From fa74d1a6e10b8a3d05f94ca876a5cccf515b5c34 Mon Sep 17 00:00:00 2001
From: HiFiPhile <admin@hifiphile.com>
Date: Thu, 11 Dec 2025 23:18:34 +0100
Subject: [PATCH] dcd/rusb2: fix fifo write

Signed-off-by: HiFiPhile <admin@hifiphile.com>
---
 src/portable/renesas/rusb2/dcd_rusb2.c | 27 +++++++++++++++++---------
 src/tusb_option.h                      |  2 +-
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/portable/renesas/rusb2/dcd_rusb2.c b/src/portable/renesas/rusb2/dcd_rusb2.c
index 786b8d980..779c7bc3d 100644
--- a/src/portable/renesas/rusb2/dcd_rusb2.c
+++ b/src/portable/renesas/rusb2/dcd_rusb2.c
@@ -213,17 +213,26 @@ static void pipe_write_packet_ff(rusb2_reg_t * rusb, tu_fifo_t *f, volatile void
   tu_fifo_buffer_info_t info;
   tu_fifo_get_read_info(f, &info);
 
-  uint16_t count = tu_min16(total_len, info.linear.len);
-  pipe_write_packet(rusb, info.linear.ptr, fifo, count);
+  uint16_t cnt_lin = tu_min16(total_len, info.linear.len);
+  uint16_t cnt_wrap = tu_min16(total_len - cnt_lin, info.wrapped.len);
+  uint16_t const cnt_written = cnt_lin + cnt_wrap;
 
-  uint16_t rem = total_len - count;
-  if (rem) {
-    rem = tu_min16(rem, info.wrapped.len);
-    pipe_write_packet(rusb, info.wrapped.ptr, fifo, rem);
-    count += rem;
+  // Ensure only the last write is odd if total_len is odd
+  if (cnt_wrap == 0) {
+    pipe_write_packet(rusb, info.linear.ptr, fifo, cnt_lin);
+  } else {
+    pipe_write_packet(rusb, info.linear.ptr, fifo, cnt_lin & ~1);
+
+    if (cnt_lin & 1) {
+      uint8_t glue[2] = {info.linear.ptr[cnt_lin & ~1], info.wrapped.ptr[0]};
+      pipe_write_packet(rusb, glue, fifo, 2);
+      cnt_wrap--;
+      info.wrapped.ptr++;
+    }
+
+    pipe_write_packet(rusb, info.wrapped.ptr, fifo, cnt_wrap);
   }
-
-  tu_fifo_advance_read_pointer(f, count);
+  tu_fifo_advance_read_pointer(f, cnt_written);
 }
 
 // Read data sw fifo <-- hw fifo
diff --git a/src/tusb_option.h b/src/tusb_option.h
index be954e01a..b4acee035 100644
--- a/src/tusb_option.h
+++ b/src/tusb_option.h
@@ -361,7 +361,7 @@
 
 //------------ RUSB2 --------------//
 #if defined(TUP_USBIP_RUSB2)
-  #define CFG_TUD_EDPT_DEDICATED_HWFIFO 0 // need testing to enable
+  #define CFG_TUD_EDPT_DEDICATED_HWFIFO 1
 #endif
 
 //--------------------------------------------------------------------