1 files changed, 990 insertions, 0 deletions

diff --git a/kernel/drivers/net/ethernet/qualcomm/qca_spi.c b/kernel/drivers/net/ethernet/qualcomm/qca_spi.c
new file mode 100644
index 000000000..6af028d5f
--- /dev/null
+++ b/kernel/drivers/net/ethernet/qualcomm/qca_spi.c
@@ -0,0 +1,990 @@
+/*
+ *   Copyright (c) 2011, 2012, Qualcomm Atheros Communications Inc.
+ *   Copyright (c) 2014, I2SE GmbH
+ *
+ *   Permission to use, copy, modify, and/or distribute this software
+ *   for any purpose with or without fee is hereby granted, provided
+ *   that the above copyright notice and this permission notice appear
+ *   in all copies.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+ *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*   This module implements the Qualcomm Atheros SPI protocol for
+ *   kernel-based SPI device; it is essentially an Ethernet-to-SPI
+ *   serial converter;
+ */
+
+#include <linux/errno.h>
+#include <linux/etherdevice.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_net.h>
+#include <linux/sched.h>
+#include <linux/skbuff.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+
+#include "qca_7k.h"
+#include "qca_debug.h"
+#include "qca_framing.h"
+#include "qca_spi.h"
+
+#define MAX_DMA_BURST_LEN 5000
+
+/*   Modules parameters     */
+#define QCASPI_CLK_SPEED_MIN 1000000
+#define QCASPI_CLK_SPEED_MAX 16000000
+#define QCASPI_CLK_SPEED     8000000
+static int qcaspi_clkspeed;
+module_param(qcaspi_clkspeed, int, 0);
+MODULE_PARM_DESC(qcaspi_clkspeed, "SPI bus clock speed (Hz). Use 1000000-16000000.");
+
+#define QCASPI_BURST_LEN_MIN 1
+#define QCASPI_BURST_LEN_MAX MAX_DMA_BURST_LEN
+static int qcaspi_burst_len = MAX_DMA_BURST_LEN;
+module_param(qcaspi_burst_len, int, 0);
+MODULE_PARM_DESC(qcaspi_burst_len, "Number of data bytes per burst. Use 1-5000.");
+
+#define QCASPI_PLUGGABLE_MIN 0
+#define QCASPI_PLUGGABLE_MAX 1
+static int qcaspi_pluggable = QCASPI_PLUGGABLE_MIN;
+module_param(qcaspi_pluggable, int, 0);
+MODULE_PARM_DESC(qcaspi_pluggable, "Pluggable SPI connection (yes/no).");
+
+#define QCASPI_MTU QCAFRM_ETHMAXMTU
+#define QCASPI_TX_TIMEOUT (1 * HZ)
+#define QCASPI_QCA7K_REBOOT_TIME_MS 1000
+
+static void
+start_spi_intr_handling(struct qcaspi *qca, u16 *intr_cause)
+{
+	*intr_cause = 0;
+
+	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
+	qcaspi_read_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
+	netdev_dbg(qca->net_dev, "interrupts: 0x%04x\n", *intr_cause);
+}
+
+static void
+end_spi_intr_handling(struct qcaspi *qca, u16 intr_cause)
+{
+	u16 intr_enable = (SPI_INT_CPU_ON |
+			   SPI_INT_PKT_AVLBL |
+			   SPI_INT_RDBUF_ERR |
+			   SPI_INT_WRBUF_ERR);
+
+	qcaspi_write_register(qca, SPI_REG_INTR_CAUSE, intr_cause);
+	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, intr_enable);
+	netdev_dbg(qca->net_dev, "acking int: 0x%04x\n", intr_cause);
+}
+
+static u32
+qcaspi_write_burst(struct qcaspi *qca, u8 *src, u32 len)
+{
+	__be16 cmd;
+	struct spi_message *msg = &qca->spi_msg2;
+	struct spi_transfer *transfer = &qca->spi_xfer2[0];
+	int ret;
+
+	cmd = cpu_to_be16(QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
+	transfer->tx_buf = &cmd;
+	transfer->rx_buf = NULL;
+	transfer->len = QCASPI_CMD_LEN;
+	transfer = &qca->spi_xfer2[1];
+	transfer->tx_buf = src;
+	transfer->rx_buf = NULL;
+	transfer->len = len;
+
+	ret = spi_sync(qca->spi_dev, msg);
+
+	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
+		qcaspi_spi_error(qca);
+		return 0;
+	}
+
+	return len;
+}
+
+static u32
+qcaspi_write_legacy(struct qcaspi *qca, u8 *src, u32 len)
+{
+	struct spi_message *msg = &qca->spi_msg1;
+	struct spi_transfer *transfer = &qca->spi_xfer1;
+	int ret;
+
+	transfer->tx_buf = src;
+	transfer->rx_buf = NULL;
+	transfer->len = len;
+
+	ret = spi_sync(qca->spi_dev, msg);
+
+	if (ret || (msg->actual_length != len)) {
+		qcaspi_spi_error(qca);
+		return 0;
+	}
+
+	return len;
+}
+
+static u32
+qcaspi_read_burst(struct qcaspi *qca, u8 *dst, u32 len)
+{
+	struct spi_message *msg = &qca->spi_msg2;
+	__be16 cmd;
+	struct spi_transfer *transfer = &qca->spi_xfer2[0];
+	int ret;
+
+	cmd = cpu_to_be16(QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
+	transfer->tx_buf = &cmd;
+	transfer->rx_buf = NULL;
+	transfer->len = QCASPI_CMD_LEN;
+	transfer = &qca->spi_xfer2[1];
+	transfer->tx_buf = NULL;
+	transfer->rx_buf = dst;
+	transfer->len = len;
+
+	ret = spi_sync(qca->spi_dev, msg);
+
+	if (ret || (msg->actual_length != QCASPI_CMD_LEN + len)) {
+		qcaspi_spi_error(qca);
+		return 0;
+	}
+
+	return len;
+}
+
+static u32
+qcaspi_read_legacy(struct qcaspi *qca, u8 *dst, u32 len)
+{
+	struct spi_message *msg = &qca->spi_msg1;
+	struct spi_transfer *transfer = &qca->spi_xfer1;
+	int ret;
+
+	transfer->tx_buf = NULL;
+	transfer->rx_buf = dst;
+	transfer->len = len;
+
+	ret = spi_sync(qca->spi_dev, msg);
+
+	if (ret || (msg->actual_length != len)) {
+		qcaspi_spi_error(qca);
+		return 0;
+	}
+
+	return len;
+}
+
+static int
+qcaspi_tx_frame(struct qcaspi *qca, struct sk_buff *skb)
+{
+	u32 count;
+	u32 written;
+	u32 offset;
+	u32 len;
+
+	len = skb->len;
+
+	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, len);
+	if (qca->legacy_mode)
+		qcaspi_tx_cmd(qca, QCA7K_SPI_WRITE | QCA7K_SPI_EXTERNAL);
+
+	offset = 0;
+	while (len) {
+		count = len;
+		if (count > qca->burst_len)
+			count = qca->burst_len;
+
+		if (qca->legacy_mode) {
+			written = qcaspi_write_legacy(qca,
+						      skb->data + offset,
+						      count);
+		} else {
+			written = qcaspi_write_burst(qca,
+						     skb->data + offset,
+						     count);
+		}
+
+		if (written != count)
+			return -1;
+
+		offset += count;
+		len -= count;
+	}
+
+	return 0;
+}
+
+static int
+qcaspi_transmit(struct qcaspi *qca)
+{
+	struct net_device_stats *n_stats = &qca->net_dev->stats;
+	u16 available = 0;
+	u32 pkt_len;
+	u16 new_head;
+	u16 packets = 0;
+
+	if (qca->txr.skb[qca->txr.head] == NULL)
+		return 0;
+
+	qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA, &available);
+
+	while (qca->txr.skb[qca->txr.head]) {
+		pkt_len = qca->txr.skb[qca->txr.head]->len + QCASPI_HW_PKT_LEN;
+
+		if (available < pkt_len) {
+			if (packets == 0)
+				qca->stats.write_buf_miss++;
+			break;
+		}
+
+		if (qcaspi_tx_frame(qca, qca->txr.skb[qca->txr.head]) == -1) {
+			qca->stats.write_err++;
+			return -1;
+		}
+
+		packets++;
+		n_stats->tx_packets++;
+		n_stats->tx_bytes += qca->txr.skb[qca->txr.head]->len;
+		available -= pkt_len;
+
+		/* remove the skb from the queue */
+		/* XXX After inconsistent lock states netif_tx_lock()
+		 * has been replaced by netif_tx_lock_bh() and so on.
+		 */
+		netif_tx_lock_bh(qca->net_dev);
+		dev_kfree_skb(qca->txr.skb[qca->txr.head]);
+		qca->txr.skb[qca->txr.head] = NULL;
+		qca->txr.size -= pkt_len;
+		new_head = qca->txr.head + 1;
+		if (new_head >= qca->txr.count)
+			new_head = 0;
+		qca->txr.head = new_head;
+		if (netif_queue_stopped(qca->net_dev))
+			netif_wake_queue(qca->net_dev);
+		netif_tx_unlock_bh(qca->net_dev);
+	}
+
+	return 0;
+}
+
+static int
+qcaspi_receive(struct qcaspi *qca)
+{
+	struct net_device *net_dev = qca->net_dev;
+	struct net_device_stats *n_stats = &net_dev->stats;
+	u16 available = 0;
+	u32 bytes_read;
+	u8 *cp;
+
+	/* Allocate rx SKB if we don't have one available. */
+	if (!qca->rx_skb) {
+		qca->rx_skb = netdev_alloc_skb(net_dev,
+					       net_dev->mtu + VLAN_ETH_HLEN);
+		if (!qca->rx_skb) {
+			netdev_dbg(net_dev, "out of RX resources\n");
+			qca->stats.out_of_mem++;
+			return -1;
+		}
+	}
+
+	/* Read the packet size. */
+	qcaspi_read_register(qca, SPI_REG_RDBUF_BYTE_AVA, &available);
+	netdev_dbg(net_dev, "qcaspi_receive: SPI_REG_RDBUF_BYTE_AVA: Value: %08x\n",
+		   available);
+
+	if (available == 0) {
+		netdev_dbg(net_dev, "qcaspi_receive called without any data being available!\n");
+		return -1;
+	}
+
+	qcaspi_write_register(qca, SPI_REG_BFR_SIZE, available);
+
+	if (qca->legacy_mode)
+		qcaspi_tx_cmd(qca, QCA7K_SPI_READ | QCA7K_SPI_EXTERNAL);
+
+	while (available) {
+		u32 count = available;
+
+		if (count > qca->burst_len)
+			count = qca->burst_len;
+
+		if (qca->legacy_mode) {
+			bytes_read = qcaspi_read_legacy(qca, qca->rx_buffer,
+							count);
+		} else {
+			bytes_read = qcaspi_read_burst(qca, qca->rx_buffer,
+						       count);
+		}
+
+		netdev_dbg(net_dev, "available: %d, byte read: %d\n",
+			   available, bytes_read);
+
+		if (bytes_read) {
+			available -= bytes_read;
+		} else {
+			qca->stats.read_err++;
+			return -1;
+		}
+
+		cp = qca->rx_buffer;
+
+		while ((bytes_read--) && (qca->rx_skb)) {
+			s32 retcode;
+
+			retcode = qcafrm_fsm_decode(&qca->frm_handle,
+						    qca->rx_skb->data,
+						    skb_tailroom(qca->rx_skb),
+						    *cp);
+			cp++;
+			switch (retcode) {
+			case QCAFRM_GATHER:
+			case QCAFRM_NOHEAD:
+				break;
+			case QCAFRM_NOTAIL:
+				netdev_dbg(net_dev, "no RX tail\n");
+				n_stats->rx_errors++;
+				n_stats->rx_dropped++;
+				break;
+			case QCAFRM_INVLEN:
+				netdev_dbg(net_dev, "invalid RX length\n");
+				n_stats->rx_errors++;
+				n_stats->rx_dropped++;
+				break;
+			default:
+				qca->rx_skb->dev = qca->net_dev;
+				n_stats->rx_packets++;
+				n_stats->rx_bytes += retcode;
+				skb_put(qca->rx_skb, retcode);
+				qca->rx_skb->protocol = eth_type_trans(
+					qca->rx_skb, qca->rx_skb->dev);
+				qca->rx_skb->ip_summed = CHECKSUM_UNNECESSARY;
+				netif_rx_ni(qca->rx_skb);
+				qca->rx_skb = netdev_alloc_skb(net_dev,
+					net_dev->mtu + VLAN_ETH_HLEN);
+				if (!qca->rx_skb) {
+					netdev_dbg(net_dev, "out of RX resources\n");
+					n_stats->rx_errors++;
+					qca->stats.out_of_mem++;
+					break;
+				}
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*   Check that tx ring stores only so much bytes
+ *   that fit into the internal QCA buffer.
+ */
+
+static int
+qcaspi_tx_ring_has_space(struct tx_ring *txr)
+{
+	if (txr->skb[txr->tail])
+		return 0;
+
+	return (txr->size + QCAFRM_ETHMAXLEN < QCASPI_HW_BUF_LEN) ? 1 : 0;
+}
+
+/*   Flush the tx ring. This function is only safe to
+ *   call from the qcaspi_spi_thread.
+ */
+
+static void
+qcaspi_flush_tx_ring(struct qcaspi *qca)
+{
+	int i;
+
+	/* XXX After inconsistent lock states netif_tx_lock()
+	 * has been replaced by netif_tx_lock_bh() and so on.
+	 */
+	netif_tx_lock_bh(qca->net_dev);
+	for (i = 0; i < TX_RING_MAX_LEN; i++) {
+		if (qca->txr.skb[i]) {
+			dev_kfree_skb(qca->txr.skb[i]);
+			qca->txr.skb[i] = NULL;
+			qca->net_dev->stats.tx_dropped++;
+		}
+	}
+	qca->txr.tail = 0;
+	qca->txr.head = 0;
+	qca->txr.size = 0;
+	netif_tx_unlock_bh(qca->net_dev);
+}
+
+static void
+qcaspi_qca7k_sync(struct qcaspi *qca, int event)
+{
+	u16 signature = 0;
+	u16 spi_config;
+	u16 wrbuf_space = 0;
+	static u16 reset_count;
+
+	if (event == QCASPI_EVENT_CPUON) {
+		/* Read signature twice, if not valid
+		 * go back to unknown state.
+		 */
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+		if (signature != QCASPI_GOOD_SIGNATURE) {
+			qca->sync = QCASPI_SYNC_UNKNOWN;
+			netdev_dbg(qca->net_dev, "sync: got CPU on, but signature was invalid, restart\n");
+		} else {
+			/* ensure that the WRBUF is empty */
+			qcaspi_read_register(qca, SPI_REG_WRBUF_SPC_AVA,
+					     &wrbuf_space);
+			if (wrbuf_space != QCASPI_HW_BUF_LEN) {
+				netdev_dbg(qca->net_dev, "sync: got CPU on, but wrbuf not empty. reset!\n");
+				qca->sync = QCASPI_SYNC_UNKNOWN;
+			} else {
+				netdev_dbg(qca->net_dev, "sync: got CPU on, now in sync\n");
+				qca->sync = QCASPI_SYNC_READY;
+				return;
+			}
+		}
+	}
+
+	switch (qca->sync) {
+	case QCASPI_SYNC_READY:
+		/* Read signature, if not valid go to unknown state. */
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+		if (signature != QCASPI_GOOD_SIGNATURE) {
+			qca->sync = QCASPI_SYNC_UNKNOWN;
+			netdev_dbg(qca->net_dev, "sync: bad signature, restart\n");
+			/* don't reset right away */
+			return;
+		}
+		break;
+	case QCASPI_SYNC_UNKNOWN:
+		/* Read signature, if not valid stay in unknown state */
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+		if (signature != QCASPI_GOOD_SIGNATURE) {
+			netdev_dbg(qca->net_dev, "sync: could not read signature to reset device, retry.\n");
+			return;
+		}
+
+		/* TODO: use GPIO to reset QCA7000 in legacy mode*/
+		netdev_dbg(qca->net_dev, "sync: resetting device.\n");
+		qcaspi_read_register(qca, SPI_REG_SPI_CONFIG, &spi_config);
+		spi_config |= QCASPI_SLAVE_RESET_BIT;
+		qcaspi_write_register(qca, SPI_REG_SPI_CONFIG, spi_config);
+
+		qca->sync = QCASPI_SYNC_RESET;
+		qca->stats.trig_reset++;
+		reset_count = 0;
+		break;
+	case QCASPI_SYNC_RESET:
+		reset_count++;
+		netdev_dbg(qca->net_dev, "sync: waiting for CPU on, count %u.\n",
+			   reset_count);
+		if (reset_count >= QCASPI_RESET_TIMEOUT) {
+			/* reset did not seem to take place, try again */
+			qca->sync = QCASPI_SYNC_UNKNOWN;
+			qca->stats.reset_timeout++;
+			netdev_dbg(qca->net_dev, "sync: reset timeout, restarting process.\n");
+		}
+		break;
+	}
+}
+
+static int
+qcaspi_spi_thread(void *data)
+{
+	struct qcaspi *qca = data;
+	u16 intr_cause = 0;
+
+	netdev_info(qca->net_dev, "SPI thread created\n");
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if ((qca->intr_req == qca->intr_svc) &&
+		    (qca->txr.skb[qca->txr.head] == NULL) &&
+		    (qca->sync == QCASPI_SYNC_READY))
+			schedule();
+
+		set_current_state(TASK_RUNNING);
+
+		netdev_dbg(qca->net_dev, "have work to do. int: %d, tx_skb: %p\n",
+			   qca->intr_req - qca->intr_svc,
+			   qca->txr.skb[qca->txr.head]);
+
+		qcaspi_qca7k_sync(qca, QCASPI_EVENT_UPDATE);
+
+		if (qca->sync != QCASPI_SYNC_READY) {
+			netdev_dbg(qca->net_dev, "sync: not ready %u, turn off carrier and flush\n",
+				   (unsigned int)qca->sync);
+			netif_stop_queue(qca->net_dev);
+			netif_carrier_off(qca->net_dev);
+			qcaspi_flush_tx_ring(qca);
+			msleep(QCASPI_QCA7K_REBOOT_TIME_MS);
+		}
+
+		if (qca->intr_svc != qca->intr_req) {
+			qca->intr_svc = qca->intr_req;
+			start_spi_intr_handling(qca, &intr_cause);
+
+			if (intr_cause & SPI_INT_CPU_ON) {
+				qcaspi_qca7k_sync(qca, QCASPI_EVENT_CPUON);
+
+				/* not synced. */
+				if (qca->sync != QCASPI_SYNC_READY)
+					continue;
+
+				qca->stats.device_reset++;
+				netif_wake_queue(qca->net_dev);
+				netif_carrier_on(qca->net_dev);
+			}
+
+			if (intr_cause & SPI_INT_RDBUF_ERR) {
+				/* restart sync */
+				netdev_dbg(qca->net_dev, "===> rdbuf error!\n");
+				qca->stats.read_buf_err++;
+				qca->sync = QCASPI_SYNC_UNKNOWN;
+				continue;
+			}
+
+			if (intr_cause & SPI_INT_WRBUF_ERR) {
+				/* restart sync */
+				netdev_dbg(qca->net_dev, "===> wrbuf error!\n");
+				qca->stats.write_buf_err++;
+				qca->sync = QCASPI_SYNC_UNKNOWN;
+				continue;
+			}
+
+			/* can only handle other interrupts
+			 * if sync has occurred
+			 */
+			if (qca->sync == QCASPI_SYNC_READY) {
+				if (intr_cause & SPI_INT_PKT_AVLBL)
+					qcaspi_receive(qca);
+			}
+
+			end_spi_intr_handling(qca, intr_cause);
+		}
+
+		if (qca->sync == QCASPI_SYNC_READY)
+			qcaspi_transmit(qca);
+	}
+	set_current_state(TASK_RUNNING);
+	netdev_info(qca->net_dev, "SPI thread exit\n");
+
+	return 0;
+}
+
+static irqreturn_t
+qcaspi_intr_handler(int irq, void *data)
+{
+	struct qcaspi *qca = data;
+
+	qca->intr_req++;
+	if (qca->spi_thread &&
+	    qca->spi_thread->state != TASK_RUNNING)
+		wake_up_process(qca->spi_thread);
+
+	return IRQ_HANDLED;
+}
+
+int
+qcaspi_netdev_open(struct net_device *dev)
+{
+	struct qcaspi *qca = netdev_priv(dev);
+	int ret = 0;
+
+	if (!qca)
+		return -EINVAL;
+
+	qca->intr_req = 1;
+	qca->intr_svc = 0;
+	qca->sync = QCASPI_SYNC_UNKNOWN;
+	qcafrm_fsm_init(&qca->frm_handle);
+
+	qca->spi_thread = kthread_run((void *)qcaspi_spi_thread,
+				      qca, "%s", dev->name);
+
+	if (IS_ERR(qca->spi_thread)) {
+		netdev_err(dev, "%s: unable to start kernel thread.\n",
+			   QCASPI_DRV_NAME);
+		return PTR_ERR(qca->spi_thread);
+	}
+
+	ret = request_irq(qca->spi_dev->irq, qcaspi_intr_handler, 0,
+			  dev->name, qca);
+	if (ret) {
+		netdev_err(dev, "%s: unable to get IRQ %d (irqval=%d).\n",
+			   QCASPI_DRV_NAME, qca->spi_dev->irq, ret);
+		kthread_stop(qca->spi_thread);
+		return ret;
+	}
+
+	netif_start_queue(qca->net_dev);
+
+	return 0;
+}
+
+int
+qcaspi_netdev_close(struct net_device *dev)
+{
+	struct qcaspi *qca = netdev_priv(dev);
+
+	netif_stop_queue(dev);
+
+	qcaspi_write_register(qca, SPI_REG_INTR_ENABLE, 0);
+	free_irq(qca->spi_dev->irq, qca);
+
+	kthread_stop(qca->spi_thread);
+	qca->spi_thread = NULL;
+	qcaspi_flush_tx_ring(qca);
+
+	return 0;
+}
+
+static netdev_tx_t
+qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	u32 frame_len;
+	u8 *ptmp;
+	struct qcaspi *qca = netdev_priv(dev);
+	u16 new_tail;
+	struct sk_buff *tskb;
+	u8 pad_len = 0;
+
+	if (skb->len < QCAFRM_ETHMINLEN)
+		pad_len = QCAFRM_ETHMINLEN - skb->len;
+
+	if (qca->txr.skb[qca->txr.tail]) {
+		netdev_warn(qca->net_dev, "queue was unexpectedly full!\n");
+		netif_stop_queue(qca->net_dev);
+		qca->stats.ring_full++;
+		return NETDEV_TX_BUSY;
+	}
+
+	if ((skb_headroom(skb) < QCAFRM_HEADER_LEN) ||
+	    (skb_tailroom(skb) < QCAFRM_FOOTER_LEN + pad_len)) {
+		tskb = skb_copy_expand(skb, QCAFRM_HEADER_LEN,
+				       QCAFRM_FOOTER_LEN + pad_len, GFP_ATOMIC);
+		if (!tskb) {
+			netdev_dbg(qca->net_dev, "could not allocate tx_buff\n");
+			qca->stats.out_of_mem++;
+			return NETDEV_TX_BUSY;
+		}
+		dev_kfree_skb(skb);
+		skb = tskb;
+	}
+
+	frame_len = skb->len + pad_len;
+
+	ptmp = skb_push(skb, QCAFRM_HEADER_LEN);
+	qcafrm_create_header(ptmp, frame_len);
+
+	if (pad_len) {
+		ptmp = skb_put(skb, pad_len);
+		memset(ptmp, 0, pad_len);
+	}
+
+	ptmp = skb_put(skb, QCAFRM_FOOTER_LEN);
+	qcafrm_create_footer(ptmp);
+
+	netdev_dbg(qca->net_dev, "Tx-ing packet: Size: 0x%08x\n",
+		   skb->len);
+
+	qca->txr.size += skb->len + QCASPI_HW_PKT_LEN;
+
+	new_tail = qca->txr.tail + 1;
+	if (new_tail >= qca->txr.count)
+		new_tail = 0;
+
+	qca->txr.skb[qca->txr.tail] = skb;
+	qca->txr.tail = new_tail;
+
+	if (!qcaspi_tx_ring_has_space(&qca->txr)) {
+		netif_stop_queue(qca->net_dev);
+		qca->stats.ring_full++;
+	}
+
+	dev->trans_start = jiffies;
+
+	if (qca->spi_thread &&
+	    qca->spi_thread->state != TASK_RUNNING)
+		wake_up_process(qca->spi_thread);
+
+	return NETDEV_TX_OK;
+}
+
+static void
+qcaspi_netdev_tx_timeout(struct net_device *dev)
+{
+	struct qcaspi *qca = netdev_priv(dev);
+
+	netdev_info(qca->net_dev, "Transmit timeout at %ld, latency %ld\n",
+		    jiffies, jiffies - dev->trans_start);
+	qca->net_dev->stats.tx_errors++;
+	/* wake the queue if there is room */
+	if (qcaspi_tx_ring_has_space(&qca->txr))
+		netif_wake_queue(dev);
+}
+
+static int
+qcaspi_netdev_init(struct net_device *dev)
+{
+	struct qcaspi *qca = netdev_priv(dev);
+
+	dev->mtu = QCASPI_MTU;
+	dev->type = ARPHRD_ETHER;
+	qca->clkspeed = qcaspi_clkspeed;
+	qca->burst_len = qcaspi_burst_len;
+	qca->spi_thread = NULL;
+	qca->buffer_size = (dev->mtu + VLAN_ETH_HLEN + QCAFRM_HEADER_LEN +
+		QCAFRM_FOOTER_LEN + 4) * 4;
+
+	memset(&qca->stats, 0, sizeof(struct qcaspi_stats));
+
+	qca->rx_buffer = kmalloc(qca->buffer_size, GFP_KERNEL);
+	if (!qca->rx_buffer)
+		return -ENOBUFS;
+
+	qca->rx_skb = netdev_alloc_skb(dev, qca->net_dev->mtu + VLAN_ETH_HLEN);
+	if (!qca->rx_skb) {
+		kfree(qca->rx_buffer);
+		netdev_info(qca->net_dev, "Failed to allocate RX sk_buff.\n");
+		return -ENOBUFS;
+	}
+
+	return 0;
+}
+
+static void
+qcaspi_netdev_uninit(struct net_device *dev)
+{
+	struct qcaspi *qca = netdev_priv(dev);
+
+	kfree(qca->rx_buffer);
+	qca->buffer_size = 0;
+	if (qca->rx_skb)
+		dev_kfree_skb(qca->rx_skb);
+}
+
+static int
+qcaspi_netdev_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if ((new_mtu < QCAFRM_ETHMINMTU) || (new_mtu > QCAFRM_ETHMAXMTU))
+		return -EINVAL;
+
+	dev->mtu = new_mtu;
+
+	return 0;
+}
+
+static const struct net_device_ops qcaspi_netdev_ops = {
+	.ndo_init = qcaspi_netdev_init,
+	.ndo_uninit = qcaspi_netdev_uninit,
+	.ndo_open = qcaspi_netdev_open,
+	.ndo_stop = qcaspi_netdev_close,
+	.ndo_start_xmit = qcaspi_netdev_xmit,
+	.ndo_change_mtu = qcaspi_netdev_change_mtu,
+	.ndo_set_mac_address = eth_mac_addr,
+	.ndo_tx_timeout = qcaspi_netdev_tx_timeout,
+	.ndo_validate_addr = eth_validate_addr,
+};
+
+static void
+qcaspi_netdev_setup(struct net_device *dev)
+{
+	struct qcaspi *qca = NULL;
+
+	dev->netdev_ops = &qcaspi_netdev_ops;
+	qcaspi_set_ethtool_ops(dev);
+	dev->watchdog_timeo = QCASPI_TX_TIMEOUT;
+	dev->flags = IFF_MULTICAST;
+	dev->tx_queue_len = 100;
+
+	qca = netdev_priv(dev);
+	memset(qca, 0, sizeof(struct qcaspi));
+
+	memset(&qca->spi_xfer1, 0, sizeof(struct spi_transfer));
+	memset(&qca->spi_xfer2, 0, sizeof(struct spi_transfer) * 2);
+
+	spi_message_init(&qca->spi_msg1);
+	spi_message_add_tail(&qca->spi_xfer1, &qca->spi_msg1);
+
+	spi_message_init(&qca->spi_msg2);
+	spi_message_add_tail(&qca->spi_xfer2[0], &qca->spi_msg2);
+	spi_message_add_tail(&qca->spi_xfer2[1], &qca->spi_msg2);
+
+	memset(&qca->txr, 0, sizeof(qca->txr));
+	qca->txr.count = TX_RING_MAX_LEN;
+}
+
+static const struct of_device_id qca_spi_of_match[] = {
+	{ .compatible = "qca,qca7000" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, qca_spi_of_match);
+
+static int
+qca_spi_probe(struct spi_device *spi_device)
+{
+	struct qcaspi *qca = NULL;
+	struct net_device *qcaspi_devs = NULL;
+	u8 legacy_mode = 0;
+	u16 signature;
+	const char *mac;
+
+	if (!spi_device->dev.of_node) {
+		dev_err(&spi_device->dev, "Missing device tree\n");
+		return -EINVAL;
+	}
+
+	legacy_mode = of_property_read_bool(spi_device->dev.of_node,
+					    "qca,legacy-mode");
+
+	if (qcaspi_clkspeed == 0) {
+		if (spi_device->max_speed_hz)
+			qcaspi_clkspeed = spi_device->max_speed_hz;
+		else
+			qcaspi_clkspeed = QCASPI_CLK_SPEED;
+	}
+
+	if ((qcaspi_clkspeed < QCASPI_CLK_SPEED_MIN) ||
+	    (qcaspi_clkspeed > QCASPI_CLK_SPEED_MAX)) {
+		dev_info(&spi_device->dev, "Invalid clkspeed: %d\n",
+			 qcaspi_clkspeed);
+		return -EINVAL;
+	}
+
+	if ((qcaspi_burst_len < QCASPI_BURST_LEN_MIN) ||
+	    (qcaspi_burst_len > QCASPI_BURST_LEN_MAX)) {
+		dev_info(&spi_device->dev, "Invalid burst len: %d\n",
+			 qcaspi_burst_len);
+		return -EINVAL;
+	}
+
+	if ((qcaspi_pluggable < QCASPI_PLUGGABLE_MIN) ||
+	    (qcaspi_pluggable > QCASPI_PLUGGABLE_MAX)) {
+		dev_info(&spi_device->dev, "Invalid pluggable: %d\n",
+			 qcaspi_pluggable);
+		return -EINVAL;
+	}
+
+	dev_info(&spi_device->dev, "ver=%s, clkspeed=%d, burst_len=%d, pluggable=%d\n",
+		 QCASPI_DRV_VERSION,
+		 qcaspi_clkspeed,
+		 qcaspi_burst_len,
+		 qcaspi_pluggable);
+
+	spi_device->mode = SPI_MODE_3;
+	spi_device->max_speed_hz = qcaspi_clkspeed;
+	if (spi_setup(spi_device) < 0) {
+		dev_err(&spi_device->dev, "Unable to setup SPI device\n");
+		return -EFAULT;
+	}
+
+	qcaspi_devs = alloc_etherdev(sizeof(struct qcaspi));
+	if (!qcaspi_devs)
+		return -ENOMEM;
+
+	qcaspi_netdev_setup(qcaspi_devs);
+
+	qca = netdev_priv(qcaspi_devs);
+	if (!qca) {
+		free_netdev(qcaspi_devs);
+		dev_err(&spi_device->dev, "Fail to retrieve private structure\n");
+		return -ENOMEM;
+	}
+	qca->net_dev = qcaspi_devs;
+	qca->spi_dev = spi_device;
+	qca->legacy_mode = legacy_mode;
+
+	spi_set_drvdata(spi_device, qcaspi_devs);
+
+	mac = of_get_mac_address(spi_device->dev.of_node);
+
+	if (mac)
+		ether_addr_copy(qca->net_dev->dev_addr, mac);
+
+	if (!is_valid_ether_addr(qca->net_dev->dev_addr)) {
+		eth_hw_addr_random(qca->net_dev);
+		dev_info(&spi_device->dev, "Using random MAC address: %pM\n",
+			 qca->net_dev->dev_addr);
+	}
+
+	netif_carrier_off(qca->net_dev);
+
+	if (!qcaspi_pluggable) {
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+		qcaspi_read_register(qca, SPI_REG_SIGNATURE, &signature);
+
+		if (signature != QCASPI_GOOD_SIGNATURE) {
+			dev_err(&spi_device->dev, "Invalid signature (0x%04X)\n",
+				signature);
+			free_netdev(qcaspi_devs);
+			return -EFAULT;
+		}
+	}
+
+	if (register_netdev(qcaspi_devs)) {
+		dev_info(&spi_device->dev, "Unable to register net device %s\n",
+			 qcaspi_devs->name);
+		free_netdev(qcaspi_devs);
+		return -EFAULT;
+	}
+
+	qcaspi_init_device_debugfs(qca);
+
+	return 0;
+}
+
+static int
+qca_spi_remove(struct spi_device *spi_device)
+{
+	struct net_device *qcaspi_devs = spi_get_drvdata(spi_device);
+	struct qcaspi *qca = netdev_priv(qcaspi_devs);
+
+	qcaspi_remove_device_debugfs(qca);
+
+	unregister_netdev(qcaspi_devs);
+	free_netdev(qcaspi_devs);
+
+	return 0;
+}
+
+static const struct spi_device_id qca_spi_id[] = {
+	{ "qca7000", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, qca_spi_id);
+
+static struct spi_driver qca_spi_driver = {
+	.driver	= {
+		.name	= QCASPI_DRV_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table = qca_spi_of_match,
+	},
+	.id_table = qca_spi_id,
+	.probe    = qca_spi_probe,
+	.remove   = qca_spi_remove,
+};
+module_spi_driver(qca_spi_driver);
+
+MODULE_DESCRIPTION("Qualcomm Atheros SPI Driver");
+MODULE_AUTHOR("Qualcomm Atheros Communications");
+MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_VERSION(QCASPI_DRV_VERSION);