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// 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 <linux/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 void mcp251xfd_tx_failure_drop(const struct mcp251xfd_priv *priv,
struct mcp251xfd_tx_ring *tx_ring,
int err)
{
struct net_device *ndev = priv->ndev;
struct net_device_stats *stats = &ndev->stats;
unsigned int frame_len = 0;
u8 tx_head;
tx_ring->head--;
stats->tx_dropped++;
tx_head = mcp251xfd_get_tx_head(tx_ring);
can_free_echo_skb(ndev, tx_head, &frame_len);
netdev_completed_queue(ndev, 1, frame_len);
netif_wake_queue(ndev);
if (net_ratelimit())
netdev_err(priv->ndev, "ERROR in %s: %d\n", __func__, err);
}
void mcp251xfd_tx_obj_write_sync(struct work_struct *work)
{
struct mcp251xfd_priv *priv = container_of(work, struct mcp251xfd_priv,
tx_work);
struct mcp251xfd_tx_obj *tx_obj = priv->tx_work_obj;
struct mcp251xfd_tx_ring *tx_ring = priv->tx;
int err;
err = spi_sync(priv->spi, &tx_obj->msg);
if (err)
mcp251xfd_tx_failure_drop(priv, tx_ring, err);
}
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;
}
static bool mcp251xfd_work_busy(struct work_struct *work)
{
return work_busy(work);
}
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) ||
mcp251xfd_work_busy(&priv->tx_work))
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 == -EBUSY) {
netif_stop_queue(ndev);
priv->tx_work_obj = tx_obj;
queue_work(priv->wq, &priv->tx_work);
} else if (err) {
mcp251xfd_tx_failure_drop(priv, tx_ring, err);
}
return NETDEV_TX_OK;
}
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