NFTL Disk Driver by LinderPi · Pull Request #100858 · zephyrproject-rtos/zephyr

LinderPi · 2025-12-11T07:27:07Z

Zephyr has currently no flash translation layer implemented. This pull request adds the basic possibility to use Dhara as FTL in Zephyr. It is implemented as disk driver that can be placed between a filesystem and a flash driver. The FTL uses API extensions for bad block management, which are also faked on the flash simulator to facilitate tests.

The Dhara repository shall be moved to the Zephyr organisation as soon as the module is ready for that (#99908, #100834).

github-actions · 2025-12-11T07:28:08Z

The following west manifest projects have changed revision in this Pull Request:

Name	Old Revision	New Revision	Diff
dhara 🆕	N/A (Added)	zephyrproject-rtos/dhara@`6f163ca` (`zephyr`)	N/A

⛔ DNM label due to: 1 added project

Note: This message is automatically posted and updated by the Manifest GitHub Action.

Add extended operations to the flash API to support marking blocks as bad and checking if a block is bad. This is necessary for NAND flash devices, which can have bad blocks that need to be managed. Signed-off-by: Pascal Linder <pascal.linder@zuehlke.com> Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

NAND flash translation layers require the flash extended operations API for bad block management. Add it here without implementation to test an FTL on the flash simulator. Signed-off-by: Pascal Linder <pascal.linder@zuehlke.com>

tpambor · 2026-03-13T18:13:37Z

@de-nordic can the DNM (manifest) be removed?

jfischer-no · 2026-03-16T16:12:06Z

-#define FF_VOLUME_STRS \
-	DT_FOREACH_STATUS_OKAY(zephyr_flash_disk, _FF_DISK_NAME) \
-	DT_FOREACH_STATUS_OKAY(zephyr_ram_disk, _FF_DISK_NAME) \
-	DT_FOREACH_STATUS_OKAY(zephyr_sdmmc_disk, _FF_DISK_NAME) \
-	DT_FOREACH_STATUS_OKAY(zephyr_mmc_disk, _FF_DISK_NAME) \
-	DT_FOREACH_STATUS_OKAY(st_stm32_sdmmc, _FF_DISK_NAME)
+#define FF_VOLUME_STRS                                                                             \
+	DT_FOREACH_STATUS_OKAY(zephyr_flash_disk, _FF_DISK_NAME)                                   \
+	DT_FOREACH_STATUS_OKAY(zephyr_ram_disk, _FF_DISK_NAME)                                     \
+	DT_FOREACH_STATUS_OKAY(zephyr_sdmmc_disk, _FF_DISK_NAME)                                   \
+	DT_FOREACH_STATUS_OKAY(zephyr_mmc_disk, _FF_DISK_NAME)                                     \
+	DT_FOREACH_STATUS_OKAY(st_stm32_sdmmc, _FF_DISK_NAME)                                      \
+	DT_FOREACH_STATUS_OKAY(zephyr_ftl_dhara, _FF_DISK_NAME)


stray changes, have nothing to do with "modules: dhara: Implement Dhara disk driver as Zephyr module"

I have split them off into separate commit.

jfischer-no · 2026-03-16T16:17:22Z

+  buffer-size:
+    type: int
+    required: true
+    description: |
+      Buffer size in bytes for the FTL driver. Must be equal or greater than the page size of the
+      backing flash.
+
+  gc-ratio:
+    type: int
+    default: 15
+    description: |
+      Garbage collection ratio for the FTL driver. This is the ratio of garbage collection
+      operations to real writes when automatic collection is active. Smaller values lead to faster
+      and more predictable input/output at the expense of capacity.


Both properties sound like they are software configurations. Do they need to be configurable per instance, or can they be Kconfig options?

buffer-size is somewhat hardware related as it has to be at least the size of a page of the flash. So, if one has multiple flashes with different page sizes and this is a KConfig one has to set it to the largest and would ovetallocate for the smaller flash. This was the motivation to have it in DT. zephyr,flash-disk has similar properties with cache-size and sector-size. I have no strong opinion here, if a KConfig is preferable, I can change it.

What about gc-ratio does it make sense to be configurable per driver instance?

I have switched gc-ratio to a KConfig. The GC ratio trades off write amplification for available capacity. The capacity for rewritable blocks is the number of pages times 1/(ratio+1), and the write amplification factor is (ratio+1). I don't think this needs to be configured per instance.

Zephyr has currently no flash translation layer implemented. This commit adds the basic possibility to use Dhara as FTL in Zephyr. It is implemented as disk driver that can be placed between a filesystem and a flash driver. Signed-off-by: Pascal Linder <pascal.linder@zuehlke.com> Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

Add disk names for zephyr,ftl-dhara disks to FF_VOLUME_STRS, so that they are available for mounting. Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

Add testcase and corresponding overlay for native_sim to test the FTL (Flash Translation Layer) disk driver. Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

sonarqubecloud · 2026-03-16T23:03:39Z

Quality Gate passed

Issues
17 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

tpambor · 2026-03-18T00:43:50Z

@jfischer-no Please take another look, all comments have been addressed

de-nordic

Looks good. Thanks.

carlescufi · 2026-03-18T10:50:22Z

@tpambor I now added the "Override required" label since this must be merged with override due to a new module being added.

github-actions Bot added manifest manifest-dhara DNM (manifest) This PR should not be merged (controlled by action-manifest) labels Dec 11, 2025

zephyrbot added area: Devicetree Bindings area: Disk Access area: Boards/SoCs area: Tests Issues related to a particular existing or missing test area: MAINTAINER File area: Devicetree area: Storage Storage subsystem area: Flash labels Dec 11, 2025

zephyrbot requested review from MaureenHelm, danieldegrasse, de-nordic, decsny, jfischer-no, mbolivar, nashif, rghaddab, rruuaanng and stephanosio December 11, 2025 07:28

zephyrbot assigned de-nordic Dec 11, 2025

LinderPi mentioned this pull request Dec 11, 2025

flash: spi_nand: initial generic driver #100845

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LinderPi force-pushed the ftl_dhara branch 2 times, most recently from 5459c50 to 246fb9d Compare December 11, 2025 09:40

de-nordic requested changes Dec 11, 2025

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LinderPi force-pushed the ftl_dhara branch from 246fb9d to fb4a695 Compare December 11, 2025 16:03

LinderPi requested a review from de-nordic December 12, 2025 06:28

LinderPi force-pushed the ftl_dhara branch from fb4a695 to 612f6b7 Compare December 17, 2025 13:33

tpambor requested a review from de-nordic March 12, 2026 09:18

tpambor and others added 2 commits March 13, 2026 19:02

drivers: flash: simulator: Add extended operations

75e730e

NAND flash translation layers require the flash extended operations API for bad block management. Add it here without implementation to test an FTL on the flash simulator. Signed-off-by: Pascal Linder <pascal.linder@zuehlke.com>

tpambor force-pushed the ftl_dhara branch from 28ee8c8 to c45868b Compare March 13, 2026 18:02

de-nordic previously approved these changes Mar 13, 2026

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kartben removed the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Mar 15, 2026

tpambor mentioned this pull request Mar 16, 2026

Support flexspi nand on frdm rw612 #104870

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jfischer-no requested changes Mar 16, 2026

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tpambor force-pushed the ftl_dhara branch from c45868b to 54a48f4 Compare March 16, 2026 21:34

github-actions Bot added the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Mar 16, 2026

tpambor removed the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Mar 16, 2026

tpambor added 3 commits March 16, 2026 23:15

modules: fatfs: support ftl disks when generating FF_VOLUME_STRS

6720415

Add disk names for zephyr,ftl-dhara disks to FF_VOLUME_STRS, so that they are available for mounting. Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

tests: drivers: disk: disk_access: add test for ftl disk driver

8815bd3

Add testcase and corresponding overlay for native_sim to test the FTL (Flash Translation Layer) disk driver. Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

tpambor dismissed de-nordic’s stale review via 8815bd3 March 16, 2026 22:28

tpambor force-pushed the ftl_dhara branch from 54a48f4 to 8815bd3 Compare March 16, 2026 22:28

github-actions Bot added the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Mar 16, 2026

tpambor removed the DNM (manifest) This PR should not be merged (controlled by action-manifest) label Mar 16, 2026

tpambor requested review from de-nordic and jfischer-no March 16, 2026 22:34

de-nordic approved these changes Mar 18, 2026

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carlescufi added the Override Required label Mar 18, 2026

jfischer-no approved these changes Mar 18, 2026

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carlescufi removed the Override Required label Mar 18, 2026

MaureenHelm merged commit 02672c5 into zephyrproject-rtos:main Mar 18, 2026
33 of 34 checks passed

tpambor mentioned this pull request Apr 5, 2026

doc: releases: 4.4: Add NAND flash support #106865

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