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 000000000000..df70368bf317
--- /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");