blob: 2ae912a64d16b1457d3a4adb22471f585c686a15 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Virtual ALSA driver for PCM testing/fuzzing
*
* Copyright 2023 Ivan Orlov <ivan.orlov0322@gmail.com>
*
* This is a simple virtual ALSA driver, which can be used for audio applications/PCM middle layer
* testing or fuzzing.
* It can:
* - Simulate 'playback' and 'capture' actions
* - Generate random or pattern-based capture data
* - Check playback buffer for containing looped template, and notify about the results
* through the debugfs entry
* - Inject delays into the playback and capturing processes. See 'inject_delay' parameter.
* - Inject errors during the PCM callbacks.
* - Register custom RESET ioctl and notify when it is called through the debugfs entry
* - Work in interleaved and non-interleaved modes
* - Support up to 8 substreams
* - Support up to 4 channels
* - Support framerates from 8 kHz to 48 kHz
*
* When driver works in the capture mode with multiple channels, it duplicates the looped
* pattern to each separate channel. For example, if we have 2 channels, format = U8, interleaved
* access mode and pattern 'abacaba', the DMA buffer will look like aabbccaabbaaaa..., so buffer for
* each channel will contain abacabaabacaba... Same for the non-interleaved mode.
*
* However, it may break the capturing on the higher framerates with small period size, so it is
* better to choose larger period sizes.
*
* You can find the corresponding selftest in the 'alsa' selftests folder.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <sound/pcm.h>
#include <sound/core.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/timer.h>
#include <linux/random.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#define DEVNAME "pcmtestd"
#define CARD_NAME "pcm-test-card"
#define TIMER_PER_SEC 5
#define TIMER_INTERVAL (HZ / TIMER_PER_SEC)
#define DELAY_JIFFIES HZ
#define PLAYBACK_SUBSTREAM_CNT 8
#define CAPTURE_SUBSTREAM_CNT 8
#define MAX_CHANNELS_NUM 4
#define DEFAULT_PATTERN "abacaba"
#define DEFAULT_PATTERN_LEN 7
#define FILL_MODE_RAND 0
#define FILL_MODE_PAT 1
#define MAX_PATTERN_LEN 4096
static int index = -1;
static char *id = "pcmtest";
static bool enable = true;
static int inject_delay;
static bool inject_hwpars_err;
static bool inject_prepare_err;
static bool inject_trigger_err;
static short fill_mode = FILL_MODE_PAT;
static u8 playback_capture_test;
static u8 ioctl_reset_test;
static struct dentry *driver_debug_dir;
module_param(index, int, 0444);
MODULE_PARM_DESC(index, "Index value for " CARD_NAME " soundcard");
module_param(id, charp, 0444);
MODULE_PARM_DESC(id, "ID string for " CARD_NAME " soundcard");
module_param(enable, bool, 0444);
MODULE_PARM_DESC(enable, "Enable " CARD_NAME " soundcard.");
module_param(fill_mode, short, 0600);
MODULE_PARM_DESC(fill_mode, "Buffer fill mode: rand(0) or pattern(1)");
module_param(inject_delay, int, 0600);
MODULE_PARM_DESC(inject_delay, "Inject delays during playback/capture (in jiffies)");
module_param(inject_hwpars_err, bool, 0600);
MODULE_PARM_DESC(inject_hwpars_err, "Inject EBUSY error in the 'hw_params' callback");
module_param(inject_prepare_err, bool, 0600);
MODULE_PARM_DESC(inject_prepare_err, "Inject EINVAL error in the 'prepare' callback");
module_param(inject_trigger_err, bool, 0600);
MODULE_PARM_DESC(inject_trigger_err, "Inject EINVAL error in the 'trigger' callback");
struct pcmtst {
struct snd_pcm *pcm;
struct snd_card *card;
struct platform_device *pdev;
};
struct pcmtst_buf_iter {
size_t buf_pos; // position in the DMA buffer
size_t period_pos; // period-relative position
size_t b_rw; // Bytes to write on every timer tick
size_t s_rw_ch; // Samples to write to one channel on every tick
unsigned int sample_bytes; // sample_bits / 8
bool is_buf_corrupted; // playback test result indicator
size_t period_bytes; // bytes in a one period
bool interleaved; // Interleaved/Non-interleaved mode
size_t total_bytes; // Total bytes read/written
size_t chan_block; // Bytes in one channel buffer when non-interleaved
struct snd_pcm_substream *substream;
struct timer_list timer_instance;
};
static struct pcmtst *pcmtst;
static struct snd_pcm_hardware snd_pcmtst_hw = {
.info = (SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_BLOCK_TRANSFER |
SNDRV_PCM_INFO_NONINTERLEAVED |
SNDRV_PCM_INFO_MMAP_VALID),
.formats = SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
.rates = SNDRV_PCM_RATE_8000_48000,
.rate_min = 8000,
.rate_max = 48000,
.channels_min = 1,
.channels_max = MAX_CHANNELS_NUM,
.buffer_bytes_max = 128 * 1024,
.period_bytes_min = 4096,
.period_bytes_max = 32768,
.periods_min = 1,
.periods_max = 1024,
};
struct pattern_buf {
char *buf;
u32 len;
};
static int buf_allocated;
static struct pattern_buf patt_bufs[MAX_CHANNELS_NUM];
static inline void inc_buf_pos(struct pcmtst_buf_iter *v_iter, size_t by, size_t bytes)
{
v_iter->total_bytes += by;
v_iter->buf_pos += by;
v_iter->buf_pos %= bytes;
}
/*
* Position in the DMA buffer when we are in the non-interleaved mode. We increment buf_pos
* every time we write a byte to any channel, so the position in the current channel buffer is
* (position in the DMA buffer) / count_of_channels + size_of_channel_buf * current_channel
*/
static inline size_t buf_pos_n(struct pcmtst_buf_iter *v_iter, unsigned int channels,
unsigned int chan_num)
{
return v_iter->buf_pos / channels + v_iter->chan_block * chan_num;
}
/*
* Get the count of bytes written for the current channel in the interleaved mode.
* This is (count of samples written for the current channel) * bytes_in_sample +
* (relative position in the current sample)
*/
static inline size_t ch_pos_i(size_t b_total, unsigned int channels, unsigned int b_sample)
{
return b_total / channels / b_sample * b_sample + (b_total % b_sample);
}
static void check_buf_block_i(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
size_t i;
short ch_num;
u8 current_byte;
for (i = 0; i < v_iter->b_rw; i++) {
current_byte = runtime->dma_area[v_iter->buf_pos];
if (!current_byte)
break;
ch_num = (v_iter->total_bytes / v_iter->sample_bytes) % runtime->channels;
if (current_byte != patt_bufs[ch_num].buf[ch_pos_i(v_iter->total_bytes,
runtime->channels,
v_iter->sample_bytes)
% patt_bufs[ch_num].len]) {
v_iter->is_buf_corrupted = true;
break;
}
inc_buf_pos(v_iter, 1, runtime->dma_bytes);
}
// If we broke during the loop, add remaining bytes to the buffer position.
inc_buf_pos(v_iter, v_iter->b_rw - i, runtime->dma_bytes);
}
static void check_buf_block_ni(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
unsigned int channels = runtime->channels;
size_t i;
short ch_num;
u8 current_byte;
for (i = 0; i < v_iter->b_rw; i++) {
current_byte = runtime->dma_area[buf_pos_n(v_iter, channels, i % channels)];
if (!current_byte)
break;
ch_num = i % channels;
if (current_byte != patt_bufs[ch_num].buf[(v_iter->total_bytes / channels)
% patt_bufs[ch_num].len]) {
v_iter->is_buf_corrupted = true;
break;
}
inc_buf_pos(v_iter, 1, runtime->dma_bytes);
}
inc_buf_pos(v_iter, v_iter->b_rw - i, runtime->dma_bytes);
}
/*
* Check one block of the buffer. Here we iterate the buffer until we find '0'. This condition is
* necessary because we need to detect when the reading/writing ends, so we assume that the pattern
* doesn't contain zeros.
*/
static void check_buf_block(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
if (v_iter->interleaved)
check_buf_block_i(v_iter, runtime);
else
check_buf_block_ni(v_iter, runtime);
}
/*
* Fill buffer in the non-interleaved mode. The order of samples is C0, ..., C0, C1, ..., C1, C2...
* The channel buffers lay in the DMA buffer continuously (see default copy_user and copy_kernel
* handlers in the pcm_lib.c file).
*
* Here we increment the DMA buffer position every time we write a byte to any channel 'buffer'.
* We need this to simulate the correct hardware pointer moving.
*/
static void fill_block_pattern_n(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
size_t i;
unsigned int channels = runtime->channels;
short ch_num;
for (i = 0; i < v_iter->b_rw; i++) {
ch_num = i % channels;
runtime->dma_area[buf_pos_n(v_iter, channels, i % channels)] =
patt_bufs[ch_num].buf[(v_iter->total_bytes / channels)
% patt_bufs[ch_num].len];
inc_buf_pos(v_iter, 1, runtime->dma_bytes);
}
}
// Fill buffer in the interleaved mode. The order of samples is C0, C1, C2, C0, C1, C2, ...
static void fill_block_pattern_i(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
size_t sample;
size_t pos_in_ch, pos_pattern;
short ch, pos_sample;
pos_in_ch = ch_pos_i(v_iter->total_bytes, runtime->channels, v_iter->sample_bytes);
for (sample = 0; sample < v_iter->s_rw_ch; sample++) {
for (ch = 0; ch < runtime->channels; ch++) {
for (pos_sample = 0; pos_sample < v_iter->sample_bytes; pos_sample++) {
pos_pattern = (pos_in_ch + sample * v_iter->sample_bytes
+ pos_sample) % patt_bufs[ch].len;
runtime->dma_area[v_iter->buf_pos] = patt_bufs[ch].buf[pos_pattern];
inc_buf_pos(v_iter, 1, runtime->dma_bytes);
}
}
}
}
static void fill_block_pattern(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
if (v_iter->interleaved)
fill_block_pattern_i(v_iter, runtime);
else
fill_block_pattern_n(v_iter, runtime);
}
static void fill_block_rand_n(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
unsigned int channels = runtime->channels;
// Remaining space in all channel buffers
size_t bytes_remain = runtime->dma_bytes - v_iter->buf_pos;
unsigned int i;
for (i = 0; i < channels; i++) {
if (v_iter->b_rw <= bytes_remain) {
//b_rw - count of bytes must be written for all channels at each timer tick
get_random_bytes(runtime->dma_area + buf_pos_n(v_iter, channels, i),
v_iter->b_rw / channels);
} else {
// Write to the end of buffer and start from the beginning of it
get_random_bytes(runtime->dma_area + buf_pos_n(v_iter, channels, i),
bytes_remain / channels);
get_random_bytes(runtime->dma_area + v_iter->chan_block * i,
(v_iter->b_rw - bytes_remain) / channels);
}
}
inc_buf_pos(v_iter, v_iter->b_rw, runtime->dma_bytes);
}
static void fill_block_rand_i(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
size_t in_cur_block = runtime->dma_bytes - v_iter->buf_pos;
if (v_iter->b_rw <= in_cur_block) {
get_random_bytes(&runtime->dma_area[v_iter->buf_pos], v_iter->b_rw);
} else {
get_random_bytes(&runtime->dma_area[v_iter->buf_pos], in_cur_block);
get_random_bytes(runtime->dma_area, v_iter->b_rw - in_cur_block);
}
inc_buf_pos(v_iter, v_iter->b_rw, runtime->dma_bytes);
}
static void fill_block_random(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
if (v_iter->interleaved)
fill_block_rand_i(v_iter, runtime);
else
fill_block_rand_n(v_iter, runtime);
}
static void fill_block(struct pcmtst_buf_iter *v_iter, struct snd_pcm_runtime *runtime)
{
switch (fill_mode) {
case FILL_MODE_RAND:
fill_block_random(v_iter, runtime);
break;
case FILL_MODE_PAT:
fill_block_pattern(v_iter, runtime);
break;
}
}
/*
* Here we iterate through the buffer by (buffer_size / iterates_per_second) bytes.
* The driver uses timer to simulate the hardware pointer moving, and notify the PCM middle layer
* about period elapsed.
*/
static void timer_timeout(struct timer_list *data)
{
struct pcmtst_buf_iter *v_iter;
struct snd_pcm_substream *substream;
v_iter = from_timer(v_iter, data, timer_instance);
substream = v_iter->substream;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !v_iter->is_buf_corrupted)
check_buf_block(v_iter, substream->runtime);
else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
fill_block(v_iter, substream->runtime);
else
inc_buf_pos(v_iter, v_iter->b_rw, substream->runtime->dma_bytes);
v_iter->period_pos += v_iter->b_rw;
if (v_iter->period_pos >= v_iter->period_bytes) {
v_iter->period_pos %= v_iter->period_bytes;
snd_pcm_period_elapsed(substream);
}
mod_timer(&v_iter->timer_instance, jiffies + TIMER_INTERVAL + inject_delay);
}
static int snd_pcmtst_pcm_open(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct pcmtst_buf_iter *v_iter;
v_iter = kzalloc(sizeof(*v_iter), GFP_KERNEL);
if (!v_iter)
return -ENOMEM;
runtime->hw = snd_pcmtst_hw;
runtime->private_data = v_iter;
v_iter->substream = substream;
v_iter->buf_pos = 0;
v_iter->is_buf_corrupted = false;
v_iter->period_pos = 0;
v_iter->total_bytes = 0;
playback_capture_test = 0;
ioctl_reset_test = 0;
timer_setup(&v_iter->timer_instance, timer_timeout, 0);
mod_timer(&v_iter->timer_instance, jiffies + TIMER_INTERVAL);
return 0;
}
static int snd_pcmtst_pcm_close(struct snd_pcm_substream *substream)
{
struct pcmtst_buf_iter *v_iter = substream->runtime->private_data;
timer_shutdown_sync(&v_iter->timer_instance);
v_iter->substream = NULL;
playback_capture_test = !v_iter->is_buf_corrupted;
kfree(v_iter);
return 0;
}
static int snd_pcmtst_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct pcmtst_buf_iter *v_iter = runtime->private_data;
if (inject_trigger_err)
return -EINVAL;
v_iter->sample_bytes = runtime->sample_bits / 8;
v_iter->period_bytes = frames_to_bytes(runtime, runtime->period_size);
if (runtime->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED ||
runtime->access == SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED) {
v_iter->chan_block = runtime->dma_bytes / runtime->channels;
v_iter->interleaved = false;
} else {
v_iter->interleaved = true;
}
// We want to record RATE * ch_cnt samples per sec, it is rate * sample_bytes * ch_cnt bytes
v_iter->s_rw_ch = runtime->rate / TIMER_PER_SEC;
v_iter->b_rw = v_iter->s_rw_ch * v_iter->sample_bytes * runtime->channels;
return 0;
}
static snd_pcm_uframes_t snd_pcmtst_pcm_pointer(struct snd_pcm_substream *substream)
{
struct pcmtst_buf_iter *v_iter = substream->runtime->private_data;
return bytes_to_frames(substream->runtime, v_iter->buf_pos);
}
static int snd_pcmtst_free(struct pcmtst *pcmtst)
{
if (!pcmtst)
return 0;
kfree(pcmtst);
return 0;
}
// These callbacks are required, but empty - all freeing occurs in pdev_remove
static int snd_pcmtst_dev_free(struct snd_device *device)
{
return 0;
}
static void pcmtst_pdev_release(struct device *dev)
{
}
static int snd_pcmtst_pcm_prepare(struct snd_pcm_substream *substream)
{
if (inject_prepare_err)
return -EINVAL;
return 0;
}
static int snd_pcmtst_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
if (inject_hwpars_err)
return -EBUSY;
return 0;
}
static int snd_pcmtst_pcm_hw_free(struct snd_pcm_substream *substream)
{
return 0;
}
static int snd_pcmtst_ioctl(struct snd_pcm_substream *substream, unsigned int cmd, void *arg)
{
switch (cmd) {
case SNDRV_PCM_IOCTL1_RESET:
ioctl_reset_test = 1;
break;
}
return snd_pcm_lib_ioctl(substream, cmd, arg);
}
static const struct snd_pcm_ops snd_pcmtst_playback_ops = {
.open = snd_pcmtst_pcm_open,
.close = snd_pcmtst_pcm_close,
.trigger = snd_pcmtst_pcm_trigger,
.hw_params = snd_pcmtst_pcm_hw_params,
.ioctl = snd_pcmtst_ioctl,
.hw_free = snd_pcmtst_pcm_hw_free,
.prepare = snd_pcmtst_pcm_prepare,
.pointer = snd_pcmtst_pcm_pointer,
};
static const struct snd_pcm_ops snd_pcmtst_capture_ops = {
.open = snd_pcmtst_pcm_open,
.close = snd_pcmtst_pcm_close,
.trigger = snd_pcmtst_pcm_trigger,
.hw_params = snd_pcmtst_pcm_hw_params,
.hw_free = snd_pcmtst_pcm_hw_free,
.ioctl = snd_pcmtst_ioctl,
.prepare = snd_pcmtst_pcm_prepare,
.pointer = snd_pcmtst_pcm_pointer,
};
static int snd_pcmtst_new_pcm(struct pcmtst *pcmtst)
{
struct snd_pcm *pcm;
int err;
err = snd_pcm_new(pcmtst->card, "PCMTest", 0, PLAYBACK_SUBSTREAM_CNT,
CAPTURE_SUBSTREAM_CNT, &pcm);
if (err < 0)
return err;
pcm->private_data = pcmtst;
strcpy(pcm->name, "PCMTest");
pcmtst->pcm = pcm;
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_pcmtst_playback_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_pcmtst_capture_ops);
err = snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV, &pcmtst->pdev->dev,
0, 128 * 1024);
return err;
}
static int snd_pcmtst_create(struct snd_card *card, struct platform_device *pdev,
struct pcmtst **r_pcmtst)
{
struct pcmtst *pcmtst;
int err;
static const struct snd_device_ops ops = {
.dev_free = snd_pcmtst_dev_free,
};
pcmtst = kzalloc(sizeof(*pcmtst), GFP_KERNEL);
if (!pcmtst)
return -ENOMEM;
pcmtst->card = card;
pcmtst->pdev = pdev;
err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, pcmtst, &ops);
if (err < 0)
goto _err_free_chip;
err = snd_pcmtst_new_pcm(pcmtst);
if (err < 0)
goto _err_free_chip;
*r_pcmtst = pcmtst;
return 0;
_err_free_chip:
snd_pcmtst_free(pcmtst);
return err;
}
static int pcmtst_probe(struct platform_device *pdev)
{
struct snd_card *card;
int err;
err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
if (err)
return err;
err = snd_devm_card_new(&pdev->dev, index, id, THIS_MODULE, 0, &card);
if (err < 0)
return err;
err = snd_pcmtst_create(card, pdev, &pcmtst);
if (err < 0)
return err;
strcpy(card->driver, "PCM-TEST Driver");
strcpy(card->shortname, "PCM-Test");
strcpy(card->longname, "PCM-Test virtual driver");
err = snd_card_register(card);
if (err < 0)
return err;
return 0;
}
static int pdev_remove(struct platform_device *dev)
{
snd_pcmtst_free(pcmtst);
return 0;
}
static struct platform_device pcmtst_pdev = {
.name = "pcmtest",
.dev.release = pcmtst_pdev_release,
};
static struct platform_driver pcmtst_pdrv = {
.probe = pcmtst_probe,
.remove = pdev_remove,
.driver = {
.name = "pcmtest",
},
};
static ssize_t pattern_write(struct file *file, const char __user *u_buff, size_t len, loff_t *off)
{
struct pattern_buf *patt_buf = file->f_inode->i_private;
ssize_t to_write = len;
if (*off + to_write > MAX_PATTERN_LEN)
to_write = MAX_PATTERN_LEN - *off;
// Crop silently everything over the buffer
if (to_write <= 0)
return len;
if (copy_from_user(patt_buf->buf + *off, u_buff, to_write))
return -EFAULT;
patt_buf->len = *off + to_write;
*off += to_write;
return to_write;
}
static ssize_t pattern_read(struct file *file, char __user *u_buff, size_t len, loff_t *off)
{
struct pattern_buf *patt_buf = file->f_inode->i_private;
ssize_t to_read = len;
if (*off + to_read >= MAX_PATTERN_LEN)
to_read = MAX_PATTERN_LEN - *off;
if (to_read <= 0)
return 0;
if (copy_to_user(u_buff, patt_buf->buf + *off, to_read))
to_read = 0;
else
*off += to_read;
return to_read;
}
static const struct file_operations fill_pattern_fops = {
.read = pattern_read,
.write = pattern_write,
};
static int setup_patt_bufs(void)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(patt_bufs); i++) {
patt_bufs[i].buf = kzalloc(MAX_PATTERN_LEN, GFP_KERNEL);
if (!patt_bufs[i].buf)
break;
strcpy(patt_bufs[i].buf, DEFAULT_PATTERN);
patt_bufs[i].len = DEFAULT_PATTERN_LEN;
}
return i;
}
static const char * const pattern_files[] = { "fill_pattern0", "fill_pattern1",
"fill_pattern2", "fill_pattern3"};
static int init_debug_files(int buf_count)
{
size_t i;
char len_file_name[32];
driver_debug_dir = debugfs_create_dir("pcmtest", NULL);
if (IS_ERR(driver_debug_dir))
return PTR_ERR(driver_debug_dir);
debugfs_create_u8("pc_test", 0444, driver_debug_dir, &playback_capture_test);
debugfs_create_u8("ioctl_test", 0444, driver_debug_dir, &ioctl_reset_test);
for (i = 0; i < buf_count; i++) {
debugfs_create_file(pattern_files[i], 0600, driver_debug_dir,
&patt_bufs[i], &fill_pattern_fops);
snprintf(len_file_name, sizeof(len_file_name), "%s_len", pattern_files[i]);
debugfs_create_u32(len_file_name, 0444, driver_debug_dir, &patt_bufs[i].len);
}
return 0;
}
static void free_pattern_buffers(void)
{
int i;
for (i = 0; i < buf_allocated; i++)
kfree(patt_bufs[i].buf);
}
static void clear_debug_files(void)
{
debugfs_remove_recursive(driver_debug_dir);
}
static int __init mod_init(void)
{
int err = 0;
buf_allocated = setup_patt_bufs();
if (!buf_allocated)
return -ENOMEM;
snd_pcmtst_hw.channels_max = buf_allocated;
err = init_debug_files(buf_allocated);
if (err)
return err;
err = platform_device_register(&pcmtst_pdev);
if (err)
return err;
err = platform_driver_register(&pcmtst_pdrv);
if (err)
platform_device_unregister(&pcmtst_pdev);
return err;
}
static void __exit mod_exit(void)
{
clear_debug_files();
free_pattern_buffers();
platform_driver_unregister(&pcmtst_pdrv);
platform_device_unregister(&pcmtst_pdev);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ivan Orlov");
module_init(mod_init);
module_exit(mod_exit);