i2c: expose restart as syscall, add structure for I2C-over-DRTIO

artiq/coredevice/i2c.py

@@ -8,6 +8,11 @@ def i2c_start(busno: TInt32) -> TNone:
     raise NotImplementedError("syscall not simulated")
 
 
+@syscall(flags={"nounwind", "nowrite"})
+def i2c_restart(busno: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
 @syscall(flags={"nounwind", "nowrite"})
 def i2c_stop(busno: TInt32) -> TNone:
     raise NotImplementedError("syscall not simulated")

artiq/firmware/ksupport/api.rs

@@ -118,6 +118,7 @@ static mut API: &'static [(&'static str, *const ())] = &[
     api!(drtio_get_fifo_space_req_count = ::rtio::drtio_dbg::get_fifo_space_req_count),
 
     api!(i2c_start = ::nrt_bus::i2c::start),
+    api!(i2c_restart = ::nrt_bus::i2c::restart),
     api!(i2c_stop = ::nrt_bus::i2c::stop),
     api!(i2c_write = ::nrt_bus::i2c::write),
     api!(i2c_read = ::nrt_bus::i2c::read),

artiq/firmware/ksupport/nrt_bus.rs

@@ -4,21 +4,28 @@ pub mod i2c {
     use kernel_proto::*;
 
     pub extern fn start(busno: i32) {
-        send(&I2cStartRequest { busno: busno as u8 });
+        send(&I2cStartRequest { busno: busno as u32 });
+        recv!(&I2cBasicReply { succeeded } => if !succeeded {
+            raise!("I2CError", "I2C bus could not be accessed");
+        });
+    }
+
+    pub extern fn restart(busno: i32) {
+        send(&I2cRestartRequest { busno: busno as u32 });
         recv!(&I2cBasicReply { succeeded } => if !succeeded {
             raise!("I2CError", "I2C bus could not be accessed");
         });
     }
 
     pub extern fn stop(busno: i32) {
-        send(&I2cStopRequest { busno: busno as u8 });
+        send(&I2cStopRequest { busno: busno as u32 });
         recv!(&I2cBasicReply { succeeded } => if !succeeded {
             raise!("I2CError", "I2C bus could not be accessed");
         });
     }
 
     pub extern fn write(busno: i32, data: i32) -> bool {
-        send(&I2cWriteRequest { busno: busno as u8, data: data as u8 });
+        send(&I2cWriteRequest { busno: busno as u32, data: data as u8 });
         recv!(&I2cWriteReply { succeeded, ack } => {
             if !succeeded {
                 raise!("I2CError", "I2C bus could not be accessed");
@@ -28,7 +35,7 @@ pub mod i2c {
     }
 
     pub extern fn read(busno: i32, ack: bool) -> i32 {
-        send(&I2cReadRequest { busno: busno as u8, ack: ack });
+        send(&I2cReadRequest { busno: busno as u32, ack: ack });
         recv!(&I2cReadReply { succeeded, data } => {
             if !succeeded {
                 raise!("I2CError", "I2C bus could not be accessed");

artiq/firmware/libproto/kernel_proto.rs

@@ -80,11 +80,12 @@ pub enum Message<'a> {
     CachePutRequest { key: &'a str, value: &'a [i32] },
     CachePutReply   { succeeded: bool },
 
-    I2cStartRequest { busno: u8 },
-    I2cStopRequest { busno: u8 },
-    I2cWriteRequest { busno: u8, data: u8 },
+    I2cStartRequest { busno: u32 },
+    I2cRestartRequest { busno: u32 },
+    I2cStopRequest { busno: u32 },
+    I2cWriteRequest { busno: u32, data: u8 },
     I2cWriteReply { succeeded: bool, ack: bool },
-    I2cReadRequest { busno: u8, ack: bool },
+    I2cReadRequest { busno: u32, ack: bool },
     I2cReadReply { succeeded: bool, data: u8 },
     I2cBasicReply { succeeded: bool },
 

artiq/firmware/runtime/kern_hwreq.rs

@@ -1,10 +1,132 @@
 use session::{kern_acknowledge, kern_send};
 use rtio_mgt;
-use board;
 use kernel_proto as kern;
 use std::io;
 use sched::Io;
 
+// TODO
+#[cfg(has_drtio)]
+mod drtio_i2c {
+    pub fn start(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn restart(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn stop(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn write(_busno: u32, _data: u8) -> Result<bool, ()> {
+        Err(())
+    }
+
+    pub fn read(_busno: u32, _ack: bool) -> Result<u8, ()> {
+        Err(())
+    }
+}
+
+#[cfg(not(has_drtio))]
+mod drtio_i2c {
+    pub fn start(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn restart(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn stop(_busno: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn write(_busno: u32, _data: u8) -> Result<bool, ()> {
+        Err(())
+    }
+
+    pub fn read(_busno: u32, _ack: bool) -> Result<u8, ()> {
+        Err(())
+    }
+}
+
+mod i2c {
+    use board;
+    use super::drtio_i2c;
+
+    pub fn start(busno: u32) -> Result<(), ()> {
+        let drtio = busno >> 16;
+        let dev_busno = busno as u8;
+        if drtio == 0 {
+            board::i2c::start(dev_busno)
+        } else {
+            drtio_i2c::start(busno)
+        }
+    }
+
+    pub fn restart(busno: u32) -> Result<(), ()> {
+        let drtio = busno >> 16;
+        let dev_busno = busno as u8;
+        if drtio == 0 {
+            board::i2c::restart(dev_busno)
+        } else {
+            drtio_i2c::restart(busno)
+        }
+    }
+
+    pub fn stop(busno: u32) -> Result<(), ()> {
+        let drtio = busno >> 16;
+        let dev_busno = busno as u8;
+        if drtio == 0 {
+            board::i2c::stop(dev_busno)
+        } else {
+            drtio_i2c::stop(busno)
+        }
+    }
+
+    pub fn write(busno: u32, data: u8) -> Result<bool, ()> {
+        let drtio = busno >> 16;
+        let dev_busno = busno as u8;
+        if drtio == 0 {
+            board::i2c::write(dev_busno, data)
+        } else {
+            drtio_i2c::write(busno, data)
+        }
+    }
+
+    pub fn read(busno: u32, ack: bool) -> Result<u8, ()> {
+        let drtio = busno >> 16;
+        let dev_busno = busno as u8;
+        if drtio == 0 {
+            board::i2c::read(dev_busno, ack)
+        } else {
+            drtio_i2c::read(busno, ack)
+        }
+    }
+}
+
+// TODO
+#[cfg(has_drtio)]
+mod drtio_spi {
+    pub fn set_config(_busno: u32, _flags: u8, _write_div: u8, _read_div: u8) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn set_xfer(_busno: u32, _chip_select: u16, _write_length: u8, _read_length: u8) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn write(_busno: u32, _data: u32) -> Result<(), ()> {
+        Err(())
+    }
+
+    pub fn read(_busno: u32) -> Result<u32, ()> {
+        Err(())
+    }
+}
+
+#[cfg(not(has_drtio))]
 mod drtio_spi {
     pub fn set_config(_busno: u32, _flags: u8, _write_div: u8, _read_div: u8) -> Result<(), ()> {
         Err(())
@@ -99,25 +221,29 @@ pub fn process_kern_hwreq(io: &Io, request: &kern::Message) -> io::Result<bool>
         }
 
         &kern::I2cStartRequest { busno } => {
-            let succeeded = board::i2c::start(busno).is_ok();
+            let succeeded = i2c::start(busno).is_ok();
+            kern_send(io, &kern::I2cBasicReply { succeeded: succeeded })
+        }
+        &kern::I2cRestartRequest { busno } => {
+            let succeeded = i2c::restart(busno).is_ok();
             kern_send(io, &kern::I2cBasicReply { succeeded: succeeded })
         }
         &kern::I2cStopRequest { busno } => {
-            let succeeded = board::i2c::stop(busno).is_ok();
+            let succeeded = i2c::stop(busno).is_ok();
             kern_send(io, &kern::I2cBasicReply { succeeded: succeeded })
         }
         &kern::I2cWriteRequest { busno, data } => {
-            match board::i2c::write(busno, data) {
+            match i2c::write(busno, data) {
                 Ok(ack) => kern_send(io, &kern::I2cWriteReply { succeeded: true, ack: ack }),
                 Err(_) => kern_send(io, &kern::I2cWriteReply { succeeded: false, ack: false })
             }
         }
         &kern::I2cReadRequest { busno, ack } => {
-            match board::i2c::read(busno, ack) {
+            match i2c::read(busno, ack) {
                 Ok(data) => kern_send(io, &kern::I2cReadReply { succeeded: true, data: data }),
                 Err(_) => kern_send(io, &kern::I2cReadReply { succeeded: false, data: 0xff })
             }
-        },
+        }
 
         &kern::SpiSetConfigRequest { busno, flags, write_div, read_div } => {
             let succeeded = spi::set_config(busno, flags, write_div, read_div).is_ok();
@@ -136,7 +262,7 @@ pub fn process_kern_hwreq(io: &Io, request: &kern::Message) -> io::Result<bool>
                 Ok(data) => kern_send(io, &kern::SpiReadReply { succeeded: true, data: data }),
                 Err(_) => kern_send(io, &kern::SpiReadReply { succeeded: false, data: 0 })
             }
-        },
+        }
 
         _ => return Ok(false)
     }.and(Ok(true))