Add support for Raspberry Pi Pico 2 flash controller.

[hanan619]

The original Pico uses an SSI flash controller, which already has support
in Zephyr. The Pico 2 uses a different QMI flash controller. This PR adds
QMI controller support to Zephyr:

• Added QMI controller implementation in flash_rpi_pico.c
• Enabled the flash controller node in rp2350.dtsi

[ajf58]

@hanan619 it looks like you've copied code directly from the Pico SDK. This is not permitted: the Pico SDK is under the BSD 3-Clause, and Zephyr is Apache 2.0

[ajf58]

I'd like to have some clarification about the provenance of the changes before reviewing further.

[hanan619]

I'd like to have some clarification about the provenance of the changes before reviewing further.

I’d like to point out that the existing RP2040 (Pico1) flash implementation in Zephyr also follows the Pico SDK and includes direct references to its source. My implementation for RP2350 (Pico2) continues this approach for consistency across Raspberry Pi platforms.
Regarding licensing: the Pico SDK is under the BSD-3-Clause license, which is permissive and compatible with Apache 2.0, provided proper attribution is given. Since Zephyr already contains BSD-licensed contributions (such as the RP2040 code), I believe this implementation does not introduce a new licensing concern.
To make this even clearer, I updated the attribution comment in the code to explicitly cite the relevant sources used for RP2350, including:
• pico-bootrom for generic flash logic
• pico-bootrom-rp2350 for RP2350-specific logic
• and the pico-sdk flash code
Given that the RP2040 driver follows this same pattern and was accepted, I believe the same should apply to RP2350.
Please let me know if you would prefer the attribution comment be adjusted further to meet Zephyr’s contribution guidelines more explicitly.

[ajf58]

I’d like to point out that the existing RP2040 (Pico1) flash implementation in Zephyr also follows the Pico SDK and includes direct references to its source.

This https://github.com/zephyrproject-rtos/zephyr/pull/89182/files#diff-5b63ca534e31287da5b9512b307ebf0a52703e12edb4bece40956c0c2bef0b48R2-R3 certainly is a little concerning: Raspberry Pi haven't offered up anything under Apache 2.0 . Re-labelling Raspberry Pi's BSD 3-Clause as Apache 2.0 is not permitted. I'll raise this concern in an issue, and edit this message with a link to it here.

My implementation for RP2350 (Pico2) continues this approach for consistency across Raspberry Pi platforms.

I don't ascribe to a mindset of "everyone else is misbehaving, so I'll misbehave too." I wasn't a reviewer of the previous code, so my focus is brought to this here.

Regarding licensing: the Pico SDK is under the BSD-3-Clause license, which is permissive and compatible with Apache 2.0, provided proper attribution is given.

1. Proper attribution hasn't been given: clause 1 of the BSD 3 Clause (emphasis mine):

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

That list of conditions (and/or the reference to the code being released under BSD 3 Clause.

2. The Zephyr project has its own rules/policies regarding mixing in code released under different licences.

Please let me know if you would prefer the attribution comment be adjusted further to meet Zephyr’s contribution guidelines more explicitly.

Thanks, I think it's best for some of the more experienced reviewers to comment on this. @henrikbrixandersen , I think you've contirbuted feedback on similar licencing terms, would you be able to comment?

[kartben]

From https://docs.zephyrproject.org/latest/contribute/guidelines.html#licensing:
Importing code into the Zephyr OS from other projects that use a license other than the Apache 2.0 license needs to be fully understood in context and approved by the Zephyr governing board.

Can't your contribution just be (your) Zephyr glue code around code being pulled from the pico-sdk zephyr module?

[hanan619]

Partial writes are not supported in pico-sdk. Therefore someone has added partial_write implementation in zephyr flash for rp2040.
I think we can remove the partial write support for both rp2040 and rp2350 and let the pico-sdk team add proper support in bootrom repo.
There is already an issue raised and work in progress for this task
raspberrypi/pico-sdk#1169

[soburi]

@hanan619

It seems that the check was missed in the original code, so we need to consider how to deal with it.

Here, the request is to move the HAL-derived sources to https://github.com/zephyrproject-rtos/hal_rpi_pico rather than https://github.com/raspberrypi/pico-sdk

so there is no problem with putting the zephyr-specific modification, and no required upstreaming.

I think it is possible to move the HAL-derived sources and their modifications from here to

https://github.com/zephyrproject-rtos/hal_rpi_pico/tree/zephyr/src/rp2_common/hardware_flash.

[hanan619]

the zephyr-specific modification, and n

I have created a PR in hal_rpi_pico for the desired changes.
zephyrproject-rtos/hal_rpi_pico#11

[github-actions]

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

Name	Old Revision	New Revision	Diff
hal_rpi_pico	zephyrproject-rtos/hal_rpi_pico@7b57b24 (zephyr)	zephyrproject-rtos/hal_rpi_pico#11	zephyrproject-rtos/hal_rpi_pico#11/files

⛔ DNM label due to: 1 project with PR revision

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

[hanan619]

From https://docs.zephyrproject.org/latest/contribute/guidelines.html#licensing: Importing code into the Zephyr OS from other projects that use a license other than the Apache 2.0 license needs to be fully understood in context and approved by the Zephyr governing board.

Can't your contribution just be (your) Zephyr glue code around code being pulled from the pico-sdk zephyr module?

I have updated the PR.
Moved partial write changes to hal_rpi_pico and linked them to zephyr

[sonarqubecloud]

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

[hanan619]

Please assign someone to PR zephyrproject-rtos/hal_rpi_pico#11