net: add Faraday FTMAC100 10/100 Ethernet driver

FTMAC100 Ethernet Media Access Controller supports 10/100 Mbps and
MII.  This driver has been working on some ARM/NDS32 SoC's including
Faraday A320 and Andes AG101.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1196 insertions, 0 deletions

diff --git a/drivers/net/ftmac100.c b/drivers/net/ftmac100.c
new file mode 100644
index 0000000..df70368
--- /dev/null
+++ b/drivers/net/ftmac100.c
@@ -0,0 +1,1196 @@
+/*
+ * Faraday FTMAC100 10/100 Ethernet
+ *
+ * (C) Copyright 2009-2011 Faraday Technology
+ * Po-Yu Chuang <ratbert@faraday-tech.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/dma-mapping.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mii.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+
+#include "ftmac100.h"
+
+#define DRV_NAME	"ftmac100"
+#define DRV_VERSION	"0.2"
+
+#define RX_QUEUE_ENTRIES	128	/* must be power of 2 */
+#define TX_QUEUE_ENTRIES	16	/* must be power of 2 */
+
+#define MAX_PKT_SIZE		1518
+#define RX_BUF_SIZE		2044	/* must be smaller than 0x7ff */
+
+#if MAX_PKT_SIZE > 0x7ff
+#error invalid MAX_PKT_SIZE
+#endif
+
+#if RX_BUF_SIZE > 0x7ff || RX_BUF_SIZE > PAGE_SIZE
+#error invalid RX_BUF_SIZE
+#endif
+
+/******************************************************************************
+ * private data
+ *****************************************************************************/
+struct ftmac100_descs {
+	struct ftmac100_rxdes rxdes[RX_QUEUE_ENTRIES];
+	struct ftmac100_txdes txdes[TX_QUEUE_ENTRIES];
+};
+
+struct ftmac100 {
+	struct resource *res;
+	void __iomem *base;
+	int irq;
+
+	struct ftmac100_descs *descs;
+	dma_addr_t descs_dma_addr;
+
+	unsigned int rx_pointer;
+	unsigned int tx_clean_pointer;
+	unsigned int tx_pointer;
+	unsigned int tx_pending;
+
+	spinlock_t tx_lock;
+
+	struct net_device *netdev;
+	struct device *dev;
+	struct napi_struct napi;
+
+	struct mii_if_info mii;
+};
+
+static int ftmac100_alloc_rx_page(struct ftmac100 *priv, struct ftmac100_rxdes *rxdes);
+
+/******************************************************************************
+ * internal functions (hardware register access)
+ *****************************************************************************/
+#define INT_MASK_ALL_ENABLED	(FTMAC100_INT_RPKT_FINISH	| \
+				 FTMAC100_INT_NORXBUF		| \
+				 FTMAC100_INT_XPKT_OK		| \
+				 FTMAC100_INT_XPKT_LOST		| \
+				 FTMAC100_INT_RPKT_LOST		| \
+				 FTMAC100_INT_AHB_ERR		| \
+				 FTMAC100_INT_PHYSTS_CHG)
+
+#define INT_MASK_ALL_DISABLED	0
+
+static void ftmac100_enable_all_int(struct ftmac100 *priv)
+{
+	iowrite32(INT_MASK_ALL_ENABLED, priv->base + FTMAC100_OFFSET_IMR);
+}
+
+static void ftmac100_disable_all_int(struct ftmac100 *priv)
+{
+	iowrite32(INT_MASK_ALL_DISABLED, priv->base + FTMAC100_OFFSET_IMR);
+}
+
+static void ftmac100_set_rx_ring_base(struct ftmac100 *priv, dma_addr_t addr)
+{
+	iowrite32(addr, priv->base + FTMAC100_OFFSET_RXR_BADR);
+}
+
+static void ftmac100_set_tx_ring_base(struct ftmac100 *priv, dma_addr_t addr)
+{
+	iowrite32(addr, priv->base + FTMAC100_OFFSET_TXR_BADR);
+}
+
+static void ftmac100_txdma_start_polling(struct ftmac100 *priv)
+{
+	iowrite32(1, priv->base + FTMAC100_OFFSET_TXPD);
+}
+
+static int ftmac100_reset(struct ftmac100 *priv)
+{
+	struct net_device *netdev = priv->netdev;
+	int i;
+
+	/* NOTE: reset clears all registers */
+	iowrite32(FTMAC100_MACCR_SW_RST, priv->base + FTMAC100_OFFSET_MACCR);
+
+	for (i = 0; i < 5; i++) {
+		unsigned int maccr;
+
+		maccr = ioread32(priv->base + FTMAC100_OFFSET_MACCR);
+		if (!(maccr & FTMAC100_MACCR_SW_RST)) {
+			/*
+			 * FTMAC100_MACCR_SW_RST cleared does not indicate
+			 * that hardware reset completed (what the f*ck).
+			 * We still need to wait for a while.
+			 */
+			usleep_range(500, 1000);
+			return 0;
+		}
+
+		usleep_range(1000, 10000);
+	}
+
+	netdev_err(netdev, "software reset failed\n");
+	return -EIO;
+}
+
+static void ftmac100_set_mac(struct ftmac100 *priv, const unsigned char *mac)
+{
+	unsigned int maddr = mac[0] << 8 | mac[1];
+	unsigned int laddr = mac[2] << 24 | mac[3] << 16 | mac[4] << 8 | mac[5];
+
+	iowrite32(maddr, priv->base + FTMAC100_OFFSET_MAC_MADR);
+	iowrite32(laddr, priv->base + FTMAC100_OFFSET_MAC_LADR);
+}
+
+#define MACCR_ENABLE_ALL	(FTMAC100_MACCR_XMT_EN	| \
+				 FTMAC100_MACCR_RCV_EN	| \
+				 FTMAC100_MACCR_XDMA_EN	| \
+				 FTMAC100_MACCR_RDMA_EN	| \
+				 FTMAC100_MACCR_CRC_APD	| \
+				 FTMAC100_MACCR_FULLDUP	| \
+				 FTMAC100_MACCR_RX_RUNT	| \
+				 FTMAC100_MACCR_RX_BROADPKT)
+
+static int ftmac100_start_hw(struct ftmac100 *priv)
+{
+	struct net_device *netdev = priv->netdev;
+
+	if (ftmac100_reset(priv))
+		return -EIO;
+
+	/* setup ring buffer base registers */
+	ftmac100_set_rx_ring_base(priv,
+				  priv->descs_dma_addr +
+				  offsetof(struct ftmac100_descs, rxdes));
+	ftmac100_set_tx_ring_base(priv,
+				  priv->descs_dma_addr +
+				  offsetof(struct ftmac100_descs, txdes));
+
+	iowrite32(FTMAC100_APTC_RXPOLL_CNT(1), priv->base + FTMAC100_OFFSET_APTC);
+
+	ftmac100_set_mac(priv, netdev->dev_addr);
+
+	iowrite32(MACCR_ENABLE_ALL, priv->base + FTMAC100_OFFSET_MACCR);
+	return 0;
+}
+
+static void ftmac100_stop_hw(struct ftmac100 *priv)
+{
+	iowrite32(0, priv->base + FTMAC100_OFFSET_MACCR);
+}
+
+/******************************************************************************
+ * internal functions (receive descriptor)
+ *****************************************************************************/
+static bool ftmac100_rxdes_first_segment(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_FRS);
+}
+
+static bool ftmac100_rxdes_last_segment(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_LRS);
+}
+
+static bool ftmac100_rxdes_owned_by_dma(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RXDMA_OWN);
+}
+
+static void ftmac100_rxdes_set_dma_own(struct ftmac100_rxdes *rxdes)
+{
+	/* clear status bits */
+	rxdes->rxdes0 = cpu_to_le32(FTMAC100_RXDES0_RXDMA_OWN);
+}
+
+static bool ftmac100_rxdes_rx_error(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RX_ERR);
+}
+
+static bool ftmac100_rxdes_crc_error(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_CRC_ERR);
+}
+
+static bool ftmac100_rxdes_frame_too_long(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_FTL);
+}
+
+static bool ftmac100_rxdes_runt(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RUNT);
+}
+
+static bool ftmac100_rxdes_odd_nibble(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RX_ODD_NB);
+}
+
+static unsigned int ftmac100_rxdes_frame_length(struct ftmac100_rxdes *rxdes)
+{
+	return le32_to_cpu(rxdes->rxdes0) & FTMAC100_RXDES0_RFL;
+}
+
+static bool ftmac100_rxdes_multicast(struct ftmac100_rxdes *rxdes)
+{
+	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_MULTICAST);
+}
+
+static void ftmac100_rxdes_set_buffer_size(struct ftmac100_rxdes *rxdes,
+					   unsigned int size)
+{
+	rxdes->rxdes1 &= cpu_to_le32(FTMAC100_RXDES1_EDORR);
+	rxdes->rxdes1 |= cpu_to_le32(FTMAC100_RXDES1_RXBUF_SIZE(size));
+}
+
+static void ftmac100_rxdes_set_end_of_ring(struct ftmac100_rxdes *rxdes)
+{
+	rxdes->rxdes1 |= cpu_to_le32(FTMAC100_RXDES1_EDORR);
+}
+
+static void ftmac100_rxdes_set_dma_addr(struct ftmac100_rxdes *rxdes,
+					dma_addr_t addr)
+{
+	rxdes->rxdes2 = cpu_to_le32(addr);
+}
+
+static dma_addr_t ftmac100_rxdes_get_dma_addr(struct ftmac100_rxdes *rxdes)
+{
+	return le32_to_cpu(rxdes->rxdes2);
+}
+
+/*
+ * rxdes3 is not used by hardware. We use it to keep track of page.
+ * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
+ */
+static void ftmac100_rxdes_set_page(struct ftmac100_rxdes *rxdes, struct page *page)
+{
+	rxdes->rxdes3 = (unsigned int)page;
+}
+
+static struct page *ftmac100_rxdes_get_page(struct ftmac100_rxdes *rxdes)
+{
+	return (struct page *)rxdes->rxdes3;
+}
+
+/******************************************************************************
+ * internal functions (receive)
+ *****************************************************************************/
+static int ftmac100_next_rx_pointer(int pointer)
+{
+	return (pointer + 1) & (RX_QUEUE_ENTRIES - 1);
+}
+
+static void ftmac100_rx_pointer_advance(struct ftmac100 *priv)
+{
+	priv->rx_pointer = ftmac100_next_rx_pointer(priv->rx_pointer);
+}
+
+static struct ftmac100_rxdes *ftmac100_current_rxdes(struct ftmac100 *priv)
+{
+	return &priv->descs->rxdes[priv->rx_pointer];
+}
+
+static struct ftmac100_rxdes *
+ftmac100_rx_locate_first_segment(struct ftmac100 *priv)
+{
+	struct ftmac100_rxdes *rxdes = ftmac100_current_rxdes(priv);
+
+	while (!ftmac100_rxdes_owned_by_dma(rxdes)) {
+		if (ftmac100_rxdes_first_segment(rxdes))
+			return rxdes;
+
+		ftmac100_rxdes_set_dma_own(rxdes);
+		ftmac100_rx_pointer_advance(priv);
+		rxdes = ftmac100_current_rxdes(priv);
+	}
+
+	return NULL;
+}
+
+static bool ftmac100_rx_packet_error(struct ftmac100 *priv,
+				     struct ftmac100_rxdes *rxdes)
+{
+	struct net_device *netdev = priv->netdev;
+	bool error = false;
+
+	if (unlikely(ftmac100_rxdes_rx_error(rxdes))) {
+		if (net_ratelimit())
+			netdev_info(netdev, "rx err\n");
+
+		netdev->stats.rx_errors++;
+		error = true;
+	}
+
+	if (unlikely(ftmac100_rxdes_crc_error(rxdes))) {
+		if (net_ratelimit())
+			netdev_info(netdev, "rx crc err\n");
+
+		netdev->stats.rx_crc_errors++;
+		error = true;
+	}
+
+	if (unlikely(ftmac100_rxdes_frame_too_long(rxdes))) {
+		if (net_ratelimit())
+			netdev_info(netdev, "rx frame too long\n");
+
+		netdev->stats.rx_length_errors++;
+		error = true;
+	} else if (unlikely(ftmac100_rxdes_runt(rxdes))) {
+		if (net_ratelimit())
+			netdev_info(netdev, "rx runt\n");
+
+		netdev->stats.rx_length_errors++;
+		error = true;
+	} else if (unlikely(ftmac100_rxdes_odd_nibble(rxdes))) {
+		if (net_ratelimit())
+			netdev_info(netdev, "rx odd nibble\n");
+
+		netdev->stats.rx_length_errors++;
+		error = true;
+	}
+
+	return error;
+}
+
+static void ftmac100_rx_drop_packet(struct ftmac100 *priv)
+{
+	struct net_device *netdev = priv->netdev;
+	struct ftmac100_rxdes *rxdes = ftmac100_current_rxdes(priv);
+	bool done = false;
+
+	if (net_ratelimit())
+		netdev_dbg(netdev, "drop packet %p\n", rxdes);
+
+	do {
+		if (ftmac100_rxdes_last_segment(rxdes))
+			done = true;
+
+		ftmac100_rxdes_set_dma_own(rxdes);
+		ftmac100_rx_pointer_advance(priv);
+		rxdes = ftmac100_current_rxdes(priv);
+	} while (!done && !ftmac100_rxdes_owned_by_dma(rxdes));
+
+	netdev->stats.rx_dropped++;
+}
+
+static bool ftmac100_rx_packet(struct ftmac100 *priv, int *processed)
+{
+	struct net_device *netdev = priv->netdev;
+	struct ftmac100_rxdes *rxdes;
+	struct sk_buff *skb;
+	struct page *page;
+	dma_addr_t map;
+	int length;
+
+	rxdes = ftmac100_rx_locate_first_segment(priv);
+	if (!rxdes)
+		return false;
+
+	if (unlikely(ftmac100_rx_packet_error(priv, rxdes))) {
+		ftmac100_rx_drop_packet(priv);
+		return true;
+	}
+
+	/*
+	 * It is impossible to get multi-segment packets
+	 * because we always provide big enough receive buffers.
+	 */
+	if (unlikely(!ftmac100_rxdes_last_segment(rxdes)))
+		BUG();
+
+	/* start processing */
+	skb = netdev_alloc_skb_ip_align(netdev, 128);
+	if (unlikely(!skb)) {
+		if (net_ratelimit())
+			netdev_err(netdev, "rx skb alloc failed\n");
+
+		ftmac100_rx_drop_packet(priv);
+		return true;
+	}
+
+	if (unlikely(ftmac100_rxdes_multicast(rxdes)))
+		netdev->stats.multicast++;
+
+	map = ftmac100_rxdes_get_dma_addr(rxdes);
+	dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);
+
+	length = ftmac100_rxdes_frame_length(rxdes);
+	page = ftmac100_rxdes_get_page(rxdes);
+	skb_fill_page_desc(skb, 0, page, 0, length);
+	skb->len += length;
+	skb->data_len += length;
+	skb->truesize += length;
+	__pskb_pull_tail(skb, min(length, 64));
+
+	ftmac100_alloc_rx_page(priv, rxdes);
+
+	ftmac100_rx_pointer_advance(priv);
+
+	skb->protocol = eth_type_trans(skb, netdev);
+
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += skb->len;
+
+	/* push packet to protocol stack */
+	netif_receive_skb(skb);
+
+	(*processed)++;
+	return true;
+}
+
+/******************************************************************************
+ * internal functions (transmit descriptor)
+ *****************************************************************************/
+static void ftmac100_txdes_reset(struct ftmac100_txdes *txdes)
+{
+	/* clear all except end of ring bit */
+	txdes->txdes0 = 0;
+	txdes->txdes1 &= cpu_to_le32(FTMAC100_TXDES1_EDOTR);
+	txdes->txdes2 = 0;
+	txdes->txdes3 = 0;
+}
+
+static bool ftmac100_txdes_owned_by_dma(struct ftmac100_txdes *txdes)
+{
+	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXDMA_OWN);
+}
+
+static void ftmac100_txdes_set_dma_own(struct ftmac100_txdes *txdes)
+{
+	/*
+	 * Make sure dma own bit will not be set before any other
+	 * descriptor fields.
+	 */
+	wmb();
+	txdes->txdes0 |= cpu_to_le32(FTMAC100_TXDES0_TXDMA_OWN);
+}
+
+static bool ftmac100_txdes_excessive_collision(struct ftmac100_txdes *txdes)
+{
+	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXPKT_EXSCOL);
+}
+
+static bool ftmac100_txdes_late_collision(struct ftmac100_txdes *txdes)
+{
+	return txdes->txdes0 & cpu_to_le32(FTMAC100_TXDES0_TXPKT_LATECOL);
+}
+
+static void ftmac100_txdes_set_end_of_ring(struct ftmac100_txdes *txdes)
+{
+	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_EDOTR);
+}
+
+static void ftmac100_txdes_set_first_segment(struct ftmac100_txdes *txdes)
+{
+	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_FTS);
+}
+
+static void ftmac100_txdes_set_last_segment(struct ftmac100_txdes *txdes)
+{
+	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_LTS);
+}
+
+static void ftmac100_txdes_set_txint(struct ftmac100_txdes *txdes)
+{
+	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_TXIC);
+}
+
+static void ftmac100_txdes_set_buffer_size(struct ftmac100_txdes *txdes,
+					   unsigned int len)
+{
+	txdes->txdes1 |= cpu_to_le32(FTMAC100_TXDES1_TXBUF_SIZE(len));
+}
+
+static void ftmac100_txdes_set_dma_addr(struct ftmac100_txdes *txdes,
+					dma_addr_t addr)
+{
+	txdes->txdes2 = cpu_to_le32(addr);
+}
+
+static dma_addr_t ftmac100_txdes_get_dma_addr(struct ftmac100_txdes *txdes)
+{
+	return le32_to_cpu(txdes->txdes2);
+}
+
+/*
+ * txdes3 is not used by hardware. We use it to keep track of socket buffer.
+ * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
+ */
+static void ftmac100_txdes_set_skb(struct ftmac100_txdes *txdes, struct sk_buff *skb)
+{
+	txdes->txdes3 = (unsigned int)skb;
+}
+
+static struct sk_buff *ftmac100_txdes_get_skb(struct ftmac100_txdes *txdes)
+{
+	return (struct sk_buff *)txdes->txdes3;
+}
+
+/******************************************************************************
+ * internal functions (transmit)
+ *****************************************************************************/
+static int ftmac100_next_tx_pointer(int pointer)
+{
+	return (pointer + 1) & (TX_QUEUE_ENTRIES - 1);
+}
+
+static void ftmac100_tx_pointer_advance(struct ftmac100 *priv)
+{
+	priv->tx_pointer = ftmac100_next_tx_pointer(priv->tx_pointer);
+}
+
+static void ftmac100_tx_clean_pointer_advance(struct ftmac100 *priv)
+{
+	priv->tx_clean_pointer = ftmac100_next_tx_pointer(priv->tx_clean_pointer);
+}
+
+static struct ftmac100_txdes *ftmac100_current_txdes(struct ftmac100 *priv)
+{
+	return &priv->descs->txdes[priv->tx_pointer];
+}
+
+static struct ftmac100_txdes *ftmac100_current_clean_txdes(struct ftmac100 *priv)
+{
+	return &priv->descs->txdes[priv->tx_clean_pointer];
+}
+
+static bool ftmac100_tx_complete_packet(struct ftmac100 *priv)
+{
+	struct net_device *netdev = priv->netdev;
+	struct ftmac100_txdes *txdes;
+	struct sk_buff *skb;
+	dma_addr_t map;
+
+	if (priv->tx_pending == 0)
+		return false;
+
+	txdes = ftmac100_current_clean_txdes(priv);
+
+	if (ftmac100_txdes_owned_by_dma(txdes))
+		return false;
+
+	skb = ftmac100_txdes_get_skb(txdes);
+	map = ftmac100_txdes_get_dma_addr(txdes);
+
+	if (unlikely(ftmac100_txdes_excessive_collision(txdes) ||
+		     ftmac100_txdes_late_collision(txdes))) {
+		/*
+		 * packet transmitted to ethernet lost due to late collision
+		 * or excessive collision
+		 */
+		netdev->stats.tx_aborted_errors++;
+	} else {
+		netdev->stats.tx_packets++;
+		netdev->stats.tx_bytes += skb->len;
+	}
+
+	dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
+	dev_kfree_skb(skb);
+
+	ftmac100_txdes_reset(txdes);
+
+	ftmac100_tx_clean_pointer_advance(priv);
+
+	spin_lock(&priv->tx_lock);
+	priv->tx_pending--;
+	spin_unlock(&priv->tx_lock);
+	netif_wake_queue(netdev);
+
+	return true;
+}
+
+static void ftmac100_tx_complete(struct ftmac100 *priv)
+{
+	while (ftmac100_tx_complete_packet(priv))
+		;
+}
+
+static int ftmac100_xmit(struct ftmac100 *priv, struct sk_buff *skb,
+			 dma_addr_t map)
+{
+	struct net_device *netdev = priv->netdev;
+	struct ftmac100_txdes *txdes;
+	unsigned int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;
+
+	txdes = ftmac100_current_txdes(priv);
+	ftmac100_tx_pointer_advance(priv);
+
+	/* setup TX descriptor */
+	ftmac100_txdes_set_skb(txdes, skb);
+	ftmac100_txdes_set_dma_addr(txdes, map);
+
+	ftmac100_txdes_set_first_segment(txdes);
+	ftmac100_txdes_set_last_segment(txdes);
+	ftmac100_txdes_set_txint(txdes);
+	ftmac100_txdes_set_buffer_size(txdes, len);
+
+	spin_lock(&priv->tx_lock);
+	priv->tx_pending++;
+	if (priv->tx_pending == TX_QUEUE_ENTRIES)
+		netif_stop_queue(netdev);
+
+	/* start transmit */
+	ftmac100_txdes_set_dma_own(txdes);
+	spin_unlock(&priv->tx_lock);
+
+	ftmac100_txdma_start_polling(priv);
+	return NETDEV_TX_OK;
+}
+
+/******************************************************************************
+ * internal functions (buffer)
+ *****************************************************************************/
+static int ftmac100_alloc_rx_page(struct ftmac100 *priv, struct ftmac100_rxdes *rxdes)
+{
+	struct net_device *netdev = priv->netdev;
+	struct page *page;
+	dma_addr_t map;
+
+	page = alloc_page(GFP_KERNEL);
+	if (!page) {
+		if (net_ratelimit())
+			netdev_err(netdev, "failed to allocate rx page\n");
+		return -ENOMEM;
+	}
+
+	map = dma_map_page(priv->dev, page, 0, RX_BUF_SIZE, DMA_FROM_DEVICE);
+	if (unlikely(dma_mapping_error(priv->dev, map))) {
+		if (net_ratelimit())
+			netdev_err(netdev, "failed to map rx page\n");
+		__free_page(page);
+		return -ENOMEM;
+	}
+
+	ftmac100_rxdes_set_page(rxdes, page);
+	ftmac100_rxdes_set_dma_addr(rxdes, map);
+	ftmac100_rxdes_set_buffer_size(rxdes, RX_BUF_SIZE);
+	ftmac100_rxdes_set_dma_own(rxdes);
+	return 0;
+}
+
+static void ftmac100_free_buffers(struct ftmac100 *priv)
+{
+	int i;
+
+	for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
+		struct ftmac100_rxdes *rxdes = &priv->descs->rxdes[i];
+		struct page *page = ftmac100_rxdes_get_page(rxdes);
+		dma_addr_t map = ftmac100_rxdes_get_dma_addr(rxdes);
+
+		if (!page)
+			continue;
+
+		dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);
+		__free_page(page);
+	}
+
+	for (i = 0; i < TX_QUEUE_ENTRIES; i++) {
+		struct ftmac100_txdes *txdes = &priv->descs->txdes[i];
+		struct sk_buff *skb = ftmac100_txdes_get_skb(txdes);
+		dma_addr_t map = ftmac100_txdes_get_dma_addr(txdes);
+
+		if (!skb)
+			continue;
+
+		dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
+		dev_kfree_skb(skb);
+	}
+
+	dma_free_coherent(priv->dev, sizeof(struct ftmac100_descs),
+			  priv->descs, priv->descs_dma_addr);
+}
+
+static int ftmac100_alloc_buffers(struct ftmac100 *priv)
+{
+	int i;
+
+	priv->descs = dma_alloc_coherent(priv->dev, sizeof(struct ftmac100_descs),
+					 &priv->descs_dma_addr, GFP_KERNEL);
+	if (!priv->descs)
+		return -ENOMEM;
+
+	memset(priv->descs, 0, sizeof(struct ftmac100_descs));
+
+	/* initialize RX ring */
+	ftmac100_rxdes_set_end_of_ring(&priv->descs->rxdes[RX_QUEUE_ENTRIES - 1]);
+
+	for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
+		struct ftmac100_rxdes *rxdes = &priv->descs->rxdes[i];
+
+		if (ftmac100_alloc_rx_page(priv, rxdes))
+			goto err;
+	}
+
+	/* initialize TX ring */
+	ftmac100_txdes_set_end_of_ring(&priv->descs->txdes[TX_QUEUE_ENTRIES - 1]);
+	return 0;
+
+err:
+	ftmac100_free_buffers(priv);
+	return -ENOMEM;
+}
+
+/******************************************************************************
+ * struct mii_if_info functions
+ *****************************************************************************/
+static int ftmac100_mdio_read(struct net_device *netdev, int phy_id, int reg)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	unsigned int phycr;
+	int i;
+
+	phycr = FTMAC100_PHYCR_PHYAD(phy_id) |
+		FTMAC100_PHYCR_REGAD(reg) |
+		FTMAC100_PHYCR_MIIRD;
+
+	iowrite32(phycr, priv->base + FTMAC100_OFFSET_PHYCR);
+
+	for (i = 0; i < 10; i++) {
+		phycr = ioread32(priv->base + FTMAC100_OFFSET_PHYCR);
+
+		if ((phycr & FTMAC100_PHYCR_MIIRD) == 0)
+			return phycr & FTMAC100_PHYCR_MIIRDATA;
+
+		usleep_range(100, 1000);
+	}
+
+	netdev_err(netdev, "mdio read timed out\n");
+	return 0;
+}
+
+static void ftmac100_mdio_write(struct net_device *netdev, int phy_id, int reg,
+				int data)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	unsigned int phycr;
+	int i;
+
+	phycr = FTMAC100_PHYCR_PHYAD(phy_id) |
+		FTMAC100_PHYCR_REGAD(reg) |
+		FTMAC100_PHYCR_MIIWR;
+
+	data = FTMAC100_PHYWDATA_MIIWDATA(data);
+
+	iowrite32(data, priv->base + FTMAC100_OFFSET_PHYWDATA);
+	iowrite32(phycr, priv->base + FTMAC100_OFFSET_PHYCR);
+
+	for (i = 0; i < 10; i++) {
+		phycr = ioread32(priv->base + FTMAC100_OFFSET_PHYCR);
+
+		if ((phycr & FTMAC100_PHYCR_MIIWR) == 0)
+			return;
+
+		usleep_range(100, 1000);
+	}
+
+	netdev_err(netdev, "mdio write timed out\n");
+}
+
+/******************************************************************************
+ * struct ethtool_ops functions
+ *****************************************************************************/
+static void ftmac100_get_drvinfo(struct net_device *netdev,
+				 struct ethtool_drvinfo *info)
+{
+	strcpy(info->driver, DRV_NAME);
+	strcpy(info->version, DRV_VERSION);
+	strcpy(info->bus_info, dev_name(&netdev->dev));
+}
+
+static int ftmac100_get_settings(struct net_device *netdev, struct ethtool_cmd *cmd)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	return mii_ethtool_gset(&priv->mii, cmd);
+}
+
+static int ftmac100_set_settings(struct net_device *netdev, struct ethtool_cmd *cmd)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	return mii_ethtool_sset(&priv->mii, cmd);
+}
+
+static int ftmac100_nway_reset(struct net_device *netdev)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	return mii_nway_restart(&priv->mii);
+}
+
+static u32 ftmac100_get_link(struct net_device *netdev)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	return mii_link_ok(&priv->mii);
+}
+
+static const struct ethtool_ops ftmac100_ethtool_ops = {
+	.set_settings		= ftmac100_set_settings,
+	.get_settings		= ftmac100_get_settings,
+	.get_drvinfo		= ftmac100_get_drvinfo,
+	.nway_reset		= ftmac100_nway_reset,
+	.get_link		= ftmac100_get_link,
+};
+
+/******************************************************************************
+ * interrupt handler
+ *****************************************************************************/
+static irqreturn_t ftmac100_interrupt(int irq, void *dev_id)
+{
+	struct net_device *netdev = dev_id;
+	struct ftmac100 *priv = netdev_priv(netdev);
+
+	if (likely(netif_running(netdev))) {
+		/* Disable interrupts for polling */
+		ftmac100_disable_all_int(priv);
+		napi_schedule(&priv->napi);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/******************************************************************************
+ * struct napi_struct functions
+ *****************************************************************************/
+static int ftmac100_poll(struct napi_struct *napi, int budget)
+{
+	struct ftmac100 *priv = container_of(napi, struct ftmac100, napi);
+	struct net_device *netdev = priv->netdev;
+	unsigned int status;
+	bool completed = true;
+	int rx = 0;
+
+	status = ioread32(priv->base + FTMAC100_OFFSET_ISR);
+
+	if (status & (FTMAC100_INT_RPKT_FINISH | FTMAC100_INT_NORXBUF)) {
+		/*
+		 * FTMAC100_INT_RPKT_FINISH:
+		 *	RX DMA has received packets into RX buffer successfully
+		 *
+		 * FTMAC100_INT_NORXBUF:
+		 *	RX buffer unavailable
+		 */
+		bool retry;
+
+		do {
+			retry = ftmac100_rx_packet(priv, &rx);
+		} while (retry && rx < budget);
+
+		if (retry && rx == budget)
+			completed = false;
+	}
+
+	if (status & (FTMAC100_INT_XPKT_OK | FTMAC100_INT_XPKT_LOST)) {
+		/*
+		 * FTMAC100_INT_XPKT_OK:
+		 *	packet transmitted to ethernet successfully
+		 *
+		 * FTMAC100_INT_XPKT_LOST:
+		 *	packet transmitted to ethernet lost due to late
+		 *	collision or excessive collision
+		 */
+		ftmac100_tx_complete(priv);
+	}
+
+	if (status & (FTMAC100_INT_NORXBUF | FTMAC100_INT_RPKT_LOST |
+		      FTMAC100_INT_AHB_ERR | FTMAC100_INT_PHYSTS_CHG)) {
+		if (net_ratelimit())
+			netdev_info(netdev, "[ISR] = 0x%x: %s%s%s%s\n", status,
+				    status & FTMAC100_INT_NORXBUF ? "NORXBUF " : "",
+				    status & FTMAC100_INT_RPKT_LOST ? "RPKT_LOST " : "",
+				    status & FTMAC100_INT_AHB_ERR ? "AHB_ERR " : "",
+				    status & FTMAC100_INT_PHYSTS_CHG ? "PHYSTS_CHG" : "");
+
+		if (status & FTMAC100_INT_NORXBUF) {
+			/* RX buffer unavailable */
+			netdev->stats.rx_over_errors++;
+		}
+
+		if (status & FTMAC100_INT_RPKT_LOST) {
+			/* received packet lost due to RX FIFO full */
+			netdev->stats.rx_fifo_errors++;
+		}
+
+		if (status & FTMAC100_INT_PHYSTS_CHG) {
+			/* PHY link status change */
+			mii_check_link(&priv->mii);
+		}
+	}
+
+	if (completed) {
+		/* stop polling */
+		napi_complete(napi);
+		ftmac100_enable_all_int(priv);
+	}
+
+	return rx;
+}
+
+/******************************************************************************
+ * struct net_device_ops functions
+ *****************************************************************************/
+static int ftmac100_open(struct net_device *netdev)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	int err;
+
+	err = ftmac100_alloc_buffers(priv);
+	if (err) {
+		netdev_err(netdev, "failed to allocate buffers\n");
+		goto err_alloc;
+	}
+
+	err = request_irq(priv->irq, ftmac100_interrupt, 0, netdev->name, netdev);
+	if (err) {
+		netdev_err(netdev, "failed to request irq %d\n", priv->irq);
+		goto err_irq;
+	}
+
+	priv->rx_pointer = 0;
+	priv->tx_clean_pointer = 0;
+	priv->tx_pointer = 0;
+	priv->tx_pending = 0;
+
+	err = ftmac100_start_hw(priv);
+	if (err)
+		goto err_hw;
+
+	napi_enable(&priv->napi);
+	netif_start_queue(netdev);
+
+	ftmac100_enable_all_int(priv);
+
+	return 0;
+
+err_hw:
+	free_irq(priv->irq, netdev);
+err_irq:
+	ftmac100_free_buffers(priv);
+err_alloc:
+	return err;
+}
+
+static int ftmac100_stop(struct net_device *netdev)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+
+	ftmac100_disable_all_int(priv);
+	netif_stop_queue(netdev);
+	napi_disable(&priv->napi);
+	ftmac100_stop_hw(priv);
+	free_irq(priv->irq, netdev);
+	ftmac100_free_buffers(priv);
+
+	return 0;
+}
+
+static int ftmac100_hard_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	dma_addr_t map;
+
+	if (unlikely(skb->len > MAX_PKT_SIZE)) {
+		if (net_ratelimit())
+			netdev_dbg(netdev, "tx packet too big\n");
+
+		netdev->stats.tx_dropped++;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	map = dma_map_single(priv->dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(priv->dev, map))) {
+		/* drop packet */
+		if (net_ratelimit())
+			netdev_err(netdev, "map socket buffer failed\n");
+
+		netdev->stats.tx_dropped++;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
+	return ftmac100_xmit(priv, skb, map);
+}
+
+/* optional */
+static int ftmac100_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
+{
+	struct ftmac100 *priv = netdev_priv(netdev);
+	struct mii_ioctl_data *data = if_mii(ifr);
+
+	return generic_mii_ioctl(&priv->mii, data, cmd, NULL);
+}
+
+static const struct net_device_ops ftmac100_netdev_ops = {
+	.ndo_open		= ftmac100_open,
+	.ndo_stop		= ftmac100_stop,
+	.ndo_start_xmit		= ftmac100_hard_start_xmit,
+	.ndo_set_mac_address	= eth_mac_addr,
+	.ndo_validate_addr	= eth_validate_addr,
+	.ndo_do_ioctl		= ftmac100_do_ioctl,
+};
+
+/******************************************************************************
+ * struct platform_driver functions
+ *****************************************************************************/
+static int ftmac100_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	int irq;
+	struct net_device *netdev;
+	struct ftmac100 *priv;
+	int err;
+
+	if (!pdev)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENXIO;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	/* setup net_device */
+	netdev = alloc_etherdev(sizeof(*priv));
+	if (!netdev) {
+		err = -ENOMEM;
+		goto err_alloc_etherdev;
+	}
+
+	SET_NETDEV_DEV(netdev, &pdev->dev);
+	SET_ETHTOOL_OPS(netdev, &ftmac100_ethtool_ops);
+	netdev->netdev_ops = &ftmac100_netdev_ops;
+
+	platform_set_drvdata(pdev, netdev);
+
+	/* setup private data */
+	priv = netdev_priv(netdev);
+	priv->netdev = netdev;
+	priv->dev = &pdev->dev;
+
+	spin_lock_init(&priv->tx_lock);
+
+	/* initialize NAPI */
+	netif_napi_add(netdev, &priv->napi, ftmac100_poll, 64);
+
+	/* map io memory */
+	priv->res = request_mem_region(res->start, resource_size(res),
+				       dev_name(&pdev->dev));
+	if (!priv->res) {
+		dev_err(&pdev->dev, "Could not reserve memory region\n");
+		err = -ENOMEM;
+		goto err_req_mem;
+	}
+
+	priv->base = ioremap(res->start, res->end - res->start);
+	if (!priv->base) {
+		dev_err(&pdev->dev, "Failed to ioremap ethernet registers\n");
+		err = -EIO;
+		goto err_ioremap;
+	}
+
+	priv->irq = irq;
+
+	/* initialize struct mii_if_info */
+	priv->mii.phy_id	= 0;
+	priv->mii.phy_id_mask	= 0x1f;
+	priv->mii.reg_num_mask	= 0x1f;
+	priv->mii.dev		= netdev;
+	priv->mii.mdio_read	= ftmac100_mdio_read;
+	priv->mii.mdio_write	= ftmac100_mdio_write;
+
+	/* register network device */
+	err = register_netdev(netdev);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to register netdev\n");
+		goto err_register_netdev;
+	}
+
+	netdev_info(netdev, "irq %d, mapped at %p\n", priv->irq, priv->base);
+
+	if (!is_valid_ether_addr(netdev->dev_addr)) {
+		random_ether_addr(netdev->dev_addr);
+		netdev_info(netdev, "generated random MAC address %pM\n",
+			    netdev->dev_addr);
+	}
+
+	return 0;
+
+err_register_netdev:
+	iounmap(priv->base);
+err_ioremap:
+	release_resource(priv->res);
+err_req_mem:
+	netif_napi_del(&priv->napi);
+	platform_set_drvdata(pdev, NULL);
+	free_netdev(netdev);
+err_alloc_etherdev:
+	return err;
+}
+
+static int __exit ftmac100_remove(struct platform_device *pdev)
+{
+	struct net_device *netdev;
+	struct ftmac100 *priv;
+
+	netdev = platform_get_drvdata(pdev);
+	priv = netdev_priv(netdev);
+
+	unregister_netdev(netdev);
+
+	iounmap(priv->base);
+	release_resource(priv->res);
+
+	netif_napi_del(&priv->napi);
+	platform_set_drvdata(pdev, NULL);
+	free_netdev(netdev);
+	return 0;
+}
+
+static struct platform_driver ftmac100_driver = {
+	.probe		= ftmac100_probe,
+	.remove		= __exit_p(ftmac100_remove),
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+/******************************************************************************
+ * initialization / finalization
+ *****************************************************************************/
+static int __init ftmac100_init(void)
+{
+	pr_info("Loading version " DRV_VERSION " ...\n");
+	return platform_driver_register(&ftmac100_driver);
+}
+
+static void __exit ftmac100_exit(void)
+{
+	platform_driver_unregister(&ftmac100_driver);
+}
+
+module_init(ftmac100_init);
+module_exit(ftmac100_exit);
+
+MODULE_AUTHOR("Po-Yu Chuang <ratbert@faraday-tech.com>");
+MODULE_DESCRIPTION("FTMAC100 driver");
+MODULE_LICENSE("GPL");