drivers/wireless/cc1101: Add MSK/4-FSK, dynamic PATABLE ramping, and fix IOCTL safety

[AuroraRAS]

Summary

This PR introduces a comprehensive refactoring and stabilization of the CC1101 wireless character driver. It aligns the driver's software logic with the physical hardware state machine defined in the Texas Instruments specifications (DN013/SWRA151A), ensuring safe cross-band operation and robust IOCTL memory safety.

Key Modifications:

• Modulation Support: Extended ioctl.h to include WLIOC_MSK and WLIOC_4FSK. Implemented strict hardware constraint checks in WLIOC_SETMODU (e.g., rejecting MSK if baud rate <= 26 kBaud, enforcing Manchester coding exclusions).
• Dynamic PA Ramping: Deprecated static rfsettings->PA logic. Introduced a frequency-aware g_cc1101_pa_calibration matrix to dynamically reconstruct the PATABLE via Burst Access. This natively resolves ASK/OOK pulse truncation and minimizes FSK adjacent-channel splatter.
• Standardized TX Power: WLIOC_SETTXPOWER and WLIOC_GETTXPOWER now strictly operate on dBm units (as defined by ioctl.h) using a quantized nearest-match algorithm, abandoning the arbitrary 0-8 indexing.
• Math & Overflow Safety: Implemented hard clamping for mantissa calculations in WLIOC_FSK_SETBITRATE (256-511) and WLIOC_FSK_SETFDEV (8-15) to prevent silent register wrap-around under extreme input parameters.
• Kernel Memory Safety: Replaced uncompiled DEBUGASSERT checks with strict if (ptr == NULL) return -EFAULT; validations across all IOCTL branches to prevent user-space-triggered segmentation faults.
• Low-Power Reliability: Added a mandatory PATABLE reconstruction call inside cc1101_powerup() to fix the known hardware issue where indices 1-7 are lost during SLEEP state.

Impact

• Is new feature added? Yes. MSK and 4-FSK modulation.
• Is existing feature changed? Yes. WLIOC_SETTXPOWER now accepts dBm instead of raw index values.
• Impact on Build: None.
• Impact on Hardware: Significantly improves RF spectral purity and communication stability across diverse frequency bands (315/433/868/915 MHz).

Testing

I confirm that changes are verified locally.

• Build Host: Fedora 43

• Target Architecture: Xtensa / ESP32 (Hardware setup featuring dual CC1101 transceivers and an nRF24L01, EvilCrowRF-V2 layout).

• Testing Methods & Results:

  • IOCTL Parameter & Clamping Verification: Successfully validated the full suite of standard IOCTLs (WLIOC_SETRADIOFREQ, WLIOC_SETTXPOWER, WLIOC_SETMODU, WLIOC_FSK_SETBITRATE, WLIOC_FSK_SETFDEV) on both /dev/radio0 and /dev/radio1. The mathematical saturation and clamping logic proved accurate against the hardware limits (e.g., configuring a 250,000 bps target bitrate cleanly quantized to an actual 249,938 bps; 47,000 Hz target FDEV quantized to 44,433 Hz).
  • Cross-Band RF Validation: Executed bidirectional TX/RX payload verification and 100-packet throughput stress tests across all four primary ISM bands to guarantee the new dynamic PATABLE generator adapts correctly to WLIOC_SETRADIOFREQ calls:
    • 315 MHz & 433 MHz: Achieved near-perfect reliability with 98%–100% packet delivery rates and throughputs peaking at ~3.95 KB/s (31.5 kbps).
    • 868 MHz & 915 MHz: Payload verification passed successfully in both directions. Stress tests completed with delivery rates ranging from 54% to 91%, handling the dynamic frequency shifts without state machine lockups.
  • Driver Coexistence / Regression:
    Confirmed that the SPI bus and IOCTL interface behavior for other wireless drivers on the same hardware (/dev/nrf24l01) remain completely unaffected by the CC1101 IOCTL architecture changes.