net: ks8851: Separate SPI operations into separate file

Pull all the SPI bus specific code into a separate file, so that it is
not mixed with the common code. Rename ks8851.c to ks8851_common.c. The
ks8851_common.c is linked with ks8851_spi.c now, so it can call the
accessors in the ks8851_spi.c without any pointer indirection.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Petr Stetiar <ynezz@true.cz>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 485 insertions, 0 deletions

diff --git a/drivers/net/ethernet/micrel/ks8851_spi.c b/drivers/net/ethernet/micrel/ks8851_spi.c
new file mode 100644
index 000000000000..4ec7f1615977
--- /dev/null
+++ b/drivers/net/ethernet/micrel/ks8851_spi.c
@@ -0,0 +1,485 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* drivers/net/ethernet/micrel/ks8851.c
+ *
+ * Copyright 2009 Simtec Electronics
+ *	http://www.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DEBUG
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/cache.h>
+#include <linux/crc32.h>
+#include <linux/mii.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_net.h>
+
+#include "ks8851.h"
+
+static int msg_enable;
+
+/**
+ * struct ks8851_net_spi - KS8851 SPI driver private data
+ * @lock: Lock to ensure that the device is not accessed when busy.
+ * @tx_work: Work queue for tx packets
+ * @ks8851: KS8851 driver common private data
+ * @spidev: The spi device we're bound to.
+ * @spi_msg1: pre-setup SPI transfer with one message, @spi_xfer1.
+ * @spi_msg2: pre-setup SPI transfer with two messages, @spi_xfer2.
+ * @spi_xfer1: @spi_msg1 SPI transfer structure
+ * @spi_xfer2: @spi_msg2 SPI transfer structure
+ *
+ * The @lock ensures that the chip is protected when certain operations are
+ * in progress. When the read or write packet transfer is in progress, most
+ * of the chip registers are not ccessible until the transfer is finished and
+ * the DMA has been de-asserted.
+ */
+struct ks8851_net_spi {
+	struct ks8851_net	ks8851;
+	struct mutex		lock;
+	struct work_struct	tx_work;
+	struct spi_device	*spidev;
+	struct spi_message	spi_msg1;
+	struct spi_message	spi_msg2;
+	struct spi_transfer	spi_xfer1;
+	struct spi_transfer	spi_xfer2[2];
+};
+
+#define to_ks8851_spi(ks) container_of((ks), struct ks8851_net_spi, ks8851)
+
+/* SPI frame opcodes */
+#define KS_SPIOP_RD	0x00
+#define KS_SPIOP_WR	0x40
+#define KS_SPIOP_RXFIFO	0x80
+#define KS_SPIOP_TXFIFO	0xC0
+
+/* shift for byte-enable data */
+#define BYTE_EN(_x)	((_x) << 2)
+
+/* turn register number and byte-enable mask into data for start of packet */
+#define MK_OP(_byteen, _reg)	\
+	(BYTE_EN(_byteen) | (_reg) << (8 + 2) | (_reg) >> 6)
+
+/**
+ * ks8851_lock_spi - register access lock
+ * @ks: The chip state
+ * @flags: Spinlock flags
+ *
+ * Claim chip register access lock
+ */
+static void ks8851_lock_spi(struct ks8851_net *ks, unsigned long *flags)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+
+	mutex_lock(&kss->lock);
+}
+
+/**
+ * ks8851_unlock_spi - register access unlock
+ * @ks: The chip state
+ * @flags: Spinlock flags
+ *
+ * Release chip register access lock
+ */
+static void ks8851_unlock_spi(struct ks8851_net *ks, unsigned long *flags)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+
+	mutex_unlock(&kss->lock);
+}
+
+/* SPI register read/write calls.
+ *
+ * All these calls issue SPI transactions to access the chip's registers. They
+ * all require that the necessary lock is held to prevent accesses when the
+ * chip is busy transferring packet data (RX/TX FIFO accesses).
+ */
+
+/**
+ * ks8851_wrreg16_spi - write 16bit register value to chip via SPI
+ * @ks: The chip state
+ * @reg: The register address
+ * @val: The value to write
+ *
+ * Issue a write to put the value @val into the register specified in @reg.
+ */
+static void ks8851_wrreg16_spi(struct ks8851_net *ks, unsigned int reg,
+			       unsigned int val)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+	struct spi_transfer *xfer = &kss->spi_xfer1;
+	struct spi_message *msg = &kss->spi_msg1;
+	__le16 txb[2];
+	int ret;
+
+	txb[0] = cpu_to_le16(MK_OP(reg & 2 ? 0xC : 0x03, reg) | KS_SPIOP_WR);
+	txb[1] = cpu_to_le16(val);
+
+	xfer->tx_buf = txb;
+	xfer->rx_buf = NULL;
+	xfer->len = 4;
+
+	ret = spi_sync(kss->spidev, msg);
+	if (ret < 0)
+		netdev_err(ks->netdev, "spi_sync() failed\n");
+}
+
+/**
+ * ks8851_rdreg - issue read register command and return the data
+ * @ks: The device state
+ * @op: The register address and byte enables in message format.
+ * @rxb: The RX buffer to return the result into
+ * @rxl: The length of data expected.
+ *
+ * This is the low level read call that issues the necessary spi message(s)
+ * to read data from the register specified in @op.
+ */
+static void ks8851_rdreg(struct ks8851_net *ks, unsigned int op,
+			 u8 *rxb, unsigned int rxl)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+	struct spi_transfer *xfer;
+	struct spi_message *msg;
+	__le16 *txb = (__le16 *)ks->txd;
+	u8 *trx = ks->rxd;
+	int ret;
+
+	txb[0] = cpu_to_le16(op | KS_SPIOP_RD);
+
+	if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX) {
+		msg = &kss->spi_msg2;
+		xfer = kss->spi_xfer2;
+
+		xfer->tx_buf = txb;
+		xfer->rx_buf = NULL;
+		xfer->len = 2;
+
+		xfer++;
+		xfer->tx_buf = NULL;
+		xfer->rx_buf = trx;
+		xfer->len = rxl;
+	} else {
+		msg = &kss->spi_msg1;
+		xfer = &kss->spi_xfer1;
+
+		xfer->tx_buf = txb;
+		xfer->rx_buf = trx;
+		xfer->len = rxl + 2;
+	}
+
+	ret = spi_sync(kss->spidev, msg);
+	if (ret < 0)
+		netdev_err(ks->netdev, "read: spi_sync() failed\n");
+	else if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX)
+		memcpy(rxb, trx, rxl);
+	else
+		memcpy(rxb, trx + 2, rxl);
+}
+
+/**
+ * ks8851_rdreg16_spi - read 16 bit register from device via SPI
+ * @ks: The chip information
+ * @reg: The register address
+ *
+ * Read a 16bit register from the chip, returning the result
+ */
+static unsigned int ks8851_rdreg16_spi(struct ks8851_net *ks, unsigned int reg)
+{
+	__le16 rx = 0;
+
+	ks8851_rdreg(ks, MK_OP(reg & 2 ? 0xC : 0x3, reg), (u8 *)&rx, 2);
+	return le16_to_cpu(rx);
+}
+
+/**
+ * ks8851_rdfifo_spi - read data from the receive fifo via SPI
+ * @ks: The device state.
+ * @buff: The buffer address
+ * @len: The length of the data to read
+ *
+ * Issue an RXQ FIFO read command and read the @len amount of data from
+ * the FIFO into the buffer specified by @buff.
+ */
+static void ks8851_rdfifo_spi(struct ks8851_net *ks, u8 *buff, unsigned int len)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+	struct spi_transfer *xfer = kss->spi_xfer2;
+	struct spi_message *msg = &kss->spi_msg2;
+	u8 txb[1];
+	int ret;
+
+	netif_dbg(ks, rx_status, ks->netdev,
+		  "%s: %d@%p\n", __func__, len, buff);
+
+	/* set the operation we're issuing */
+	txb[0] = KS_SPIOP_RXFIFO;
+
+	xfer->tx_buf = txb;
+	xfer->rx_buf = NULL;
+	xfer->len = 1;
+
+	xfer++;
+	xfer->rx_buf = buff;
+	xfer->tx_buf = NULL;
+	xfer->len = len;
+
+	ret = spi_sync(kss->spidev, msg);
+	if (ret < 0)
+		netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__);
+}
+
+/**
+ * ks8851_wrfifo_spi - write packet to TX FIFO via SPI
+ * @ks: The device state.
+ * @txp: The sk_buff to transmit.
+ * @irq: IRQ on completion of the packet.
+ *
+ * Send the @txp to the chip. This means creating the relevant packet header
+ * specifying the length of the packet and the other information the chip
+ * needs, such as IRQ on completion. Send the header and the packet data to
+ * the device.
+ */
+static void ks8851_wrfifo_spi(struct ks8851_net *ks, struct sk_buff *txp,
+			      bool irq)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+	struct spi_transfer *xfer = kss->spi_xfer2;
+	struct spi_message *msg = &kss->spi_msg2;
+	unsigned int fid = 0;
+	int ret;
+
+	netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n",
+		  __func__, txp, txp->len, txp->data, irq);
+
+	fid = ks->fid++;
+	fid &= TXFR_TXFID_MASK;
+
+	if (irq)
+		fid |= TXFR_TXIC;	/* irq on completion */
+
+	/* start header at txb[1] to align txw entries */
+	ks->txh.txb[1] = KS_SPIOP_TXFIFO;
+	ks->txh.txw[1] = cpu_to_le16(fid);
+	ks->txh.txw[2] = cpu_to_le16(txp->len);
+
+	xfer->tx_buf = &ks->txh.txb[1];
+	xfer->rx_buf = NULL;
+	xfer->len = 5;
+
+	xfer++;
+	xfer->tx_buf = txp->data;
+	xfer->rx_buf = NULL;
+	xfer->len = ALIGN(txp->len, 4);
+
+	ret = spi_sync(kss->spidev, msg);
+	if (ret < 0)
+		netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__);
+}
+
+/**
+ * ks8851_rx_skb_spi - receive skbuff
+ * @ks: The device state
+ * @skb: The skbuff
+ */
+static void ks8851_rx_skb_spi(struct ks8851_net *ks, struct sk_buff *skb)
+{
+	netif_rx_ni(skb);
+}
+
+/**
+ * ks8851_tx_work - process tx packet(s)
+ * @work: The work strucutre what was scheduled.
+ *
+ * This is called when a number of packets have been scheduled for
+ * transmission and need to be sent to the device.
+ */
+static void ks8851_tx_work(struct work_struct *work)
+{
+	struct ks8851_net_spi *kss;
+	struct ks8851_net *ks;
+	unsigned long flags;
+	struct sk_buff *txb;
+	bool last;
+
+	kss = container_of(work, struct ks8851_net_spi, tx_work);
+	ks = &kss->ks8851;
+	last = skb_queue_empty(&ks->txq);
+
+	ks8851_lock_spi(ks, &flags);
+
+	while (!last) {
+		txb = skb_dequeue(&ks->txq);
+		last = skb_queue_empty(&ks->txq);
+
+		if (txb) {
+			ks8851_wrreg16_spi(ks, KS_RXQCR,
+					   ks->rc_rxqcr | RXQCR_SDA);
+			ks8851_wrfifo_spi(ks, txb, last);
+			ks8851_wrreg16_spi(ks, KS_RXQCR, ks->rc_rxqcr);
+			ks8851_wrreg16_spi(ks, KS_TXQCR, TXQCR_METFE);
+
+			ks8851_done_tx(ks, txb);
+		}
+	}
+
+	ks8851_unlock_spi(ks, &flags);
+}
+
+/**
+ * ks8851_flush_tx_work_spi - flush outstanding TX work
+ * @ks: The device state
+ */
+static void ks8851_flush_tx_work_spi(struct ks8851_net *ks)
+{
+	struct ks8851_net_spi *kss = to_ks8851_spi(ks);
+
+	flush_work(&kss->tx_work);
+}
+
+/**
+ * calc_txlen - calculate size of message to send packet
+ * @len: Length of data
+ *
+ * Returns the size of the TXFIFO message needed to send
+ * this packet.
+ */
+static unsigned int calc_txlen(unsigned int len)
+{
+	return ALIGN(len + 4, 4);
+}
+
+/**
+ * ks8851_start_xmit_spi - transmit packet using SPI
+ * @skb: The buffer to transmit
+ * @dev: The device used to transmit the packet.
+ *
+ * Called by the network layer to transmit the @skb. Queue the packet for
+ * the device and schedule the necessary work to transmit the packet when
+ * it is free.
+ *
+ * We do this to firstly avoid sleeping with the network device locked,
+ * and secondly so we can round up more than one packet to transmit which
+ * means we can try and avoid generating too many transmit done interrupts.
+ */
+static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb,
+					 struct net_device *dev)
+{
+	unsigned int needed = calc_txlen(skb->len);
+	struct ks8851_net *ks = netdev_priv(dev);
+	netdev_tx_t ret = NETDEV_TX_OK;
+	struct ks8851_net_spi *kss;
+
+	kss = to_ks8851_spi(ks);
+
+	netif_dbg(ks, tx_queued, ks->netdev,
+		  "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data);
+
+	spin_lock(&ks->statelock);
+
+	if (needed > ks->tx_space) {
+		netif_stop_queue(dev);
+		ret = NETDEV_TX_BUSY;
+	} else {
+		ks->tx_space -= needed;
+		skb_queue_tail(&ks->txq, skb);
+	}
+
+	spin_unlock(&ks->statelock);
+	schedule_work(&kss->tx_work);
+
+	return ret;
+}
+
+static int ks8851_probe_spi(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct ks8851_net_spi *kss;
+	struct net_device *netdev;
+	struct ks8851_net *ks;
+
+	netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_spi));
+	if (!netdev)
+		return -ENOMEM;
+
+	spi->bits_per_word = 8;
+
+	ks = netdev_priv(netdev);
+
+	ks->lock = ks8851_lock_spi;
+	ks->unlock = ks8851_unlock_spi;
+	ks->rdreg16 = ks8851_rdreg16_spi;
+	ks->wrreg16 = ks8851_wrreg16_spi;
+	ks->rdfifo = ks8851_rdfifo_spi;
+	ks->wrfifo = ks8851_wrfifo_spi;
+	ks->start_xmit = ks8851_start_xmit_spi;
+	ks->rx_skb = ks8851_rx_skb_spi;
+	ks->flush_tx_work = ks8851_flush_tx_work_spi;
+
+#define STD_IRQ (IRQ_LCI |	/* Link Change */	\
+		 IRQ_TXI |	/* TX done */		\
+		 IRQ_RXI |	/* RX done */		\
+		 IRQ_SPIBEI |	/* SPI bus error */	\
+		 IRQ_TXPSI |	/* TX process stop */	\
+		 IRQ_RXPSI)	/* RX process stop */
+	ks->rc_ier = STD_IRQ;
+
+	kss = to_ks8851_spi(ks);
+
+	kss->spidev = spi;
+	mutex_init(&kss->lock);
+	INIT_WORK(&kss->tx_work, ks8851_tx_work);
+
+	/* initialise pre-made spi transfer messages */
+	spi_message_init(&kss->spi_msg1);
+	spi_message_add_tail(&kss->spi_xfer1, &kss->spi_msg1);
+
+	spi_message_init(&kss->spi_msg2);
+	spi_message_add_tail(&kss->spi_xfer2[0], &kss->spi_msg2);
+	spi_message_add_tail(&kss->spi_xfer2[1], &kss->spi_msg2);
+
+	netdev->irq = spi->irq;
+
+	return ks8851_probe_common(netdev, dev, msg_enable);
+}
+
+static int ks8851_remove_spi(struct spi_device *spi)
+{
+	return ks8851_remove_common(&spi->dev);
+}
+
+static const struct of_device_id ks8851_match_table[] = {
+	{ .compatible = "micrel,ks8851" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ks8851_match_table);
+
+static struct spi_driver ks8851_driver = {
+	.driver = {
+		.name = "ks8851",
+		.of_match_table = ks8851_match_table,
+		.pm = &ks8851_pm_ops,
+	},
+	.probe = ks8851_probe_spi,
+	.remove = ks8851_remove_spi,
+};
+module_spi_driver(ks8851_driver);
+
+MODULE_DESCRIPTION("KS8851 Network driver");
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL");
+
+module_param_named(message, msg_enable, int, 0);
+MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)");
+MODULE_ALIAS("spi:ks8851");