Add config_models.py file for Pydantic validation

Author: robtaylor

chipflow_lib/config_models.py

@@ -0,0 +1,79 @@
+# SPDX-License-Identifier: BSD-2-Clause
+import enum
+import re
+from typing import Dict, List, Optional, Union, Literal, Any
+
+from pydantic import BaseModel, Field, model_validator, ValidationInfo, field_validator
+
+from .platforms.utils import Process
+
+
+class PadConfig(BaseModel):
+    """Configuration for a pad in chipflow.toml."""
+    type: Literal["io", "i", "o", "oe", "clock", "reset", "power", "ground"]
+    loc: str
+
+    @model_validator(mode="after")
+    def validate_loc_format(self):
+        """Validate that the location is in the correct format."""
+        if not re.match(r"^[NSWE]?[0-9]+$", self.loc):
+            raise ValueError(f"Invalid location format: {self.loc}, expected format: [NSWE]?[0-9]+")
+        return self
+    
+    @classmethod
+    def validate_pad_dict(cls, v: dict, info: ValidationInfo):
+        """Custom validation for pad dicts from TOML that may not have all fields."""
+        if isinstance(v, dict):
+            # Handle legacy format - if 'type' is missing but should be inferred from context
+            if 'loc' in v and 'type' not in v:
+                if info.field_name == 'power':
+                    v['type'] = 'power'
+                    
+            # Map legacy 'clk' type to 'clock' to match our enum
+            if 'type' in v and v['type'] == 'clk':
+                v['type'] = 'clock'
+                
+            return v
+        return v
+
+
+class SiliconConfig(BaseModel):
+    """Configuration for silicon in chipflow.toml."""
+    process: Process
+    package: Literal["caravel", "cf20", "pga144"]
+    pads: Dict[str, PadConfig] = {}
+    power: Dict[str, PadConfig] = {}
+    debug: Optional[Dict[str, bool]] = None
+    
+    @field_validator('pads', 'power', mode='before')
+    @classmethod
+    def validate_pad_dicts(cls, v, info: ValidationInfo):
+        """Pre-process pad dictionaries to handle legacy format."""
+        if isinstance(v, dict):
+            result = {}
+            for key, pad_dict in v.items():
+                # Apply the pad validator with context about which field we're in
+                validated_pad = PadConfig.validate_pad_dict(pad_dict, info)
+                result[key] = validated_pad
+            return result
+        return v
+
+
+class StepsConfig(BaseModel):
+    """Configuration for steps in chipflow.toml."""
+    silicon: str
+
+
+class ChipFlowConfig(BaseModel):
+    """Root configuration for chipflow.toml."""
+    project_name: Optional[str] = None
+    top: Dict[str, Any] = {}
+    steps: StepsConfig
+    silicon: SiliconConfig
+    clocks: Optional[Dict[str, str]] = None
+    resets: Optional[Dict[str, str]] = None
+
+
+class Config(BaseModel):
+    """Root configuration model for chipflow.toml."""
+    chipflow: ChipFlowConfig