diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c | 125 |
1 files changed, 65 insertions, 60 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c index e5bd57b65a..5b0c7890d4 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c @@ -2,7 +2,7 @@ // // mcp251xfd - Microchip MCP251xFD Family CAN controller driver // -// Copyright (c) 2019, 2020, 2021 Pengutronix, +// Copyright (c) 2019, 2020, 2021, 2023 Pengutronix, // Marc Kleine-Budde <kernel@pengutronix.de> // // Based on: @@ -16,6 +16,11 @@ #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) @@ -56,55 +61,38 @@ static int mcp251xfd_check_tef_tail(const struct mcp251xfd_priv *priv) } 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; + u32 seq, tef_tail_masked, tef_tail; struct sk_buff *skb; - u32 seq, seq_masked, tef_tail_masked, tef_tail; - seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK, + /* 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); - - /* 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); + + /* 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]; @@ -120,28 +108,44 @@ mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv, return 0; } -static int mcp251xfd_tef_ring_update(struct mcp251xfd_priv *priv) +static int +mcp251xfd_get_tef_len(struct mcp251xfd_priv *priv, u8 *len_p) { const struct mcp251xfd_tx_ring *tx_ring = priv->tx; - unsigned int new_head; - u8 chip_tx_tail; + const u8 shift = tx_ring->obj_num_shift_to_u8; + u8 chip_tx_tail, tail, len; + u32 fifo_sta; int err; - err = mcp251xfd_tx_tail_get_from_chip(priv, &chip_tx_tail); + err = regmap_read(priv->map_reg, MCP251XFD_REG_FIFOSTA(priv->tx->fifo_nr), + &fifo_sta); 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, ... + 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. */ - 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; + 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)); - /* ... but it cannot exceed the TX head. */ - priv->tef->head = min(new_head, tx_ring->head); + len = (chip_tx_tail << shift) - (tail << shift); + *len_p = len >> shift; - return mcp251xfd_check_tef_tail(priv); + return 0; } static inline int @@ -182,13 +186,12 @@ int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) u8 tef_tail, len, l; int err, i; - err = mcp251xfd_tef_ring_update(priv); + err = mcp251xfd_get_tef_len(priv, &len); if (err) return err; tef_tail = mcp251xfd_get_tef_tail(priv); - len = mcp251xfd_get_tef_len(priv); - l = mcp251xfd_get_tef_linear_len(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; @@ -203,12 +206,12 @@ int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) 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. + /* -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 == -EAGAIN) + if (err == -EBADMSG) goto out_netif_wake_queue; if (err) return err; @@ -223,6 +226,8 @@ int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv) 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. * |