(chip, CHI32_CONTROL_REG,
get_dsp_register(chip, CHI32_CONTROL_REG) | 0x900);
code = (u16 *)fw->data;
/* Skip the header section; the first word in the array is the size of the first section, so the first real section of code is pointed
to by Code[0]. */
index = code[0];
/* Skip the section size, LRS block type, and DSP memory type */
index += 3;
/* Get the number of DSP words to write */
words = code[index++];
/* Get the DSP address for this block; 24 bits, so build from two words */
address = ((u32)code[index] << 16) + code[index + 1];
index += 2;
/* Write the count to the DSP */ if (write_dsp(chip, words)) {
dev_err(chip->card->dev, "install_resident_loader: Failed to write word count!\n"); goto irl_error;
} /* Write the DSP address */ if (write_dsp(chip, address)) {
dev_err(chip->card->dev, "install_resident_loader: Failed to write DSP address!\n"); goto irl_error;
} /* Write out this block of code to the DSP */ for (i = 0; i < words; i++) {
u32 data;
data = ((u32)code[index] << 16) + code[index + 1]; if (write_dsp(chip, data)) {
dev_err(chip->card->dev, "install_resident_loader: Failed to write DSP code\n"); goto irl_error;
}
index += 2;
}
/* Wait for flag 5 to come up */ for (i = 0; i < 200; i++) { /* Timeout is 50us * 200 = 10ms */
udelay(50);
status = get_dsp_register(chip, CHI32_STATUS_REG); if (status & CHI32_STATUS_REG_HF5) break;
}
if (i == 200) {
dev_err(chip->card->dev, "Resident loader failed to set HF5\n"); goto irl_error;
}
/* Wait 10ms for HF3 to indicate that software reset is complete */ for (i = 0; i < 1000; i++) { /* Timeout is 10us * 1000 = 10ms */ if (get_dsp_register(chip, CHI32_STATUS_REG) &
CHI32_STATUS_REG_HF3) break;
udelay(10);
}
if (i == 1000) {
dev_err(chip->card->dev, "load_dsp: Timeout waiting for CHI32_STATUS_REG_HF3\n"); return -EIO;
}
/* Set DSP format bits for 24 bit mode now that soft reset is done */
set_dsp_register(chip, CHI32_CONTROL_REG,
get_dsp_register(chip, CHI32_CONTROL_REG) | 0x900);
/* Main loader loop */
index = code[0]; for (;;) { int block_type, mem_type;
/* Total Block Size */
index++;
/* Block Type */
block_type = code[index]; if (block_type == 4) /* We're finished */ break;
index++;
/* Memory Type P=0,X=1,Y=2 */
mem_type = code[index++];
/* Block Code Size */
words = code[index++]; if (words == 0) /* We're finished */ break;
if (write_dsp(chip, words) < 0) {
dev_err(chip->card->dev, "load_dsp: failed to write number of DSP words\n"); return -EIO;
} if (write_dsp(chip, address) < 0) {
dev_err(chip->card->dev, "load_dsp: failed to write DSP address\n"); return -EIO;
} if (write_dsp(chip, mem_type) < 0) {
dev_err(chip->card->dev, "load_dsp: failed to write DSP memory type\n"); return -EIO;
} /* Code */ for (i = 0; i < words; i++, index+=2) {
data = ((u32)code[index] << 16) + code[index + 1]; if (write_dsp(chip, data) < 0) {
dev_err(chip->card->dev, "load_dsp: failed to write DSP data\n"); return -EIO;
}
}
}
if (write_dsp(chip, 0) < 0) { /* We're done!!! */
dev_err(chip->card->dev, "load_dsp: Failed to write final zero\n"); return -EIO;
}
udelay(10);
for (i = 0; i < 5000; i++) { /* Timeout is 100us * 5000 = 500ms */ /* Wait for flag 4 - indicates that the DSP loaded OK */ if (get_dsp_register(chip, CHI32_STATUS_REG) &
CHI32_STATUS_REG_HF4) {
set_dsp_register(chip, CHI32_CONTROL_REG,
get_dsp_register(chip, CHI32_CONTROL_REG) & ~0x1b00);
if (write_dsp(chip, DSP_FNC_SET_COMMPAGE_ADDR) < 0) {
dev_err(chip->card->dev, "load_dsp: Failed to write DSP_FNC_SET_COMMPAGE_ADDR\n"); return -EIO;
}
if (write_dsp(chip, chip->comm_page_phys) < 0) {
dev_err(chip->card->dev, "load_dsp: Failed to write comm page address\n"); return -EIO;
}
/* Get the serial number via slave mode. This is triggered by the SET_COMMPAGE_ADDR command. We don't actually use the serial number but we have to
get it as part of the DSP init voodoo. */ if (read_sn(chip) < 0) {
dev_err(chip->card->dev, "load_dsp: Failed to read serial number\n"); return -EIO;
}
chip->dsp_code = code; /* Show which DSP code loaded */
chip->bad_board = false; /* DSP OK */ return 0;
}
udelay(100);
}
dev_err(chip->card->dev, "load_dsp: DSP load timed out waiting for HF4\n"); return -EIO;
}
/* load_firmware takes care of loading the DSP and any ASIC code. */ staticint load_firmware(struct echoaudio *chip)
{ conststruct firmware *fw; int box_type, err;
if (snd_BUG_ON(!chip->comm_page)) return -EPERM;
/* See if the ASIC is present and working - only if the DSP is already loaded */ if (chip->dsp_code) {
box_type = check_asic_status(chip); if (box_type >= 0) return box_type; /* ASIC check failed; force the DSP to reload */
chip->dsp_code = NULL;
}
/* Set the nominal level for an input or output bus (true = -10dBV, false = +4dBu) */ staticint set_nominal_level(struct echoaudio *chip, u16 index, char consumer)
{ if (snd_BUG_ON(index >= num_busses_out(chip) + num_busses_in(chip))) return -EINVAL;
/* Wait for the handshake (OK even if ASIC is not loaded) */ if (wait_handshake(chip)) return -EIO;
/* Set the gain for a single physical output channel (dB). */ staticint set_output_gain(struct echoaudio *chip, u16 channel, s8 gain)
{ if (snd_BUG_ON(channel >= num_busses_out(chip))) return -EINVAL;
if (wait_handshake(chip)) return -EIO;
/* Save the new value */
chip->output_gain[channel] = gain;
chip->comm_page->line_out_level[channel] = gain; return 0;
}
#ifdef ECHOCARD_HAS_MONITOR /* Set the monitor level from an input bus to an output bus. */ staticint set_monitor_gain(struct echoaudio *chip, u16 output, u16 input,
s8 gain)
{ if (snd_BUG_ON(output >= num_busses_out(chip) ||
input >= num_busses_in(chip))) return -EINVAL;
/* Tell the DSP to read and update output, nominal & monitor levels in comm page. */ staticint update_output_line_level(struct echoaudio *chip)
{ if (wait_handshake(chip)) return -EIO;
clear_handshake(chip); return send_vector(chip, DSP_VC_UPDATE_OUTVOL);
}
/* Tell the DSP to read and update input levels in comm page */ staticint update_input_line_level(struct echoaudio *chip)
{ if (wait_handshake(chip)) return -EIO;
clear_handshake(chip); return send_vector(chip, DSP_VC_UPDATE_INGAIN);
}
/* set_meters_on turns the meters on or off. If meters are turned on, the DSP
will write the meter and clock detect values to the comm page at about 30Hz */ staticvoid set_meters_on(struct echoaudio *chip, char on)
{ if (on && !chip->meters_enabled) {
send_vector(chip, DSP_VC_METERS_ON);
chip->meters_enabled = 1;
} elseif (!on && chip->meters_enabled) {
send_vector(chip, DSP_VC_METERS_OFF);
chip->meters_enabled = 0;
memset((s8 *)chip->comm_page->vu_meter, ECHOGAIN_MUTED,
DSP_MAXPIPES);
memset((s8 *)chip->comm_page->peak_meter, ECHOGAIN_MUTED,
DSP_MAXPIPES);
}
}
/* Fill out an the given array using the current values in the comm page. Meters are written in the comm page by the DSP in this order: Output busses Input busses Output pipes (vmixer cards only)
This function assumes there are no more than 16 in/out busses or pipes
Meters is an array [3][16][2] of long. */ staticvoid get_audio_meters(struct echoaudio *chip, long *meters)
{ unsignedint i, m, n;
for (i = 0 ; i < 96; i++)
meters[i] = 0;
for (m = 0, n = 0, i = 0; i < num_busses_out(chip); i++, m++) {
meters[n++] = chip->comm_page->vu_meter[m];
meters[n++] = chip->comm_page->peak_meter[m];
}
for (n = 32, i = 0; i < num_busses_in(chip); i++, m++) {
meters[n++] = chip->comm_page->vu_meter[m];
meters[n++] = chip->comm_page->peak_meter[m];
} #ifdef ECHOCARD_HAS_VMIXER for (n = 64, i = 0; i < num_pipes_out(chip); i++, m++) {
meters[n++] = chip->comm_page->vu_meter[m];
meters[n++] = chip->comm_page->peak_meter[m];
} #endif
}
staticint restore_dsp_rettings(struct echoaudio *chip)
{ int i, o, err;
err = check_asic_status(chip); if (err < 0) return err;
/* Gina20/Darla20 only. Should be harmless for other cards. */
chip->comm_page->gd_clock_state = GD_CLOCK_UNDEF;
chip->comm_page->gd_spdif_status = GD_SPDIF_STATUS_UNDEF;
chip->comm_page->handshake = cpu_to_le32(0xffffffff);
/* Restore output busses */ for (i = 0; i < num_busses_out(chip); i++) {
err = set_output_gain(chip, i, chip->output_gain[i]); if (err < 0) return err;
}
#ifdef ECHOCARD_HAS_VMIXER for (i = 0; i < num_pipes_out(chip); i++) for (o = 0; o < num_busses_out(chip); o++) {
err = set_vmixer_gain(chip, o, i,
chip->vmixer_gain[o][i]); if (err < 0) return err;
} if (update_vmixer_level(chip) < 0) return -EIO; #endif/* ECHOCARD_HAS_VMIXER */
#ifdef ECHOCARD_HAS_MONITOR for (o = 0; o < num_busses_out(chip); o++) for (i = 0; i < num_busses_in(chip); i++) {
err = set_monitor_gain(chip, o, i,
chip->monitor_gain[o][i]); if (err < 0) return err;
} #endif/* ECHOCARD_HAS_MONITOR */
#ifdef ECHOCARD_HAS_INPUT_GAIN for (i = 0; i < num_busses_in(chip); i++) {
err = set_input_gain(chip, i, chip->input_gain[i]); if (err < 0) return err;
} #endif/* ECHOCARD_HAS_INPUT_GAIN */
err = update_output_line_level(chip); if (err < 0) return err;
err = update_input_line_level(chip); if (err < 0) return err;
err = set_sample_rate(chip, chip->sample_rate); if (err < 0) return err;
if (chip->meters_enabled) {
err = send_vector(chip, DSP_VC_METERS_ON); if (err < 0) return err;
}
#ifdef ECHOCARD_HAS_DIGITAL_MODE_SWITCH if (set_digital_mode(chip, chip->digital_mode) < 0) return -EIO; #endif
#ifdef ECHOCARD_HAS_DIGITAL_IO if (set_professional_spdif(chip, chip->professional_spdif) < 0) return -EIO; #endif
#ifdef ECHOCARD_HAS_PHANTOM_POWER if (set_phantom_power(chip, chip->phantom_power) < 0) return -EIO; #endif
#ifdef ECHOCARD_HAS_EXTERNAL_CLOCK /* set_input_clock() also restores automute setting */ if (set_input_clock(chip, chip->input_clock) < 0) return -EIO; #endif
#ifdef ECHOCARD_HAS_OUTPUT_CLOCK_SWITCH if (set_output_clock(chip, chip->output_clock) < 0) return -EIO; #endif
if (wait_handshake(chip) < 0) return -EIO;
clear_handshake(chip); if (send_vector(chip, DSP_VC_UPDATE_FLAGS) < 0) return -EIO;
return 0;
}
/**************************************************************************** Transport functions
****************************************************************************/
/* set_audio_format() sets the format of the audio data in host memory for this pipe. Note that _MS_ (mono-to-stereo) playback modes are not used by ALSA
but they are here because they are just mono while capturing */ staticvoid set_audio_format(struct echoaudio *chip, u16 pipe_index, conststruct audioformat *format)
{
u16 dsp_format;
dsp_format = DSP_AUDIOFORM_SS_16LE;
/* Look for super-interleave (no big-endian and 8 bits) */ if (format->interleave > 2) { switch (format->bits_per_sample) { case 16:
dsp_format = DSP_AUDIOFORM_SUPER_INTERLEAVE_16LE; break; case 24:
dsp_format = DSP_AUDIOFORM_SUPER_INTERLEAVE_24LE; break; case 32:
dsp_format = DSP_AUDIOFORM_SUPER_INTERLEAVE_32LE; break;
}
dsp_format |= format->interleave;
} elseif (format->data_are_bigendian) { /* For big-endian data, only 32 bit samples are supported */ switch (format->interleave) { case 1:
dsp_format = DSP_AUDIOFORM_MM_32BE; break; #ifdef ECHOCARD_HAS_STEREO_BIG_ENDIAN32 case 2:
dsp_format = DSP_AUDIOFORM_SS_32BE; break; #endif
}
} elseif (format->interleave == 1 &&
format->bits_per_sample == 32 && !format->mono_to_stereo) { /* 32 bit little-endian mono->mono case */
dsp_format = DSP_AUDIOFORM_MM_32LE;
} else { /* Handle the other little-endian formats */ switch (format->bits_per_sample) { case 8: if (format->interleave == 2)
dsp_format = DSP_AUDIOFORM_SS_8; else
dsp_format = DSP_AUDIOFORM_MS_8; break; default: case 16: if (format->interleave == 2)
dsp_format = DSP_AUDIOFORM_SS_16LE; else
dsp_format = DSP_AUDIOFORM_MS_16LE; break; case 24: if (format->interleave == 2)
dsp_format = DSP_AUDIOFORM_SS_24LE; else
dsp_format = DSP_AUDIOFORM_MS_24LE; break; case 32: if (format->interleave == 2)
dsp_format = DSP_AUDIOFORM_SS_32LE; else
dsp_format = DSP_AUDIOFORM_MS_32LE; break;
}
}
dev_dbg(chip->card->dev, "set_audio_format[%d] = %x\n", pipe_index, dsp_format);
chip->comm_page->audio_format[pipe_index] = cpu_to_le16(dsp_format);
}
/* start_transport starts transport for a set of pipes. The bits 1 in channel_mask specify what pipes to start. Only the bit of the first channel must be set, regardless its interleave.
Same thing for pause_ and stop_ -trasport below. */ staticint start_transport(struct echoaudio *chip, u32 channel_mask,
u32 cyclic_mask)
{
/* Go to sleep */ if (chip->dsp_code) { /* Make load_firmware do a complete reload */
chip->dsp_code = NULL; /* Put the DSP to sleep */ return send_vector(chip, DSP_VC_GO_COMATOSE);
} return 0;
}
/* Fills the comm page with default values */ staticint init_dsp_comm_page(struct echoaudio *chip)
{ /* Check if the compiler added extra padding inside the structure */ if (offsetof(struct comm_page, midi_output) != 0xbe0) {
dev_err(chip->card->dev, "init_dsp_comm_page() - Invalid struct comm_page structure\n"); return -EPERM;
}
/* Init all the basic stuff */
chip->card_name = ECHOCARD_NAME;
chip->bad_board = true; /* Set true until DSP loaded */
chip->dsp_code = NULL; /* Current DSP code not loaded */
chip->asic_loaded = false;
memset(chip->comm_page, 0, sizeof(struct comm_page));
/* Init the comm page */
chip->comm_page->comm_size =
cpu_to_le32(sizeof(struct comm_page));
chip->comm_page->handshake = cpu_to_le32(0xffffffff);
chip->comm_page->midi_out_free_count =
cpu_to_le32(DSP_MIDI_OUT_FIFO_SIZE);
chip->comm_page->sample_rate = cpu_to_le32(44100);
/* Set line levels so we don't blast any inputs on startup */
memset(chip->comm_page->monitors, ECHOGAIN_MUTED, MONITOR_ARRAY_SIZE);
memset(chip->comm_page->vmixer, ECHOGAIN_MUTED, VMIXER_ARRAY_SIZE);
return 0;
}
/* This function initializes the chip structure with default values, ie. all * muted and internal clock source. Then it copies the settings to the DSP. * This MUST be called after the DSP is up and running !
*/ staticint init_line_levels(struct echoaudio *chip)
{
memset(chip->output_gain, ECHOGAIN_MUTED, sizeof(chip->output_gain));
memset(chip->input_gain, ECHOGAIN_MUTED, sizeof(chip->input_gain));
memset(chip->monitor_gain, ECHOGAIN_MUTED, sizeof(chip->monitor_gain));
memset(chip->vmixer_gain, ECHOGAIN_MUTED, sizeof(chip->vmixer_gain));
chip->input_clock = ECHO_CLOCK_INTERNAL;
chip->output_clock = ECHO_CLOCK_WORD;
chip->sample_rate = 44100; return restore_dsp_rettings(chip);
}
/* This is low level part of the interrupt handler. It returns -1 if the IRQ is not ours, or N>=0 if it is, where N is the number
of midi data in the input queue. */ staticint service_irq(struct echoaudio *chip)
{ int st;
/* Read the DSP status register and see if this DSP generated this interrupt */ if (get_dsp_register(chip, CHI32_STATUS_REG) & CHI32_STATUS_IRQ) {
st = 0; #ifdef ECHOCARD_HAS_MIDI /* Get and parse midi data if present */ if (chip->comm_page->midi_input[0]) /* The count is at index 0 */
st = midi_service_irq(chip); /* Returns how many midi bytes we received */ #endif /* Clear the hardware interrupt */
chip->comm_page->midi_input[0] = 0;
send_vector(chip, DSP_VC_ACK_INT); return st;
} return -1;
}
/****************************************************************************** Functions for opening and closing pipes
******************************************************************************/
/* allocate_pipes is used to reserve audio pipes for your exclusive use.
The call will fail if some pipes are already allocated. */ staticint allocate_pipes(struct echoaudio *chip, struct audiopipe *pipe, int pipe_index, int interleave)
{ int i;
u32 channel_mask;
/* The counter register is where the DSP writes the 32 bit DMA position for a pipe. The DSP is constantly updating this value as
it moves data. The DMA counter is in units of bytes, not samples. */
pipe->dma_counter = (__le32 *)&chip->comm_page->position[pipe_index];
*pipe->dma_counter = 0; return pipe_index;
}
/****************************************************************************** Functions for managing the scatter-gather list
******************************************************************************/
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.