fix drtioaux packet corruption

Co-authored-by: mwojcik <mw@m-labs.hk>
Co-committed-by: mwojcik <mw@m-labs.hk>

src/libboard_artiq/src/drtioaux.rs

@@ -3,6 +3,7 @@ use crc;
 use core_io::{ErrorKind as IoErrorKind, Error as IoError};
 use io::{proto::ProtoRead, proto::ProtoWrite, Cursor};
 use libboard_zynq::{timer::GlobalTimer, time::Milliseconds};
+use libcortex_a9::asm::dmb;
 use crate::mem::mem::DRTIOAUX_MEM;
 use crate::pl::csr::DRTIOAUX;
 use crate::drtioaux_proto::Error as ProtocolError;
@@ -57,14 +58,15 @@ pub fn has_rx_error(linkno: u8) -> bool {
     }
 }
 
-pub fn copy_work_buffer(src: *mut u16, dst: *mut u16, len: isize) {
+pub fn copy_work_buffer(src: *mut u32, dst: *mut u32, len: isize) {
     // AXI writes must be 4-byte aligned (drtio proto doesn't care for that),
     // and AXI burst reads/writes are not implemented yet in gateware
     // thus the need for a work buffer for transmitting and copying it over
     unsafe {
-        for i in (0..(len/2)).step_by(2) {
+        for i in 0..(len/4) {
             *dst.offset(i) = *src.offset(i);
-            *dst.offset(i+1) = *src.offset(i+1);
+            //data memory barrier to prevent bursts
+            dmb();
         }
     }
 }
@@ -75,11 +77,11 @@ fn receive<F, T>(linkno: u8, f: F) -> Result<Option<T>, Error>
     let linkidx = linkno as usize;
     unsafe {
         if (DRTIOAUX[linkidx].aux_rx_present_read)() == 1 {
-            let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2) as *mut u16;
+            let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2) as *mut u32;
             let len = (DRTIOAUX[linkidx].aux_rx_length_read)() as usize;
             // work buffer to accomodate axi burst reads
             let mut buf: [u8; 1024] = [0; 1024];
-            copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u16, len as isize);
+            copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u32, len as isize);
             let result = f(&buf[0..len]);
             (DRTIOAUX[linkidx].aux_rx_present_write)(1);
             Ok(Some(result?))
@@ -133,12 +135,12 @@ fn transmit<F>(linkno: u8, f: F) -> Result<(), Error>
     let linkno = linkno as usize;
     unsafe {
         while (DRTIOAUX[linkno].aux_tx_read)() != 0 {}
-        let ptr = DRTIOAUX_MEM[linkno].base as *mut u16;
+        let ptr = DRTIOAUX_MEM[linkno].base as *mut u32;
         let len = DRTIOAUX_MEM[linkno].size / 2;
         // work buffer, works with unaligned mem access
         let mut buf: [u8; 1024] = [0; 1024]; 
         let len = f(&mut buf[0..len])?;
-        copy_work_buffer(buf.as_mut_ptr() as *mut u16, ptr, len as isize);
+        copy_work_buffer(buf.as_mut_ptr() as *mut u32, ptr, len as isize);
         (DRTIOAUX[linkno].aux_tx_length_write)(len as u16);
         (DRTIOAUX[linkno].aux_tx_write)(1);
         Ok(())

src/libboard_artiq/src/drtioaux_async.rs

@@ -42,11 +42,11 @@ async fn receive<F, T>(linkno: u8, f: F) -> Result<Option<T>, Error>
     let linkidx = linkno as usize;
     unsafe {
         if (DRTIOAUX[linkidx].aux_rx_present_read)() == 1 {
-            let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2) as *mut u16;
+            let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2) as *mut u32;
             let len = (DRTIOAUX[linkidx].aux_rx_length_read)() as usize;
             // work buffer to accomodate axi burst reads
             let mut buf: [u8; 1024] = [0; 1024];
-            copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u16, len as isize);
+            copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u32, len as isize);
             let result = f(&buf[0..len]);
             (DRTIOAUX[linkidx].aux_rx_present_write)(1);
             Ok(Some(result?))
@@ -106,12 +106,12 @@ async fn transmit<F>(linkno: u8, f: F) -> Result<(), Error>
     let linkno = linkno as usize;
     unsafe {
         let _ = block_async!(tx_ready(linkno)).await;
-        let ptr = DRTIOAUX_MEM[linkno].base as *mut u16;
+        let ptr = DRTIOAUX_MEM[linkno].base as *mut u32;
         let len = DRTIOAUX_MEM[linkno].size / 2;
         // work buffer, works with unaligned mem access
         let mut buf: [u8; 1024] = [0; 1024]; 
         let len = f(&mut buf[0..len])?;
-        copy_work_buffer(buf.as_mut_ptr() as *mut u16, ptr, len as isize);
+        copy_work_buffer(buf.as_mut_ptr() as *mut u32, ptr, len as isize);
         (DRTIOAUX[linkno].aux_tx_length_write)(len as u16);
         (DRTIOAUX[linkno].aux_tx_write)(1);
         Ok(())