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use crate::architecture::arm::{
ArmError, DapAccess, FullyQualifiedApAddress, RegisterParseError,
ap::{AccessPortType, ApAccess, ApRegAccess, ApRegister, CFG, define_ap_register},
};
use super::{AddressIncrement, DataSize};
/// Memory AP
///
/// The memory AP can be used to access a memory-mapped
/// set of debug resources of the attached system.
#[derive(Debug)]
pub struct AmbaAxi3Axi4 {
address: FullyQualifiedApAddress,
csw: CSW,
cfg: CFG,
}
impl AmbaAxi3Axi4 {
/// Creates a new AmbaAhb5Hprot with `address` as base address.
pub fn new<P: DapAccess>(
probe: &mut P,
address: FullyQualifiedApAddress,
) -> Result<Self, ArmError> {
let csw = probe.read_raw_ap_register(&address, CSW::ADDRESS)?;
let cfg = probe.read_raw_ap_register(&address, CFG::ADDRESS)?;
let (csw, cfg) = (csw.try_into()?, cfg.try_into()?);
let me = Self { address, csw, cfg };
let csw = CSW {
DbgSwEnable: true,
Privileged: true,
AddrInc: AddressIncrement::Single,
..me.csw
};
probe.write_ap_register(&me, csw)?;
Ok(Self { csw, ..me })
}
}
impl super::MemoryApType for AmbaAxi3Axi4 {
type CSW = CSW;
fn status<P: ApAccess + ?Sized>(&mut self, probe: &mut P) -> Result<CSW, ArmError> {
const { assert!(crate::architecture::arm::ap::CSW::ADDRESS == CSW::ADDRESS) };
self.csw = probe.read_ap_register(self)?;
Ok(self.csw)
}
fn try_set_datasize<P: ApAccess + ?Sized>(
&mut self,
probe: &mut P,
data_size: DataSize,
) -> Result<(), ArmError> {
match data_size {
DataSize::U8 | DataSize::U16 | DataSize::U32 if data_size != self.csw.Size => {
let csw = CSW {
Size: data_size,
..self.csw
};
probe.write_ap_register(self, csw)?;
self.csw = csw;
}
DataSize::U64 | DataSize::U128 | DataSize::U256 if data_size != self.csw.Size => {
if !self.has_large_data_extension() {
return Err(ArmError::UnsupportedTransferWidth(
data_size.to_byte_count() * 8,
));
}
let csw = CSW {
Size: data_size,
..self.csw
};
probe.write_ap_register(self, csw)?;
// MEM-AP Large Data Extension:
// "If the CSW.Size field is written with a value corresponding to a size that is not
// supported, or with a reserved value:
// • A read of the field returns a value corresponding to a supported size."
//
// So read back CSW to see if the extended size is actually supported.
self.csw = probe.read_ap_register(self)?;
if csw.Size != self.csw.Size {
return Err(ArmError::UnsupportedTransferWidth(
data_size.to_byte_count() * 8,
));
}
}
_ => {}
}
Ok(())
}
fn has_large_address_extension(&self) -> bool {
self.cfg.LA
}
fn has_large_data_extension(&self) -> bool {
self.cfg.LD
}
fn supports_only_32bit_data_size(&self) -> bool {
// Amba AHB5 must support word, half-word and byte size transfers.
false
}
}
impl AccessPortType for AmbaAxi3Axi4 {
fn ap_address(&self) -> &FullyQualifiedApAddress {
&self.address
}
}
impl ApRegAccess<CSW> for AmbaAxi3Axi4 {}
super::attached_regs_to_mem_ap!(memory_ap_regs => AmbaAxi3Axi4);
define_ap_register!(
/// Control and Status Word register
///
/// The control and status word register (CSW) is used
/// to configure memory access through the memory AP.
name: CSW,
address: 0x00,
fields: [
/// Is debug software access enabled.
DbgSwEnable: bool, // [31]
Instruction: bool, // [30]
/// Is the transaction request non-secure
///
/// - If 1 a non-secure transfer is initiated.
/// - If 0 and SPIDEN is 1 then a secure transfer is initiated.
/// - If 0 and SPIDEN is 0 then no transaction is initiated.
NonSecure: bool, // [29]
/// Is this transaction privileged
Privileged: bool, // [28]
/// Drives `AxCACHE[3:0]` where x is R for reads and W for writes.
/// Amba AXI4 requires asymmetrical usage of `ARCACHE` and `AWCACHE`.
CACHE: u8, // [27:24]
/// Secure Debug Enabled.
///
/// This bit reflects the state of the CoreSight authentication signal.
SPIDEN: bool, // [23]
/// A transfer is in progress.
/// Can be used to poll whether an aborted transaction has completed.
/// Read only.
TrInProg: bool, // [7]
/// `1` if transactions can be issued through this access port at the moment.
/// Read only.
DeviceEn: bool, // [6]
/// The address increment on DRW access.
AddrInc: AddressIncrement, // [5:4]
/// The access size of this memory AP.
Size: DataSize, // [2:0]
/// Reserved bit, kept to preserve IMPLEMENTATION DEFINED statuses.
_reserved_bits: u32 // mask
],
from: value => Ok(CSW {
DbgSwEnable: ((value >> 31) & 0x01) != 0,
Instruction: ((value >> 30) & 0x01) != 0,
NonSecure: ((value >> 29) & 0x01) != 0,
Privileged: ((value >> 28) & 0x01) != 0,
CACHE: ((value >> 24) & 0xF) as u8,
SPIDEN: ((value >> 23) & 0x01) != 0,
TrInProg: ((value >> 7) & 0x01) != 0,
DeviceEn: ((value >> 6) & 0x01) != 0,
AddrInc: AddressIncrement::from_u8(((value >> 4) & 0x03) as u8).ok_or_else(|| RegisterParseError::new("CSW", value))?,
Size: DataSize::try_from((value & 0x07) as u8).map_err(|_| RegisterParseError::new("CSW", value))?,
_reserved_bits: value & 0x007F_FF08,
}),
to: value => (u32::from(value.DbgSwEnable) << 31)
| (u32::from(value.Instruction ) << 30)
| (u32::from(value.NonSecure ) << 29)
| (u32::from(value.Privileged ) << 28)
| (u32::from(value.CACHE ) << 24)
| (u32::from(value.SPIDEN ) << 23)
| (u32::from(value.TrInProg ) << 7)
| (u32::from(value.DeviceEn ) << 6)
| (u32::from(value.AddrInc as u8) << 4)
| (value.Size as u32)
| value._reserved_bits
);