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commit d50c41dbd93baced3faa774cfbbfab6de61ef5f7 Author: p-szafonimateusz <[email protected]> AuthorDate: Wed Jun 10 15:13:27 2026 +0200 drivers/can/ctucanfd_pci.c: fix unaligned MMIO writes to TX data registers. The TX data loops wrote each payload byte to a 32-bit register at a byte-incrementing offset, issuing unaligned 32-bit MMIO. ARM64 raises an alignment fault so nothing transmits. Pack 4 bytes per word-aligned write instead. Signed-off-by: p-szafonimateusz <[email protected]> --- drivers/can/ctucanfd_pci.c | 45 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 9 deletions(-) diff --git a/drivers/can/ctucanfd_pci.c b/drivers/can/ctucanfd_pci.c index ba9399ff118..2e555dc4aff 100644 --- a/drivers/can/ctucanfd_pci.c +++ b/drivers/can/ctucanfd_pci.c @@ -651,10 +651,19 @@ static int ctucanfd_chrdev_send(FAR struct can_dev_s *dev, bytes = MIN(msg->cm_hdr.ch_dlc, CAN_MAX_DLEN); } - for (i = 0; i < bytes; i++) + /* Pack bytes into aligned register writes and pad the final word. */ + + for (i = 0; i < bytes; i += 4) { - ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, - msg->cm_data[i]); + regval = (uint32_t)msg->cm_data[i]; + regval |= (uint32_t)(i + 1 < bytes ? msg->cm_data[i + 1] : 0) + << 8; + regval |= (uint32_t)(i + 2 < bytes ? msg->cm_data[i + 2] : 0) + << 16; + regval |= (uint32_t)(i + 3 < bytes ? msg->cm_data[i + 3] : 0) + << 24; + + ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, regval); } /* Set TX ready */ @@ -1170,10 +1179,19 @@ static int ctucanfd_sock_transmit(FAR struct netdev_lowerhalf_s *dev, ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_TSL, 0); ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_TSU, 0); - for (i = 0; i < frame->can_dlc; i++) + /* Pack bytes into aligned register writes and pad the final word. */ + + for (i = 0; i < frame->can_dlc; i += 4) { - ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, - frame->data[i]); + regval = (uint32_t)frame->data[i]; + regval |= (uint32_t)(i + 1 < frame->can_dlc ? + frame->data[i + 1] : 0) << 8; + regval |= (uint32_t)(i + 2 < frame->can_dlc ? + frame->data[i + 2] : 0) << 16; + regval |= (uint32_t)(i + 3 < frame->can_dlc ? + frame->data[i + 3] : 0) << 24; + + ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, regval); } } #ifdef CONFIG_NET_CAN_CANFD @@ -1216,10 +1234,19 @@ static int ctucanfd_sock_transmit(FAR struct netdev_lowerhalf_s *dev, ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_TSL, 0); ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_TSU, 0); - for (i = 0; i < frame->len; i++) + /* Pack bytes into aligned register writes and pad the final word. */ + + for (i = 0; i < frame->len; i += 4) { - ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, - frame->data[i]); + regval = (uint32_t)frame->data[i]; + regval |= (uint32_t)(i + 1 < frame->len ? frame->data[i + 1] : 0) + << 8; + regval |= (uint32_t)(i + 2 < frame->len ? frame->data[i + 2] : 0) + << 16; + regval |= (uint32_t)(i + 3 < frame->len ? frame->data[i + 3] : 0) + << 24; + + ctucanfd_putreg(priv, offset + CTUCANFD_TXBUF_DATA + i, regval); } } #endif
