Commit a68eda20 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

can: mcp251xfd: mcp251xfd_tx_obj_from_skb(): don't copy data for RTR CAN frames in TX-path 

In Classical CAN there are RTR frames. RTR frames have the RTR bit set, may
have a dlc != 0, but contain no data.

This patch optimizes the TX-path to not copy any data for RTR frames.

Link: https://lore.kernel.org/r/20210114153448.1506901-5-mkl@pengutronix.de


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent e20b85c7

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

+11 −5
Original line number Diff line number Diff line
@@ -2304,7 +2304,7 @@ mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv, 
	union mcp251xfd_tx_obj_load_buf *load_buf;

	u8 dlc;

	u32 id, flags;

	int pad_len, len;

	int len_sanitized = 0, len;



	if (cfd->can_id & CAN_EFF_FLAG) {

		u32 sid, eid;
@@ -2331,6 +2331,8 @@ mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv, 


	if (cfd->can_id & CAN_RTR_FLAG)

		flags |= MCP251XFD_OBJ_FLAGS_RTR;

	else

		len_sanitized = canfd_sanitize_len(cfd->len);



	/* CANFD */

	if (can_is_canfd_skb(skb)) {
@@ -2356,14 +2358,18 @@ mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv, 
	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)

	if (MCP251XFD_SANITIZE_CAN && len_sanitized) {

		int pad_len;



		pad_len = len_sanitized - cfd->len;

		if (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)

		len += round_up(can_fd_dlc2len(dlc), sizeof(u32));

		len += round_up(len_sanitized, sizeof(u32));

	else

		len += round_up(cfd->len, sizeof(u32));