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DmaLinuxGpioPort.cs
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DmaLinuxGpioPort.cs
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using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Threading;
using Mono.Unix.Native;
using RobotSharp.Gpio;
using RobotSharp.Gpio.SoftwarePwm;
using RobotSharp.Tools;
using System.Threading.Tasks;
namespace RobotSharp.Pi2Go.Gpio
{
public class DmaLinuxGpioPort : IGpioPort
{
private readonly IOperatingSystemService operatingSystemService;
private readonly SoftwarePwm softwarePwm;
private const int BCM2708_PERI_BASE_DEFAULT = 536870912; //0x2000000;
private const int GPIO_BASE_OFFSET = 2097152; // = 0x20000;
private const int PAGE_SIZE = 4 * 1024;
private const int BLOCK_SIZE = 4 * 1024;
private const int FSEL_OFFSET = 0; // 0x0000
private const int SET_OFFSET = 7; // 0x001c / 4
private const int CLR_OFFSET = 10; // 0x0028 / 4
private const int PINLEVEL_OFFSET = 13; // 0x0034 / 4
private const int PULLUPDN_OFFSET = 37; // 0x0094 / 4
private const int PULLUPDNCLK_OFFSET = 38; // 0x0098 / 4
private const int INPUT = 1; // is really 0 for control register!
private const int OUTPUT = 0; // is really 1 for control register!
private const int PUD_OFF = 0;
private const int PUD_DOWN = 1;
private const int PUD_UP = 2;
private const int HIGH = 1;
private const int LOW = 0;
private const string DevMemFilePath = "/dev/mem";
private const string DeviceTreePath = "/proc/device-tree/soc/ranges";
private const string DeviceTreeAccessMode = "rb";
private IntPtr gpioMap;
private int devMemFileDescriptor;
private bool setup;
public DmaLinuxGpioPort(IOperatingSystemService operatingSystemService)
{
this.operatingSystemService = operatingSystemService;
softwarePwm = new SoftwarePwm(operatingSystemService, this);
}
public void Setup()
{
if (setup) return;
// get file descriptor for /dev/mem
devMemFileDescriptor = Syscall.open(DevMemFilePath, OpenFlags.O_RDWR | OpenFlags.O_SYNC);
var gpioMem = Stdlib.malloc(BLOCK_SIZE + (PAGE_SIZE - 1));
var gpioMemInt = gpioMem.ToInt32();
if ((gpioMemInt % PAGE_SIZE) == 1)
gpioMem = IntPtr.Add(gpioMem, PAGE_SIZE - (gpioMemInt % PAGE_SIZE));
var periBase = GetPeriBase();
var gpioBase = (periBase == 0 ? BCM2708_PERI_BASE_DEFAULT : periBase) + GPIO_BASE_OFFSET;
gpioMap = Syscall.mmap(gpioMem, BLOCK_SIZE, MmapProts.PROT_READ | MmapProts.PROT_WRITE,
MmapFlags.MAP_SHARED, devMemFileDescriptor, gpioBase);
setup = true;
}
public unsafe void Setup(int pin, Direction direction, PullUpDown pullUpDown)
{
var gpioMapPtr = (int*)gpioMap;
var offset = FSEL_OFFSET + (pin / 10);
var shift = (pin % 10) * 3;
SetPullUpDown(gpioMapPtr, pin, pullUpDown);
if (direction == Direction.Output)
*(gpioMapPtr + offset) = (*(gpioMapPtr + offset) & ~(7 << shift)) | (1 << shift);
else
*(gpioMapPtr + offset) = (*(gpioMapPtr + offset) & ~(7 << shift));
}
public unsafe void Output(int pin, HighLow value, long duration = -1)
{
// calculate offset
var offset =
value == HighLow.High
? SET_OFFSET + (pin / 32)
: CLR_OFFSET + (pin / 32);
// get unsafe base map pointer
var basePtr = (int*)gpioMap;
// write value to memory at (base + offset)
*(basePtr + offset) = 1 << (pin % 32);
if (duration != -1)
operatingSystemService.NanoSleep(duration);
}
public void Output(IEnumerable<GpioPortOperation> operations)
{
if (operations == null) throw new ArgumentNullException("operations");
foreach (var operation in operations)
Output(operation.Pin, operation.Value, operation.Duration);
}
public unsafe HighLow Input(int pin)
{
var basePtr = (int*)gpioMap;
var offset = PINLEVEL_OFFSET + (pin / 32);
var mask = (1 << pin % 32);
var value = *(basePtr + offset) & mask;
return value == HIGH ? HighLow.High : HighLow.Low;
}
private unsafe int GetPinDirection(int pin)
{
var gpioMapPtr = (int*)gpioMap;
var offset = FSEL_OFFSET + (pin / 10);
var shift = (pin % 10) * 3;
var value = *(gpioMapPtr + offset);
value >>= shift;
value &= 7;
// possible value for input : 0=input, 1=output, 4=alt0
return value;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static unsafe void SetPullUpDown(int* gpioMapPtr, int gpio, PullUpDown pud)
{
var clkOffset = PULLUPDNCLK_OFFSET + (gpio / 32);
var shift = (gpio % 32);
if (pud == PullUpDown.Down)
*(gpioMapPtr + PULLUPDN_OFFSET) = (*(gpioMapPtr + PULLUPDN_OFFSET) & ~3) | PUD_DOWN;
else if (pud == PullUpDown.Up)
*(gpioMapPtr + PULLUPDN_OFFSET) = (*(gpioMapPtr + PULLUPDN_OFFSET) & ~3) | PUD_UP;
else
*(gpioMapPtr + PULLUPDN_OFFSET) &= ~3;
Thread.SpinWait(150);
*(gpioMapPtr + clkOffset) = 1 << shift;
Thread.SpinWait(150);
*(gpioMapPtr + PULLUPDN_OFFSET) &= ~3;
*(gpioMapPtr + clkOffset) = 0;
}
private static int GetPeriBase()
{
var fp = Stdlib.fopen(DeviceTreePath, DeviceTreeAccessMode);
if (fp == IntPtr.Zero) return 0;
var buf = new byte[4];
// get peri base from device tree
Stdlib.fseek(fp, 4, SeekFlags.SEEK_SET);
var periBase = 0;
if (Stdlib.fread(buf, 1, (ulong)buf.Length, fp) == (ulong)buf.Length)
periBase = buf[0] << 24 | buf[1] << 16 | buf[2] << 8 | buf[3] << 0;
Stdlib.fclose(fp);
return periBase;
}
~DmaLinuxGpioPort()
{
Dispose(false);
}
private bool disposed;
protected void Dispose(bool disposing)
{
if (disposed) return;
if (!setup)
{
disposed = true;
return;
}
if (disposing)
{
// dispose managed resources
}
// dispose unmanaged resources
// unmap memory mapped file from /dev/mem from current process address space
Syscall.munmap(gpioMap, BLOCK_SIZE);
// release file descriptor for /dev/mem
Syscall.close(devMemFileDescriptor);
setup = false;
disposed = true;
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
public void StartPwm(int pin)
{
softwarePwm.StartPwm(pin);
}
public void ControlPwm(int pin, float? frequency, float? dutyCycle)
{
softwarePwm.ControlPwm(pin, frequency, dutyCycle);
}
public void StopPwm(int pin)
{
softwarePwm.StopPwm(pin);
}
#region dummy async implementations
public async Task SetupAsync(int pin, Direction direction, PullUpDown pullUpDown)
{
Setup(pin, direction, pullUpDown);
}
public async Task OutputAsync(int pin, HighLow value, long duration = -1)
{
Output(pin, value, duration);
}
public async Task OutputAsync(IEnumerable<GpioPortOperation> operations)
{
Output(operations);
}
public async Task<HighLow> InputAsync(int pin)
{
return Input(pin);
}
public async Task StartPwmAsync(int pin)
{
StartPwm(pin);
}
public async Task ControlPwmAsync(int pin, float? frequency, float? dutyCycle)
{
ControlPwm(pin, frequency, dutyCycle);
}
public async Task StopPwmAsync(int pin)
{
StopPwm(pin);
}
#endregion
}
}