267 lines
6.7 KiB
C
267 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// mcp251xfd - Microchip MCP251xFD Family CAN controller driver
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//
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// Copyright (c) 2019, 2020, 2021 Pengutronix,
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// Marc Kleine-Budde <kernel@pengutronix.de>
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//
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// Based on:
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//
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// CAN bus driver for Microchip 25XXFD CAN Controller with SPI Interface
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//
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// Copyright (c) 2019 Martin Sperl <kernel@martin.sperl.org>
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//
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#include <linux/bitfield.h>
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#include "mcp251xfd.h"
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static inline int
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mcp251xfd_tef_tail_get_from_chip(const struct mcp251xfd_priv *priv,
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u8 *tef_tail)
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{
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u32 tef_ua;
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int err;
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err = regmap_read(priv->map_reg, MCP251XFD_REG_TEFUA, &tef_ua);
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if (err)
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return err;
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*tef_tail = tef_ua / sizeof(struct mcp251xfd_hw_tef_obj);
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return 0;
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}
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static int mcp251xfd_check_tef_tail(const struct mcp251xfd_priv *priv)
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{
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u8 tef_tail_chip, tef_tail;
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int err;
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if (!IS_ENABLED(CONFIG_CAN_MCP251XFD_SANITY))
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return 0;
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err = mcp251xfd_tef_tail_get_from_chip(priv, &tef_tail_chip);
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if (err)
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return err;
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tef_tail = mcp251xfd_get_tef_tail(priv);
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if (tef_tail_chip != tef_tail) {
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netdev_err(priv->ndev,
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"TEF tail of chip (0x%02x) and ours (0x%08x) inconsistent.\n",
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tef_tail_chip, tef_tail);
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return -EILSEQ;
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}
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return 0;
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}
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static int
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mcp251xfd_handle_tefif_recover(const struct mcp251xfd_priv *priv, const u32 seq)
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{
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const struct mcp251xfd_tx_ring *tx_ring = priv->tx;
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u32 tef_sta;
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int err;
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err = regmap_read(priv->map_reg, MCP251XFD_REG_TEFSTA, &tef_sta);
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if (err)
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return err;
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if (tef_sta & MCP251XFD_REG_TEFSTA_TEFOVIF) {
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netdev_err(priv->ndev,
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"Transmit Event FIFO buffer overflow.\n");
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return -ENOBUFS;
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}
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netdev_info(priv->ndev,
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"Transmit Event FIFO buffer %s. (seq=0x%08x, tef_tail=0x%08x, tef_head=0x%08x, tx_head=0x%08x).\n",
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tef_sta & MCP251XFD_REG_TEFSTA_TEFFIF ?
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"full" : tef_sta & MCP251XFD_REG_TEFSTA_TEFNEIF ?
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"not empty" : "empty",
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seq, priv->tef->tail, priv->tef->head, tx_ring->head);
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/* The Sequence Number in the TEF doesn't match our tef_tail. */
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return -EAGAIN;
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}
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static int
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mcp251xfd_handle_tefif_one(struct mcp251xfd_priv *priv,
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const struct mcp251xfd_hw_tef_obj *hw_tef_obj,
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unsigned int *frame_len_ptr)
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{
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struct net_device_stats *stats = &priv->ndev->stats;
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struct sk_buff *skb;
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u32 seq, seq_masked, tef_tail_masked, tef_tail;
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seq = FIELD_GET(MCP251XFD_OBJ_FLAGS_SEQ_MCP2518FD_MASK,
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hw_tef_obj->flags);
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/* Use the MCP2517FD mask on the MCP2518FD, too. We only
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* compare 7 bits, this should be enough to detect
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* net-yet-completed, i.e. old TEF objects.
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*/
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seq_masked = seq &
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field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK);
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tef_tail_masked = priv->tef->tail &
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field_mask(MCP251XFD_OBJ_FLAGS_SEQ_MCP2517FD_MASK);
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if (seq_masked != tef_tail_masked)
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return mcp251xfd_handle_tefif_recover(priv, seq);
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tef_tail = mcp251xfd_get_tef_tail(priv);
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skb = priv->can.echo_skb[tef_tail];
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if (skb)
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mcp251xfd_skb_set_timestamp(priv, skb, hw_tef_obj->ts);
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stats->tx_bytes +=
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can_rx_offload_get_echo_skb(&priv->offload,
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tef_tail, hw_tef_obj->ts,
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frame_len_ptr);
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stats->tx_packets++;
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priv->tef->tail++;
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return 0;
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}
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static int mcp251xfd_tef_ring_update(struct mcp251xfd_priv *priv)
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{
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const struct mcp251xfd_tx_ring *tx_ring = priv->tx;
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unsigned int new_head;
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u8 chip_tx_tail;
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int err;
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err = mcp251xfd_tx_tail_get_from_chip(priv, &chip_tx_tail);
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if (err)
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return err;
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/* chip_tx_tail, is the next TX-Object send by the HW.
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* The new TEF head must be >= the old head, ...
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*/
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new_head = round_down(priv->tef->head, tx_ring->obj_num) + chip_tx_tail;
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if (new_head <= priv->tef->head)
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new_head += tx_ring->obj_num;
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/* ... but it cannot exceed the TX head. */
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priv->tef->head = min(new_head, tx_ring->head);
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return mcp251xfd_check_tef_tail(priv);
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}
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static inline int
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mcp251xfd_tef_obj_read(const struct mcp251xfd_priv *priv,
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struct mcp251xfd_hw_tef_obj *hw_tef_obj,
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const u8 offset, const u8 len)
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{
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const struct mcp251xfd_tx_ring *tx_ring = priv->tx;
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const int val_bytes = regmap_get_val_bytes(priv->map_rx);
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if (IS_ENABLED(CONFIG_CAN_MCP251XFD_SANITY) &&
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(offset > tx_ring->obj_num ||
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len > tx_ring->obj_num ||
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offset + len > tx_ring->obj_num)) {
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netdev_err(priv->ndev,
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"Trying to read too many TEF objects (max=%d, offset=%d, len=%d).\n",
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tx_ring->obj_num, offset, len);
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return -ERANGE;
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}
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return regmap_bulk_read(priv->map_rx,
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mcp251xfd_get_tef_obj_addr(offset),
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hw_tef_obj,
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sizeof(*hw_tef_obj) / val_bytes * len);
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}
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static inline void mcp251xfd_ecc_tefif_successful(struct mcp251xfd_priv *priv)
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{
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struct mcp251xfd_ecc *ecc = &priv->ecc;
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ecc->ecc_stat = 0;
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}
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int mcp251xfd_handle_tefif(struct mcp251xfd_priv *priv)
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{
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struct mcp251xfd_hw_tef_obj hw_tef_obj[MCP251XFD_TX_OBJ_NUM_MAX];
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unsigned int total_frame_len = 0;
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u8 tef_tail, len, l;
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int err, i;
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err = mcp251xfd_tef_ring_update(priv);
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if (err)
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return err;
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tef_tail = mcp251xfd_get_tef_tail(priv);
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len = mcp251xfd_get_tef_len(priv);
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l = mcp251xfd_get_tef_linear_len(priv);
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err = mcp251xfd_tef_obj_read(priv, hw_tef_obj, tef_tail, l);
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if (err)
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return err;
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if (l < len) {
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err = mcp251xfd_tef_obj_read(priv, &hw_tef_obj[l], 0, len - l);
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if (err)
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return err;
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}
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for (i = 0; i < len; i++) {
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unsigned int frame_len = 0;
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err = mcp251xfd_handle_tefif_one(priv, &hw_tef_obj[i], &frame_len);
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/* -EAGAIN means the Sequence Number in the TEF
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* doesn't match our tef_tail. This can happen if we
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* read the TEF objects too early. Leave loop let the
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* interrupt handler call us again.
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*/
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if (err == -EAGAIN)
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goto out_netif_wake_queue;
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if (err)
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return err;
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total_frame_len += frame_len;
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}
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out_netif_wake_queue:
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len = i; /* number of handled goods TEFs */
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if (len) {
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struct mcp251xfd_tef_ring *ring = priv->tef;
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struct mcp251xfd_tx_ring *tx_ring = priv->tx;
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int offset;
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/* Increment the TEF FIFO tail pointer 'len' times in
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* a single SPI message.
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*
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* Note:
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* Calculate offset, so that the SPI transfer ends on
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* the last message of the uinc_xfer array, which has
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* "cs_change == 0", to properly deactivate the chip
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* select.
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*/
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offset = ARRAY_SIZE(ring->uinc_xfer) - len;
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err = spi_sync_transfer(priv->spi,
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ring->uinc_xfer + offset, len);
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if (err)
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return err;
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tx_ring->tail += len;
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netdev_completed_queue(priv->ndev, len, total_frame_len);
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err = mcp251xfd_check_tef_tail(priv);
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if (err)
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return err;
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}
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mcp251xfd_ecc_tefif_successful(priv);
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if (mcp251xfd_get_tx_free(priv->tx)) {
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/* Make sure that anybody stopping the queue after
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* this sees the new tx_ring->tail.
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*/
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smp_mb();
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netif_wake_queue(priv->ndev);
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}
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if (priv->tx_coalesce_usecs_irq)
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hrtimer_start(&priv->tx_irq_timer,
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ns_to_ktime(priv->tx_coalesce_usecs_irq *
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NSEC_PER_USEC),
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HRTIMER_MODE_REL);
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return 0;
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}
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