From c4c0535afd94a2d75f4d44c5c149c5e6759050bf Mon Sep 17 00:00:00 2001
From: Sekhar Musunuri <85009537+moose73@users.noreply.github.com>
Date: Thu, 6 Nov 2025 15:01:46 -0800
Subject: [PATCH] Update dma.py

Bugfix: add start to array.physical_address
---
 pynq/lib/dma.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pynq/lib/dma.py b/pynq/lib/dma.py
index 90997c59d..c388f0c15 100644
--- a/pynq/lib/dma.py
+++ b/pynq/lib/dma.py
@@ -127,7 +127,7 @@ def transfer(self, array, start=0, nbytes=0):
         array : ContiguousArray
             An contiguously allocated array to be transferred
         start : int
-             Offset into array to start. Default is 0.
+             Byte offset into array to start. Default is 0.
         nbytes : int
              Number of bytes to transfer. Default is 0.
 
@@ -344,7 +344,7 @@ def transfer(self, array, start=0, nbytes=0, cyclic=False):
         array : ContiguousArray
             An contiguously allocated array to be transferred
         start : int
-             Offset into array to start. Default is 0.
+             Byte offset into array to start. Default is 0.
         nbytes : int
              Number of bytes to transfer. Default is 0.
         cyclic : bool
@@ -414,7 +414,7 @@ def transfer(self, array, start=0, nbytes=0, cyclic=False):
             remain -= d_len
 
             # Buffer address (64-bit)
-            self._descr[i, 2] = (array.physical_address + (i * blk_size)) & 0xFFFFFFFF
+            self._descr[i, 2] = (array.physical_address + start + (i * blk_size)) & 0xFFFFFFFF
             self._descr[i, 3] = (
                 (array.physical_address + start + (i * blk_size)) >> 32
             ) & 0xFFFFFFFF