aux: increase max payload size

README.md

@@ -62,7 +62,7 @@ Notes:
 License
 -------
 
-Copyright (C) 2019-2023 M-Labs Limited.
+Copyright (C) 2019-2024 M-Labs Limited.
 
 ARTIQ is free software: you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as published by

src/libboard_artiq/src/drtioaux.rs

@@ -77,9 +77,8 @@ where F: FnOnce(&[u8]) -> Result<T, Error> {
             let read_ptr = (DRTIOAUX[linkidx].aux_read_pointer_read)() as usize;
             let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2 + read_ptr * 0x400) as *mut u32;
             // work buffer to accomodate axi burst reads
-            // buffer at maximum proto packet size, not maximum gateware supported size
-            // to minimize copying time
-            const LEN: usize = 512;
+            // potentially: get length by checking the first byte to cut down on unnecessary copying
+            const LEN: usize = 1024;
             let mut buf: [u8; LEN] = [0; LEN];
             copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u32, LEN as isize);
             let result = f(&buf);

src/libboard_artiq/src/drtioaux_async.rs

@@ -41,9 +41,8 @@ where F: FnOnce(&[u8]) -> Result<T, Error> {
             let read_ptr = (DRTIOAUX[linkidx].aux_read_pointer_read)() as usize;
             let ptr = (DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2 + read_ptr * 0x400) as *mut u32;
             // work buffer to accomodate axi burst reads
-            // buffer at maximum proto packet size, not maximum gateware supported size
-            // to minimize required copying time
-            const LEN: usize = 512;
+            // potentially: get length by checking the first byte to cut down on unnecessary copying
+            const LEN: usize = 1024;
             let mut buf: [u8; LEN] = [0; LEN];
             copy_work_buffer(ptr, buf.as_mut_ptr() as *mut u32, LEN as isize);
             let result = f(&buf);

src/libboard_artiq/src/drtioaux_proto.rs

@@ -3,7 +3,7 @@ use io::proto::{ProtoRead, ProtoWrite};
 
 // maximum size of arbitrary payloads
 // used by satellite -> master analyzer, subkernel exceptions
-pub const SAT_PAYLOAD_MAX_SIZE: usize  = /*max size*/512 - /*CRC*/4 - /*packet ID*/1 - /*last*/1 - /*length*/2;
+pub const SAT_PAYLOAD_MAX_SIZE: usize  = /*max size*/1024 - /*CRC*/4 - /*packet ID*/1 - /*last*/1 - /*length*/2;
 // used by DDMA, subkernel program data (need to provide extra ID and destination)
 pub const MASTER_PAYLOAD_MAX_SIZE: usize = SAT_PAYLOAD_MAX_SIZE - /*source*/1 - /*destination*/1 - /*ID*/4;