feat: add SPI NOR flash command layer + spin-based kernel delay

[jinwjinl]

Description

This branch fixes a timing/starvation problem in the SPI NOR Flash command layer. The previous wait_busy polled the status register in a tight loop with no timeout and no yielding, which blocked the SPI bus for the full duration of erase operations (~110 ms per 4 KiB sector, up to ~400 ms for block erase). On a single-core cooperative scheduler this starved any task sharing the bus (LCD, net-stack) and could stall OTA flows. The fix adds a bounded, configurable timeout scheme and splits wait behavior into a yielding variant (for long erase operations) and a spin variant (for short page programs), while keeping all Flash logic userspace-unchanged.

Main changes

Timeout configuration

• Adds SpiFlashTimeouts, a per-device timeout profile covering:
  • page program,
  • sector erase,
  • 32 KiB block erase,
  • 64 KiB block erase,
  • chip erase.
• Adds configured_poll_interval(), reading CONFIG_SPI_FLASH_STATUS_POLL_INTERVAL_US to space status-register polls.
• Adds new_with_timeouts / new_with_poll_interval constructors so a caller can supply an explicit profile; Default resolves to Kconfig values.

The timeouts are defined through Kconfig:

• CONFIG_SPI_FLASH_PAGE_PROGRAM_TIMEOUT_MS
• CONFIG_SPI_FLASH_SECTOR_ERASE_TIMEOUT_MS
• CONFIG_SPI_FLASH_BLOCK_ERASE_32K_TIMEOUT_MS
• CONFIG_SPI_FLASH_BLOCK_ERASE_64K_TIMEOUT_MS
• CONFIG_SPI_FLASH_CHIP_ERASE_TIMEOUT_MS
• CONFIG_SPI_FLASH_STATUS_POLL_INTERVAL_US

Wait-busy strategies

• wait_busy_yield — used for erase operations. Polls the status register between suspend_me_for(Tick(1)) yields so the scheduler can drain other bus clients (LCD / net-stack) during the erase window. Aborts with a timeout error once the per-operation deadline passes.
• wait_busy_spin — used for page program. Tight spin on the status register, no yield, since page programs are short and yielding would only add latency.

Mapping of operations to strategy:

Operation	Wait strategy
page program	wait_busy_spin
sector erase	wait_busy_yield
32 KiB block erase	wait_busy_yield
64 KiB block erase	wait_busy_yield
chip erase	wait_busy_yield

Shared helper

• Adds wait_busy_with as the common deadline + poll loop body, parameterized by a yield hook so the yield/spin variants stay in lockstep and the deadline logic is not duplicated.

Tests

• Adds test_configured_poll_interval asserting the Kconfig-derived interval resolves to Duration::from_micros(CONFIG_SPI_FLASH_STATUS_POLL_INTERVAL_US).
• The existing test_wait_busy_timeout is kept.

[jinwjinl]

build_prs

[github-actions]

Job is started, see https://github.com/vivoblueos/kernel/actions/runs/34340522633.

[github-actions]

❌ Job failed. Failed jobs: build_and_check_boards (failure), see https://github.com/vivoblueos/kernel/actions/runs/34340522633.

[jinwjinl]

build_prs

[github-actions]

Job is started, see https://github.com/vivoblueos/kernel/actions/runs/35575781993.

[github-actions]

✅ All jobs completed successfully, see https://github.com/vivoblueos/kernel/actions/runs/35575781993.