linux-stable/sound/soc/codecs/sigmadsp.c
Niklas Carlsson 11a9b98761
ASoC: sigmadsp: Disable cache mechanism for readbacks
The ALSA control readback functionality only works for non-volatile
controls, i.e. control values that does not change on their own without
driver interaction.

This doesn't work for readbacks since the DSP firmware updates the
control value. Disable the cache mechanism in the driver if the control
name matches the prefix used for readbacks to ensure that the control
value is valid.

Signed-off-by: Niklas Carlsson <niklasc@axis.com>
Link: https://lore.kernel.org/r/20210419144901.9441-1-Niklas.Carlsson@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-04-19 16:51:52 +01:00

826 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Load Analog Devices SigmaStudio firmware files
*
* Copyright 2009-2014 Analog Devices Inc.
*/
#include <linux/crc32.h>
#include <linux/firmware.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <sound/control.h>
#include <sound/soc.h>
#include "sigmadsp.h"
#define SIGMA_MAGIC "ADISIGM"
#define SIGMA_FW_CHUNK_TYPE_DATA 0
#define SIGMA_FW_CHUNK_TYPE_CONTROL 1
#define SIGMA_FW_CHUNK_TYPE_SAMPLERATES 2
#define READBACK_CTRL_NAME "ReadBack"
struct sigmadsp_control {
struct list_head head;
uint32_t samplerates;
unsigned int addr;
unsigned int num_bytes;
const char *name;
struct snd_kcontrol *kcontrol;
bool is_readback;
bool cached;
uint8_t cache[];
};
struct sigmadsp_data {
struct list_head head;
uint32_t samplerates;
unsigned int addr;
unsigned int length;
uint8_t data[];
};
struct sigma_fw_chunk {
__le32 length;
__le32 tag;
__le32 samplerates;
} __packed;
struct sigma_fw_chunk_data {
struct sigma_fw_chunk chunk;
__le16 addr;
uint8_t data[];
} __packed;
struct sigma_fw_chunk_control {
struct sigma_fw_chunk chunk;
__le16 type;
__le16 addr;
__le16 num_bytes;
const char name[];
} __packed;
struct sigma_fw_chunk_samplerate {
struct sigma_fw_chunk chunk;
__le32 samplerates[];
} __packed;
struct sigma_firmware_header {
unsigned char magic[7];
u8 version;
__le32 crc;
} __packed;
enum {
SIGMA_ACTION_WRITEXBYTES = 0,
SIGMA_ACTION_WRITESINGLE,
SIGMA_ACTION_WRITESAFELOAD,
SIGMA_ACTION_END,
};
struct sigma_action {
u8 instr;
u8 len_hi;
__le16 len;
__be16 addr;
unsigned char payload[];
} __packed;
static int sigmadsp_write(struct sigmadsp *sigmadsp, unsigned int addr,
const uint8_t data[], size_t len)
{
return sigmadsp->write(sigmadsp->control_data, addr, data, len);
}
static int sigmadsp_read(struct sigmadsp *sigmadsp, unsigned int addr,
uint8_t data[], size_t len)
{
return sigmadsp->read(sigmadsp->control_data, addr, data, len);
}
static int sigmadsp_ctrl_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *info)
{
struct sigmadsp_control *ctrl = (void *)kcontrol->private_value;
info->type = SNDRV_CTL_ELEM_TYPE_BYTES;
info->count = ctrl->num_bytes;
return 0;
}
static int sigmadsp_ctrl_write(struct sigmadsp *sigmadsp,
struct sigmadsp_control *ctrl, void *data)
{
/* safeload loads up to 20 bytes in a atomic operation */
if (ctrl->num_bytes <= 20 && sigmadsp->ops && sigmadsp->ops->safeload)
return sigmadsp->ops->safeload(sigmadsp, ctrl->addr, data,
ctrl->num_bytes);
else
return sigmadsp_write(sigmadsp, ctrl->addr, data,
ctrl->num_bytes);
}
static int sigmadsp_ctrl_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct sigmadsp_control *ctrl = (void *)kcontrol->private_value;
struct sigmadsp *sigmadsp = snd_kcontrol_chip(kcontrol);
uint8_t *data;
int ret = 0;
mutex_lock(&sigmadsp->lock);
data = ucontrol->value.bytes.data;
if (!(kcontrol->vd[0].access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
ret = sigmadsp_ctrl_write(sigmadsp, ctrl, data);
if (ret == 0) {
memcpy(ctrl->cache, data, ctrl->num_bytes);
if (!ctrl->is_readback)
ctrl->cached = true;
}
mutex_unlock(&sigmadsp->lock);
return ret;
}
static int sigmadsp_ctrl_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct sigmadsp_control *ctrl = (void *)kcontrol->private_value;
struct sigmadsp *sigmadsp = snd_kcontrol_chip(kcontrol);
int ret = 0;
mutex_lock(&sigmadsp->lock);
if (!ctrl->cached) {
ret = sigmadsp_read(sigmadsp, ctrl->addr, ctrl->cache,
ctrl->num_bytes);
}
if (ret == 0) {
if (!ctrl->is_readback)
ctrl->cached = true;
memcpy(ucontrol->value.bytes.data, ctrl->cache,
ctrl->num_bytes);
}
mutex_unlock(&sigmadsp->lock);
return ret;
}
static void sigmadsp_control_free(struct snd_kcontrol *kcontrol)
{
struct sigmadsp_control *ctrl = (void *)kcontrol->private_value;
ctrl->kcontrol = NULL;
}
static bool sigma_fw_validate_control_name(const char *name, unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++) {
/* Normal ASCII characters are valid */
if (name[i] < ' ' || name[i] > '~')
return false;
}
return true;
}
static int sigma_fw_load_control(struct sigmadsp *sigmadsp,
const struct sigma_fw_chunk *chunk, unsigned int length)
{
const struct sigma_fw_chunk_control *ctrl_chunk;
struct sigmadsp_control *ctrl;
unsigned int num_bytes;
size_t name_len;
char *name;
int ret;
if (length <= sizeof(*ctrl_chunk))
return -EINVAL;
ctrl_chunk = (const struct sigma_fw_chunk_control *)chunk;
name_len = length - sizeof(*ctrl_chunk);
if (name_len >= SNDRV_CTL_ELEM_ID_NAME_MAXLEN)
name_len = SNDRV_CTL_ELEM_ID_NAME_MAXLEN - 1;
/* Make sure there are no non-displayable characaters in the string */
if (!sigma_fw_validate_control_name(ctrl_chunk->name, name_len))
return -EINVAL;
num_bytes = le16_to_cpu(ctrl_chunk->num_bytes);
ctrl = kzalloc(sizeof(*ctrl) + num_bytes, GFP_KERNEL);
if (!ctrl)
return -ENOMEM;
name = kzalloc(name_len + 1, GFP_KERNEL);
if (!name) {
ret = -ENOMEM;
goto err_free_ctrl;
}
memcpy(name, ctrl_chunk->name, name_len);
name[name_len] = '\0';
ctrl->name = name;
/*
* Readbacks doesn't work with non-volatile controls, since the
* firmware updates the control value without driver interaction. Mark
* the readbacks to ensure that the values are not cached.
*/
if (ctrl->name && strncmp(ctrl->name, READBACK_CTRL_NAME,
(sizeof(READBACK_CTRL_NAME) - 1)) == 0)
ctrl->is_readback = true;
ctrl->addr = le16_to_cpu(ctrl_chunk->addr);
ctrl->num_bytes = num_bytes;
ctrl->samplerates = le32_to_cpu(chunk->samplerates);
list_add_tail(&ctrl->head, &sigmadsp->ctrl_list);
return 0;
err_free_ctrl:
kfree(ctrl);
return ret;
}
static int sigma_fw_load_data(struct sigmadsp *sigmadsp,
const struct sigma_fw_chunk *chunk, unsigned int length)
{
const struct sigma_fw_chunk_data *data_chunk;
struct sigmadsp_data *data;
if (length <= sizeof(*data_chunk))
return -EINVAL;
data_chunk = (struct sigma_fw_chunk_data *)chunk;
length -= sizeof(*data_chunk);
data = kzalloc(sizeof(*data) + length, GFP_KERNEL);
if (!data)
return -ENOMEM;
data->addr = le16_to_cpu(data_chunk->addr);
data->length = length;
data->samplerates = le32_to_cpu(chunk->samplerates);
memcpy(data->data, data_chunk->data, length);
list_add_tail(&data->head, &sigmadsp->data_list);
return 0;
}
static int sigma_fw_load_samplerates(struct sigmadsp *sigmadsp,
const struct sigma_fw_chunk *chunk, unsigned int length)
{
const struct sigma_fw_chunk_samplerate *rate_chunk;
unsigned int num_rates;
unsigned int *rates;
unsigned int i;
rate_chunk = (const struct sigma_fw_chunk_samplerate *)chunk;
num_rates = (length - sizeof(*rate_chunk)) / sizeof(__le32);
if (num_rates > 32 || num_rates == 0)
return -EINVAL;
/* We only allow one samplerates block per file */
if (sigmadsp->rate_constraints.count)
return -EINVAL;
rates = kcalloc(num_rates, sizeof(*rates), GFP_KERNEL);
if (!rates)
return -ENOMEM;
for (i = 0; i < num_rates; i++)
rates[i] = le32_to_cpu(rate_chunk->samplerates[i]);
sigmadsp->rate_constraints.count = num_rates;
sigmadsp->rate_constraints.list = rates;
return 0;
}
static int sigmadsp_fw_load_v2(struct sigmadsp *sigmadsp,
const struct firmware *fw)
{
struct sigma_fw_chunk *chunk;
unsigned int length, pos;
int ret;
/*
* Make sure that there is at least one chunk to avoid integer
* underflows later on. Empty firmware is still valid though.
*/
if (fw->size < sizeof(*chunk) + sizeof(struct sigma_firmware_header))
return 0;
pos = sizeof(struct sigma_firmware_header);
while (pos < fw->size - sizeof(*chunk)) {
chunk = (struct sigma_fw_chunk *)(fw->data + pos);
length = le32_to_cpu(chunk->length);
if (length > fw->size - pos || length < sizeof(*chunk))
return -EINVAL;
switch (le32_to_cpu(chunk->tag)) {
case SIGMA_FW_CHUNK_TYPE_DATA:
ret = sigma_fw_load_data(sigmadsp, chunk, length);
break;
case SIGMA_FW_CHUNK_TYPE_CONTROL:
ret = sigma_fw_load_control(sigmadsp, chunk, length);
break;
case SIGMA_FW_CHUNK_TYPE_SAMPLERATES:
ret = sigma_fw_load_samplerates(sigmadsp, chunk, length);
break;
default:
dev_warn(sigmadsp->dev, "Unknown chunk type: %d\n",
chunk->tag);
ret = 0;
break;
}
if (ret)
return ret;
/*
* This can not overflow since if length is larger than the
* maximum firmware size (0x4000000) we'll error out earilier.
*/
pos += ALIGN(length, sizeof(__le32));
}
return 0;
}
static inline u32 sigma_action_len(struct sigma_action *sa)
{
return (sa->len_hi << 16) | le16_to_cpu(sa->len);
}
static size_t sigma_action_size(struct sigma_action *sa)
{
size_t payload = 0;
switch (sa->instr) {
case SIGMA_ACTION_WRITEXBYTES:
case SIGMA_ACTION_WRITESINGLE:
case SIGMA_ACTION_WRITESAFELOAD:
payload = sigma_action_len(sa);
break;
default:
break;
}
payload = ALIGN(payload, 2);
return payload + sizeof(struct sigma_action);
}
/*
* Returns a negative error value in case of an error, 0 if processing of
* the firmware should be stopped after this action, 1 otherwise.
*/
static int process_sigma_action(struct sigmadsp *sigmadsp,
struct sigma_action *sa)
{
size_t len = sigma_action_len(sa);
struct sigmadsp_data *data;
pr_debug("%s: instr:%i addr:%#x len:%zu\n", __func__,
sa->instr, sa->addr, len);
switch (sa->instr) {
case SIGMA_ACTION_WRITEXBYTES:
case SIGMA_ACTION_WRITESINGLE:
case SIGMA_ACTION_WRITESAFELOAD:
if (len < 3)
return -EINVAL;
data = kzalloc(sizeof(*data) + len - 2, GFP_KERNEL);
if (!data)
return -ENOMEM;
data->addr = be16_to_cpu(sa->addr);
data->length = len - 2;
memcpy(data->data, sa->payload, data->length);
list_add_tail(&data->head, &sigmadsp->data_list);
break;
case SIGMA_ACTION_END:
return 0;
default:
return -EINVAL;
}
return 1;
}
static int sigmadsp_fw_load_v1(struct sigmadsp *sigmadsp,
const struct firmware *fw)
{
struct sigma_action *sa;
size_t size, pos;
int ret;
pos = sizeof(struct sigma_firmware_header);
while (pos + sizeof(*sa) <= fw->size) {
sa = (struct sigma_action *)(fw->data + pos);
size = sigma_action_size(sa);
pos += size;
if (pos > fw->size || size == 0)
break;
ret = process_sigma_action(sigmadsp, sa);
pr_debug("%s: action returned %i\n", __func__, ret);
if (ret <= 0)
return ret;
}
if (pos != fw->size)
return -EINVAL;
return 0;
}
static void sigmadsp_firmware_release(struct sigmadsp *sigmadsp)
{
struct sigmadsp_control *ctrl, *_ctrl;
struct sigmadsp_data *data, *_data;
list_for_each_entry_safe(ctrl, _ctrl, &sigmadsp->ctrl_list, head) {
kfree(ctrl->name);
kfree(ctrl);
}
list_for_each_entry_safe(data, _data, &sigmadsp->data_list, head)
kfree(data);
INIT_LIST_HEAD(&sigmadsp->ctrl_list);
INIT_LIST_HEAD(&sigmadsp->data_list);
}
static void devm_sigmadsp_release(struct device *dev, void *res)
{
sigmadsp_firmware_release((struct sigmadsp *)res);
}
static int sigmadsp_firmware_load(struct sigmadsp *sigmadsp, const char *name)
{
const struct sigma_firmware_header *ssfw_head;
const struct firmware *fw;
int ret;
u32 crc;
/* first load the blob */
ret = request_firmware(&fw, name, sigmadsp->dev);
if (ret) {
pr_debug("%s: request_firmware() failed with %i\n", __func__, ret);
goto done;
}
/* then verify the header */
ret = -EINVAL;
/*
* Reject too small or unreasonable large files. The upper limit has been
* chosen a bit arbitrarily, but it should be enough for all practical
* purposes and having the limit makes it easier to avoid integer
* overflows later in the loading process.
*/
if (fw->size < sizeof(*ssfw_head) || fw->size >= 0x4000000) {
dev_err(sigmadsp->dev, "Failed to load firmware: Invalid size\n");
goto done;
}
ssfw_head = (void *)fw->data;
if (memcmp(ssfw_head->magic, SIGMA_MAGIC, ARRAY_SIZE(ssfw_head->magic))) {
dev_err(sigmadsp->dev, "Failed to load firmware: Invalid magic\n");
goto done;
}
crc = crc32(0, fw->data + sizeof(*ssfw_head),
fw->size - sizeof(*ssfw_head));
pr_debug("%s: crc=%x\n", __func__, crc);
if (crc != le32_to_cpu(ssfw_head->crc)) {
dev_err(sigmadsp->dev, "Failed to load firmware: Wrong crc checksum: expected %x got %x\n",
le32_to_cpu(ssfw_head->crc), crc);
goto done;
}
switch (ssfw_head->version) {
case 1:
ret = sigmadsp_fw_load_v1(sigmadsp, fw);
break;
case 2:
ret = sigmadsp_fw_load_v2(sigmadsp, fw);
break;
default:
dev_err(sigmadsp->dev,
"Failed to load firmware: Invalid version %d. Supported firmware versions: 1, 2\n",
ssfw_head->version);
ret = -EINVAL;
break;
}
if (ret)
sigmadsp_firmware_release(sigmadsp);
done:
release_firmware(fw);
return ret;
}
static int sigmadsp_init(struct sigmadsp *sigmadsp, struct device *dev,
const struct sigmadsp_ops *ops, const char *firmware_name)
{
sigmadsp->ops = ops;
sigmadsp->dev = dev;
INIT_LIST_HEAD(&sigmadsp->ctrl_list);
INIT_LIST_HEAD(&sigmadsp->data_list);
mutex_init(&sigmadsp->lock);
return sigmadsp_firmware_load(sigmadsp, firmware_name);
}
/**
* devm_sigmadsp_init() - Initialize SigmaDSP instance
* @dev: The parent device
* @ops: The sigmadsp_ops to use for this instance
* @firmware_name: Name of the firmware file to load
*
* Allocates a SigmaDSP instance and loads the specified firmware file.
*
* Returns a pointer to a struct sigmadsp on success, or a PTR_ERR() on error.
*/
struct sigmadsp *devm_sigmadsp_init(struct device *dev,
const struct sigmadsp_ops *ops, const char *firmware_name)
{
struct sigmadsp *sigmadsp;
int ret;
sigmadsp = devres_alloc(devm_sigmadsp_release, sizeof(*sigmadsp),
GFP_KERNEL);
if (!sigmadsp)
return ERR_PTR(-ENOMEM);
ret = sigmadsp_init(sigmadsp, dev, ops, firmware_name);
if (ret) {
devres_free(sigmadsp);
return ERR_PTR(ret);
}
devres_add(dev, sigmadsp);
return sigmadsp;
}
EXPORT_SYMBOL_GPL(devm_sigmadsp_init);
static int sigmadsp_rate_to_index(struct sigmadsp *sigmadsp, unsigned int rate)
{
unsigned int i;
for (i = 0; i < sigmadsp->rate_constraints.count; i++) {
if (sigmadsp->rate_constraints.list[i] == rate)
return i;
}
return -EINVAL;
}
static unsigned int sigmadsp_get_samplerate_mask(struct sigmadsp *sigmadsp,
unsigned int samplerate)
{
int samplerate_index;
if (samplerate == 0)
return 0;
if (sigmadsp->rate_constraints.count) {
samplerate_index = sigmadsp_rate_to_index(sigmadsp, samplerate);
if (samplerate_index < 0)
return 0;
return BIT(samplerate_index);
} else {
return ~0;
}
}
static bool sigmadsp_samplerate_valid(unsigned int supported,
unsigned int requested)
{
/* All samplerates are supported */
if (!supported)
return true;
return supported & requested;
}
static int sigmadsp_alloc_control(struct sigmadsp *sigmadsp,
struct sigmadsp_control *ctrl, unsigned int samplerate_mask)
{
struct snd_kcontrol_new template;
struct snd_kcontrol *kcontrol;
memset(&template, 0, sizeof(template));
template.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
template.name = ctrl->name;
template.info = sigmadsp_ctrl_info;
template.get = sigmadsp_ctrl_get;
template.put = sigmadsp_ctrl_put;
template.private_value = (unsigned long)ctrl;
template.access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
if (!sigmadsp_samplerate_valid(ctrl->samplerates, samplerate_mask))
template.access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
kcontrol = snd_ctl_new1(&template, sigmadsp);
if (!kcontrol)
return -ENOMEM;
kcontrol->private_free = sigmadsp_control_free;
ctrl->kcontrol = kcontrol;
return snd_ctl_add(sigmadsp->component->card->snd_card, kcontrol);
}
static void sigmadsp_activate_ctrl(struct sigmadsp *sigmadsp,
struct sigmadsp_control *ctrl, unsigned int samplerate_mask)
{
struct snd_card *card = sigmadsp->component->card->snd_card;
struct snd_kcontrol_volatile *vd;
struct snd_ctl_elem_id id;
bool active;
bool changed = false;
active = sigmadsp_samplerate_valid(ctrl->samplerates, samplerate_mask);
down_write(&card->controls_rwsem);
if (!ctrl->kcontrol) {
up_write(&card->controls_rwsem);
return;
}
id = ctrl->kcontrol->id;
vd = &ctrl->kcontrol->vd[0];
if (active == (bool)(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)) {
vd->access ^= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
changed = true;
}
up_write(&card->controls_rwsem);
if (active && changed) {
mutex_lock(&sigmadsp->lock);
if (ctrl->cached)
sigmadsp_ctrl_write(sigmadsp, ctrl, ctrl->cache);
mutex_unlock(&sigmadsp->lock);
}
if (changed)
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, &id);
}
/**
* sigmadsp_attach() - Attach a sigmadsp instance to a ASoC component
* @sigmadsp: The sigmadsp instance to attach
* @component: The component to attach to
*
* Typically called in the components probe callback.
*
* Note, once this function has been called the firmware must not be released
* until after the ALSA snd_card that the component belongs to has been
* disconnected, even if sigmadsp_attach() returns an error.
*/
int sigmadsp_attach(struct sigmadsp *sigmadsp,
struct snd_soc_component *component)
{
struct sigmadsp_control *ctrl;
unsigned int samplerate_mask;
int ret;
sigmadsp->component = component;
samplerate_mask = sigmadsp_get_samplerate_mask(sigmadsp,
sigmadsp->current_samplerate);
list_for_each_entry(ctrl, &sigmadsp->ctrl_list, head) {
ret = sigmadsp_alloc_control(sigmadsp, ctrl, samplerate_mask);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(sigmadsp_attach);
/**
* sigmadsp_setup() - Setup the DSP for the specified samplerate
* @sigmadsp: The sigmadsp instance to configure
* @samplerate: The samplerate the DSP should be configured for
*
* Loads the appropriate firmware program and parameter memory (if not already
* loaded) and enables the controls for the specified samplerate. Any control
* parameter changes that have been made previously will be restored.
*
* Returns 0 on success, a negative error code otherwise.
*/
int sigmadsp_setup(struct sigmadsp *sigmadsp, unsigned int samplerate)
{
struct sigmadsp_control *ctrl;
unsigned int samplerate_mask;
struct sigmadsp_data *data;
int ret;
if (sigmadsp->current_samplerate == samplerate)
return 0;
samplerate_mask = sigmadsp_get_samplerate_mask(sigmadsp, samplerate);
if (samplerate_mask == 0)
return -EINVAL;
list_for_each_entry(data, &sigmadsp->data_list, head) {
if (!sigmadsp_samplerate_valid(data->samplerates,
samplerate_mask))
continue;
ret = sigmadsp_write(sigmadsp, data->addr, data->data,
data->length);
if (ret)
goto err;
}
list_for_each_entry(ctrl, &sigmadsp->ctrl_list, head)
sigmadsp_activate_ctrl(sigmadsp, ctrl, samplerate_mask);
sigmadsp->current_samplerate = samplerate;
return 0;
err:
sigmadsp_reset(sigmadsp);
return ret;
}
EXPORT_SYMBOL_GPL(sigmadsp_setup);
/**
* sigmadsp_reset() - Notify the sigmadsp instance that the DSP has been reset
* @sigmadsp: The sigmadsp instance to reset
*
* Should be called whenever the DSP has been reset and parameter and program
* memory need to be re-loaded.
*/
void sigmadsp_reset(struct sigmadsp *sigmadsp)
{
struct sigmadsp_control *ctrl;
list_for_each_entry(ctrl, &sigmadsp->ctrl_list, head)
sigmadsp_activate_ctrl(sigmadsp, ctrl, false);
sigmadsp->current_samplerate = 0;
}
EXPORT_SYMBOL_GPL(sigmadsp_reset);
/**
* sigmadsp_restrict_params() - Applies DSP firmware specific constraints
* @sigmadsp: The sigmadsp instance
* @substream: The substream to restrict
*
* Applies samplerate constraints that may be required by the firmware Should
* typically be called from the CODEC/component drivers startup callback.
*
* Returns 0 on success, a negative error code otherwise.
*/
int sigmadsp_restrict_params(struct sigmadsp *sigmadsp,
struct snd_pcm_substream *substream)
{
if (sigmadsp->rate_constraints.count == 0)
return 0;
return snd_pcm_hw_constraint_list(substream->runtime, 0,
SNDRV_PCM_HW_PARAM_RATE, &sigmadsp->rate_constraints);
}
EXPORT_SYMBOL_GPL(sigmadsp_restrict_params);
MODULE_LICENSE("GPL");