drivers: dai: Add virtual DAI driver and tests by SurajSonawane2415 · Pull Request #95233 · zephyrproject-rtos/zephyr

SurajSonawane2415 · 2025-08-31T15:50:39Z

This PR is part of the GSoC 2025 Project: Add Virtual DAI Component to SOF and is based on SOF Issue #9349.

We introduce a new DAI_VIRTUAL type with driver its associated support to enable audio pipelines that do not rely on physical DAI hardware. This is useful in the following scenarios:

Debugging and rapid prototyping: Quickly create and test audio pipelines without needing actual hardware.
Software loopback preparation: Lays the groundwork for a memory-to-memory audio pipeline within SOF.

Key Changes

Added Virtual DAI driver (initial version with basic logs).
Added DTS binding (dai-virtual.yaml).
Updated Kconfig/CMake and integrated with i.MX8M DTS.
Added ztest-based test suite for basic API validation.

Testing

Platform: i.MX8MP EVK with Virtual DAI topology.
Environment: Zephyr-based SOF build.
Results:
- NoCodec card + Virtual DAI detected.
- Probe, config, and removal flows working as expected.
- All test cases executed successfully, all tests passed

Logs:

*** Booting Zephyr OS build 6e3ea447cbfb ***
[00:00:00.046,014] <inf> main: SOF on imx8mp_evk
[00:00:00.051,043] <inf> main: SOF initialized
[00:00:00.055,909] <inf> ipc: ipc: new cmd 0x90030000
[00:00:00.061,749] <inf> ipc: ipc: new cmd 0x30100000
[00:00:00.066,973] <inf> pipe: pipeline new pipe_id 1 priority 0
[00:00:00.074,086] <inf> ipc: ipc: new cmd 0x30010000
[00:00:00.079,312] <inf> ipc: comp new 0x924549b4U type 2 id 1.4
[00:00:00.085,734] <inf> dai_comp: DAIZ: dai_new()
[00:00:00.090,941] <inf> dai_comp: DAIZ: dai_common_new()
[00:00:00.096,757] <inf> virtual_dai: virtual_dai_config_get
[00:00:00.102,833] <inf> virtual_dai: virtual_dai_probe
[00:00:00.108,476] <inf> dma: sof_dma_get: dir=0, cap=0x0, dev=0x0, flags=0x0
[00:00:00.116,028] <inf> dma: dma_init
[00:00:00.120,198] <inf> dma: sof_dma_get(): Final selection -> ID 0, sref=1, busy=0
[00:00:00.129,043] <inf> ipc: ipc: new cmd 0x80010000
[00:00:00.134,266] <inf> ipc: ipc: dai 16.7 -> config 
[00:00:00.139,820] <inf> virtual_dai: virtual_dai_config_get
[00:00:00.145,896] <inf> virtual_dai: virtual_dai_probe
[00:00:00.151,539] <inf> dai_comp: DAIZ: dai_set_config()
[00:00:00.157,354] <inf> virtual_dai: virtual_dai_config_set
[00:00:00.163,429] <inf> virtual_dai: virtual_dai_remove
[00:00:00.169,163] <inf> ipc: ipc_comp_dai_config() dai type = 16 index = 7
[00:00:00.176,541] <inf> ipc: comp:1.4 dai_config() dai type = 16 index = 7 dd 0x92c05ee0
[00:00:00.185,132] <inf> dai_comp: DAIZ: dai_get_handshake()
[00:00:00.191,208] <inf> virtual_dai: virtual_dai_get_properties

Related Work

SOF PR: #10147 dai: Add support for Virtual DAI for rapid prototyping and software loopback
Adds Virtual DAI support on i.MX8MP with topology and emul_dma integration for software-based audio pipelines.
linux-imx PR: #30 ASoC: SOF: Add Virtual DAI support for i.MX8M
Introduces SOF_DAI_VIRTUAL type and configuration, adds topology tokens, extends IPC3 parsing, and registers a Virtual DAI backend for i.MX8M. Enables prototyping and loopback pipelines without physical DAI hardware.
linux-imx nocodec feature commit: Enabled NoCodec support for the i.MX8M platform to allow pipeline testing without real codecs.
Link: nocodec-commit

Future Work

Implement playback and record:
- Playback: log output frames and discard.
- Record: generate frames filled with zeroes.
  (Current limitation: To get aplay and arecord working, I replaced the real DMA with emul_dma for Virtual DAI. All functions execute, but data is not being copied in dma_emul_work_handler during playback.)

github-actions · 2025-08-31T15:51:16Z

Hello @SurajSonawane2415, and thank you very much for your first pull request to the Zephyr project!
Our Continuous Integration pipeline will execute a series of checks on your Pull Request commit messages and code, and you are expected to address any failures by updating the PR. Please take a look at our commit message guidelines to find out how to format your commit messages, and at our contribution workflow to understand how to update your Pull Request. If you haven't already, please make sure to review the project's Contributor Expectations and update (by amending and force-pushing the commits) your pull request if necessary.
If you are stuck or need help please join us on Discord and ask your question there. Additionally, you can escalate the review when applicable. 😊

kv2019i

Thanks @SurajSonawane24 ! Code is looking good. Only some minor notes on documentation, Kconfig defaults and log verbosity. Please see inline.

kv2019i · 2025-09-01T17:27:43Z

+
+config DAI_VIRTUAL
+	bool "Virtual DAI driver support for SOF"
+	default n


"default n" is superfluous -> https://docs.zephyrproject.org/latest/build/kconfig/tips.html#redundant-defaults

Also no need to mention SOF. While SOF is currently the primary user of DAI interface, DAIs could be used by any app.

kv2019i · 2025-09-01T17:28:56Z

+	bool "Virtual DAI driver support for SOF"
+	default n
+	help
+	  Enable support for a Virtual DAI (Digital Audio Interface) in SOF.


Ditto here.

kv2019i · 2025-09-02T07:17:02Z

+
+static int virtual_dai_probe(const struct device *dev)
+{
+	LOG_INF("%s", __func__);


I'd reduce the number of these LOG_INF()s in the merged version. I know this virtual DAI is more for R&D use, so logging can be on the more verbose side, but I'd still drop the function entry/exit logs (especially as Zephyr logging can add the function info with a build option, no need to add "func" in driver code.

rruuaanng · 2025-09-02T14:22:55Z

+description: |
+  Zephyr binding for a Virtual DAI (Digital Audio Interface).
+  This DAI is not connected to real hardware and is used for software-only
+  audio routing or testing within SOF + Zephyr systems.


Suggested change

description: |

Zephyr binding for a Virtual DAI (Digital Audio Interface).

This DAI is not connected to real hardware and is used for software-only

audio routing or testing within SOF + Zephyr systems.

title: Zephyr for a Virtual DAI (Digital Audio Interface)

description: |

This DAI is not connected to real hardware and is used for software-only

audio routing or testing within SOF + Zephyr systems.

Thank you for the suggestions, I’ve made the changes.

rruuaanng · 2025-09-02T14:25:31Z

+static const struct dai_properties
+	*virtual_dai_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)


Suggested change

static const struct dai_properties

*virtual_dai_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)

static const struct dai_properties *virtual_dai_get_properties(const struct device *dev,

enum dai_dir dir, int stream_id)

or

Suggested change

static const struct dai_properties

*virtual_dai_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)

static const struct dai_properties*

virtual_dai_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)

@rruuaanng I accepted your suggestion, just kept the * with the function name (not the type) to follow kernel coding style.

rruuaanng · 2025-09-02T14:27:56Z

+static struct virtual_dai_data virtual_dai_data_##inst = {					\
+	.cfg.type = DAI_VIRTUAL,						\
+	.cfg.dai_index = DT_INST_PROP_OR(inst, dai_index, 0),			\
+};										\
+										\
+DEVICE_DT_INST_DEFINE(inst, \
+		      &virtual_dai_init, NULL, \
+		      &virtual_dai_data_##inst, NULL, \
+		      POST_KERNEL, CONFIG_DAI_INIT_PRIORITY, \
+		      &virtual_dai_api);


Suggested change

static struct virtual_dai_data virtual_dai_data_##inst = { \

.cfg.type = DAI_VIRTUAL, \

.cfg.dai_index = DT_INST_PROP_OR(inst, dai_index, 0), \

}; \

\

DEVICE_DT_INST_DEFINE(inst, \

&virtual_dai_init, NULL, \

&virtual_dai_data_##inst, NULL, \

POST_KERNEL, CONFIG_DAI_INIT_PRIORITY, \

&virtual_dai_api);

static struct virtual_dai_data virtual_dai_data_##inst = { \

.cfg.type = DAI_VIRTUAL, \

.cfg.dai_index = DT_INST_PROP_OR(inst, dai_index, 0), \

}; \

\

DEVICE_DT_INST_DEFINE(inst, \

&virtual_dai_init, NULL, \

&virtual_dai_data_##inst, NULL, \

POST_KERNEL, CONFIG_DAI_INIT_PRIORITY, \

&virtual_dai_api);

@rruuaanng Thanks for the suggestion. Can you clarify the reason for these whitespace changes?

SurajSonawane2415 · 2025-09-03T05:22:37Z

Thanks @SurajSonawane24 ! Code is looking good. Only some minor notes on documentation, Kconfig defaults and log verbosity. Please see inline.

@kv2019i Thanks for the detailed review!

Dropped the redundant default n.
Removed “SOF” mention from Kconfig description.
Cleaned up logging by dropping function entry/exit logs, keeping only meaningful ones (using DBG instead of INF).

kv2019i

Thanks, looks good now @SurajSonawane2415 !

LaurentiuM1234

Good start, but IMO this should still be in the draft stage. I would like to see some actual functionality being implemented here. IMO, as things stand now, this PR introduces a DAI driver that doesn't seem to do anything and a test suite that doesn't test anything particularly useful?

LaurentiuM1234 · 2025-09-03T17:25:15Z

+  Zephyr binding for a Virtual DAI (Digital Audio Interface).
+  This DAI is not connected to real hardware and is used for software-only
+  audio routing or testing within SOF + Zephyr systems.
+compatible: "virtual_dai"


The format of the compatible string is "vendor,model". Also, should be virtual-dai. My suggestion would be to use zephyr,virtual-dai.

Thank you I will make the changes.

LaurentiuM1234 · 2025-09-03T17:29:38Z

 			status = "disabled";
 		};

+		virtual_dai: virtual_dai {


no virtual devices in the mainline DT, please. We can move this to the application DT overlay. See host_dma from https://github.com/thesofproject/sof/blob/main/app/boards/imx8qm_mek_mimx8qm6_adsp.overlay as an example.

Got it, thanks for pointing this out. I’ve removed it.
I’ll refer to the host_dma example you shared for guidance.

SurajSonawane2415 · 2025-09-04T09:05:25Z

Good start, but IMO this should still be in the draft stage. I would like to see some actual functionality being implemented here. IMO, as things stand now, this PR introduces a DAI driver that doesn't seem to do anything and a test suite that doesn't test anything particularly useful?

Thanks for the feedback! I’ve marked it as draft.

Introduce a virtual DAI driver for prototyping, loopback, and testing without requiring physical DAI hardware. This includes: - Initial virtual DAI implementation (logging only) - DTS binding (dai-virtual.yaml) - Kconfig and CMake updates - i.MX8M DTS integration Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

Add a basic ztest-based testsuite for the virtual DAI driver. This includes initial API coverage and simple validation. Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

sonarqubecloud · 2025-09-08T15:52:34Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

github-actions · 2025-11-08T00:35:58Z

This pull request has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 14 days. Note, that you can always re-open a closed pull request at any time.

zephyrbot added area: Devicetree area: Xtensa Xtensa Architecture area: DAI labels Aug 31, 2025

zephyrbot requested review from LaurentiuM1234, andyross, ceolin, dbaluta, dcpleung, decsny, galak, iuliana-prodan, juimonen, kv2019i, lgirdwood, mbolivar, nashif and rruuaanng August 31, 2025 15:51

zephyrbot assigned kv2019i and LaurentiuM1234 Aug 31, 2025

SurajSonawane2415 mentioned this pull request Aug 31, 2025

dai: Add support for Virtual DAI for rapid prototyping and software loopback thesofproject/sof#10147

Draft

SurajSonawane2415 force-pushed the feature/zephyr-virtual-dai branch from 9fe555a to f25130f Compare August 31, 2025 16:01

SurajSonawane2415 mentioned this pull request Sep 1, 2025

ASoC: SOF: Add Virtual DAI support for i.MX8M nxp-imx/linux-imx#30

Open

SurajSonawane2415 force-pushed the feature/zephyr-virtual-dai branch from f25130f to 7dfac22 Compare September 2, 2025 07:00

kv2019i requested changes Sep 2, 2025

View reviewed changes

rruuaanng reviewed Sep 2, 2025

View reviewed changes

SurajSonawane2415 force-pushed the feature/zephyr-virtual-dai branch from 7dfac22 to 7f3747d Compare September 3, 2025 05:22

kv2019i previously approved these changes Sep 3, 2025

View reviewed changes

LaurentiuM1234 requested changes Sep 3, 2025

View reviewed changes

SurajSonawane2415 dismissed kv2019i’s stale review via 7cc9c25 September 4, 2025 05:37

SurajSonawane2415 force-pushed the feature/zephyr-virtual-dai branch from 7f3747d to 7cc9c25 Compare September 4, 2025 05:37

SurajSonawane2415 marked this pull request as draft September 4, 2025 09:02

SurajSonawane2415 added 2 commits September 8, 2025 20:50

tests: drivers: dai: Add tests for virtual DAI

a6c0c23

Add a basic ztest-based testsuite for the virtual DAI driver. This includes initial API coverage and simple validation. Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

SurajSonawane2415 force-pushed the feature/zephyr-virtual-dai branch from 7cc9c25 to a6c0c23 Compare September 8, 2025 15:26

github-actions Bot added the Stale label Nov 8, 2025

github-actions Bot closed this Nov 22, 2025

		static const struct dai_properties
		virtual_dai_get_properties(const struct device dev, enum dai_dir dir, int stream_id)

Conversation

SurajSonawane2415 commented Aug 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Key Changes

Testing

Related Work

Future Work

Uh oh!

github-actions Bot commented Aug 31, 2025

Uh oh!

kv2019i left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

SurajSonawane2415 commented Sep 3, 2025

Uh oh!

kv2019i left a comment

Choose a reason for hiding this comment

Uh oh!

LaurentiuM1234 left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

SurajSonawane2415 commented Sep 4, 2025

Uh oh!

sonarqubecloud Bot commented Sep 8, 2025

Quality Gate passed

Uh oh!

github-actions Bot commented Nov 8, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

SurajSonawane2415 commented Aug 31, 2025 •

edited

Loading