1 files changed, 269 insertions, 0 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
new file mode 100644
index 000000000000..92f9e9b01289
--- /dev/null
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
@@ -0,0 +1,269 @@
+// 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 <asm/unaligned.h>
+
+#include "mcp251xfd.h"
+
+static inline u8
+mcp251xfd_cmd_prepare_write_reg(const struct mcp251xfd_priv *priv,
+				union mcp251xfd_write_reg_buf *write_reg_buf,
+				const u16 reg, const u32 mask, const u32 val)
+{
+	u8 first_byte, last_byte, len;
+	u8 *data;
+	__le32 val_le32;
+
+	first_byte = mcp251xfd_first_byte_set(mask);
+	last_byte = mcp251xfd_last_byte_set(mask);
+	len = last_byte - first_byte + 1;
+
+	data = mcp251xfd_spi_cmd_write(priv, write_reg_buf, reg + first_byte);
+	val_le32 = cpu_to_le32(val >> BITS_PER_BYTE * first_byte);
+	memcpy(data, &val_le32, len);
+
+	if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_REG) {
+		u16 crc;
+
+		mcp251xfd_spi_cmd_crc_set_len_in_reg(&write_reg_buf->crc.cmd,
+						     len);
+		/* CRC */
+		len += sizeof(write_reg_buf->crc.cmd);
+		crc = mcp251xfd_crc16_compute(&write_reg_buf->crc, len);
+		put_unaligned_be16(crc, (void *)write_reg_buf + len);
+
+		/* Total length */
+		len += sizeof(write_reg_buf->crc.crc);
+	} else {
+		len += sizeof(write_reg_buf->nocrc.cmd);
+	}
+
+	return len;
+}
+
+static void
+mcp251xfd_tx_ring_init_tx_obj(const struct mcp251xfd_priv *priv,
+			      const struct mcp251xfd_tx_ring *ring,
+			      struct mcp251xfd_tx_obj *tx_obj,
+			      const u8 rts_buf_len,
+			      const u8 n)
+{
+	struct spi_transfer *xfer;
+	u16 addr;
+
+	/* FIFO load */
+	addr = mcp251xfd_get_tx_obj_addr(ring, n);
+	if (priv->devtype_data.quirks & MCP251XFD_QUIRK_CRC_TX)
+		mcp251xfd_spi_cmd_write_crc_set_addr(&tx_obj->buf.crc.cmd,
+						     addr);
+	else
+		mcp251xfd_spi_cmd_write_nocrc(&tx_obj->buf.nocrc.cmd,
+					      addr);
+
+	xfer = &tx_obj->xfer[0];
+	xfer->tx_buf = &tx_obj->buf;
+	xfer->len = 0;	/* actual len is assigned on the fly */
+	xfer->cs_change = 1;
+	xfer->cs_change_delay.value = 0;
+	xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+
+	/* FIFO request to send */
+	xfer = &tx_obj->xfer[1];
+	xfer->tx_buf = &ring->rts_buf;
+	xfer->len = rts_buf_len;
+
+	/* SPI message */
+	spi_message_init_with_transfers(&tx_obj->msg, tx_obj->xfer,
+					ARRAY_SIZE(tx_obj->xfer));
+}
+
+void mcp251xfd_ring_init(struct mcp251xfd_priv *priv)
+{
+	struct mcp251xfd_tef_ring *tef_ring;
+	struct mcp251xfd_tx_ring *tx_ring;
+	struct mcp251xfd_rx_ring *rx_ring, *prev_rx_ring = NULL;
+	struct mcp251xfd_tx_obj *tx_obj;
+	struct spi_transfer *xfer;
+	u32 val;
+	u16 addr;
+	u8 len;
+	int i, j;
+
+	netdev_reset_queue(priv->ndev);
+
+	/* TEF */
+	tef_ring = priv->tef;
+	tef_ring->head = 0;
+	tef_ring->tail = 0;
+
+	/* FIFO increment TEF tail pointer */
+	addr = MCP251XFD_REG_TEFCON;
+	val = MCP251XFD_REG_TEFCON_UINC;
+	len = mcp251xfd_cmd_prepare_write_reg(priv, &tef_ring->uinc_buf,
+					      addr, val, val);
+
+	for (j = 0; j < ARRAY_SIZE(tef_ring->uinc_xfer); j++) {
+		xfer = &tef_ring->uinc_xfer[j];
+		xfer->tx_buf = &tef_ring->uinc_buf;
+		xfer->len = len;
+		xfer->cs_change = 1;
+		xfer->cs_change_delay.value = 0;
+		xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+	}
+
+	/* "cs_change == 1" on the last transfer results in an active
+	 * chip select after the complete SPI message. This causes the
+	 * controller to interpret the next register access as
+	 * data. Set "cs_change" of the last transfer to "0" to
+	 * properly deactivate the chip select at the end of the
+	 * message.
+	 */
+	xfer->cs_change = 0;
+
+	/* TX */
+	tx_ring = priv->tx;
+	tx_ring->head = 0;
+	tx_ring->tail = 0;
+	tx_ring->base = mcp251xfd_get_tef_obj_addr(tx_ring->obj_num);
+
+	/* FIFO request to send */
+	addr = MCP251XFD_REG_FIFOCON(MCP251XFD_TX_FIFO);
+	val = MCP251XFD_REG_FIFOCON_TXREQ | MCP251XFD_REG_FIFOCON_UINC;
+	len = mcp251xfd_cmd_prepare_write_reg(priv, &tx_ring->rts_buf,
+					      addr, val, val);
+
+	mcp251xfd_for_each_tx_obj(tx_ring, tx_obj, i)
+		mcp251xfd_tx_ring_init_tx_obj(priv, tx_ring, tx_obj, len, i);
+
+	/* RX */
+	mcp251xfd_for_each_rx_ring(priv, rx_ring, i) {
+		rx_ring->head = 0;
+		rx_ring->tail = 0;
+		rx_ring->nr = i;
+		rx_ring->fifo_nr = MCP251XFD_RX_FIFO(i);
+
+		if (!prev_rx_ring)
+			rx_ring->base =
+				mcp251xfd_get_tx_obj_addr(tx_ring,
+							  tx_ring->obj_num);
+		else
+			rx_ring->base = prev_rx_ring->base +
+				prev_rx_ring->obj_size *
+				prev_rx_ring->obj_num;
+
+		prev_rx_ring = rx_ring;
+
+		/* FIFO increment RX tail pointer */
+		addr = MCP251XFD_REG_FIFOCON(rx_ring->fifo_nr);
+		val = MCP251XFD_REG_FIFOCON_UINC;
+		len = mcp251xfd_cmd_prepare_write_reg(priv, &rx_ring->uinc_buf,
+						      addr, val, val);
+
+		for (j = 0; j < ARRAY_SIZE(rx_ring->uinc_xfer); j++) {
+			xfer = &rx_ring->uinc_xfer[j];
+			xfer->tx_buf = &rx_ring->uinc_buf;
+			xfer->len = len;
+			xfer->cs_change = 1;
+			xfer->cs_change_delay.value = 0;
+			xfer->cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
+		}
+
+		/* "cs_change == 1" on the last transfer results in an
+		 * active chip select after the complete SPI
+		 * message. This causes the controller to interpret
+		 * the next register access as data. Set "cs_change"
+		 * of the last transfer to "0" to properly deactivate
+		 * the chip select at the end of the message.
+		 */
+		xfer->cs_change = 0;
+	}
+}
+
+void mcp251xfd_ring_free(struct mcp251xfd_priv *priv)
+{
+	int i;
+
+	for (i = ARRAY_SIZE(priv->rx) - 1; i >= 0; i--) {
+		kfree(priv->rx[i]);
+		priv->rx[i] = NULL;
+	}
+}
+
+int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
+{
+	struct mcp251xfd_tx_ring *tx_ring;
+	struct mcp251xfd_rx_ring *rx_ring;
+	int tef_obj_size, tx_obj_size, rx_obj_size;
+	int tx_obj_num;
+	int ram_free, i;
+
+	tef_obj_size = sizeof(struct mcp251xfd_hw_tef_obj);
+	if (mcp251xfd_is_fd_mode(priv)) {
+		tx_obj_num = MCP251XFD_TX_OBJ_NUM_CANFD;
+		tx_obj_size = sizeof(struct mcp251xfd_hw_tx_obj_canfd);
+		rx_obj_size = sizeof(struct mcp251xfd_hw_rx_obj_canfd);
+	} else {
+		tx_obj_num = MCP251XFD_TX_OBJ_NUM_CAN;
+		tx_obj_size = sizeof(struct mcp251xfd_hw_tx_obj_can);
+		rx_obj_size = sizeof(struct mcp251xfd_hw_rx_obj_can);
+	}
+
+	tx_ring = priv->tx;
+	tx_ring->obj_num = tx_obj_num;
+	tx_ring->obj_size = tx_obj_size;
+
+	ram_free = MCP251XFD_RAM_SIZE - tx_obj_num *
+		(tef_obj_size + tx_obj_size);
+
+	for (i = 0;
+	     i < ARRAY_SIZE(priv->rx) && ram_free >= rx_obj_size;
+	     i++) {
+		int rx_obj_num;
+
+		rx_obj_num = ram_free / rx_obj_size;
+		rx_obj_num = min(1 << (fls(rx_obj_num) - 1),
+				 MCP251XFD_RX_OBJ_NUM_MAX);
+
+		rx_ring = kzalloc(sizeof(*rx_ring) + rx_obj_size * rx_obj_num,
+				  GFP_KERNEL);
+		if (!rx_ring) {
+			mcp251xfd_ring_free(priv);
+			return -ENOMEM;
+		}
+		rx_ring->obj_num = rx_obj_num;
+		rx_ring->obj_size = rx_obj_size;
+		priv->rx[i] = rx_ring;
+
+		ram_free -= rx_ring->obj_num * rx_ring->obj_size;
+	}
+	priv->rx_ring_num = i;
+
+	netdev_dbg(priv->ndev,
+		   "FIFO setup: TEF: %d*%d bytes = %d bytes, TX: %d*%d bytes = %d bytes\n",
+		   tx_obj_num, tef_obj_size, tef_obj_size * tx_obj_num,
+		   tx_obj_num, tx_obj_size, tx_obj_size * tx_obj_num);
+
+	mcp251xfd_for_each_rx_ring(priv, rx_ring, i) {
+		netdev_dbg(priv->ndev,
+			   "FIFO setup: RX-%d: %d*%d bytes = %d bytes\n",
+			   i, rx_ring->obj_num, rx_ring->obj_size,
+			   rx_ring->obj_size * rx_ring->obj_num);
+	}
+
+	netdev_dbg(priv->ndev,
+		   "FIFO setup: free: %d bytes\n",
+		   ram_free);
+
+	return 0;
+}