net: Micrel KS8851 SPI network driver

Network driver for the SPI version of the Micrel KS8851
network chip.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1322 insertions, 0 deletions

diff --git a/drivers/net/ks8851.c b/drivers/net/ks8851.c
new file mode 100644
index 000000000000..9a1dea60c1c4
--- /dev/null
+++ b/drivers/net/ks8851.c
@@ -0,0 +1,1322 @@
+/* drivers/net/ks8651.c
+ *
+ * Copyright 2009 Simtec Electronics
+ *      http://www.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define DEBUG
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/cache.h>
+#include <linux/crc32.h>
+#include <linux/mii.h>
+
+#include <linux/spi/spi.h>
+
+#include "ks8851.h"
+
+/**
+ * struct ks8851_rxctrl - KS8851 driver rx control
+ * @mchash: Multicast hash-table data.
+ * @rxcr1: KS_RXCR1 register setting
+ * @rxcr2: KS_RXCR2 register setting
+ *
+ * Representation of the settings needs to control the receive filtering
+ * such as the multicast hash-filter and the receive register settings. This
+ * is used to make the job of working out if the receive settings change and
+ * then issuing the new settings to the worker that will send the necessary
+ * commands.
+ */
+struct ks8851_rxctrl {
+        u16     mchash[4];
+        u16     rxcr1;
+        u16     rxcr2;
+};
+
+/**
+ * union ks8851_tx_hdr - tx header data
+ * @txb: The header as bytes
+ * @txw: The header as 16bit, little-endian words
+ *
+ * A dual representation of the tx header data to allow
+ * access to individual bytes, and to allow 16bit accesses
+ * with 16bit alignment.
+ */
+union ks8851_tx_hdr {
+        u8      txb[6];
+        __le16  txw[3];
+};
+
+/**
+ * struct ks8851_net - KS8851 driver private data
+ * @netdev: The network device we're bound to
+ * @spidev: The spi device we're bound to.
+ * @lock: Lock to ensure that the device is not accessed when busy.
+ * @statelock: Lock on this structure for tx list.
+ * @mii: The MII state information for the mii calls.
+ * @rxctrl: RX settings for @rxctrl_work.
+ * @tx_work: Work queue for tx packets
+ * @irq_work: Work queue for servicing interrupts
+ * @rxctrl_work: Work queue for updating RX mode and multicast lists
+ * @txq: Queue of packets for transmission.
+ * @spi_msg1: pre-setup SPI transfer with one message, @spi_xfer1.
+ * @spi_msg2: pre-setup SPI transfer with two messages, @spi_xfer2.
+ * @txh: Space for generating packet TX header in DMA-able data
+ * @rxd: Space for receiving SPI data, in DMA-able space.
+ * @txd: Space for transmitting SPI data, in DMA-able space.
+ * @msg_enable: The message flags controlling driver output (see ethtool).
+ * @fid: Incrementing frame id tag.
+ * @rc_ier: Cached copy of KS_IER.
+ * @rc_rxqcr: Cached copy of KS_RXQCR.
+ *
+ * The @lock ensures that the chip is protected when certain operations are
+ * in progress. When the read or write packet transfer is in progress, most
+ * of the chip registers are not ccessible until the transfer is finished and
+ * the DMA has been de-asserted.
+ *
+ * The @statelock is used to protect information in the structure which may
+ * need to be accessed via several sources, such as the network driver layer
+ * or one of the work queues.
+ *
+ * We align the buffers we may use for rx/tx to ensure that if the SPI driver
+ * wants to DMA map them, it will not have any problems with data the driver
+ * modifies.
+ */
+struct ks8851_net {
+        struct net_device       *netdev;
+        struct spi_device       *spidev;
+        struct mutex            lock;
+        spinlock_t              statelock;
+
+        union ks8851_tx_hdr     txh ____cacheline_aligned;
+        u8                      rxd[8];
+        u8                      txd[8];
+
+        u32                     msg_enable ____cacheline_aligned;
+        u16                     tx_space;
+        u8                      fid;
+
+        u16                     rc_ier;
+        u16                     rc_rxqcr;
+
+        struct mii_if_info      mii;
+        struct ks8851_rxctrl    rxctrl;
+
+        struct work_struct      tx_work;
+        struct work_struct      irq_work;
+        struct work_struct      rxctrl_work;
+
+        struct sk_buff_head     txq;
+
+        struct spi_message      spi_msg1;
+        struct spi_message      spi_msg2;
+        struct spi_transfer     spi_xfer1;
+        struct spi_transfer     spi_xfer2[2];
+};
+
+static int msg_enable;
+
+#define ks_info(_ks, _msg...) dev_info(&(_ks)->spidev->dev, _msg)
+#define ks_warn(_ks, _msg...) dev_warn(&(_ks)->spidev->dev, _msg)
+#define ks_dbg(_ks, _msg...) dev_dbg(&(_ks)->spidev->dev, _msg)
+#define ks_err(_ks, _msg...) dev_err(&(_ks)->spidev->dev, _msg)
+
+/* shift for byte-enable data */
+#define BYTE_EN(_x)     ((_x) << 2)
+
+/* turn register number and byte-enable mask into data for start of packet */
+#define MK_OP(_byteen, _reg) (BYTE_EN(_byteen) | (_reg)  << (8+2) | (_reg) >> 6)
+
+/* SPI register read/write calls.
+ *
+ * All these calls issue SPI transactions to access the chip's registers. They
+ * all require that the necessary lock is held to prevent accesses when the
+ * chip is busy transfering packet data (RX/TX FIFO accesses).
+ */
+
+/**
+ * ks8851_wrreg16 - write 16bit register value to chip
+ * @ks: The chip state
+ * @reg: The register address
+ * @val: The value to write
+ *
+ * Issue a write to put the value @val into the register specified in @reg.
+ */
+static void ks8851_wrreg16(struct ks8851_net *ks, unsigned reg, unsigned val)
+{
+        struct spi_transfer *xfer = &ks->spi_xfer1;
+        struct spi_message *msg = &ks->spi_msg1;
+        __le16 txb[2];
+        int ret;
+
+        txb[0] = cpu_to_le16(MK_OP(reg & 2 ? 0xC : 0x03, reg) | KS_SPIOP_WR);
+        txb[1] = cpu_to_le16(val);
+
+        xfer->tx_buf = txb;
+        xfer->rx_buf = NULL;
+        xfer->len = 4;
+
+        ret = spi_sync(ks->spidev, msg);
+        if (ret < 0)
+                ks_err(ks, "spi_sync() failed\n");
+}
+
+/**
+ * ks8851_rx_1msg - select whether to use one or two messages for spi read
+ * @ks: The device structure
+ *
+ * Return whether to generate a single message with a tx and rx buffer
+ * supplied to spi_sync(), or alternatively send the tx and rx buffers
+ * as separate messages.
+ *
+ * Depending on the hardware in use, a single message may be more efficient
+ * on interrupts or work done by the driver.
+ *
+ * This currently always returns true until we add some per-device data passed
+ * from the platform code to specify which mode is better.
+ */
+static inline bool ks8851_rx_1msg(struct ks8851_net *ks)
+{
+        return true;
+}
+
+/**
+ * ks8851_rdreg - issue read register command and return the data
+ * @ks: The device state
+ * @op: The register address and byte enables in message format.
+ * @rxb: The RX buffer to return the result into
+ * @rxl: The length of data expected.
+ *
+ * This is the low level read call that issues the necessary spi message(s)
+ * to read data from the register specified in @op.
+ */
+static void ks8851_rdreg(struct ks8851_net *ks, unsigned op,
+                         u8 *rxb, unsigned rxl)
+{
+        struct spi_transfer *xfer;
+        struct spi_message *msg;
+        __le16 *txb = (__le16 *)ks->txd;
+        u8 *trx = ks->rxd;
+        int ret;
+
+        txb[0] = cpu_to_le16(op | KS_SPIOP_RD);
+
+        if (ks8851_rx_1msg(ks)) {
+                msg = &ks->spi_msg1;
+                xfer = &ks->spi_xfer1;
+
+                xfer->tx_buf = txb;
+                xfer->rx_buf = trx;
+                xfer->len = rxl + 2;
+        } else {
+                msg = &ks->spi_msg2;
+                xfer = ks->spi_xfer2;
+
+                xfer->tx_buf = txb;
+                xfer->rx_buf = NULL;
+                xfer->len = 2;
+
+                xfer++;
+                xfer->tx_buf = NULL;
+                xfer->rx_buf = trx;
+                xfer->len = rxl;
+        }
+
+        ret = spi_sync(ks->spidev, msg);
+        if (ret < 0)
+                ks_err(ks, "read: spi_sync() failed\n");
+        else if (ks8851_rx_1msg(ks))
+                memcpy(rxb, trx + 2, rxl);
+        else
+                memcpy(rxb, trx, rxl);
+}
+
+/**
+ * ks8851_rdreg8 - read 8 bit register from device
+ * @ks: The chip information
+ * @reg: The register address
+ *
+ * Read a 8bit register from the chip, returning the result
+*/
+static unsigned ks8851_rdreg8(struct ks8851_net *ks, unsigned reg)
+{
+        u8 rxb[1];
+
+        ks8851_rdreg(ks, MK_OP(1 << (reg & 3), reg), rxb, 1);
+        return rxb[0];
+}
+
+/**
+ * ks8851_rdreg16 - read 16 bit register from device
+ * @ks: The chip information
+ * @reg: The register address
+ *
+ * Read a 16bit register from the chip, returning the result
+*/
+static unsigned ks8851_rdreg16(struct ks8851_net *ks, unsigned reg)
+{
+        __le16 rx = 0;
+
+        ks8851_rdreg(ks, MK_OP(reg & 2 ? 0xC : 0x3, reg), (u8 *)&rx, 2);
+        return le16_to_cpu(rx);
+}
+
+/**
+ * ks8851_rdreg32 - read 32 bit register from device
+ * @ks: The chip information
+ * @reg: The register address
+ *
+ * Read a 32bit register from the chip.
+ *
+ * Note, this read requires the address be aligned to 4 bytes.
+*/
+static unsigned ks8851_rdreg32(struct ks8851_net *ks, unsigned reg)
+{
+        __le32 rx = 0;
+
+        WARN_ON(reg & 3);
+
+        ks8851_rdreg(ks, MK_OP(0xf, reg), (u8 *)&rx, 4);
+        return le32_to_cpu(rx);
+}
+
+/**
+ * ks8851_soft_reset - issue one of the soft reset to the device
+ * @ks: The device state.
+ * @op: The bit(s) to set in the GRR
+ *
+ * Issue the relevant soft-reset command to the device's GRR register
+ * specified by @op.
+ *
+ * Note, the delays are in there as a caution to ensure that the reset
+ * has time to take effect and then complete. Since the datasheet does
+ * not currently specify the exact sequence, we have chosen something
+ * that seems to work with our device.
+ */
+static void ks8851_soft_reset(struct ks8851_net *ks, unsigned op)
+{
+        ks8851_wrreg16(ks, KS_GRR, op);
+        mdelay(1);      /* wait a short time to effect reset */
+        ks8851_wrreg16(ks, KS_GRR, 0);
+        mdelay(1);      /* wait for condition to clear */
+}
+
+/**
+ * ks8851_write_mac_addr - write mac address to device registers
+ * @dev: The network device
+ *
+ * Update the KS8851 MAC address registers from the address in @dev.
+ *
+ * This call assumes that the chip is not running, so there is no need to
+ * shutdown the RXQ process whilst setting this.
+*/
+static int ks8851_write_mac_addr(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        u16 *mcp = (u16 *)dev->dev_addr;
+
+        mutex_lock(&ks->lock);
+
+        ks8851_wrreg16(ks, KS_MARL, mcp[0]);
+        ks8851_wrreg16(ks, KS_MARM, mcp[1]);
+        ks8851_wrreg16(ks, KS_MARH, mcp[2]);
+
+        mutex_unlock(&ks->lock);
+
+        return 0;
+}
+
+/**
+ * ks8851_init_mac - initialise the mac address
+ * @ks: The device structure
+ *
+ * Get or create the initial mac address for the device and then set that
+ * into the station address register. Currently we assume that the device
+ * does not have a valid mac address in it, and so we use random_ether_addr()
+ * to create a new one.
+ *
+ * In future, the driver should check to see if the device has an EEPROM
+ * attached and whether that has a valid ethernet address in it.
+ */
+static void ks8851_init_mac(struct ks8851_net *ks)
+{
+        struct net_device *dev = ks->netdev;
+
+        random_ether_addr(dev->dev_addr);
+        ks8851_write_mac_addr(dev);
+}
+
+/**
+ * ks8851_irq - device interrupt handler
+ * @irq: Interrupt number passed from the IRQ hnalder.
+ * @pw: The private word passed to register_irq(), our struct ks8851_net.
+ *
+ * Disable the interrupt from happening again until we've processed the
+ * current status by scheduling ks8851_irq_work().
+ */
+static irqreturn_t ks8851_irq(int irq, void *pw)
+{
+        struct ks8851_net *ks = pw;
+
+        disable_irq_nosync(irq);
+        schedule_work(&ks->irq_work);
+        return IRQ_HANDLED;
+}
+
+/**
+ * ks8851_rdfifo - read data from the receive fifo
+ * @ks: The device state.
+ * @buff: The buffer address
+ * @len: The length of the data to read
+ *
+ * Issue an RXQ FIFO read command and read the @len ammount of data from
+ * the FIFO into the buffer specified by @buff.
+ */
+static void ks8851_rdfifo(struct ks8851_net *ks, u8 *buff, unsigned len)
+{
+        struct spi_transfer *xfer = ks->spi_xfer2;
+        struct spi_message *msg = &ks->spi_msg2;
+        u8 txb[1];
+        int ret;
+
+        if (netif_msg_rx_status(ks))
+                ks_dbg(ks, "%s: %d@%p\n", __func__, len, buff);
+
+        /* set the operation we're issuing */
+        txb[0] = KS_SPIOP_RXFIFO;
+
+        xfer->tx_buf = txb;
+        xfer->rx_buf = NULL;
+        xfer->len = 1;
+
+        xfer++;
+        xfer->rx_buf = buff;
+        xfer->tx_buf = NULL;
+        xfer->len = len;
+
+        ret = spi_sync(ks->spidev, msg);
+        if (ret < 0)
+                ks_err(ks, "%s: spi_sync() failed\n", __func__);
+}
+
+/**
+ * ks8851_dbg_dumpkkt - dump initial packet contents to debug
+ * @ks: The device state
+ * @rxpkt: The data for the received packet
+ *
+ * Dump the initial data from the packet to dev_dbg().
+*/
+static void ks8851_dbg_dumpkkt(struct ks8851_net *ks, u8 *rxpkt)
+{
+        ks_dbg(ks, "pkt %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x\n",
+               rxpkt[4], rxpkt[5], rxpkt[6], rxpkt[7],
+               rxpkt[8], rxpkt[9], rxpkt[10], rxpkt[11],
+               rxpkt[12], rxpkt[13], rxpkt[14], rxpkt[15]);
+}
+
+/**
+ * ks8851_rx_pkts - receive packets from the host
+ * @ks: The device information.
+ *
+ * This is called from the IRQ work queue when the system detects that there
+ * are packets in the receive queue. Find out how many packets there are and
+ * read them from the FIFO.
+ */
+static void ks8851_rx_pkts(struct ks8851_net *ks)
+{
+        struct sk_buff *skb;
+        unsigned rxfc;
+        unsigned rxlen;
+        unsigned rxstat;
+        u32 rxh;
+        u8 *rxpkt;
+
+        rxfc = ks8851_rdreg8(ks, KS_RXFC);
+
+        if (netif_msg_rx_status(ks))
+                ks_dbg(ks, "%s: %d packets\n", __func__, rxfc);
+
+        /* Currently we're issuing a read per packet, but we could possibly
+         * improve the code by issuing a single read, getting the receive
+         * header, allocating the packet and then reading the packet data
+         * out in one go.
+         *
+         * This form of operation would require us to hold the SPI bus'
+         * chipselect low during the entie transaction to avoid any
+         * reset to the data stream comming from the chip.
+         */
+
+        for (; rxfc != 0; rxfc--) {
+                rxh = ks8851_rdreg32(ks, KS_RXFHSR);
+                rxstat = rxh & 0xffff;
+                rxlen = rxh >> 16;
+
+                if (netif_msg_rx_status(ks))
+                        ks_dbg(ks, "rx: stat 0x%04x, len 0x%04x\n",
+                                rxstat, rxlen);
+
+                /* the length of the packet includes the 32bit CRC */
+
+                /* set dma read address */
+                ks8851_wrreg16(ks, KS_RXFDPR, RXFDPR_RXFPAI | 0x00);
+
+                /* start the packet dma process, and set auto-dequeue rx */
+                ks8851_wrreg16(ks, KS_RXQCR,
+                               ks->rc_rxqcr | RXQCR_SDA | RXQCR_ADRFE);
+
+                if (rxlen > 0) {
+                        skb = netdev_alloc_skb(ks->netdev, rxlen + 2 + 8);
+                        if (!skb) {
+                                /* todo - dump frame and move on */
+                        }
+
+                        /* two bytes to ensure ip is aligned, and four bytes
+                         * for the status header and 4 bytes of garbage */
+                        skb_reserve(skb, 2 + 4 + 4);
+
+                        rxpkt = skb_put(skb, rxlen - 4) - 8;
+
+                        /* align the packet length to 4 bytes, and add 4 bytes
+                         * as we're getting the rx status header as well */
+                        ks8851_rdfifo(ks, rxpkt, ALIGN(rxlen, 4) + 8);
+
+                        if (netif_msg_pktdata(ks))
+                                ks8851_dbg_dumpkkt(ks, rxpkt);
+
+                        skb->protocol = eth_type_trans(skb, ks->netdev);
+                        netif_rx(skb);
+
+                        ks->netdev->stats.rx_packets++;
+                        ks->netdev->stats.rx_bytes += rxlen - 4;
+                }
+
+                ks8851_wrreg16(ks, KS_RXQCR, ks->rc_rxqcr);
+        }
+}
+
+/**
+ * ks8851_irq_work - work queue handler for dealing with interrupt requests
+ * @work: The work structure that was scheduled by schedule_work()
+ *
+ * This is the handler invoked when the ks8851_irq() is called to find out
+ * what happened, as we cannot allow ourselves to sleep whilst waiting for
+ * anything other process has the chip's lock.
+ *
+ * Read the interrupt status, work out what needs to be done and then clear
+ * any of the interrupts that are not needed.
+ */
+static void ks8851_irq_work(struct work_struct *work)
+{
+        struct ks8851_net *ks = container_of(work, struct ks8851_net, irq_work);
+        unsigned status;
+        unsigned handled = 0;
+
+        mutex_lock(&ks->lock);
+
+        status = ks8851_rdreg16(ks, KS_ISR);
+
+        if (netif_msg_intr(ks))
+                dev_dbg(&ks->spidev->dev, "%s: status 0x%04x\n",
+                        __func__, status);
+
+        if (status & IRQ_LCI) {
+                /* should do something about checking link status */
+                handled |= IRQ_LCI;
+        }
+
+        if (status & IRQ_LDI) {
+                u16 pmecr = ks8851_rdreg16(ks, KS_PMECR);
+                pmecr &= ~PMECR_WKEVT_MASK;
+                ks8851_wrreg16(ks, KS_PMECR, pmecr | PMECR_WKEVT_LINK);
+
+                handled |= IRQ_LDI;
+        }
+
+        if (status & IRQ_RXPSI)
+                handled |= IRQ_RXPSI;
+
+        if (status & IRQ_TXI) {
+                handled |= IRQ_TXI;
+
+                /* no lock here, tx queue should have been stopped */
+
+                /* update our idea of how much tx space is available to the
+                 * system */
+                ks->tx_space = ks8851_rdreg16(ks, KS_TXMIR);
+
+                if (netif_msg_intr(ks))
+                        ks_dbg(ks, "%s: txspace %d\n", __func__, ks->tx_space);
+        }
+
+        if (status & IRQ_RXI)
+                handled |= IRQ_RXI;
+
+        if (status & IRQ_SPIBEI) {
+                dev_err(&ks->spidev->dev, "%s: spi bus error\n", __func__);
+                handled |= IRQ_SPIBEI;
+        }
+
+        ks8851_wrreg16(ks, KS_ISR, handled);
+
+        if (status & IRQ_RXI) {
+                /* the datasheet says to disable the rx interrupt during
+                 * packet read-out, however we're masking the interrupt
+                 * from the device so do not bother masking just the RX
+                 * from the device. */
+
+                ks8851_rx_pkts(ks);
+        }
+
+        /* if something stopped the rx process, probably due to wanting
+         * to change the rx settings, then do something about restarting
+         * it. */
+        if (status & IRQ_RXPSI) {
+                struct ks8851_rxctrl *rxc = &ks->rxctrl;
+
+                /* update the multicast hash table */
+                ks8851_wrreg16(ks, KS_MAHTR0, rxc->mchash[0]);
+                ks8851_wrreg16(ks, KS_MAHTR1, rxc->mchash[1]);
+                ks8851_wrreg16(ks, KS_MAHTR2, rxc->mchash[2]);
+                ks8851_wrreg16(ks, KS_MAHTR3, rxc->mchash[3]);
+
+                ks8851_wrreg16(ks, KS_RXCR2, rxc->rxcr2);
+                ks8851_wrreg16(ks, KS_RXCR1, rxc->rxcr1);
+        }
+
+        mutex_unlock(&ks->lock);
+
+        if (status & IRQ_TXI)
+                netif_wake_queue(ks->netdev);
+
+        enable_irq(ks->netdev->irq);
+}
+
+/**
+ * calc_txlen - calculate size of message to send packet
+ * @len: Lenght of data
+ *
+ * Returns the size of the TXFIFO message needed to send
+ * this packet.
+ */
+static inline unsigned calc_txlen(unsigned len)
+{
+        return ALIGN(len + 4, 4);
+}
+
+/**
+ * ks8851_wrpkt - write packet to TX FIFO
+ * @ks: The device state.
+ * @txp: The sk_buff to transmit.
+ * @irq: IRQ on completion of the packet.
+ *
+ * Send the @txp to the chip. This means creating the relevant packet header
+ * specifying the length of the packet and the other information the chip
+ * needs, such as IRQ on completion. Send the header and the packet data to
+ * the device.
+ */
+static void ks8851_wrpkt(struct ks8851_net *ks, struct sk_buff *txp, bool irq)
+{
+        struct spi_transfer *xfer = ks->spi_xfer2;
+        struct spi_message *msg = &ks->spi_msg2;
+        unsigned fid = 0;
+        int ret;
+
+        if (netif_msg_tx_queued(ks))
+                dev_dbg(&ks->spidev->dev, "%s: skb %p, %d@%p, irq %d\n",
+                        __func__, txp, txp->len, txp->data, irq);
+
+        fid = ks->fid++;
+        fid &= TXFR_TXFID_MASK;
+
+        if (irq)
+                fid |= TXFR_TXIC;       /* irq on completion */
+
+        /* start header at txb[1] to align txw entries */
+        ks->txh.txb[1] = KS_SPIOP_TXFIFO;
+        ks->txh.txw[1] = cpu_to_le16(fid);
+        ks->txh.txw[2] = cpu_to_le16(txp->len);
+
+        xfer->tx_buf = &ks->txh.txb[1];
+        xfer->rx_buf = NULL;
+        xfer->len = 5;
+
+        xfer++;
+        xfer->tx_buf = txp->data;
+        xfer->rx_buf = NULL;
+        xfer->len = ALIGN(txp->len, 4);
+
+        ret = spi_sync(ks->spidev, msg);
+        if (ret < 0)
+                ks_err(ks, "%s: spi_sync() failed\n", __func__);
+}
+
+/**
+ * ks8851_done_tx - update and then free skbuff after transmitting
+ * @ks: The device state
+ * @txb: The buffer transmitted
+ */
+static void ks8851_done_tx(struct ks8851_net *ks, struct sk_buff *txb)
+{
+        struct net_device *dev = ks->netdev;
+
+        dev->stats.tx_bytes += txb->len;
+        dev->stats.tx_packets++;
+
+        dev_kfree_skb(txb);
+}
+
+/**
+ * ks8851_tx_work - process tx packet(s)
+ * @work: The work strucutre what was scheduled.
+ *
+ * This is called when a number of packets have been scheduled for
+ * transmission and need to be sent to the device.
+ */
+static void ks8851_tx_work(struct work_struct *work)
+{
+        struct ks8851_net *ks = container_of(work, struct ks8851_net, tx_work);
+        struct sk_buff *txb;
+        bool last = false;
+
+        mutex_lock(&ks->lock);
+
+        while (!last) {
+                txb = skb_dequeue(&ks->txq);
+                last = skb_queue_empty(&ks->txq);
+
+                ks8851_wrreg16(ks, KS_RXQCR, ks->rc_rxqcr | RXQCR_SDA);
+                ks8851_wrpkt(ks, txb, last);
+                ks8851_wrreg16(ks, KS_RXQCR, ks->rc_rxqcr);
+                ks8851_wrreg16(ks, KS_TXQCR, TXQCR_METFE);
+
+                ks8851_done_tx(ks, txb);
+        }
+
+        mutex_unlock(&ks->lock);
+}
+
+/**
+ * ks8851_set_powermode - set power mode of the device
+ * @ks: The device state
+ * @pwrmode: The power mode value to write to KS_PMECR.
+ *
+ * Change the power mode of the chip.
+ */
+static void ks8851_set_powermode(struct ks8851_net *ks, unsigned pwrmode)
+{
+        unsigned pmecr;
+
+        if (netif_msg_hw(ks))
+                ks_dbg(ks, "setting power mode %d\n", pwrmode);
+
+        pmecr = ks8851_rdreg16(ks, KS_PMECR);
+        pmecr &= ~PMECR_PM_MASK;
+        pmecr |= pwrmode;
+
+        ks8851_wrreg16(ks, KS_PMECR, pmecr);
+}
+
+/**
+ * ks8851_net_open - open network device
+ * @dev: The network device being opened.
+ *
+ * Called when the network device is marked active, such as a user executing
+ * 'ifconfig up' on the device.
+ */
+static int ks8851_net_open(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+
+        /* lock the card, even if we may not actually be doing anything
+         * else at the moment */
+        mutex_lock(&ks->lock);
+
+        if (netif_msg_ifup(ks))
+                ks_dbg(ks, "opening %s\n", dev->name);
+
+        /* bring chip out of any power saving mode it was in */
+        ks8851_set_powermode(ks, PMECR_PM_NORMAL);
+
+        /* issue a soft reset to the RX/TX QMU to put it into a known
+         * state. */
+        ks8851_soft_reset(ks, GRR_QMU);
+
+        /* setup transmission parameters */
+
+        ks8851_wrreg16(ks, KS_TXCR, (TXCR_TXE | /* enable transmit process */
+                                     TXCR_TXPE | /* pad to min length */
+                                     TXCR_TXCRC | /* add CRC */
+                                     TXCR_TXFCE)); /* enable flow control */
+
+        /* auto-increment tx data, reset tx pointer */
+        ks8851_wrreg16(ks, KS_TXFDPR, TXFDPR_TXFPAI);
+
+        /* setup receiver control */
+
+        ks8851_wrreg16(ks, KS_RXCR1, (RXCR1_RXPAFMA | /*  from mac filter */
+                                      RXCR1_RXFCE | /* enable flow control */
+                                      RXCR1_RXBE | /* broadcast enable */
+                                      RXCR1_RXUE | /* unicast enable */
+                                      RXCR1_RXE)); /* enable rx block */
+
+        /* transfer entire frames out in one go */
+        ks8851_wrreg16(ks, KS_RXCR2, RXCR2_SRDBL_FRAME);
+
+        /* set receive counter timeouts */
+        ks8851_wrreg16(ks, KS_RXDTTR, 1000); /* 1ms after first frame to IRQ */
+        ks8851_wrreg16(ks, KS_RXDBCTR, 4096); /* >4Kbytes in buffer to IRQ */
+        ks8851_wrreg16(ks, KS_RXFCTR, 10);  /* 10 frames to IRQ */
+
+        ks->rc_rxqcr = (RXQCR_RXFCTE |  /* IRQ on frame count exceeded */
+                        RXQCR_RXDBCTE | /* IRQ on byte count exceeded */
+                        RXQCR_RXDTTE);  /* IRQ on time exceeded */
+
+        ks8851_wrreg16(ks, KS_RXQCR, ks->rc_rxqcr);
+
+        /* clear then enable interrupts */
+
+#define STD_IRQ (IRQ_LCI |      /* Link Change */       \
+                 IRQ_TXI |      /* TX done */           \
+                 IRQ_RXI |      /* RX done */           \
+                 IRQ_SPIBEI |   /* SPI bus error */     \
+                 IRQ_TXPSI |    /* TX process stop */   \
+                 IRQ_RXPSI)     /* RX process stop */
+
+        ks->rc_ier = STD_IRQ;
+        ks8851_wrreg16(ks, KS_ISR, STD_IRQ);
+        ks8851_wrreg16(ks, KS_IER, STD_IRQ);
+
+        netif_start_queue(ks->netdev);
+
+        if (netif_msg_ifup(ks))
+                ks_dbg(ks, "network device %s up\n", dev->name);
+
+        mutex_unlock(&ks->lock);
+        return 0;
+}
+
+/**
+ * ks8851_net_stop - close network device
+ * @dev: The device being closed.
+ *
+ * Called to close down a network device which has been active. Cancell any
+ * work, shutdown the RX and TX process and then place the chip into a low
+ * power state whilst it is not being used.
+ */
+static int ks8851_net_stop(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+
+        if (netif_msg_ifdown(ks))
+                ks_info(ks, "%s: shutting down\n", dev->name);
+
+        netif_stop_queue(dev);
+
+        mutex_lock(&ks->lock);
+
+        /* stop any outstanding work */
+        flush_work(&ks->irq_work);
+        flush_work(&ks->tx_work);
+        flush_work(&ks->rxctrl_work);
+
+        /* turn off the IRQs and ack any outstanding */
+        ks8851_wrreg16(ks, KS_IER, 0x0000);
+        ks8851_wrreg16(ks, KS_ISR, 0xffff);
+
+        /* shutdown RX process */
+        ks8851_wrreg16(ks, KS_RXCR1, 0x0000);
+
+        /* shutdown TX process */
+        ks8851_wrreg16(ks, KS_TXCR, 0x0000);
+
+        /* set powermode to soft power down to save power */
+        ks8851_set_powermode(ks, PMECR_PM_SOFTDOWN);
+
+        /* ensure any queued tx buffers are dumped */
+        while (!skb_queue_empty(&ks->txq)) {
+                struct sk_buff *txb = skb_dequeue(&ks->txq);
+
+                if (netif_msg_ifdown(ks))
+                        ks_dbg(ks, "%s: freeing txb %p\n", __func__, txb);
+
+                dev_kfree_skb(txb);
+        }
+
+        mutex_unlock(&ks->lock);
+        return 0;
+}
+
+/**
+ * ks8851_start_xmit - transmit packet
+ * @skb: The buffer to transmit
+ * @dev: The device used to transmit the packet.
+ *
+ * Called by the network layer to transmit the @skb. Queue the packet for
+ * the device and schedule the necessary work to transmit the packet when
+ * it is free.
+ *
+ * We do this to firstly avoid sleeping with the network device locked,
+ * and secondly so we can round up more than one packet to transmit which
+ * means we can try and avoid generating too many transmit done interrupts.
+ */
+static int ks8851_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        unsigned needed = calc_txlen(skb->len);
+        int ret = NETDEV_TX_OK;
+
+        if (netif_msg_tx_queued(ks))
+                ks_dbg(ks, "%s: skb %p, %d@%p\n", __func__,
+                       skb, skb->len, skb->data);
+
+        spin_lock(&ks->statelock);
+
+        if (needed > ks->tx_space) {
+                netif_stop_queue(dev);
+                ret = NETDEV_TX_BUSY;
+        } else {
+                ks->tx_space -= needed;
+                skb_queue_tail(&ks->txq, skb);
+        }
+
+        spin_unlock(&ks->statelock);
+        schedule_work(&ks->tx_work);
+
+        return ret;
+}
+
+/**
+ * ks8851_rxctrl_work - work handler to change rx mode
+ * @work: The work structure this belongs to.
+ *
+ * Lock the device and issue the necessary changes to the receive mode from
+ * the network device layer. This is done so that we can do this without
+ * having to sleep whilst holding the network device lock.
+ *
+ * Since the recommendation from Micrel is that the RXQ is shutdown whilst the
+ * receive parameters are programmed, we issue a write to disable the RXQ and
+ * then wait for the interrupt handler to be triggered once the RXQ shutdown is
+ * complete. The interrupt handler then writes the new values into the chip.
+ */
+static void ks8851_rxctrl_work(struct work_struct *work)
+{
+        struct ks8851_net *ks = container_of(work, struct ks8851_net, rxctrl_work);
+
+        mutex_lock(&ks->lock);
+
+        /* need to shutdown RXQ before modifying filter parameters */
+        ks8851_wrreg16(ks, KS_RXCR1, 0x00);
+
+        mutex_unlock(&ks->lock);
+}
+
+static void ks8851_set_rx_mode(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        struct ks8851_rxctrl rxctrl;
+
+        memset(&rxctrl, 0, sizeof(rxctrl));
+
+        if (dev->flags & IFF_PROMISC) {
+                /* interface to receive everything */
+
+                rxctrl.rxcr1 = RXCR1_RXAE | RXCR1_RXINVF;
+        } else if (dev->flags & IFF_ALLMULTI) {
+                /* accept all multicast packets */
+
+                rxctrl.rxcr1 = (RXCR1_RXME | RXCR1_RXAE |
+                                RXCR1_RXPAFMA | RXCR1_RXMAFMA);
+        } else if (dev->flags & IFF_MULTICAST && dev->mc_count > 0) {
+                struct dev_mc_list *mcptr = dev->mc_list;
+                u32 crc;
+                int i;
+
+                /* accept some multicast */
+
+                for (i = dev->mc_count; i > 0; i--) {
+                        crc = ether_crc(ETH_ALEN, mcptr->dmi_addr);
+                        crc >>= (32 - 6);  /* get top six bits */
+
+                        rxctrl.mchash[crc >> 4] |= (1 << (crc & 0xf));
+                        mcptr = mcptr->next;
+                }
+
+                rxctrl.rxcr1 = RXCR1_RXME | RXCR1_RXAE | RXCR1_RXPAFMA;
+        } else {
+                /* just accept broadcast / unicast */
+                rxctrl.rxcr1 = RXCR1_RXPAFMA;
+        }
+
+        rxctrl.rxcr1 |= (RXCR1_RXUE | /* unicast enable */
+                         RXCR1_RXBE | /* broadcast enable */
+                         RXCR1_RXE | /* RX process enable */
+                         RXCR1_RXFCE); /* enable flow control */
+
+        rxctrl.rxcr2 |= RXCR2_SRDBL_FRAME;
+
+        /* schedule work to do the actual set of the data if needed */
+
+        spin_lock(&ks->statelock);
+
+        if (memcmp(&rxctrl, &ks->rxctrl, sizeof(rxctrl)) != 0) {
+                memcpy(&ks->rxctrl, &rxctrl, sizeof(ks->rxctrl));
+                schedule_work(&ks->rxctrl_work);
+        }
+
+        spin_unlock(&ks->statelock);
+}
+
+static int ks8851_set_mac_address(struct net_device *dev, void *addr)
+{
+        struct sockaddr *sa = addr;
+
+        if (netif_running(dev))
+                return -EBUSY;
+
+        if (!is_valid_ether_addr(sa->sa_data))
+                return -EADDRNOTAVAIL;
+
+        memcpy(dev->dev_addr, sa->sa_data, ETH_ALEN);
+        return ks8851_write_mac_addr(dev);
+}
+
+static int ks8851_net_ioctl(struct net_device *dev, struct ifreq *req, int cmd)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+
+        if (!netif_running(dev))
+                return -EINVAL;
+
+        return generic_mii_ioctl(&ks->mii, if_mii(req), cmd, NULL);
+}
+
+static const struct net_device_ops ks8851_netdev_ops = {
+        .ndo_open               = ks8851_net_open,
+        .ndo_stop               = ks8851_net_stop,
+        .ndo_do_ioctl           = ks8851_net_ioctl,
+        .ndo_start_xmit         = ks8851_start_xmit,
+        .ndo_set_mac_address    = ks8851_set_mac_address,
+        .ndo_set_rx_mode        = ks8851_set_rx_mode,
+        .ndo_change_mtu         = eth_change_mtu,
+        .ndo_validate_addr      = eth_validate_addr,
+};
+
+/* ethtool support */
+
+static void ks8851_get_drvinfo(struct net_device *dev,
+                               struct ethtool_drvinfo *di)
+{
+        strlcpy(di->driver, "KS8851", sizeof(di->driver));
+        strlcpy(di->version, "1.00", sizeof(di->version));
+        strlcpy(di->bus_info, dev_name(dev->dev.parent), sizeof(di->bus_info));
+}
+
+static u32 ks8851_get_msglevel(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return ks->msg_enable;
+}
+
+static void ks8851_set_msglevel(struct net_device *dev, u32 to)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        ks->msg_enable = to;
+}
+
+static int ks8851_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return mii_ethtool_gset(&ks->mii, cmd);
+}
+
+static int ks8851_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return mii_ethtool_sset(&ks->mii, cmd);
+}
+
+static u32 ks8851_get_link(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return mii_link_ok(&ks->mii);
+}
+
+static int ks8851_nway_reset(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return mii_nway_restart(&ks->mii);
+}
+
+static const struct ethtool_ops ks8851_ethtool_ops = {
+        .get_drvinfo    = ks8851_get_drvinfo,
+        .get_msglevel   = ks8851_get_msglevel,
+        .set_msglevel   = ks8851_set_msglevel,
+        .get_settings   = ks8851_get_settings,
+        .set_settings   = ks8851_set_settings,
+        .get_link       = ks8851_get_link,
+        .nway_reset     = ks8851_nway_reset,
+};
+
+/* MII interface controls */
+
+/**
+ * ks8851_phy_reg - convert MII register into a KS8851 register
+ * @reg: MII register number.
+ *
+ * Return the KS8851 register number for the corresponding MII PHY register
+ * if possible. Return zero if the MII register has no direct mapping to the
+ * KS8851 register set.
+ */
+static int ks8851_phy_reg(int reg)
+{
+        switch (reg) {
+        case MII_BMCR:
+                return KS_P1MBCR;
+        case MII_BMSR:
+                return KS_P1MBSR;
+        case MII_PHYSID1:
+                return KS_PHY1ILR;
+        case MII_PHYSID2:
+                return KS_PHY1IHR;
+        case MII_ADVERTISE:
+                return KS_P1ANAR;
+        case MII_LPA:
+                return KS_P1ANLPR;
+        }
+
+        return 0x0;
+}
+
+/**
+ * ks8851_phy_read - MII interface PHY register read.
+ * @dev: The network device the PHY is on.
+ * @phy_addr: Address of PHY (ignored as we only have one)
+ * @reg: The register to read.
+ *
+ * This call reads data from the PHY register specified in @reg. Since the
+ * device does not support all the MII registers, the non-existant values
+ * are always returned as zero.
+ *
+ * We return zero for unsupported registers as the MII code does not check
+ * the value returned for any error status, and simply returns it to the
+ * caller. The mii-tool that the driver was tested with takes any -ve error
+ * as real PHY capabilities, thus displaying incorrect data to the user.
+ */
+static int ks8851_phy_read(struct net_device *dev, int phy_addr, int reg)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        int ksreg;
+        int result;
+
+        ksreg = ks8851_phy_reg(reg);
+        if (!ksreg)
+                return 0x0;     /* no error return allowed, so use zero */
+
+        mutex_lock(&ks->lock);
+        result = ks8851_rdreg16(ks, ksreg);
+        mutex_unlock(&ks->lock);
+
+        return result;
+}
+
+static void ks8851_phy_write(struct net_device *dev,
+                             int phy, int reg, int value)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        int ksreg;
+
+        ksreg = ks8851_phy_reg(reg);
+        if (ksreg) {
+                mutex_lock(&ks->lock);
+                ks8851_wrreg16(ks, ksreg, value);
+                mutex_unlock(&ks->lock);
+        }
+}
+
+/**
+ * ks8851_read_selftest - read the selftest memory info.
+ * @ks: The device state
+ *
+ * Read and check the TX/RX memory selftest information.
+ */
+static int ks8851_read_selftest(struct ks8851_net *ks)
+{
+        unsigned both_done = MBIR_TXMBF | MBIR_RXMBF;
+        int ret = 0;
+        unsigned rd;
+
+        rd = ks8851_rdreg16(ks, KS_MBIR);
+
+        if ((rd & both_done) != both_done) {
+                ks_warn(ks, "Memory selftest not finished\n");
+                return 0;
+        }
+
+        if (rd & MBIR_TXMBFA) {
+                ks_err(ks, "TX memory selftest fail\n");
+                ret |= 1;
+        }
+
+        if (rd & MBIR_RXMBFA) {
+                ks_err(ks, "RX memory selftest fail\n");
+                ret |= 2;
+        }
+
+        return 0;
+}
+
+/* driver bus management functions */
+
+static int __devinit ks8851_probe(struct spi_device *spi)
+{
+        struct net_device *ndev;
+        struct ks8851_net *ks;
+        int ret;
+
+        ndev = alloc_etherdev(sizeof(struct ks8851_net));
+        if (!ndev) {
+                dev_err(&spi->dev, "failed to alloc ethernet device\n");
+                return -ENOMEM;
+        }
+
+        spi->bits_per_word = 8;
+
+        ks = netdev_priv(ndev);
+
+        ks->netdev = ndev;
+        ks->spidev = spi;
+        ks->tx_space = 6144;
+
+        mutex_init(&ks->lock);
+        spin_lock_init(&ks->statelock);
+
+        INIT_WORK(&ks->tx_work, ks8851_tx_work);
+        INIT_WORK(&ks->irq_work, ks8851_irq_work);
+        INIT_WORK(&ks->rxctrl_work, ks8851_rxctrl_work);
+
+        /* initialise pre-made spi transfer messages */
+
+        spi_message_init(&ks->spi_msg1);
+        spi_message_add_tail(&ks->spi_xfer1, &ks->spi_msg1);
+
+        spi_message_init(&ks->spi_msg2);
+        spi_message_add_tail(&ks->spi_xfer2[0], &ks->spi_msg2);
+        spi_message_add_tail(&ks->spi_xfer2[1], &ks->spi_msg2);
+
+        /* setup mii state */
+        ks->mii.dev             = ndev;
+        ks->mii.phy_id          = 1,
+        ks->mii.phy_id_mask     = 1;
+        ks->mii.reg_num_mask    = 0xf;
+        ks->mii.mdio_read       = ks8851_phy_read;
+        ks->mii.mdio_write      = ks8851_phy_write;
+
+        dev_info(&spi->dev, "message enable is %d\n", msg_enable);
+
+        /* set the default message enable */
+        ks->msg_enable = netif_msg_init(msg_enable, (NETIF_MSG_DRV |
+                                                     NETIF_MSG_PROBE |
+                                                     NETIF_MSG_LINK));
+
+        skb_queue_head_init(&ks->txq);
+
+        SET_ETHTOOL_OPS(ndev, &ks8851_ethtool_ops);
+        SET_NETDEV_DEV(ndev, &spi->dev);
+
+        dev_set_drvdata(&spi->dev, ks);
+
+        ndev->if_port = IF_PORT_100BASET;
+        ndev->netdev_ops = &ks8851_netdev_ops;
+        ndev->irq = spi->irq;
+
+        /* simple check for a valid chip being connected to the bus */
+
+        if ((ks8851_rdreg16(ks, KS_CIDER) & ~CIDER_REV_MASK) != CIDER_ID) {
+                dev_err(&spi->dev, "failed to read device ID\n");
+                ret = -ENODEV;
+                goto err_id;
+        }
+
+        ks8851_read_selftest(ks);
+        ks8851_init_mac(ks);
+
+        ret = request_irq(spi->irq, ks8851_irq, IRQF_TRIGGER_LOW,
+                          ndev->name, ks);
+        if (ret < 0) {
+                dev_err(&spi->dev, "failed to get irq\n");
+                goto err_irq;
+        }
+
+        ret = register_netdev(ndev);
+        if (ret) {
+                dev_err(&spi->dev, "failed to register network device\n");
+                goto err_netdev;
+        }
+
+        dev_info(&spi->dev, "revision %d, MAC %pM, IRQ %d\n",
+                 CIDER_REV_GET(ks8851_rdreg16(ks, KS_CIDER)),
+                 ndev->dev_addr, ndev->irq);
+
+        return 0;
+
+
+err_netdev:
+        free_irq(ndev->irq, ndev);
+
+err_id:
+err_irq:
+        free_netdev(ndev);
+        return ret;
+}
+
+static int __devexit ks8851_remove(struct spi_device *spi)
+{
+        struct ks8851_net *priv = dev_get_drvdata(&spi->dev);
+
+        if (netif_msg_drv(priv))
+                dev_info(&spi->dev, "remove");
+
+        unregister_netdev(priv->netdev);
+        free_irq(spi->irq, priv);
+        free_netdev(priv->netdev);
+
+        return 0;
+}
+
+static struct spi_driver ks8851_driver = {
+        .driver = {
+                .name = "ks8851",
+                .owner = THIS_MODULE,
+        },
+        .probe = ks8851_probe,
+        .remove = __devexit_p(ks8851_remove),
+};
+
+static int __init ks8851_init(void)
+{
+        return spi_register_driver(&ks8851_driver);
+}
+
+static void __exit ks8851_exit(void)
+{
+        spi_unregister_driver(&ks8851_driver);
+}
+
+module_init(ks8851_init);
+module_exit(ks8851_exit);
+
+MODULE_DESCRIPTION("KS8851 Network driver");
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL");
+
+module_param_named(message, msg_enable, int, 0);
+MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)");