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Added STM32F1 RTC peripheral #176

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202 changes: 202 additions & 0 deletions src/Emulator/Peripherals/Peripherals/Timers/STM32F1_RTC.cs
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// Made from scratch by Gissio (C)-2025:
// * Implements STM32F1 RTC peripheral
// * Second and alarm interrupts
// * Prescaler handling

using System.Collections.Generic;

using Antmicro.Renode.Core;
using Antmicro.Renode.Core.Structure.Registers;
using Antmicro.Renode.Logging;
using Antmicro.Renode.Peripherals.Bus;
using Antmicro.Renode.Time;

namespace Antmicro.Renode.Peripherals.Timers
{
[AllowedTranslations(AllowedTranslation.ByteToDoubleWord | AllowedTranslation.WordToDoubleWord)]
public sealed class STM32F1_RTC : IDoubleWordPeripheral, IKnownSize, IProvidesRegisterCollection<DoubleWordRegisterCollection>
{
public STM32F1_RTC(IMachine machine, long frequency = DefaultFrequency) : base()
{
IRQ = new GPIO();

eventTimer = new LimitTimer(machine.ClockSource, frequency, this, nameof(eventTimer),
1, direction: Direction.Ascending, enabled: true, eventEnabled: true, divider: 0x4000);
eventTimer.LimitReached += UpdateTimer;

var registersMap = new Dictionary<long, DoubleWordRegister>
{
{(long)Registers.ControlHigh, new DoubleWordRegister(this)
.WithFlag(0, out secondsInterruptEnable, FieldMode.Read | FieldMode.Write, name: "SECIE")
.WithFlag(1, out alarmInterruptEnable, FieldMode.Read | FieldMode.Write, name: "ALRIE")
.WithFlag(2, name: "OWIE")
.WithReservedBits(3, 29)
},
{(long)Registers.ControlLow, new DoubleWordRegister(this)
.WithFlag(0, FieldMode.Read | FieldMode.WriteOneToClear,
writeCallback: (_, value) =>
{
secondsInterruptFlag = value;
UpdateInterruptFlags();
}, valueProviderCallback: _ => secondsInterruptFlag, name: "SECF")
.WithFlag(1, FieldMode.Read | FieldMode.WriteOneToClear,
writeCallback: (_, value) =>
{
alarmInterruptFlag = false;
UpdateInterruptFlags();
}, valueProviderCallback: _ => alarmInterruptFlag, name: "ALRF")
.WithFlag(2, FieldMode.Read | FieldMode.WriteOneToClear, name: "OWF")
.WithFlag(3, FieldMode.Read,
valueProviderCallback: _ => true, name: "RSF")
.WithFlag(4, name: "CNF")
.WithFlag(5, FieldMode.Read,
valueProviderCallback: _ => true, name: "RTOFF")
.WithReservedBits(6, 26)
},
{(long)Registers.PrescalerLoadHigh, new DoubleWordRegister(this)
.WithValueField(0, 4,
writeCallback: (_, value) =>
{
prescalerDivider = (prescalerDivider & 0x0ffff) | ((uint)value << 16);
eventTimer.Divider = (int)(prescalerDivider + 1);
}, valueProviderCallback: _ => ((prescalerDivider & 0xf0000) >> 16), name: "PRLH")
.WithReservedBits(4, 28)
},
{(long)Registers.PrescalerLoadLow, new DoubleWordRegister(this, 0x8000)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
prescalerDivider = (prescalerDivider & 0xf0000) | ((uint)value << 0);
eventTimer.Divider = (int)(prescalerDivider + 1);
},
valueProviderCallback: _ => (prescalerDivider & 0x0ffff) >> 0, name: "PRLL")
},
{(long)Registers.PrescalerDividerHigh, new DoubleWordRegister(this)
.WithValueField(0, 4,
writeCallback: (_, value) =>
{
prescalerCounter = (prescalerCounter & 0x0ffff) | ((uint)value << 16);
},
valueProviderCallback: _ => (prescalerCounter & 0xf0000) >> 16, name: "DIVH")
.WithReservedBits(4, 28)
},
{(long)Registers.PrescalerDividerLow, new DoubleWordRegister(this)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
prescalerCounter = (prescalerCounter & 0xf0000) | ((uint)value << 0);
},
valueProviderCallback: _ => (prescalerCounter & 0x0ffff) >> 0, name: "DIVL")
},
{(long)Registers.CounterHigh, new DoubleWordRegister(this)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
counter = (counter & 0x0000ffff) | ((uint)value << 16);
},
valueProviderCallback: _ => (counter & 0xffff0000) >> 16, name: "CNTH")
},
{(long)Registers.CounterLow, new DoubleWordRegister(this)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
counter = (counter & 0xffff0000) | ((uint)value << 0);
},
valueProviderCallback: _ => (counter & 0x0000ffff) >> 0, name: "CNTL")
},
{(long)Registers.AlarmHigh, new DoubleWordRegister(this)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
alarm = (alarm & 0x0000ffff) | ((uint)value << 16);
},
valueProviderCallback: _ => (alarm & 0xffff0000) >> 16, name: "ALRH")
},
{(long)Registers.AlarmLow, new DoubleWordRegister(this)
.WithValueField(0, 32,
writeCallback: (_, value) =>
{
alarm = (alarm & 0xffff0000) | ((uint)value << 0);
},
valueProviderCallback: _ => (alarm & 0x0000ffff) >> 0, name: "ALRL")
},
};

RegistersCollection = new DoubleWordRegisterCollection(this, registersMap);
}

public uint ReadDoubleWord(long offset)
{
return RegistersCollection.Read(offset);
}

public void WriteDoubleWord(long offset, uint value)
{
RegistersCollection.Write(offset, value);
}

public void Reset()
{
RegistersCollection.Reset();
eventTimer.Reset();
IRQ.Unset();
}

private void UpdateTimer()
{
counter++;
secondsInterruptFlag = true;

if (counter == alarm)
{
alarmInterruptFlag = true;
}

UpdateInterruptFlags();
}

private void UpdateInterruptFlags()
{
var state = false;

state |= secondsInterruptFlag && secondsInterruptEnable.Value;
state |= alarmInterruptFlag && alarmInterruptEnable.Value;

IRQ.Set(state);
}

public long Size => 0x400;

private const long DefaultFrequency = 32768;
private const int DefaultPrescalerDivider = 0x8000;

public DoubleWordRegisterCollection RegistersCollection { get; }

private readonly LimitTimer eventTimer;

public GPIO IRQ { get; }

private IFlagRegisterField secondsInterruptEnable;
private bool secondsInterruptFlag;
private IFlagRegisterField alarmInterruptEnable;
private bool alarmInterruptFlag;
private uint prescalerDivider;
private uint prescalerCounter;
private uint counter;
private uint alarm;

private enum Registers
{
ControlHigh = 0x0,
ControlLow = 0x4,
PrescalerLoadHigh = 0x8,
PrescalerLoadLow = 0xC,
PrescalerDividerHigh = 0x10,
PrescalerDividerLow = 0x14,
CounterHigh = 0x18,
CounterLow = 0x1C,
AlarmHigh = 0x20,
AlarmLow = 0x24,
}
}
}