can: rockchip_canfd: add TX PATH

The IP core has a TX event FIFO. In other IP cores, this type of FIFO
usually contains the events that a CAN frame has been successfully
sent. However, the IP core on the rk3568v2 the FIFO also holds events
of unsuccessful transmission attempts.

It turned out that the best way to work around this problem is to set
the IP core to self-receive mode (RXSTX), filter out the self-received
frames and insert them into the complete TX path.

Add a pair new functions to check if 2 struct canfd_frame are equal.
The 1st checks if the header of the CAN frames are equal, the 2nd
checks if the data portion are equal:

- rkcanfd_can_frame_header_equal()
- rkcanfd_can_frame_data_equal()

Tested-by: Alibek Omarov <a1ba.omarov@gmail.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20240904-rockchip-canfd-v5-11-8ae22bcb27cc@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 94 insertions, 0 deletions

diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 89c65db3b2dc..668a902f4c2a 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -4,9 +4,103 @@
 //               Marc Kleine-Budde <kernel@pengutronix.de>
 //
 
+#include <net/netdev_queues.h>
+
 #include "rockchip_canfd.h"
 
+static void rkcanfd_start_xmit_write_cmd(const struct rkcanfd_priv *priv,
+					 const u32 reg_cmd)
+{
+	rkcanfd_write(priv, RKCANFD_REG_CMD, reg_cmd);
+}
+
 int rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
+	struct rkcanfd_priv *priv = netdev_priv(ndev);
+	u32 reg_frameinfo, reg_id, reg_cmd;
+	unsigned int tx_head, frame_len;
+	const struct canfd_frame *cfd;
+	int err;
+	u8 i;
+
+	if (can_dropped_invalid_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
+	if (!netif_subqueue_maybe_stop(priv->ndev, 0,
+				       rkcanfd_get_tx_free(priv),
+				       RKCANFD_TX_STOP_THRESHOLD,
+				       RKCANFD_TX_START_THRESHOLD)) {
+		if (net_ratelimit())
+			netdev_info(priv->ndev,
+				    "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, tx_pending=%d)\n",
+				    priv->tx_head, priv->tx_tail,
+				    rkcanfd_get_tx_pending(priv));
+
+		return NETDEV_TX_BUSY;
+	}
+
+	cfd = (struct canfd_frame *)skb->data;
+
+	if (cfd->can_id & CAN_EFF_FLAG) {
+		reg_frameinfo = RKCANFD_REG_FD_FRAMEINFO_FRAME_FORMAT;
+		reg_id = FIELD_PREP(RKCANFD_REG_FD_ID_EFF, cfd->can_id);
+	} else {
+		reg_frameinfo = 0;
+		reg_id = FIELD_PREP(RKCANFD_REG_FD_ID_SFF, cfd->can_id);
+	}
+
+	if (cfd->can_id & CAN_RTR_FLAG)
+		reg_frameinfo |= RKCANFD_REG_FD_FRAMEINFO_RTR;
+
+	if (can_is_canfd_skb(skb)) {
+		reg_frameinfo |= RKCANFD_REG_FD_FRAMEINFO_FDF;
+
+		if (cfd->flags & CANFD_BRS)
+			reg_frameinfo |= RKCANFD_REG_FD_FRAMEINFO_BRS;
+
+		reg_frameinfo |= FIELD_PREP(RKCANFD_REG_FD_FRAMEINFO_DATA_LENGTH,
+					    can_fd_len2dlc(cfd->len));
+	} else {
+		reg_frameinfo |= FIELD_PREP(RKCANFD_REG_FD_FRAMEINFO_DATA_LENGTH,
+					    cfd->len);
+	}
+
+	tx_head = rkcanfd_get_tx_head(priv);
+	reg_cmd = RKCANFD_REG_CMD_TX_REQ(tx_head);
+
+	rkcanfd_write(priv, RKCANFD_REG_FD_TXFRAMEINFO, reg_frameinfo);
+	rkcanfd_write(priv, RKCANFD_REG_FD_TXID, reg_id);
+	for (i = 0; i < cfd->len; i += 4)
+		rkcanfd_write(priv, RKCANFD_REG_FD_TXDATA0 + i,
+			      *(u32 *)(cfd->data + i));
+
+	frame_len = can_skb_get_frame_len(skb);
+	err = can_put_echo_skb(skb, ndev, tx_head, frame_len);
+	if (!err)
+		netdev_sent_queue(priv->ndev, frame_len);
+
+	WRITE_ONCE(priv->tx_head, priv->tx_head + 1);
+
+	rkcanfd_start_xmit_write_cmd(priv, reg_cmd);
+
+	netif_subqueue_maybe_stop(priv->ndev, 0,
+				  rkcanfd_get_tx_free(priv),
+				  RKCANFD_TX_STOP_THRESHOLD,
+				  RKCANFD_TX_START_THRESHOLD);
+
 	return NETDEV_TX_OK;
 }
+
+void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
+				unsigned int *frame_len_p)
+{
+	struct net_device_stats *stats = &priv->ndev->stats;
+	unsigned int tx_tail;
+
+	tx_tail = rkcanfd_get_tx_tail(priv);
+	stats->tx_bytes +=
+		can_rx_offload_get_echo_skb_queue_timestamp(&priv->offload,
+							    tx_tail, ts,
+							    frame_len_p);
+	stats->tx_packets++;
+}