// SPDX-License-Identifier: GPL-2.0
//
// mcp251xfd - Microchip MCP251xFD Family CAN controller driver
//
// Copyright (c) 2019, 2020, 2021, 2023 Pengutronix,
// Marc Kleine-Budde <[email protected]>
//
// Based on:
//
// CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
//
// Copyright (c) 2019 Martin Sperl <[email protected]>
//
#include <linux/bitfield.h>
#include "mcp251xfd.h"
static inline bool mcp251xfd_tx_fifo_sta_full(u32 fifo_sta)
{
return !(fifo_sta & MCP251XFD_REG_FIFOSTA_TFNRFNIF);
}
static inline int
mcp251xfd_tef_tail_get_from_chip(const struct mcp251xfd_priv *priv,
u8 *tef_tail)
{
u32 tef_ua;
int err;
err = regmap_read(priv->map_reg, MCP251XFD_REG_TEFUA, &tef_ua);
if (err)
return err;
*tef_tail = tef_ua / sizeof(struct mcp251xfd_hw_tef_obj);
return 0;
}
static int mcp251xfd_check_tef_tail(const struct mcp251xfd_priv *priv)
{
u8 tef_tail_chip, tef_tail;
int err;
if (!IS_ENABLED(CONFIG_CAN_MCP251XFD_SANITY))
return 0;
err = mcp251xfd_tef_tail_get_from_chip(priv, &tef_tail_chip);
if (err)
return err;
tef_tail = mcp251xfd_get_tef_tail(priv);
if (tef_tail_chip != tef_tail) {
netdev_err(priv->ndev,
"TEF tail of chip (0x%02x) and ours (0x%08x) inconsistent.\n",
tef_tail_chip, tef_tail);
return -EILSEQ;
}
return 0;
}
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;
/* 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);
tef_tail_masked = priv->tef->tail &
field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK);
/* 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];
if (skb)
mcp251xfd_skb_set_timestamp_raw(priv, skb, hw_tef_obj->ts);
stats->tx_bytes +=
can_rx_offload_get_echo_skb_queue_timestamp(&priv->offload,
tef_tail, hw_tef_obj->ts,
frame_len_ptr);
stats->tx_packets++;
priv->tef->tail++;
return 0;
}
static int
mcp251xfd_get_tef_len(struct mcp251xfd_priv *priv, u8 *len_p)
{
const struct mcp251xfd_tx_ring *tx_ring = priv->tx;
const u8 shift = tx_ring->obj_num_shift_to_u8;
u8 chip_tx_tail, tail, len;
u32 fifo_sta;
int err;
err = regmap_read(priv->map_reg, MCP251XFD_REG_FIFOSTA(priv->tx->fifo_nr),
&fifo_sta);
if (err)
return err;
if (mcp251xfd_tx_fifo_sta_full(fifo_sta)) {
*len_p = tx_ring->obj_num;
return 0;
}
chip_tx_tail = FIELD_GET(MCP251XFD_REG_FIFOSTA_FIFOCI_MASK, fifo_sta);
err = mcp251xfd_check_tef_tail(priv);
if (err)
return err;
tail = mcp251xfd_get_tef_tail(priv);
/* First shift to full u8. The subtraction works on signed
* values, that keeps the difference steady around the u8
* overflow. The right shift acts on len, which is an u8.
*/
BUILD_BUG_ON(sizeof(tx_ring->obj_num) != sizeof(chip_tx_tail));
BUILD_BUG_ON(sizeof(tx_ring->obj_num) != sizeof(tail));
BUILD_BUG_ON(sizeof(tx_ring->obj_num) != sizeof(len));
len = (chip_tx_tail << shift) - (tail << shift);
*len_p = len >> shift;
return 0;
}
static inline int
mcp251xfd_tef_obj_read(const struct mcp251xfd_priv *priv,
struct mcp251xfd_hw_tef_obj *hw_tef_obj,
const u8 offset, const u8 len)
{
const struct mcp251xfd_tx_ring *tx_ring = priv->tx;
const int val_bytes = regmap_get_val_bytes(priv->map_rx);
if (IS_ENABLED(CONFIG_CAN_MCP251XFD_SANITY) &&
(offset > tx_ring->obj_num ||
len > tx_ring->obj_num ||
offset + len > tx_ring->obj_num)) {
netdev_err(priv->ndev,
"Trying to read too many TEF objects (max=%d, offset=%d, len=%d).\n",
tx_ring->obj_num, offset, len);
return -ERANGE;
}
return regmap_bulk_read(priv->map_rx,
mcp251xfd_get_tef_obj_addr(offset),
hw_tef_obj,
sizeof(*hw_tef_obj) / val_bytes * len);
}
static inline void mcp251xfd_ecc_tefif_successful(struct mcp251xfd_priv *priv)
{
struct mcp251xfd_ecc *ecc = &priv->ecc;
ecc->ecc_stat = 0;
}
int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv)
{
struct mcp251xfd_hw_tef_obj hw_tef_obj[MCP251XFD_TX_OBJ_NUM_MAX];
unsigned int total_frame_len = 0;
u8 tef_tail, len, l;
int err, i;
err = mcp251xfd_get_tef_len(priv, &len);
if (err)
return err;
tef_tail = mcp251xfd_get_tef_tail(priv);
l = mcp251xfd_get_tef_linear_len(priv, len);
err = mcp251xfd_tef_obj_read(priv, hw_tef_obj, tef_tail, l);
if (err)
return err;
if (l < len) {
err = mcp251xfd_tef_obj_read(priv, &hw_tef_obj[l], 0, len - l);
if (err)
return err;
}
for (i = 0; i < len; i++) {
unsigned int frame_len = 0;
err = mcp251xfd_handle_tefif_one(priv, &hw_tef_obj[i], &frame_len);
/* -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 == -EBADMSG)
goto out_netif_wake_queue;
if (err)
return err;
total_frame_len += frame_len;
}
out_netif_wake_queue:
len = i; /* number of handled goods TEFs */
if (len) {
struct mcp251xfd_tef_ring *ring = priv->tef;
struct mcp251xfd_tx_ring *tx_ring = priv->tx;
int offset;
ring->head += len;
/* Increment the TEF FIFO tail pointer 'len' times in
* a single SPI message.
*
* Note:
* Calculate offset, so that the SPI transfer ends on
* the last message of the uinc_xfer array, which has
* "cs_change == 0", to properly deactivate the chip
* select.
*/
offset = ARRAY_SIZE(ring->uinc_xfer) - len;
err = spi_sync_transfer(priv->spi,
ring->uinc_xfer + offset, len);
if (err)
return err;
tx_ring->tail += len;
netdev_completed_queue(priv->ndev, len, total_frame_len);
err = mcp251xfd_check_tef_tail(priv);
if (err)
return err;
}
mcp251xfd_ecc_tefif_successful(priv);
if (mcp251xfd_get_tx_free(priv->tx)) {
/* Make sure that anybody stopping the queue after
* this sees the new tx_ring->tail.
*/
smp_mb();
netif_wake_queue(priv->ndev);
}
if (priv->tx_coalesce_usecs_irq)
hrtimer_start(&priv->tx_irq_timer,
ns_to_ktime(priv->tx_coalesce_usecs_irq *
NSEC_PER_USEC),
HRTIMER_MODE_REL);
return 0;
}
Codebase Browser
linux