diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c | 260 |
1 files changed, 260 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..406166005b99 --- /dev/null +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -0,0 +1,260 @@ +// 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/bitfield.h> + +#include "mcp251xfd.h" + +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_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; + struct sk_buff *skb; + u32 seq, seq_masked, tef_tail_masked, tef_tail; + + seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_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); + + tef_tail = mcp251xfd_get_tef_tail(priv); + skb = priv->can.echo_skb[tef_tail]; + if (skb) + mcp251xfd_skb_set_timestamp(priv, skb, hw_tef_obj->ts); + stats->tx_bytes += + can_rx_offload_get_echo_skb(&priv->offload, + tef_tail, hw_tef_obj->ts, + frame_len_ptr); + stats->tx_packets++; + priv->tef->tail++; + + return 0; +} + +static int mcp251xfd_tef_ring_update(struct mcp251xfd_priv *priv) +{ + const struct mcp251xfd_tx_ring *tx_ring = priv->tx; + unsigned int new_head; + u8 chip_tx_tail; + int err; + + err = mcp251xfd_tx_tail_get_from_chip(priv, &chip_tx_tail); + if (err) + return err; + + /* chip_tx_tail, is the next TX-Object send by the HW. + * The new TEF head must be >= the old head, ... + */ + new_head = round_down(priv->tef->head, tx_ring->obj_num) + chip_tx_tail; + if (new_head <= priv->tef->head) + new_head += tx_ring->obj_num; + + /* ... but it cannot exceed the TX head. */ + priv->tef->head = min(new_head, tx_ring->head); + + return mcp251xfd_check_tef_tail(priv); +} + +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_tef_ring_update(priv); + if (err) + return err; + + tef_tail = mcp251xfd_get_tef_tail(priv); + len = mcp251xfd_get_tef_len(priv); + l = mcp251xfd_get_tef_linear_len(priv); + 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); + /* -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. + */ + if (err == -EAGAIN) + 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; + + /* 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); + } + + return 0; +} |