hidden fields are not handled on write only register

[krcb197]

PeakRDL Python allows some instance names to be hidden, e.g. RSVD.

The write_fields method of a Write Only Register forces all fields in a register to execute a single write, which is needed as a read-modify-write is not possible and generally write only registers have hardware actions associated with them. The function signature of the write_fields method needs to have all currently accessible fields as arguments

Consider the following system rdl:

addrmap reserved_elements {
        reg  {
        default sw = w;
        default hw = r;
        field { fieldwidth=1; } RSVD;
        field { fieldwidth=1; } field_a;
    } write_only_register;

When this is exported with hidden_inst_name_regex set to None, the following will be generated:

    def write_fields(self,RSVD : int,field_a : int) -> None: # type: ignore[override]
        """
        Do a write to the register, updating all fields
        """
        reg_value = 0

        reg_value &= self.RSVD.inverse_bitmask
        reg_value |= self.RSVD._encode_write_value(RSVD)
        
        reg_value &= self.field_a.inverse_bitmask
        reg_value |= self.field_a._encode_write_value(field_a)
        
        self.write(reg_value)

However, when the hidden_inst_name_regex set to "(?:[\w_\[\]]+\.)+RSVD", the following will be generated:

    def write_fields(self,field_a : int) -> None: # type: ignore[override]
        """
        Do a write to the register, updating all fields
        """
        reg_value = 0       

        reg_value &= self.field_a.inverse_bitmask
        reg_value |= self.field_a._encode_write_value(field_a)
        
        self.write(reg_value)

This is not the case

The problem is that the template was using the children iterator from the underlying the system rdl compiler and not the filtered version.