diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c new file mode 100644 index 000000000000..e94321849fd7 --- /dev/null +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// mcp251xfd - Microchip MCP251xFD Family CAN controller driver +// +// Copyright (c) 2019, 2020, 2021, 2023 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/bitfield.h> + +#include "mcp251xfd.h" + +static inline bool mcp251xfd_tx_fifo_sta_empty(u32 fifo_sta) +{ + return fifo_sta & MCP251XFD_REG_FIFOSTA_TFERFFIF; +} + +static inline bool mcp251xfd_tx_fifo_sta_less_than_half_full(u32 fifo_sta) +{ + return fifo_sta & MCP251XFD_REG_FIFOSTA_TFHRFHIF; +} + +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 the chip says the TX-FIFO is empty, but there are no TX + * buffers free in the ring, we assume all have been sent. + */ + if (mcp251xfd_tx_fifo_sta_empty(fifo_sta) && + mcp251xfd_get_tx_free(tx_ring) == 0) { + *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 >>= shift; + + /* According to mcp2518fd erratum DS80000789E 6. the FIFOCI + * bits of a FIFOSTA register, here the TX-FIFO tail index + * might be corrupted. + * + * However here it seems the bit indicating that the TX-FIFO + * is empty (MCP251XFD_REG_FIFOSTA_TFERFFIF) is not correct + * while the TX-FIFO tail index is. + * + * We assume the TX-FIFO is empty, i.e. all pending CAN frames + * haven been send, if: + * - Chip's head and tail index are equal (len == 0). + * - The TX-FIFO is less than half full. + * (The TX-FIFO empty case has already been checked at the + * beginning of this function.) + * - No free buffers in the TX ring. + */ + if (len == 0 && mcp251xfd_tx_fifo_sta_less_than_half_full(fifo_sta) && + mcp251xfd_get_tx_free(tx_ring) == 0) + len = tx_ring->obj_num; + + *len_p = len; + + 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; +} |