diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c index b33192964cf7..902eb767426d 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -60,56 +60,39 @@ static int mcp251xfd_check_tef_tail(const struct mcp251xfd_priv *priv) return 0; } -static int -mcp251xfd_handle_tefif_recover(const struct mcp251xfd_priv *priv, const u32 seq) -{ - const struct mcp251xfd_tx_ring *tx_ring = priv->tx; - u32 tef_sta; - int err; - - err = regmap_read(priv->map_reg, MCP251XFD_REG_TEFSTA, &tef_sta); - if (err) - return err; - - if (tef_sta & MCP251XFD_REG_TEFSTA_TEFOVIF) { - netdev_err(priv->ndev, - "Transmit Event FIFO buffer overflow.\n"); - return -ENOBUFS; - } - - netdev_info(priv->ndev, - "Transmit Event FIFO buffer %s. (seq=0x%08x, tef_tail=0x%08x, tef_head=0x%08x, tx_head=0x%08x).\n", - tef_sta & MCP251XFD_REG_TEFSTA_TEFFIF ? - "full" : tef_sta & MCP251XFD_REG_TEFSTA_TEFNEIF ? - "not empty" : "empty", - seq, priv->tef->tail, priv->tef->head, tx_ring->head); - - /* The Sequence Number in the TEF doesn't match our tef_tail. */ - return -EAGAIN; -} - static int mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv, const struct mcp251xfd_hw_tef_obj *hw_tef_obj, unsigned int *frame_len_ptr) { struct net_device_stats *stats = &priv->ndev->stats; + u32 seq, tef_tail_masked, tef_tail; struct sk_buff *skb; - u32 seq, seq_masked, tef_tail_masked, tef_tail; - seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK, + /* Use the MCP2517FD mask on the MCP2518FD, too. We only + * compare 7 bits, this is enough to detect old TEF objects. + */ + seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK, hw_tef_obj->flags); - - /* Use the MCP2517FD mask on the MCP2518FD, too. We only - * compare 7 bits, this should be enough to detect - * net-yet-completed, i.e. old TEF objects. - */ - seq_masked = seq & - field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK); tef_tail_masked = priv->tef->tail & field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK); - if (seq_masked != tef_tail_masked) - return mcp251xfd_handle_tefif_recover(priv, seq); + + /* According to mcp2518fd erratum DS80000789E 6. the FIFOCI + * bits of a FIFOSTA register, here the TX FIFO tail index + * might be corrupted and we might process past the TEF FIFO's + * head into old CAN frames. + * + * Compare the sequence number of the currently processed CAN + * frame with the expected sequence number. Abort with + * -EBADMSG if an old CAN frame is detected. + */ + if (seq != tef_tail_masked) { + netdev_dbg(priv->ndev, "%s: chip=0x%02x ring=0x%02x\n", __func__, + seq, tef_tail_masked); + stats->tx_fifo_errors++; + + return -EBADMSG; + } tef_tail = mcp251xfd_get_tef_tail(priv); skb = priv->can.echo_skb[tef_tail]; @@ -223,12 +206,12 @@ int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) unsigned int frame_len = 0; err = mcp251xfd_handle_tefif_one(priv, &hw_tef_obj[i], &frame_len); - /* -EAGAIN means the Sequence Number in the TEF - * doesn't match our tef_tail. This can happen if we - * read the TEF objects too early. Leave loop let the - * interrupt handler call us again. + /* -EBADMSG means we're affected by mcp2518fd erratum + * DS80000789E 6., i.e. the Sequence Number in the TEF + * doesn't match our tef_tail. Don't process any + * further and mark processed frames as good. */ - if (err == -EAGAIN) + if (err == -EBADMSG) goto out_netif_wake_queue; if (err) return err;