feat(adaption): 添加自适应控制模块实现DE域自适应算法

- 实现了AGC自动增益控制，带PI控制器实现增益调节
- 实现了DFE决策反馈均衡器权值更新，支持LMS、Sign-LMS和NLMS算法
- 添加采样器阈值和迟滞窗的自适应调整功能
- 增加CDR相位PI控制器，实现相位闭环调节
- 支持多速率调度，快路径和慢路径分离处理
- 实现冻结检测与快照回滚确保安全稳定性
- 提供完整接口端口及参数配置结构
- 完成模块内部状态初始化、周期性更新与重置信号处理

Author: LewisLiuLiuLiu

include/ams/adaption.h

@@ -0,0 +1,271 @@
+#ifndef SERDES_AMS_ADAPTION_H
+#define SERDES_AMS_ADAPTION_H
+
+#include <systemc>
+#include <vector>
+#include "common/parameters.h"
+
+namespace serdes {
+
+/**
+ * @brief AdaptionDe - DE Domain Adaptive Control Module
+ * 
+ * This module implements the adaptive control algorithms for SerDes link:
+ * - AGC (Automatic Gain Control) with PI controller
+ * - DFE tap update (LMS/Sign-LMS/NLMS algorithms)
+ * - Threshold adaptation
+ * - CDR PI controller
+ * 
+ * Features:
+ * - Multi-rate scheduling: fast path (CDR PI, threshold) and slow path (AGC, DFE)
+ * - Safety mechanisms: freeze on error, rollback to snapshot
+ * - Parameter clamping and rate limiting
+ */
+class AdaptionDe : public sc_core::sc_module {
+public:
+    // ========================================================================
+    // Input Ports (from RX/CDR/System)
+    // ========================================================================
+    sc_core::sc_in<double> phase_error;       // Phase error from CDR (s or normalized UI)
+    sc_core::sc_in<double> amplitude_rms;     // Amplitude RMS from RX amplitude statistics
+    sc_core::sc_in<int> error_count;          // Error count from Sampler decision errors
+    sc_core::sc_in<double> isi_metric;        // ISI metric (optional, for DFE strategy)
+    sc_core::sc_in<int> mode;                 // Operating mode: 0=init, 1=training, 2=data, 3=freeze
+    sc_core::sc_in<bool> reset;               // Global reset signal
+    sc_core::sc_in<double> scenario_switch;   // Scenario switch event (optional)
+    
+    // ========================================================================
+    // Output Ports (to RX/CDR)
+    // ========================================================================
+    sc_core::sc_out<double> vga_gain;         // VGA gain setting (linear)
+    sc_core::sc_out<double> ctle_zero;        // CTLE zero frequency (Hz, optional)
+    sc_core::sc_out<double> ctle_pole;        // CTLE pole frequency (Hz, optional)
+    sc_core::sc_out<double> ctle_dc_gain;     // CTLE DC gain (linear, optional)
+    
+    // DFE taps (fixed 8 independent ports)
+    sc_core::sc_out<double> dfe_tap1;
+    sc_core::sc_out<double> dfe_tap2;
+    sc_core::sc_out<double> dfe_tap3;
+    sc_core::sc_out<double> dfe_tap4;
+    sc_core::sc_out<double> dfe_tap5;
+    sc_core::sc_out<double> dfe_tap6;
+    sc_core::sc_out<double> dfe_tap7;
+    sc_core::sc_out<double> dfe_tap8;
+    
+    sc_core::sc_out<double> sampler_threshold;    // Sampler threshold (V)
+    sc_core::sc_out<double> sampler_hysteresis;   // Sampler hysteresis (V)
+    sc_core::sc_out<double> phase_cmd;            // Phase interpolator command (s)
+    sc_core::sc_out<int> update_count;            // Update counter for diagnostics
+    sc_core::sc_out<bool> freeze_flag;            // Freeze/rollback status flag
+    
+    // ========================================================================
+    // Constructor and Process Declaration
+    // ========================================================================
+    SC_HAS_PROCESS(AdaptionDe);
+    
+    /**
+     * @brief Constructor
+     * @param nm Module name
+     * @param params Adaption parameters
+     */
+    AdaptionDe(sc_core::sc_module_name nm, const AdaptionParams& params);
+    
+    /**
+     * @brief Destructor
+     */
+    ~AdaptionDe();
+    
+    // ========================================================================
+    // Public Methods for External Access
+    // ========================================================================
+    
+    /**
+     * @brief Get current AGC gain
+     */
+    double get_current_gain() const { return m_current_gain; }
+    
+    /**
+     * @brief Get current DFE taps
+     */
+    const double* get_dfe_taps() const { return m_dfe_taps; }
+    
+    /**
+     * @brief Get update count
+     */
+    int get_update_count() const { return m_update_count; }
+    
+    /**
+     * @brief Check if frozen
+     */
+    bool is_frozen() const { return m_freeze_flag; }
+    
+private:
+    // ========================================================================
+    // Parameters
+    // ========================================================================
+    AdaptionParams m_params;
+    
+    // ========================================================================
+    // Internal State Variables
+    // ========================================================================
+    // AGC state
+    double m_agc_integral;          // PI controller integral term
+    double m_current_gain;          // Current VGA gain
+    double m_prev_gain;             // Previous gain (for rate limiting)
+    
+    // DFE state
+    double m_dfe_taps[8];           // Fixed 8 DFE taps
+    double m_dfe_history[8];        // Decision history for feedback
+    
+    // CDR PI state
+    double m_cdr_integral;          // PI controller integral term
+    double m_current_phase_cmd;     // Current phase command
+    
+    // Threshold state
+    double m_current_threshold;     // Current sampler threshold
+    double m_current_hysteresis;    // Current hysteresis window
+    int m_prev_error_count;         // Previous error count for trend detection
+    
+    // Update tracking
+    int m_update_count;             // Total update count
+    int m_fast_update_count;        // Fast path update count
+    int m_slow_update_count;        // Slow path update count
+    bool m_freeze_flag;             // Freeze flag
+    
+    // Snapshot structure for rollback
+    struct Snapshot {
+        double vga_gain;
+        double dfe_taps[8];
+        double threshold;
+        double hysteresis;
+        double phase_cmd;
+        sc_core::sc_time timestamp;
+        bool valid;
+        
+        Snapshot() : vga_gain(0), threshold(0), hysteresis(0), 
+                     phase_cmd(0), valid(false) {
+            for (int i = 0; i < 8; ++i) dfe_taps[i] = 0;
+        }
+    };
+    std::vector<Snapshot> m_snapshots;
+    sc_core::sc_time m_last_snapshot_time;
+    
+    // Timing
+    sc_core::sc_time m_fast_period;
+    sc_core::sc_time m_slow_period;
+    
+    // ========================================================================
+    // SC_METHOD/SC_THREAD Processes
+    // ========================================================================
+    
+    /**
+     * @brief Fast path update process (CDR PI + threshold adaptation)
+     * Called at fast_update_period interval
+     */
+    void fast_path_process();
+    
+    /**
+     * @brief Slow path update process (AGC + DFE tap update)
+     * Called at slow_update_period interval
+     */
+    void slow_path_process();
+    
+    /**
+     * @brief Reset handler process
+     * Triggered by reset signal
+     */
+    void reset_process();
+    
+    // ========================================================================
+    // Algorithm Implementation Methods
+    // ========================================================================
+    
+    /**
+     * @brief AGC PI controller update
+     * @param amplitude Current amplitude RMS
+     * @return Updated gain value
+     */
+    double agc_pi_update(double amplitude);
+    
+    /**
+     * @brief DFE LMS algorithm update
+     * @param error Decision error
+     */
+    void dfe_lms_update(double error);
+    
+    /**
+     * @brief DFE Sign-LMS algorithm update
+     * @param error Decision error
+     */
+    void dfe_sign_lms_update(double error);
+    
+    /**
+     * @brief DFE NLMS algorithm update
+     * @param error Decision error
+     */
+    void dfe_nlms_update(double error);
+    
+    /**
+     * @brief Threshold adaptation update
+     * @param error_count Current error count
+     * @return Updated threshold value
+     */
+    double threshold_adapt(int error_count);
+    
+    /**
+     * @brief CDR PI controller update
+     * @param phase_err Phase error input
+     * @return Updated phase command
+     */
+    double cdr_pi_update(double phase_err);
+    
+    // ========================================================================
+    // Safety and Helper Methods
+    // ========================================================================
+    
+    /**
+     * @brief Check for freeze conditions
+     * @return true if should freeze
+     */
+    bool check_freeze_condition();
+    
+    /**
+     * @brief Save current parameters to snapshot
+     */
+    void save_snapshot();
+    
+    /**
+     * @brief Rollback to last valid snapshot
+     * @return true if rollback successful
+     */
+    bool rollback_to_snapshot();
+    
+    /**
+     * @brief Clamp value to range
+     */
+    double clamp(double val, double min_val, double max_val) const;
+    
+    /**
+     * @brief Sign function
+     */
+    double sign(double val) const;
+    
+    /**
+     * @brief Write all DFE tap outputs
+     */
+    void write_dfe_outputs();
+    
+    /**
+     * @brief Initialize all internal states
+     */
+    void initialize_state();
+    
+    /**
+     * @brief Write all outputs with current state
+     */
+    void write_all_outputs();
+};
+
+} // namespace serdes
+
+#endif // SERDES_AMS_ADAPTION_H