Add external flash support and dual-bank flash swap functionality for PSoC6 devices by Pushyanth-Infineon · Pull Request #700 · wolfSSL/wolfBoot

Pushyanth-Infineon · 2026-02-26T22:11:36Z

Description

Add external flash support and dual-bank flash swap functionality for PSoC6 devices.
Removed NVM_FLASH_WRITEONCE restriction for PSoC6 devices.
Update flash hal functions of PSoC6 to support read-modify-erase-write way to perform the programming of flash

Testing

Tested using CY8CPROTO-062-4343W with the project: https://github.com/Pushyanth-Infineon/mtb-example-wolfboot-tpm

Usage:

Import the project into ModusToolbox IDE using project-creator.
Switch to master branch in wolfssl submodule which have fix for includes in wolfcrypt psoc6 port:

    cd ../mtb_shared/wolfboot/wolfboot-psoc6/lib/wolfssl
    git switch master
    git pull origin

Program the bootloader and main application using ModusToolbox.

Checklist

added tests
updated/added doxygen
updated appropriate READMEs
Updated manual and documentation

Copilot

Pull request overview

This PR adds external flash support and dual-bank flash swap functionality for PSoC6 devices, along with enhanced flash programming capabilities using a read-modify-erase-write approach.

Changes:

Removed NVM_FLASH_WRITEONCE restriction to enable flexible flash programming
Added external QSPI flash support with SFDP-based configuration and temporary sector management
Implemented dual-bank flash swap for hardware-assisted firmware updates
Enhanced internal flash operations with optimized erase size selection (sector/subsector/row)

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
hal/psoc6.c	Core implementation of external flash, dual-bank swap, and enhanced flash HAL functions
docs/Targets.md	Documentation for new external flash and dual-bank features
config/examples/cypsoc6.config	Updated default configuration with NVM_FLASH_WRITEONCE=0 and fixed swap address

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dgarske · 2026-02-27T18:47:05Z

Okay to test. Contributor agreement on file. Over to @danielinux to review.

danielinux

Thanks for this contribution! A couple of minor things:

check the return value of ext_flash_read() as described in docs/HAL.md
it looks like the content of the temp sector is never restored at the end of ext_flash_write()

danielinux · 2026-03-03T08:46:15Z

hal/psoc6.c

+    }
+
+    offset = address - base_address;
+    return Cy_SMIF_MemRead(SMIF0, smif_blk_config->memConfig[0], offset, data,


looks like SMIF might be returning a status (0 for success) here? Double check that ext_flash_read eventually returns the number of bytes transferred to data, not 0, on success.

Updated to return the number of bytes read from the external flash.

danielinux · 2026-03-03T09:01:05Z

hal/psoc6.c

+
+    /* Write the row data */
+    status = Cy_SMIF_MemWrite(SMIF0, smif_blk_config->memConfig[0],
+                              address - base_address, data, len, &smif_context);


Only the new data is written to the source sector, but the "remaining" backup data from the temp sector seems to never be copied back to the source sector after erase.

The rows before the written data, or after data + len, in the same sector, should be restored with their original values in tmp_sector

ext_flash_write is implemented to ensure same sector is not erased each time the row is programmed. The algorithm is as follows:

Read recovery marker — load tmp_sector_info from emulated EEPROM; check if magic is valid and sector_address matches the current write's sector.

If no valid marker (first write into this sector):

Erase EEPROM marker.

Erase SWAP_TMP_SECTOR_ADDR.

Copy entire source sector → SWAP_TMP_SECTOR_ADDR, one row at a time.

Write magic + sector address to EEPROM (power-fail checkpoint).

Erase the source sector.

If valid marker (subsequent rows in same sector):

Source sector is already erased from step 3 — skip backup and erase entirely.

Read each target row; if any is not all 0xFF, erase the source sector and stop checking.

This handles the edge case where the source sector was partially re-written before a second write call to the same sector.

Program the row — write len bytes to address via Cy_SMIF_MemWrite.

The sector backup + erase (step 2) is done once per sector. Subsequent writes to the same sector skip directly to step 4, avoiding redundant erase cycles. ext_flash_read transparently redirects reads for the active sector to SWAP_TMP_SECTOR_ADDR, preserving data integrity. ext_flash_lock clears the EEPROM marker when all writes to the sector are complete.

danielinux · 2026-03-03T09:12:20Z

hal/psoc6.c

+ * @param data    Pointer to destination buffer
+ * @param len     Number of bytes to read (must be > 0)
+ *
+ * @return 0 on success, -1 on invalid parameters, or SMIF error code on failure


Please follow the API and return len on success

Updated to return the number bytes instead of success or failure.

… PSoC6 devices. Removed NVM_FLASH_WRITEONCE restriction for psoc6. Update flash hal functions to support read-modify-erase-write way to perform the programming of flash.

danielinux requested a review from Copilot February 27, 2026 16:38

Copilot AI reviewed Feb 27, 2026

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Copilot started reviewing on behalf of danielinux February 27, 2026 17:17 View session

dgarske assigned danielinux Feb 27, 2026

dgarske assigned wolfSSL-Bot Feb 27, 2026

danielinux requested changes Mar 3, 2026

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danielinux assigned Pushyanth-Infineon and unassigned wolfSSL-Bot Mar 3, 2026

Pushyanth-Infineon force-pushed the psoc6_extflash_dualbank_support branch from 07505a1 to 53d6227 Compare March 3, 2026 17:47

Add external flash support and dual-bank flash swap functionality for…

46ed900

… PSoC6 devices. Removed NVM_FLASH_WRITEONCE restriction for psoc6. Update flash hal functions to support read-modify-erase-write way to perform the programming of flash.

Pushyanth-Infineon force-pushed the psoc6_extflash_dualbank_support branch from 53d6227 to 46ed900 Compare March 3, 2026 19:57

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Add external flash support and dual-bank flash swap functionality for PSoC6 devices#700

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Pushyanth-Infineon commented Feb 26, 2026

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