data_collection: OTA over SMP/UDP, and use the upstream RPi camera shield

[rosterloh]

Draft: blocked on rosterloh/zephyr-drivers. west.yml pins rosterloh-drivers to main, and this app now needs the board's 360 MHz CPU fix, the corrected PSRAM size and the csi_* shield labels, plus the CSI receiver driver. CI will fail until rosterloh/zephyr-drivers#28 and the CSI PR merge and main advances. Mark ready after that.

MCUboot works on this board after all

The last attempt concluded that MCUboot could not run on the ESP32-P4-Nano because it is a rev v1.3 engineering sample — the ROM loaded the second-stage bootloader corrupt and it panicked with an illegal instruction before reaching the application, and this reproduced on Espressif's own esp32p4_function_ev_board.

That was an upstream software bug, not a silicon limitation, and Espressif fixed it:

adc3d53fd33  soc: esp32p4: Fix MCUboot RAM layout on rev 1.3   (Raffael Rostagno, Espressif)

  Pre-v3 P4 puts the 2nd-stage bootloader in low SRAM (below 0x4ff3abd0),
  not at the top of the app region like v3.x. [...] Fixes MCUboot startup
  crash on rev 1.3.

Corroborating: Espressif's in-tree waveshare_esp32p4_eth board also selects SOC_ESP32P4_REV_1_3 and defaults BOOTLOADER_MCUBOOT=y. MCUboot on pre-v3 P4 is upstream-supported now.

So the README section telling readers OTA was impossible on this hardware is deleted and OTA is enabled.

Revert-capable OTA, not just OTA

soc/espressif/Kconfig.sysbuild overrides the generic sysbuild default with default MCUBOOT_MODE_OVERWRITE_ONLY if SOC_FAMILY_ESPRESSIF_ESP32, so relying on defaults gives overwrite-only: the uploaded image replaces slot0 permanently, image test is indistinguishable from image confirm, and a bad image bricks the board until someone reflashes over USB. Wrong trade for a device whose purpose is being managed over the network, so sysbuild.conf selects swap-using-move explicitly.

Verified end to end on hardware

Over SMP/UDP against the board at a DHCP address, both paths:

Step	Result
image upload (359932 B)	~78 KiB/s, 4 s
image test <hash> + reset	slot0 new image active (unconfirmed), slot1 old confirmed
reset without confirming	reverted to the old image, active confirmed
image confirm <hash> + reset	new image active confirmed, persists

Boot chain:

I (soc_init): MCUboot 2nd stage bootloader
I (soc_init): chip revision: v1.3
I (boot): Loading image 0 - slot 0 from flash, area id: 2
*** Booting Zephyr OS build v4.4.0-10994-gcee159bb557d ***

Camera: use the upstream shield

Zephyr ships boards/shields/raspberry_pi_camera_module_2 for exactly the IMX219 module this board's CSI connector accepts, so the hand-rolled 61-line board overlay was reimplementing an upstream file. Deleted; the shield now supplies the imx219@10 node, endpoint wiring and chosen zephyr,camera. SHIELD is set in CMakeLists.txt rather than left to the caller, because the camera is part of this application and the poe app task has no --shield passthrough.

Two gotchas documented

• mcumgr image confirm with no hash fails against this firmware with Error: 3 and changes nothing; passing the running image's hash works. The request is rejected at img_mgmt_state.c:833 before reaching the confirm logic.
• The DHCP address is effectively never logged. main.c registers the NET_EVENT_IPV4_ADDR_ADD callback ~10.6 s in, but the lease lands just after link-up at ~2.7 s, so the event fires with nobody listening. Documented, not fixed — the fix is to also read the current address at startup.

Not fixed here

CSI capture still fails at runtime with Failed to dequeue frame (-11) / video_esp32_csi: DW-GDMA error status 0x40000000. Pre-existing, unchanged by this work, tracked separately.

🤖 Generated with Claude Code

[rosterloh]

Unblocked: rosterloh/zephyr-drivers#28 and #29 have both merged, so rosterloh-drivers main now carries the 360 MHz CPU fix, the corrected 32 MB PSRAM size, the csi_* shield labels and the CSI receiver driver.

Re-verified against the merged pins rather than local branches, after poe west-update (which also advanced Zephyr cee159bb557 → 3a6406439c5):

• poe app data_collection --sysbuild builds clean, shield picked up (-- Shield(s): raspberry_pi_camera_module_2)
• flashed both domains and booted:

I (soc_init): MCUboot 2nd stage bootloader
I (boot): Loading image 0 - slot 0 from flash, area id: 2
I (hex_psram): density      : 0x07 (256 Mbit)
<inf> phy_mii: PHY (1) ID 2430C54
*** Booting Zephyr OS build v4.4.0-11199-g3a6406439c5a ***