Add documentation for the new Virtual PCM Test Driver. It covers all
possible usage cases: errors and delay injections, random and
pattern-based data generation, playback and ioctl redefinition
functionalities testing.
We have a lot of different virtual media drivers, which can be used for
testing of the userspace applications and media subsystem middle layer.
However, all of them are aimed at testing the video functionality and
simulating the video devices. For audio devices we have only snd-dummy
module, which is good in simulating the correct behavior of an ALSA device.
I decided to write a tool, which would help to test the userspace ALSA
programs (and the PCM middle layer as well) under unusual circumstances
to figure out how they would behave. So I came up with this Virtual PCM
Test Driver.
This new Virtual PCM Test Driver has several features which can be useful
during the userspace ALSA applications testing/fuzzing, or testing/fuzzing
of the PCM middle layer. Not all of them can be implemented using the
existing virtual drivers (like dummy or loopback). Here is what can this
driver do:
- Simulate both capture and playback processes
- Check the playback stream for containing the looped pattern
- Generate random or pattern-based capture data
- Inject delays into the playback and capturing processes
- Inject errors during the PCM callbacks
Also, this driver can check the playback stream for containing the
predefined pattern, which is used in the corresponding selftest to check
the PCM middle layer data transferring functionality. Additionally, this
driver redefines the default RESET ioctl, and the selftest covers this PCM
API functionality as well.
The driver supports both interleaved and non-interleaved access modes, and
have separate pattern buffers for each channel. The driver supports up to
4 channels and up to 8 substreams.
Signed-off-by: Ivan Orlov <[email protected]>
---
V1 -> V2:
- Rename the driver from from 'valsa' to 'pcmtest'.
- Implement support for interleaved and non-interleaved access modes
- Add support for 8 substreams and 4 channels
- Extend supported formats
- Extend and rewrite in C the selftest for the driver
V2 -> V3:
- Add separate pattern buffers for each channel
- Speed up the capture data generation when using interleaved access mode
- Extend the corresponding selftest to cover the multiple channels
capturing and playback functionalities when using interleaved access mode.
- Fix documentation issues
Documentation/sound/cards/index.rst | 1 +
Documentation/sound/cards/pcmtest.rst | 120 ++++++++++++++++++++++++++
2 files changed, 121 insertions(+)
create mode 100644 Documentation/sound/cards/pcmtest.rst
diff --git a/Documentation/sound/cards/index.rst b/Documentation/sound/cards/index.rst
index c016f8c3b88b..49c1f2f688f8 100644
--- a/Documentation/sound/cards/index.rst
+++ b/Documentation/sound/cards/index.rst
@@ -17,3 +17,4 @@ Card-Specific Information
hdspm
serial-u16550
img-spdif-in
+ pcmtest
diff --git a/Documentation/sound/cards/pcmtest.rst b/Documentation/sound/cards/pcmtest.rst
new file mode 100644
index 000000000000..e163522f3205
--- /dev/null
+++ b/Documentation/sound/cards/pcmtest.rst
@@ -0,0 +1,120 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+The Virtual PCM Test Driver
+===========================
+
+The Virtual PCM Test Driver emulates a generic PCM device, and can be used for
+testing/fuzzing of the userspace ALSA applications, as well as for testing/fuzzing of
+the PCM middle layer. Additionally, it can be used for simulating hard to reproduce
+problems with PCM devices.
+
+What can this driver do?
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+At this moment the driver can do the following things:
+ * Simulate both capture and playback processes
+ * Generate random or pattern-based capturing data
+ * Inject delays into the playback and capturing processes
+ * Inject errors during the PCM callbacks
+
+It supports up to 8 substreams and 4 channels. Also it supports both interleaved and
+non-interleaved access modes.
+
+Also, this driver can check the playback stream for containing the predefined pattern,
+which is used in the corresponding selftest (alsa/pcmtest-test.sh) to check the PCM middle
+layer data transferring functionality. Additionally, this driver redefines the default
+RESET ioctl, and the selftest covers this PCM API functionality as well.
+
+Configuration
+-------------
+
+The driver has several parameters besides the common ALSA module parameters:
+
+ * fill_mode (bool) - Buffer fill mode (see below)
+ * inject_delay (int)
+ * inject_hwpars_err (bool)
+ * inject_prepare_err (bool)
+ * inject_trigger_err (bool)
+
+
+Capture Data Generation
+-----------------------
+
+The driver has two modes of data generation: the first (0 in the fill_mode parameter)
+means random data generation, the second (1 in the fill_mode) - pattern-based
+data generation. Let's look at the second mode.
+
+First of all, you may want to specify the pattern for data generation. You can do it
+by writing the pattern to the debugfs file. There are pattern buffer debugfs entries
+for each channel, as well as entries which contain the pattern buffer length.
+
+ * /sys/kernel/debug/pcmtest/fill_pattern[0-3]
+ * /sys/kernel/debug/pcmtest/fill_pattern[0-3]_len
+
+To set the pattern for the channel 0 you can execute the following command:
+
+.. code-block:: bash
+
+ echo -n mycoolpattern > /sys/kernel/debug/pcmtest/fill_pattern0
+
+Then, after every capture action performed on the 'pcmtest' device the buffer for the
+channel 0 will contain 'mycoolpatternmycoolpatternmycoolpatternmy...'.
+
+The pattern itself can be up to 4096 bytes long.
+
+Delay injection
+---------------
+
+The driver has 'inject_delay' parameter, which has very self-descriptive name and
+can be used for time delay/speedup simulations. The parameter has integer type, and
+it means the delay added between module's internal timer ticks.
+
+If the 'inject_delay' value is positive, the buffer will be filled slower, if it is
+negative - faster. You can try it yourself by starting a recording in any
+audiorecording application (like Audacity) and selecting the 'pcmtest' device as a
+source.
+
+This parameter can be also used for generating a huge amount of sound data in a very
+short period of time (with the negative 'inject_delay' value).
+
+Errors injection
+----------------
+
+This module can be used for injecting errors into the PCM communication process. This
+action can help you to figure out how the userspace ALSA program behaves under unusual
+circumstances.
+
+For example, you can make all 'hw_params' PCM callback calls return EBUSY error by
+writing '1' to the 'inject_hwpars_err' module parameter:
+
+.. code-block:: bash
+
+ echo 1 > /sys/module/snd_pcmtest/parameters/inject_hwpars_err
+
+Errors can be injected into the following PCM callbacks:
+
+ * hw_params (EBUSY)
+ * prepare (EINVAL)
+ * trigger (EINVAL)
+
+Playback test
+-------------
+
+This driver can be also used for the playback functionality testing - every time you
+write the playback data to the 'pcmtest' PCM device and close it, the driver checks the
+buffer for containing the looped pattern (which is specified in the fill_pattern
+debugfs file for each channel). If the playback buffer content represents the looped
+pattern, 'pc_test' debugfs entry is set into '1'. Otherwise, the driver sets it to '0'.
+
+ioctl redefinition test
+-----------------------
+
+The driver redefines the 'reset' ioctl, which is default for all PCM devices. To test
+this functionality, we can trigger the reset ioctl and check the 'ioctl_test' debugfs
+entry:
+
+.. code-block:: bash
+
+ cat /sys/kernel/debug/pcmtest/ioctl_test
+
+If the ioctl is triggered successfully, this file will contain '1', and '0' otherwise.
--
2.34.1
We have a lot of different virtual media drivers, which can be used for
testing of the userspace applications and media subsystem middle layer.
However, all of them are aimed at testing the video functionality and
simulating the video devices. For audio devices we have only snd-dummy
module, which is good in simulating the correct behavior of an ALSA device.
I decided to write a tool, which would help to test the userspace ALSA
programs (and the PCM middle layer as well) under unusual circumstances
to figure out how they would behave. So I came up with this Virtual PCM
Test Driver.
This new Virtual PCM Test Driver has several features which can be useful
during the userspace ALSA applications testing/fuzzing, or testing/fuzzing
of the PCM middle layer. Not all of them can be implemented using the
existing virtual drivers (like dummy or loopback). Here is what can this
driver do:
- Simulate both capture and playback processes
- Generate random or pattern-based capture data
- Inject delays into the playback and capturing processes
- Inject errors during the PCM callbacks
Also, this driver can check the playback stream for containing the
predefined pattern, which is used in the corresponding selftest to check
the PCM middle layer data transferring functionality. Additionally, this
driver redefines the default RESET ioctl, and the selftest covers this PCM
API functionality as well.
The driver supports both interleaved and non-interleaved access modes, and
have separate pattern buffers for each channel. The driver supports up to
4 channels and up to 8 substreams.
Signed-off-by: Ivan Orlov <[email protected]>
---
V1 -> V2:
- Rename the driver from from 'valsa' to 'pcmtest'.
- Implement support for interleaved and non-interleaved access modes
- Add support for 8 substreams and 4 channels
- Extend supported formats
- Extend and rewrite in C the selftest for the driver
V2 -> V3:
- Add separate pattern buffers for each channel
- Speed up the capture data generation when using interleaved access mode
- Extend the corresponding selftest to cover the multiple channels
capturing and playback functionalities when using interleaved access mode.
- Fix documentation issues
MAINTAINERS | 8 +
sound/drivers/Kconfig | 16 +
sound/drivers/Makefile | 2 +
sound/drivers/pcmtest.c | 727 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 753 insertions(+)
create mode 100644 sound/drivers/pcmtest.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 2a42a75c304c..db44af5b83f5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22429,6 +22429,14 @@ L: [email protected]
S: Maintained
F: fs/vboxsf/*
+VIRTUAL PCM TEST DRIVER
+M: Ivan Orlov <[email protected]>
+L: [email protected]
+S: Maintained
+F: Documentation/sound/cards/pcmtest.rst
+F: sound/drivers/pcmtest.c
+F: tools/testing/selftests/alsa/test-pcmtest-driver.c
+
VIRTUAL SERIO DEVICE DRIVER
M: Stephen Chandler Paul <[email protected]>
S: Maintained
diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index be3009746f3a..7a0f9f409642 100644
--- a/sound/drivers/Kconfig
+++ b/sound/drivers/Kconfig
@@ -109,6 +109,22 @@ config SND_ALOOP
To compile this driver as a module, choose M here: the module
will be called snd-aloop.
+config SND_PCMTEST
+ tristate "Virtual PCM test driver"
+ select SND_PCM
+ help
+ Say 'Y' or 'M' to include support for the Virtual PCM test driver.
+ This driver is aimed at extended testing of the userspace applications
+ which use the ALSA API, as well as the PCM middle layer testing.
+
+ It can generate random or pattern-based data into the capture stream,
+ check the playback stream for containing the selected pattern, inject
+ time delays during capture/playback, redefine the RESET ioctl operation
+ to perform the PCM middle layer testing and inject errors during the
+ PCM callbacks. It supports both interleaved and non-interleaved access
+ modes. You can find the corresponding selftest in the 'alsa'
+ selftests folder.
+
config SND_VIRMIDI
tristate "Virtual MIDI soundcard"
depends on SND_SEQUENCER
diff --git a/sound/drivers/Makefile b/sound/drivers/Makefile
index b60303180a1b..2c0c7092d396 100644
--- a/sound/drivers/Makefile
+++ b/sound/drivers/Makefile
@@ -8,6 +8,7 @@ snd-dummy-objs := dummy.o
snd-aloop-objs := aloop.o
snd-mtpav-objs := mtpav.o
snd-mts64-objs := mts64.o
+snd-pcmtest-objs := pcmtest.o
snd-portman2x4-objs := portman2x4.o
snd-serial-u16550-objs := serial-u16550.o
snd-serial-generic-objs := serial-generic.o
@@ -17,6 +18,7 @@ snd-virmidi-objs := virmidi.o
obj-$(CONFIG_SND_DUMMY) += snd-dummy.o
obj-$(CONFIG_SND_ALOOP) += snd-aloop.o
obj-$(CONFIG_SND_VIRMIDI) += snd-virmidi.o
+obj-$(CONFIG_SND_PCMTEST) += snd-pcmtest.o
obj-$(CONFIG_SND_SERIAL_U16550) += snd-serial-u16550.o
obj-$(CONFIG_SND_SERIAL_GENERIC) += snd-serial-generic.o
obj-$(CONFIG_SND_MTPAV) += snd-mtpav.o
diff --git a/sound/drivers/pcmtest.c b/sound/drivers/pcmtest.c
new file mode 100644
index 000000000000..2ae912a64d16
--- /dev/null
+++ b/sound/drivers/pcmtest.c
@@ -0,0 +1,727 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtual ALSA driver for PCM testing/fuzzing
+ *
+ * Copyright 2023 Ivan Orlov <[email protected]>
+ *
+ * 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);
--
2.34.1
This test covers the new Virtual PCM Test Driver, including the capturing,
playback and ioctl redefinition functionalities for both interleaved and
non-interleaved access modes. This test is also helpful as an usage example
of the 'pcmtest' driver.
We have a lot of different virtual media drivers, which can be used for
testing of the userspace applications and media subsystem middle layer.
However, all of them are aimed at testing the video functionality and
simulating the video devices. For audio devices we have only snd-dummy
module, which is good in simulating the correct behavior of an ALSA device.
I decided to write a tool, which would help to test the userspace ALSA
programs (and the PCM middle layer as well) under unusual circumstances
to figure out how they would behave. So I came up with this Virtual PCM
Test Driver.
This new Virtual PCM Test Driver has several features which can be useful
during the userspace ALSA applications testing/fuzzing, or testing/fuzzing
of the PCM middle layer. Not all of them can be implemented using the
existing virtual drivers (like dummy or loopback). Here is what can this
driver do:
- Simulate both capture and playback processes
- Generate random or pattern-based capture data
- Check the playback stream for containing the looped pattern
- Inject delays into the playback and capturing processes
- Inject errors during the PCM callbacks
Also, this driver can check the playback stream for containing the
predefined pattern, which is used in the corresponding selftest to check
the PCM middle layer data transferring functionality. Additionally, this
driver redefines the default RESET ioctl, and the selftest covers this PCM
API functionality as well.
The driver supports both interleaved and non-interleaved access modes, and
have separate pattern buffers for each channel. The driver supports up to
4 channels and up to 8 substreams.
Signed-off-by: Ivan Orlov <[email protected]>
---
V1 -> V2:
- Rename the driver from from 'valsa' to 'pcmtest'.
- Implement support for interleaved and non-interleaved access modes
- Add support for 8 substreams and 4 channels
- Extend supported formats
- Extend and rewrite in C the selftest for the driver
V2 -> V3:
- Add separate pattern buffers for each channel
- Speed up the capture data generation when using interleaved access mode
- Extend the corresponding selftest to cover the multiple channels
capturing and playback functionalities when using interleaved access mode.
- Fix documentation issues
tools/testing/selftests/alsa/Makefile | 2 +-
.../selftests/alsa/test-pcmtest-driver.c | 333 ++++++++++++++++++
2 files changed, 334 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/alsa/test-pcmtest-driver.c
diff --git a/tools/testing/selftests/alsa/Makefile b/tools/testing/selftests/alsa/Makefile
index 901949db80ad..5af9ba8a4645 100644
--- a/tools/testing/selftests/alsa/Makefile
+++ b/tools/testing/selftests/alsa/Makefile
@@ -12,7 +12,7 @@ LDLIBS+=-lpthread
OVERRIDE_TARGETS = 1
-TEST_GEN_PROGS := mixer-test pcm-test
+TEST_GEN_PROGS := mixer-test pcm-test test-pcmtest-driver
TEST_GEN_PROGS_EXTENDED := libatest.so
diff --git a/tools/testing/selftests/alsa/test-pcmtest-driver.c b/tools/testing/selftests/alsa/test-pcmtest-driver.c
new file mode 100644
index 000000000000..4d51dae11ad6
--- /dev/null
+++ b/tools/testing/selftests/alsa/test-pcmtest-driver.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This is the test which covers PCM middle layer data transferring using
+ * the virtual pcm test driver (snd-pcmtest).
+ *
+ * Copyright 2023 Ivan Orlov <[email protected]>
+ */
+#include <string.h>
+#include <alsa/asoundlib.h>
+#include "../kselftest_harness.h"
+
+#define CH_NUM 4
+
+struct pattern_buf {
+ char buf[1024];
+ int len;
+};
+
+struct pattern_buf patterns[CH_NUM];
+
+struct pcmtest_test_params {
+ unsigned long buffer_size;
+ unsigned long period_size;
+ unsigned long channels;
+ unsigned int rate;
+ snd_pcm_access_t access;
+ size_t sec_buf_len;
+ size_t sample_size;
+ int time;
+ snd_pcm_format_t format;
+};
+
+static int read_patterns(void)
+{
+ FILE *fp, *fpl;
+ int i;
+ char pf[64];
+ char plf[64];
+
+ for (i = 0; i < CH_NUM; i++) {
+ sprintf(plf, "/sys/kernel/debug/pcmtest/fill_pattern%d_len", i);
+ fpl = fopen(plf, "r");
+ if (!fpl)
+ return -1;
+ fscanf(fpl, "%u", patterns[i].len);
+ fclose(fpl);
+
+ sprintf(pf, "/sys/kernel/debug/pcmtest/fill_pattern%d", i);
+ fp = fopen(pf, "r");
+ if (!fp) {
+ fclose(fpl);
+ return -1;
+ }
+ fread(patterns[i].buf, 1, patterns[i].len, fp);
+ fclose(fp);
+ }
+
+ return 0;
+}
+
+static int get_test_results(char *debug_name)
+{
+ int result;
+ FILE *f;
+ char fname[128];
+
+ sprintf(fname, "/sys/kernel/debug/pcmtest/%s", debug_name);
+
+ f = fopen(fname, "r");
+ if (!f) {
+ printf("Failed to open file\n");
+ return -1;
+ }
+ fscanf(f, "%d", &result);
+ fclose(f);
+
+ return result;
+}
+
+static size_t get_sec_buf_len(unsigned int rate, unsigned long channels, snd_pcm_format_t format)
+{
+ return rate * channels * snd_pcm_format_physical_width(format) / 8;
+}
+
+static int setup_handle(snd_pcm_t **handle, snd_pcm_sw_params_t *swparams,
+ snd_pcm_hw_params_t *hwparams, struct pcmtest_test_params *params,
+ int card, snd_pcm_stream_t stream)
+{
+ char pcm_name[32];
+ int err;
+
+ sprintf(pcm_name, "hw:%d,0,0", card);
+ err = snd_pcm_open(handle, pcm_name, stream, 0);
+ if (err < 0)
+ return err;
+ snd_pcm_hw_params_any(*handle, hwparams);
+ snd_pcm_hw_params_set_rate_resample(*handle, hwparams, 0);
+ snd_pcm_hw_params_set_access(*handle, hwparams, params->access);
+ snd_pcm_hw_params_set_format(*handle, hwparams, params->format);
+ snd_pcm_hw_params_set_channels(*handle, hwparams, params->channels);
+ snd_pcm_hw_params_set_rate_near(*handle, hwparams, ¶ms->rate, 0);
+ snd_pcm_hw_params_set_period_size_near(*handle, hwparams, ¶ms->period_size, 0);
+ snd_pcm_hw_params_set_buffer_size_near(*handle, hwparams, ¶ms->buffer_size);
+ snd_pcm_hw_params(*handle, hwparams);
+ snd_pcm_sw_params_current(*handle, swparams);
+
+ snd_pcm_hw_params_set_rate_resample(*handle, hwparams, 0);
+ snd_pcm_sw_params_set_avail_min(*handle, swparams, params->period_size);
+ snd_pcm_hw_params_set_buffer_size_near(*handle, hwparams, ¶ms->buffer_size);
+ snd_pcm_hw_params_set_period_size_near(*handle, hwparams, ¶ms->period_size, 0);
+ snd_pcm_sw_params(*handle, swparams);
+ snd_pcm_hw_params(*handle, hwparams);
+
+ return 0;
+}
+
+FIXTURE(pcmtest) {
+ int card;
+ snd_pcm_sw_params_t *swparams;
+ snd_pcm_hw_params_t *hwparams;
+ struct pcmtest_test_params params;
+};
+
+FIXTURE_TEARDOWN(pcmtest) {
+}
+
+FIXTURE_SETUP(pcmtest) {
+ char *card_name;
+ int err;
+
+ if (geteuid())
+ SKIP(exit(-1), "This test needs root to run!");
+
+ err = read_patterns();
+ if (err)
+ SKIP(exit(-1), "Can't read patterns. Probably, module isn't loaded");
+
+ card_name = malloc(127);
+ ASSERT_NE(card_name, NULL);
+ self->params.buffer_size = 16384;
+ self->params.period_size = 4096;
+ self->params.channels = CH_NUM;
+ self->params.rate = 8000;
+ self->params.access = SND_PCM_ACCESS_RW_INTERLEAVED;
+ self->params.format = SND_PCM_FORMAT_S16_LE;
+ self->card = -1;
+ self->params.sample_size = snd_pcm_format_physical_width(self->params.format) / 8;
+
+ self->params.sec_buf_len = get_sec_buf_len(self->params.rate, self->params.channels,
+ self->params.format);
+ self->params.time = 4;
+
+ while (snd_card_next(&self->card) >= 0) {
+ if (self->card == -1)
+ break;
+ snd_card_get_name(self->card, &card_name);
+ if (!strcmp(card_name, "PCM-Test"))
+ break;
+ }
+ free(card_name);
+ ASSERT_NE(self->card, -1);
+}
+
+/*
+ * Here we are trying to send the looped monotonically increasing sequence of bytes to the driver.
+ * If our data isn't corrupted, the driver will set the content of 'pc_test' debugfs file to '1'
+ */
+TEST_F(pcmtest, playback) {
+ snd_pcm_t *handle;
+ unsigned char *it;
+ size_t write_res;
+ int test_results;
+ int i, cur_ch, pos_in_ch;
+ void *samples;
+ struct pcmtest_test_params *params = &self->params;
+
+ samples = calloc(self->params.sec_buf_len * self->params.time, 1);
+ ASSERT_NE(samples, NULL);
+
+ snd_pcm_sw_params_alloca(&self->swparams);
+ snd_pcm_hw_params_alloca(&self->hwparams);
+
+ ASSERT_EQ(setup_handle(&handle, self->swparams, self->hwparams, params,
+ self->card, SND_PCM_STREAM_PLAYBACK), 0);
+ snd_pcm_format_set_silence(params->format, samples,
+ params->rate * params->channels * params->time);
+ it = samples;
+ for (i = 0; i < self->params.sec_buf_len * params->time; i++) {
+ cur_ch = (i / params->sample_size) % CH_NUM;
+ pos_in_ch = i / params->sample_size / CH_NUM * params->sample_size
+ + (i % params->sample_size);
+ it[i] = patterns[cur_ch].buf[pos_in_ch % patterns[cur_ch].len];
+ }
+ write_res = snd_pcm_writei(handle, samples, params->rate * params->time);
+ ASSERT_GE(write_res, 0);
+
+ snd_pcm_close(handle);
+ free(samples);
+ test_results = get_test_results("pc_test");
+ ASSERT_EQ(test_results, 1);
+}
+
+/*
+ * Here we test that the virtual alsa driver returns looped and monotonically increasing sequence
+ * of bytes. In the interleaved mode the buffer will contain samples in the following order:
+ * C0, C1, C2, C3, C0, C1, ...
+ */
+TEST_F(pcmtest, capture) {
+ snd_pcm_t *handle;
+ unsigned char *it;
+ size_t read_res;
+ int i, cur_ch, pos_in_ch;
+ void *samples;
+ struct pcmtest_test_params *params = &self->params;
+
+ samples = calloc(self->params.sec_buf_len * self->params.time, 1);
+ ASSERT_NE(samples, NULL);
+
+ snd_pcm_sw_params_alloca(&self->swparams);
+ snd_pcm_hw_params_alloca(&self->hwparams);
+
+ ASSERT_EQ(setup_handle(&handle, self->swparams, self->hwparams,
+ params, self->card, SND_PCM_STREAM_CAPTURE), 0);
+ snd_pcm_format_set_silence(params->format, samples,
+ params->rate * params->channels * params->time);
+ read_res = snd_pcm_readi(handle, samples, params->rate * params->time);
+ ASSERT_GE(read_res, 0);
+ snd_pcm_close(handle);
+ it = (unsigned char *)samples;
+ for (i = 0; i < self->params.sec_buf_len * self->params.time; i++) {
+ cur_ch = (i / params->sample_size) % CH_NUM;
+ pos_in_ch = i / params->sample_size / CH_NUM * params->sample_size
+ + (i % params->sample_size);
+ ASSERT_EQ(it[i], patterns[cur_ch].buf[pos_in_ch % patterns[cur_ch].len]);
+ }
+ free(samples);
+}
+
+// Test capture in the non-interleaved access mode. The are buffers for each recorded channel
+TEST_F(pcmtest, ni_capture) {
+ snd_pcm_t *handle;
+ struct pcmtest_test_params params = self->params;
+ char **chan_samples;
+ size_t i, j, read_res;
+
+ chan_samples = calloc(CH_NUM, sizeof(*chan_samples));
+ ASSERT_NE(chan_samples, NULL);
+
+ snd_pcm_sw_params_alloca(&self->swparams);
+ snd_pcm_hw_params_alloca(&self->hwparams);
+
+ params.access = SND_PCM_ACCESS_RW_NONINTERLEAVED;
+
+ ASSERT_EQ(setup_handle(&handle, self->swparams, self->hwparams,
+ ¶ms, self->card, SND_PCM_STREAM_CAPTURE), 0);
+
+ for (i = 0; i < CH_NUM; i++)
+ chan_samples[i] = calloc(params.sec_buf_len * params.time, 1);
+
+ for (i = 0; i < 1; i++) {
+ read_res = snd_pcm_readn(handle, (void **)chan_samples, params.rate * params.time);
+ ASSERT_GE(read_res, 0);
+ }
+ snd_pcm_close(handle);
+
+ for (i = 0; i < CH_NUM; i++) {
+ for (j = 0; j < params.rate * params.time; j++)
+ ASSERT_EQ(chan_samples[i][j], patterns[i].buf[j % patterns[i].len]);
+ free(chan_samples[i]);
+ }
+ free(chan_samples);
+}
+
+TEST_F(pcmtest, ni_playback) {
+ snd_pcm_t *handle;
+ struct pcmtest_test_params params = self->params;
+ char **chan_samples;
+ size_t i, j, read_res;
+ int test_res;
+
+ chan_samples = calloc(CH_NUM, sizeof(*chan_samples));
+ ASSERT_NE(chan_samples, NULL);
+
+ snd_pcm_sw_params_alloca(&self->swparams);
+ snd_pcm_hw_params_alloca(&self->hwparams);
+
+ params.access = SND_PCM_ACCESS_RW_NONINTERLEAVED;
+
+ ASSERT_EQ(setup_handle(&handle, self->swparams, self->hwparams,
+ ¶ms, self->card, SND_PCM_STREAM_PLAYBACK), 0);
+
+ for (i = 0; i < CH_NUM; i++) {
+ chan_samples[i] = calloc(params.sec_buf_len * params.time, 1);
+ for (j = 0; j < params.sec_buf_len * params.time; j++)
+ chan_samples[i][j] = patterns[i].buf[j % patterns[i].len];
+ }
+
+ for (i = 0; i < 1; i++) {
+ read_res = snd_pcm_writen(handle, (void **)chan_samples, params.rate * params.time);
+ ASSERT_GE(read_res, 0);
+ }
+
+ snd_pcm_close(handle);
+ test_res = get_test_results("pc_test");
+ ASSERT_EQ(test_res, 1);
+
+ for (i = 0; i < CH_NUM; i++)
+ free(chan_samples[i]);
+ free(chan_samples);
+}
+
+/*
+ * Here we are testing the custom ioctl definition inside the virtual driver. If it triggers
+ * successfully, the driver sets the content of 'ioctl_test' debugfs file to '1'.
+ */
+TEST_F(pcmtest, reset_ioctl) {
+ snd_pcm_t *handle;
+ unsigned char *it;
+ int test_res;
+ struct pcmtest_test_params *params = &self->params;
+
+ snd_pcm_sw_params_alloca(&self->swparams);
+ snd_pcm_hw_params_alloca(&self->hwparams);
+
+ ASSERT_EQ(setup_handle(&handle, self->swparams, self->hwparams, params,
+ self->card, SND_PCM_STREAM_CAPTURE), 0);
+ snd_pcm_reset(handle);
+ test_res = get_test_results("ioctl_test");
+ ASSERT_EQ(test_res, 1);
+ snd_pcm_close(handle);
+}
+
+TEST_HARNESS_MAIN
--
2.34.1
On 06. 06. 23 15:38, Ivan Orlov wrote:
> Add documentation for the new Virtual PCM Test Driver. It covers all
> possible usage cases: errors and delay injections, random and
> pattern-based data generation, playback and ioctl redefinition
> functionalities testing.
Acked-by: Jaroslav Kysela <[email protected]>
--
Jaroslav Kysela <[email protected]>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
On 06. 06. 23 15:38, Ivan Orlov wrote:
> We have a lot of different virtual media drivers, which can be used for
> testing of the userspace applications and media subsystem middle layer.
> However, all of them are aimed at testing the video functionality and
> simulating the video devices. For audio devices we have only snd-dummy
> module, which is good in simulating the correct behavior of an ALSA device.
> I decided to write a tool, which would help to test the userspace ALSA
> programs (and the PCM middle layer as well) under unusual circumstances
> to figure out how they would behave. So I came up with this Virtual PCM
> Test Driver.
Acked-by: Jaroslav Kysela <[email protected]>
--
Jaroslav Kysela <[email protected]>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
On 06. 06. 23 15:38, Ivan Orlov wrote:
> This test covers the new Virtual PCM Test Driver, including the capturing,
> playback and ioctl redefinition functionalities for both interleaved and
> non-interleaved access modes. This test is also helpful as an usage example
> of the 'pcmtest' driver.
>
> We have a lot of different virtual media drivers, which can be used for
> testing of the userspace applications and media subsystem middle layer.
> However, all of them are aimed at testing the video functionality and
> simulating the video devices. For audio devices we have only snd-dummy
> module, which is good in simulating the correct behavior of an ALSA device.
> I decided to write a tool, which would help to test the userspace ALSA
> programs (and the PCM middle layer as well) under unusual circumstances
> to figure out how they would behave. So I came up with this Virtual PCM
> Test Driver.
Acked-by: Jaroslav Kysela <[email protected]>
--
Jaroslav Kysela <[email protected]>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
On Tue, Jun 06, 2023 at 05:38:05PM +0400, Ivan Orlov wrote:
> diff --git a/Documentation/sound/cards/pcmtest.rst b/Documentation/sound/cards/pcmtest.rst
> new file mode 100644
> index 000000000000..e163522f3205
> --- /dev/null
> +++ b/Documentation/sound/cards/pcmtest.rst
> @@ -0,0 +1,120 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +The Virtual PCM Test Driver
> +===========================
> +
> +The Virtual PCM Test Driver emulates a generic PCM device, and can be used for
> +testing/fuzzing of the userspace ALSA applications, as well as for testing/fuzzing of
> +the PCM middle layer. Additionally, it can be used for simulating hard to reproduce
> +problems with PCM devices.
> +
> +What can this driver do?
> +~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +At this moment the driver can do the following things:
> + * Simulate both capture and playback processes
> + * Generate random or pattern-based capturing data
> + * Inject delays into the playback and capturing processes
> + * Inject errors during the PCM callbacks
> +
> +It supports up to 8 substreams and 4 channels. Also it supports both interleaved and
> +non-interleaved access modes.
> +
> +Also, this driver can check the playback stream for containing the predefined pattern,
> +which is used in the corresponding selftest (alsa/pcmtest-test.sh) to check the PCM middle
> +layer data transferring functionality. Additionally, this driver redefines the default
> +RESET ioctl, and the selftest covers this PCM API functionality as well.
> +
> +Configuration
> +-------------
> +
> +The driver has several parameters besides the common ALSA module parameters:
> +
> + * fill_mode (bool) - Buffer fill mode (see below)
> + * inject_delay (int)
> + * inject_hwpars_err (bool)
> + * inject_prepare_err (bool)
> + * inject_trigger_err (bool)
> +
> +
> +Capture Data Generation
> +-----------------------
> +
> +The driver has two modes of data generation: the first (0 in the fill_mode parameter)
> +means random data generation, the second (1 in the fill_mode) - pattern-based
> +data generation. Let's look at the second mode.
> +
> +First of all, you may want to specify the pattern for data generation. You can do it
> +by writing the pattern to the debugfs file. There are pattern buffer debugfs entries
> +for each channel, as well as entries which contain the pattern buffer length.
> +
> + * /sys/kernel/debug/pcmtest/fill_pattern[0-3]
> + * /sys/kernel/debug/pcmtest/fill_pattern[0-3]_len
> +
> +To set the pattern for the channel 0 you can execute the following command:
> +
> +.. code-block:: bash
> +
> + echo -n mycoolpattern > /sys/kernel/debug/pcmtest/fill_pattern0
> +
> +Then, after every capture action performed on the 'pcmtest' device the buffer for the
> +channel 0 will contain 'mycoolpatternmycoolpatternmycoolpatternmy...'.
> +
> +The pattern itself can be up to 4096 bytes long.
> +
> +Delay injection
> +---------------
> +
> +The driver has 'inject_delay' parameter, which has very self-descriptive name and
> +can be used for time delay/speedup simulations. The parameter has integer type, and
> +it means the delay added between module's internal timer ticks.
> +
> +If the 'inject_delay' value is positive, the buffer will be filled slower, if it is
> +negative - faster. You can try it yourself by starting a recording in any
> +audiorecording application (like Audacity) and selecting the 'pcmtest' device as a
> +source.
> +
> +This parameter can be also used for generating a huge amount of sound data in a very
> +short period of time (with the negative 'inject_delay' value).
> +
> +Errors injection
> +----------------
> +
> +This module can be used for injecting errors into the PCM communication process. This
> +action can help you to figure out how the userspace ALSA program behaves under unusual
> +circumstances.
> +
> +For example, you can make all 'hw_params' PCM callback calls return EBUSY error by
> +writing '1' to the 'inject_hwpars_err' module parameter:
> +
> +.. code-block:: bash
> +
> + echo 1 > /sys/module/snd_pcmtest/parameters/inject_hwpars_err
> +
> +Errors can be injected into the following PCM callbacks:
> +
> + * hw_params (EBUSY)
> + * prepare (EINVAL)
> + * trigger (EINVAL)
> +
> +Playback test
> +-------------
> +
> +This driver can be also used for the playback functionality testing - every time you
> +write the playback data to the 'pcmtest' PCM device and close it, the driver checks the
> +buffer for containing the looped pattern (which is specified in the fill_pattern
> +debugfs file for each channel). If the playback buffer content represents the looped
> +pattern, 'pc_test' debugfs entry is set into '1'. Otherwise, the driver sets it to '0'.
> +
> +ioctl redefinition test
> +-----------------------
> +
> +The driver redefines the 'reset' ioctl, which is default for all PCM devices. To test
> +this functionality, we can trigger the reset ioctl and check the 'ioctl_test' debugfs
> +entry:
> +
> +.. code-block:: bash
> +
> + cat /sys/kernel/debug/pcmtest/ioctl_test
> +
> +If the ioctl is triggered successfully, this file will contain '1', and '0' otherwise.
LGTM, thanks!
Reviewed-by: Bagas Sanjaya <[email protected]>
--
An old man doll... just what I always wanted! - Clara