drivers/net/can/spi/mcp251xfd/mcp251xfd-tef.c - SHIFTPHONES/mainline/linux - Gitiles

 // 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;
 }
	// 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;
	}