CAN-FD frames have only specific frame length (0, 1, 2, 3, 4, 5, 6, 7, 8, 12,
16, 20, 24, 32, 48, 64). A CAN-FD frame provided by user space might not cover
the whole CAN-FD frame. To avoid sending garbage over the CAN bus the driver
pads the CAN frame with 0x0 (if MCP251XFD_SANITIZE_CAN is activated).
This patch cleans up the pad len calculation. Rounding to full u32 brings no
benefit, in case of CRC transfers, the hw_tx_obj->data is not aligned to u32
anyway.
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 73e048607223..a8470e081ff0 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2300,7 +2300,7 @@ mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv,
union mcp251xfd_tx_obj_load_buf *load_buf;
u8 dlc;
u32 id, flags;
- int offset, len;
+ int pad_len, len;
if (cfd->can_id & CAN_EFF_FLAG) {
u32 sid, eid;
@@ -2348,13 +2348,14 @@ mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv,
put_unaligned_le32(id, &hw_tx_obj->id);
put_unaligned_le32(flags, &hw_tx_obj->flags);
- /* Clear data at end of CAN frame */
- offset = round_down(cfd->len, sizeof(u32));
- len = round_up(can_fd_dlc2len(dlc), sizeof(u32)) - offset;
- if (MCP251XFD_SANITIZE_CAN && len)
- memset(hw_tx_obj->data + offset, 0x0, len);
+ /* Copy data */
memcpy(hw_tx_obj->data, cfd->data, cfd->len);
+ /* Clear unused data at end of CAN frame */
+ pad_len = can_fd_dlc2len(dlc) - cfd->len;
+ if (MCP251XFD_SANITIZE_CAN && pad_len)
+ memset(hw_tx_obj->data + cfd->len, 0x0, pad_len);
+
/* Number of bytes to be written into the RAM of the controller */
len = sizeof(hw_tx_obj->id) + sizeof(hw_tx_obj->flags);
if (MCP251XFD_SANITIZE_CAN)
--
2.29.2
