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.
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 023b993a3b09..f6e684210689 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2301,7 +2301,7 @@ 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;
@@ -2328,6 +2328,8 @@ 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)) {
@@ -2353,14 +2355,18 @@ 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)
- memset(hw_tx_obj->data + cfd->len, 0x0, 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));
--
2.29.2
