Rename ULL functions callable from LLL context to follow ull_*_lll_* convention

[Copilot]

ULL functions callable from LLL (ISR) context lacked consistent naming to indicate ISR-safety. Renamed 18 functions to include _lll_ infix for immediate identification.

Changes

Function naming pattern:

// Before
void ull_rx_put(memq_link_t *link, void *rx);
struct lll_event *ull_prepare_enqueue(...);
void *ull_event_done(void *param);

// After  
void ull_lll_rx_put(memq_link_t *link, void *rx);
struct lll_event *ull_prepare_lll_enqueue(...);
void *ull_event_lll_done(void *param);

Scope:

• Prepare/Event (7): ull_prepare_enqueue → ull_prepare_lll_enqueue, ull_event_done → ull_event_lll_done, etc.
• RX PDU (5): ull_pdu_rx_alloc* → ull_pdu_lll_rx_alloc*, ull_iso_pdu_rx_alloc* → ull_iso_pdu_lll_rx_alloc*
• RX Sched (5): ull_rx_put → ull_lll_rx_put, ull_rx_sched → ull_lll_rx_sched, ISO variants
• TX ACK (1): ull_iso_tx_ack_dequeue → ull_iso_lll_tx_ack_dequeue

Files modified:

• Declarations: ll_sw/lll.h
• Definitions: ll_sw/ull.c (13), ll_sw/ull_iso.c (4)
• Call sites: 15 Nordic LLL files, 4 OpenISA LLL files, 3 other ll_sw files

Stats: 25 files, 255 insertions, 255 deletions (pure rename)

Rationale

The _lll_ infix makes architectural boundaries explicit in function names, reducing risk of calling non-ISR-safe ULL functions from ISR context.

Original prompt

Refactor ULL Functions Called from LLL Context

Background

In the Zephyr Bluetooth Controller implementation, there is a clear separation between:

• LLL (Lower Link Layer): Runs in interrupt/ISR context
• ULL (Upper Link Layer): Runs in thread/mayfly context

Some ULL functions are designed to be called from the LLL execution context (ISR). To improve code clarity and maintainability, these functions should follow a naming convention that makes it immediately obvious they are LLL-callable: ull_<module>_lll_<function>.

Problem

Currently, many core ULL functions that are called from LLL context do NOT follow this naming convention. This makes it difficult to identify which ULL functions are safe to call from LLL/ISR context.

Functions to Refactor

The following ULL functions are called from LLL context but lack the _lll_ infix (defined in subsys/bluetooth/controller/ll_sw/lll.h):

Prepare/Event Management:

• ull_prepare_enqueue() → ull_prepare_lll_enqueue()
• ull_prepare_dequeue_get() → ull_prepare_lll_dequeue_get()
• ull_prepare_dequeue_iter() → ull_prepare_lll_dequeue_iter()
• ull_prepare_dequeue() → ull_prepare_lll_dequeue()
• ull_event_done_extra_get() → ull_event_lll_done_extra_get()
• ull_done_extra_type_set() → ull_lll_done_extra_type_set()
• ull_event_done() → ull_event_lll_done()

RX PDU Allocation:

• ull_pdu_rx_alloc_peek() → ull_pdu_lll_rx_alloc_peek()
• ull_pdu_rx_alloc_peek_iter() → ull_pdu_lll_rx_alloc_peek_iter()
• ull_pdu_rx_alloc() → ull_pdu_lll_rx_alloc()
• ull_iso_pdu_rx_alloc_peek() → ull_iso_pdu_lll_rx_alloc_peek()
• ull_iso_pdu_rx_alloc() → ull_iso_pdu_lll_rx_alloc()

RX Scheduling:

• ull_rx_put() → ull_lll_rx_put()
• ull_rx_sched() → ull_lll_rx_sched()
• ull_rx_put_sched() → ull_lll_rx_put_sched()
• ull_iso_rx_put() → ull_iso_lll_rx_put()
• ull_iso_rx_sched() → ull_iso_lll_rx_sched()

TX ACK:

• ull_iso_tx_ack_dequeue() → ull_iso_lll_tx_ack_dequeue()

Requirements

1. Rename all identified functions to include _lll_ infix in the name
2. Update all call sites across the codebase (primarily in subsys/bluetooth/controller/ll_sw/)
3. Update function declarations in header files
4. Update function definitions in source files
5. Maintain backward compatibility where necessary (e.g., if functions are part of a stable API)
6. Update any related documentation or comments

Files to Modify

Primary files include:

• subsys/bluetooth/controller/ll_sw/lll.h - Function declarations
• subsys/bluetooth/controller/ll_sw/ull.c - Function definitions
• subsys/bluetooth/controller/ll_sw/ull_iso.c - ISO-specific functions
• All LLL implementation files in subsys/bluetooth/controller/ll_sw/nordic/lll/ and subsys/bluetooth/controller/ll_sw/openisa/lll/
• Any other files that call these functions

Success Criteria

1. All ULL functions called from LLL context follow the ull_*_lll_* naming convention
2. Code compiles without errors or warnings
3. No functional changes - this is a pure refactoring
4. All existing tests pass

Notes

• This is part of a larger code quality improvement effort to make the codebase more maintainable
• The refactoring should preserve all existing functionality
• Focus on clarity and consistency in naming

This pull request was created from Copilot chat.

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