Commit 4248ba9e authored by Markus Schneider-Pargmann's avatar Markus Schneider-Pargmann Committed by Marc Kleine-Budde
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can: m_can: Write transmit header and data in one transaction 



Combine header and data before writing to the transmit fifo to reduce
the overhead for peripheral chips.

Signed-off-by: default avatarMarkus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: default avatarSimon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/all/20240207093220.2681425-4-msp@baylibre.com


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent ba72f6c7

drivers/net/can/m_can/m_can.c

+21 −14
Original line number Diff line number Diff line
@@ -320,6 +320,12 @@ struct id_and_dlc { 
	u32 dlc;

};



struct m_can_fifo_element {

	u32 id;

	u32 dlc;

	u8 data[CANFD_MAX_DLEN];

};



static inline u32 m_can_read(struct m_can_classdev *cdev, enum m_can_reg reg)

{

	return cdev->ops->read_reg(cdev, reg);
@@ -1637,9 +1643,10 @@ static int m_can_next_echo_skb_occupied(struct net_device *dev, int putidx) 
static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev)

{

	struct canfd_frame *cf = (struct canfd_frame *)cdev->tx_skb->data;

	u8 len_padded = DIV_ROUND_UP(cf->len, 4);

	struct m_can_fifo_element fifo_element;

	struct net_device *dev = cdev->net;

	struct sk_buff *skb = cdev->tx_skb;

	struct id_and_dlc fifo_header;

	u32 cccr, fdflags;

	u32 txfqs;

	int err;
@@ -1650,27 +1657,27 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) 
	/* Generate ID field for TX buffer Element */

	/* Common to all supported M_CAN versions */

	if (cf->can_id & CAN_EFF_FLAG) {

		fifo_header.id = cf->can_id & CAN_EFF_MASK;

		fifo_header.id |= TX_BUF_XTD;

		fifo_element.id = cf->can_id & CAN_EFF_MASK;

		fifo_element.id |= TX_BUF_XTD;

	} else {

		fifo_header.id = ((cf->can_id & CAN_SFF_MASK) << 18);

		fifo_element.id = ((cf->can_id & CAN_SFF_MASK) << 18);

	}



	if (cf->can_id & CAN_RTR_FLAG)

		fifo_header.id |= TX_BUF_RTR;

		fifo_element.id |= TX_BUF_RTR;



	if (cdev->version == 30) {

		netif_stop_queue(dev);



		fifo_header.dlc = can_fd_len2dlc(cf->len) << 16;

		fifo_element.dlc = can_fd_len2dlc(cf->len) << 16;



		/* Write the frame ID, DLC, and payload to the FIFO element. */

		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_header, 2);

		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_ID, &fifo_element, 2);

		if (err)

			goto out_fail;



		err = m_can_fifo_write(cdev, 0, M_CAN_FIFO_DATA,

				       cf->data, DIV_ROUND_UP(cf->len, 4));

				       cf->data, len_padded);

		if (err)

			goto out_fail;
@@ -1732,15 +1739,15 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) 
				fdflags |= TX_BUF_BRS;

		}



		fifo_header.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |

		fifo_element.dlc = FIELD_PREP(TX_BUF_MM_MASK, putidx) |

			FIELD_PREP(TX_BUF_DLC_MASK, can_fd_len2dlc(cf->len)) |

			fdflags | TX_BUF_EFC;

		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID, &fifo_header, 2);

		if (err)

			goto out_fail;



		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_DATA,

				       cf->data, DIV_ROUND_UP(cf->len, 4));

		memcpy_and_pad(fifo_element.data, CANFD_MAX_DLEN, &cf->data,

			       cf->len, 0);



		err = m_can_fifo_write(cdev, putidx, M_CAN_FIFO_ID,

				       &fifo_element, 2 + len_padded);

		if (err)

			goto out_fail;