diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c new file mode 100644 index 000000000000..160528d3cc26 --- /dev/null +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tx.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// mcp251xfd - Microchip MCP251xFD Family CAN controller driver +// +// Copyright (c) 2019, 2020, 2021 Pengutronix, +// Marc Kleine-Budde <kernel@pengutronix.de> +// +// Based on: +// +// CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface +// +// Copyright (c) 2019 Martin Sperl <kernel@martin.sperl.org> +// + +#include <asm/unaligned.h> +#include <linux/bitfield.h> + +#include "mcp251xfd.h" + +static inline struct +mcp251xfd_tx_obj *mcp251xfd_get_tx_obj_next(struct mcp251xfd_tx_ring *tx_ring) +{ + u8 tx_head; + + tx_head = mcp251xfd_get_tx_head(tx_ring); + + return &tx_ring->obj[tx_head]; +} + +static void +mcp251xfd_tx_obj_from_skb(const struct mcp251xfd_priv *priv, + struct mcp251xfd_tx_obj *tx_obj, + const struct sk_buff *skb, + unsigned int seq) +{ + const struct canfd_frame *cfd = (struct canfd_frame *)skb->data; + struct mcp251xfd_hw_tx_obj_raw *hw_tx_obj; + union mcp251xfd_tx_obj_load_buf *load_buf; + u8 dlc; + u32 id, flags; + int len_sanitized = 0, len; + + if (cfd->can_id & CAN_EFF_FLAG) { + u32 sid, eid; + + sid = FIELD_GET(MCP251XFD_REG_FRAME_EFF_SID_MASK, cfd->can_id); + eid = FIELD_GET(MCP251XFD_REG_FRAME_EFF_EID_MASK, cfd->can_id); + + id = FIELD_PREP(MCP251XFD_OBJ_ID_EID_MASK, eid) | + FIELD_PREP(MCP251XFD_OBJ_ID_SID_MASK, sid); + + flags = MCP251XFD_OBJ_FLAGS_IDE; + } else { + id = FIELD_PREP(MCP251XFD_OBJ_ID_SID_MASK, cfd->can_id); + flags = 0; + } + + /* Use the MCP2518FD mask even on the MCP2517FD. It doesn't + * harm, only the lower 7 bits will be transferred into the + * TEF object. + */ + flags |= FIELD_PREP(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK, seq); + + 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)) { + if (cfd->flags & CANFD_ESI) + flags |= MCP251XFD_OBJ_FLAGS_ESI; + + flags |= MCP251XFD_OBJ_FLAGS_FDF; + + if (cfd->flags & CANFD_BRS) + flags |= MCP251XFD_OBJ_FLAGS_BRS; + + dlc = can_fd_len2dlc(cfd->len); + } else { + dlc = can_get_cc_dlc((struct can_frame *)cfd, + priv->can.ctrlmode); + } + + flags |= FIELD_PREP(MCP251XFD_OBJ_FLAGS_DLC_MASK, dlc); + + load_buf = &tx_obj->buf; + if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_TX) + hw_tx_obj = &load_buf->crc.hw_tx_obj; + else + hw_tx_obj = &load_buf->nocrc.hw_tx_obj; + + put_unaligned_le32(id, &hw_tx_obj->id); + put_unaligned_le32(flags, &hw_tx_obj->flags); + + /* Copy data */ + memcpy(hw_tx_obj->data, cfd->data, cfd->len); + + /* Clear unused data at end of CAN frame */ + 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(len_sanitized, sizeof(u32)); + else + len += round_up(cfd->len, sizeof(u32)); + + if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_TX) { + u16 crc; + + mcp251xfd_spi_cmd_crc_set_len_in_ram(&load_buf->crc.cmd, + len); + /* CRC */ + len += sizeof(load_buf->crc.cmd); + crc = mcp251xfd_crc16_compute(&load_buf->crc, len); + put_unaligned_be16(crc, (void *)load_buf + len); + + /* Total length */ + len += sizeof(load_buf->crc.crc); + } else { + len += sizeof(load_buf->nocrc.cmd); + } + + tx_obj->xfer[0].len = len; +} + +static int mcp251xfd_tx_obj_write(const struct mcp251xfd_priv *priv, + struct mcp251xfd_tx_obj *tx_obj) +{ + return spi_async(priv->spi, &tx_obj->msg); +} + +static bool mcp251xfd_tx_busy(const struct mcp251xfd_priv *priv, + struct mcp251xfd_tx_ring *tx_ring) +{ + if (mcp251xfd_get_tx_free(tx_ring) > 0) + return false; + + netif_stop_queue(priv->ndev); + + /* Memory barrier before checking tx_free (head and tail) */ + smp_mb(); + + if (mcp251xfd_get_tx_free(tx_ring) == 0) { + netdev_dbg(priv->ndev, + "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n", + tx_ring->head, tx_ring->tail, + tx_ring->head - tx_ring->tail); + + return true; + } + + netif_start_queue(priv->ndev); + + return false; +} + +netdev_tx_t mcp251xfd_start_xmit(struct sk_buff *skb, + struct net_device *ndev) +{ + struct mcp251xfd_priv *priv = netdev_priv(ndev); + struct mcp251xfd_tx_ring *tx_ring = priv->tx; + struct mcp251xfd_tx_obj *tx_obj; + unsigned int frame_len; + u8 tx_head; + int err; + + if (can_dev_dropped_skb(ndev, skb)) + return NETDEV_TX_OK; + + if (mcp251xfd_tx_busy(priv, tx_ring)) + return NETDEV_TX_BUSY; + + tx_obj = mcp251xfd_get_tx_obj_next(tx_ring); + mcp251xfd_tx_obj_from_skb(priv, tx_obj, skb, tx_ring->head); + + /* Stop queue if we occupy the complete TX FIFO */ + tx_head = mcp251xfd_get_tx_head(tx_ring); + tx_ring->head++; + if (mcp251xfd_get_tx_free(tx_ring) == 0) + netif_stop_queue(ndev); + + 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); + + err = mcp251xfd_tx_obj_write(priv, tx_obj); + if (err) + goto out_err; + + return NETDEV_TX_OK; + + out_err: + netdev_err(priv->ndev, "ERROR in %s: %d\n", __func__, err); + + return NETDEV_TX_OK; +} |