arm_vgic 0.5.0

ARM Virtual Generic Interrupt Controller (VGIC) implementation.
Documentation 
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// Copyright 2025 The Axvisor Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use ax_errno::AxResult;
use axdevice_base::{AccessWidth, BaseDeviceOps, DeviceAddrRange, EmuDeviceType};
use axvm_types::GuestPhysAddrRange;

use crate::vgic::Vgic;

impl BaseDeviceOps<GuestPhysAddrRange> for Vgic {
    /// Gets the emulator type of the current device.
    ///
    /// This function returns the emulator device type of the current instance. Specifically, it always returns `EmuDeviceType::EmuDeviceTGicdV2`,
    /// indicating that the emulator device is of type `EmuDeviceTGicdV2`.
    ///
    /// # Returns
    /// - Returns an instance of the `EmuDeviceType` enum, representing the specific type of the emulator device.
    fn emu_type(&self) -> EmuDeviceType {
        EmuDeviceType::InterruptController
    }

    /// Returns the address range for the device.
    ///
    /// This function defines the address range accessible to the device, starting from `0x800_0000`,
    /// with a length of `0x10000` (64KB). It is used to specify where the device can read or write in memory.
    ///
    /// # Returns
    /// An `AddrRange` instance representing the address range from `0x800_0000` to `0x800_FFFF`.
    fn address_range(&self) -> GuestPhysAddrRange {
        GuestPhysAddrRange::from_start_size(0x800_0000.into(), 0x10000)
    }

    /// Handles memory read operations.
    ///
    /// Based on the given physical address and read width, performs the corresponding read operation.
    /// Supports reading 1 byte, 2 bytes, and 4 bytes. This function dereferences the provided physical
    /// address and calls the specific read function based on the width parameter.
    ///
    /// Parameters:
    /// - `addr`: The physical address to read from.
    /// - `width`: The width of the data to be read, determining the size of the read operation.
    ///
    /// Returns:
    /// - `AxResult<usize>`: The result of the read operation, including any errors and the size of the data read.
    fn handle_read(
        &self,
        addr: <GuestPhysAddrRange as DeviceAddrRange>::Addr,
        width: AccessWidth,
    ) -> AxResult<usize> {
        // Perform bitwise operation to ensure the address is aligned to byte boundaries
        let addr = addr.as_usize() & 0xfff;

        // Match different read operations based on the width parameter
        match width {
            AccessWidth::Byte => {
                // Handle 1-byte read
                self.handle_read8(addr)
            }
            AccessWidth::Word => {
                // Handle 2-byte read
                self.handle_read16(addr)
            }
            AccessWidth::Dword => {
                // Handle 4-byte read
                self.handle_read32(addr)
            }
            // Return success for unsupported widths without performing any operation
            _ => Ok(0),
        }
    }
    /// Handles write operations of different widths.
    ///
    /// This function performs a write operation based on the given physical address, width, and value.
    /// It first converts the physical address to a `usize` and applies a mask to ensure proper alignment.
    /// Then, depending on the width parameter, it calls the corresponding write handling function.
    ///
    /// Parameters:
    /// - `addr`: The physical address to write to.
    /// - `width`: The byte width of the data to be written (1, 2, 4 for 8-bit, 16-bit, and 32-bit data respectively).
    /// - `val`: The value to be written.
    fn handle_write(
        &self,
        addr: <GuestPhysAddrRange as DeviceAddrRange>::Addr,
        width: AccessWidth,
        val: usize,
    ) -> AxResult {
        // Convert the physical address to a `usize` and apply a mask to ensure proper alignment
        let addr = addr.as_usize() & 0xfff;

        // Depending on the width parameter, perform the corresponding write operation
        match width {
            AccessWidth::Byte => {
                // Handle 8-bit write operation
                self.handle_write8(addr, val);
                Ok(())
            }
            AccessWidth::Word => {
                // Handle 16-bit write operation
                self.handle_write16(addr, val);
                Ok(())
            }
            AccessWidth::Dword => {
                // Handle 32-bit write operation
                self.handle_write32(addr, val);
                Ok(())
            }
            // For other width values, do nothing
            _ => Ok(()),
        }
    }
}