Save sram context after changing MPU, DSP or core clocks

[linux-ginger.git] / drivers / net / pasemi_mac.c

/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Driver for the PA Semi PWRficient onchip 1G/10G Ethernet MACs
 *
 * 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.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/of_mdio.h>
#include <linux/etherdevice.h>
#include <asm/dma-mapping.h>
#include <linux/in.h>
#include <linux/skbuff.h>

#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/checksum.h>
#include <linux/inet_lro.h>

#include <asm/irq.h>
#include <asm/firmware.h>
#include <asm/pasemi_dma.h>

#include "pasemi_mac.h"

/* We have our own align, since ppc64 in general has it at 0 because
 * of design flaws in some of the server bridge chips. However, for
 * PWRficient doing the unaligned copies is more expensive than doing
 * unaligned DMA, so make sure the data is aligned instead.
 */
#define LOCAL_SKB_ALIGN 2

/* TODO list
 *
 * - Multicast support
 * - Large MTU support
 * - SW LRO
 * - Multiqueue RX/TX
 */

#define LRO_MAX_AGGR 64

#define PE_MIN_MTU      64
#define PE_MAX_MTU      9000
#define PE_DEF_MTU      ETH_DATA_LEN

#define DEFAULT_MSG_ENABLE        \
        (NETIF_MSG_DRV          | \
         NETIF_MSG_PROBE        | \
         NETIF_MSG_LINK         | \
         NETIF_MSG_TIMER        | \
         NETIF_MSG_IFDOWN       | \
         NETIF_MSG_IFUP         | \
         NETIF_MSG_RX_ERR       | \
         NETIF_MSG_TX_ERR)

MODULE_LICENSE("GPL");
MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
MODULE_DESCRIPTION("PA Semi PWRficient Ethernet driver");

static int debug = -1;  /* -1 == use DEFAULT_MSG_ENABLE as value */
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "PA Semi MAC bitmapped debugging message enable value");

extern const struct ethtool_ops pasemi_mac_ethtool_ops;

static int translation_enabled(void)
{
#if defined(CONFIG_PPC_PASEMI_IOMMU_DMA_FORCE)
        return 1;
#else
        return firmware_has_feature(FW_FEATURE_LPAR);
#endif
}

static void write_iob_reg(unsigned int reg, unsigned int val)
{
        pasemi_write_iob_reg(reg, val);
}

static unsigned int read_mac_reg(const struct pasemi_mac *mac, unsigned int reg)
{
        return pasemi_read_mac_reg(mac->dma_if, reg);
}

static void write_mac_reg(const struct pasemi_mac *mac, unsigned int reg,
                          unsigned int val)
{
        pasemi_write_mac_reg(mac->dma_if, reg, val);
}

static unsigned int read_dma_reg(unsigned int reg)
{
        return pasemi_read_dma_reg(reg);
}

static void write_dma_reg(unsigned int reg, unsigned int val)
{
        pasemi_write_dma_reg(reg, val);
}

static struct pasemi_mac_rxring *rx_ring(const struct pasemi_mac *mac)
{
        return mac->rx;
}

static struct pasemi_mac_txring *tx_ring(const struct pasemi_mac *mac)
{
        return mac->tx;
}

static inline void prefetch_skb(const struct sk_buff *skb)
{
        const void *d = skb;

        prefetch(d);
        prefetch(d+64);
        prefetch(d+128);
        prefetch(d+192);
}

static int mac_to_intf(struct pasemi_mac *mac)
{
        struct pci_dev *pdev = mac->pdev;
        u32 tmp;
        int nintf, off, i, j;
        int devfn = pdev->devfn;

        tmp = read_dma_reg(PAS_DMA_CAP_IFI);
        nintf = (tmp & PAS_DMA_CAP_IFI_NIN_M) >> PAS_DMA_CAP_IFI_NIN_S;
        off = (tmp & PAS_DMA_CAP_IFI_IOFF_M) >> PAS_DMA_CAP_IFI_IOFF_S;

        /* IOFF contains the offset to the registers containing the
         * DMA interface-to-MAC-pci-id mappings, and NIN contains number
         * of total interfaces. Each register contains 4 devfns.
         * Just do a linear search until we find the devfn of the MAC
         * we're trying to look up.
         */

        for (i = 0; i < (nintf+3)/4; i++) {
                tmp = read_dma_reg(off+4*i);
                for (j = 0; j < 4; j++) {
                        if (((tmp >> (8*j)) & 0xff) == devfn)
                                return i*4 + j;
                }
        }
        return -1;
}

static void pasemi_mac_intf_disable(struct pasemi_mac *mac)
{
        unsigned int flags;

        flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);
        flags &= ~PAS_MAC_CFG_PCFG_PE;
        write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);
}

static void pasemi_mac_intf_enable(struct pasemi_mac *mac)
{
        unsigned int flags;

        flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);
        flags |= PAS_MAC_CFG_PCFG_PE;
        write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);
}

static int pasemi_get_mac_addr(struct pasemi_mac *mac)
{
        struct pci_dev *pdev = mac->pdev;
        struct device_node *dn = pci_device_to_OF_node(pdev);
        int len;
        const u8 *maddr;
        u8 addr[6];

        if (!dn) {
                dev_dbg(&pdev->dev,
                          "No device node for mac, not configuring\n");
                return -ENOENT;
        }

        maddr = of_get_property(dn, "local-mac-address", &len);

        if (maddr && len == 6) {
                memcpy(mac->mac_addr, maddr, 6);
                return 0;
        }

        /* Some old versions of firmware mistakenly uses mac-address
         * (and as a string) instead of a byte array in local-mac-address.
         */

        if (maddr == NULL)
                maddr = of_get_property(dn, "mac-address", NULL);

        if (maddr == NULL) {
                dev_warn(&pdev->dev,
                         "no mac address in device tree, not configuring\n");
                return -ENOENT;
        }

        if (sscanf(maddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx", &addr[0],
                   &addr[1], &addr[2], &addr[3], &addr[4], &addr[5]) != 6) {
                dev_warn(&pdev->dev,
                         "can't parse mac address, not configuring\n");
                return -EINVAL;
        }

        memcpy(mac->mac_addr, addr, 6);

        return 0;
}

static int pasemi_mac_set_mac_addr(struct net_device *dev, void *p)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        struct sockaddr *addr = p;
        unsigned int adr0, adr1;

        if (!is_valid_ether_addr(addr->sa_data))
                return -EINVAL;

        memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);

        adr0 = dev->dev_addr[2] << 24 |
               dev->dev_addr[3] << 16 |
               dev->dev_addr[4] << 8 |
               dev->dev_addr[5];
        adr1 = read_mac_reg(mac, PAS_MAC_CFG_ADR1);
        adr1 &= ~0xffff;
        adr1 |= dev->dev_addr[0] << 8 | dev->dev_addr[1];

        pasemi_mac_intf_disable(mac);
        write_mac_reg(mac, PAS_MAC_CFG_ADR0, adr0);
        write_mac_reg(mac, PAS_MAC_CFG_ADR1, adr1);
        pasemi_mac_intf_enable(mac);

        return 0;
}

static int get_skb_hdr(struct sk_buff *skb, void **iphdr,
                       void **tcph, u64 *hdr_flags, void *data)
{
        u64 macrx = (u64) data;
        unsigned int ip_len;
        struct iphdr *iph;

        /* IPv4 header checksum failed */
        if ((macrx & XCT_MACRX_HTY_M) != XCT_MACRX_HTY_IPV4_OK)
                return -1;

        /* non tcp packet */
        skb_reset_network_header(skb);
        iph = ip_hdr(skb);
        if (iph->protocol != IPPROTO_TCP)
                return -1;

        ip_len = ip_hdrlen(skb);
        skb_set_transport_header(skb, ip_len);
        *tcph = tcp_hdr(skb);

        /* check if ip header and tcp header are complete */
        if (ntohs(iph->tot_len) < ip_len + tcp_hdrlen(skb))
                return -1;

        *hdr_flags = LRO_IPV4 | LRO_TCP;
        *iphdr = iph;

        return 0;
}

static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
                                    const int nfrags,
                                    struct sk_buff *skb,
                                    const dma_addr_t *dmas)
{
        int f;
        struct pci_dev *pdev = mac->dma_pdev;

        pci_unmap_single(pdev, dmas[0], skb_headlen(skb), PCI_DMA_TODEVICE);

        for (f = 0; f < nfrags; f++) {
                skb_frag_t *frag = &skb_shinfo(skb)->frags[f];

                pci_unmap_page(pdev, dmas[f+1], frag->size, PCI_DMA_TODEVICE);
        }
        dev_kfree_skb_irq(skb);

        /* Freed descriptor slot + main SKB ptr + nfrags additional ptrs,
         * aligned up to a power of 2
         */
        return (nfrags + 3) & ~1;
}

static struct pasemi_mac_csring *pasemi_mac_setup_csring(struct pasemi_mac *mac)
{
        struct pasemi_mac_csring *ring;
        u32 val;
        unsigned int cfg;
        int chno;

        ring = pasemi_dma_alloc_chan(TXCHAN, sizeof(struct pasemi_mac_csring),
                                       offsetof(struct pasemi_mac_csring, chan));

        if (!ring) {
                dev_err(&mac->pdev->dev, "Can't allocate checksum channel\n");
                goto out_chan;
        }

        chno = ring->chan.chno;

        ring->size = CS_RING_SIZE;
        ring->next_to_fill = 0;

        /* Allocate descriptors */
        if (pasemi_dma_alloc_ring(&ring->chan, CS_RING_SIZE))
                goto out_ring_desc;

        write_dma_reg(PAS_DMA_TXCHAN_BASEL(chno),
                      PAS_DMA_TXCHAN_BASEL_BRBL(ring->chan.ring_dma));
        val = PAS_DMA_TXCHAN_BASEU_BRBH(ring->chan.ring_dma >> 32);
        val |= PAS_DMA_TXCHAN_BASEU_SIZ(CS_RING_SIZE >> 3);

        write_dma_reg(PAS_DMA_TXCHAN_BASEU(chno), val);

        ring->events[0] = pasemi_dma_alloc_flag();
        ring->events[1] = pasemi_dma_alloc_flag();
        if (ring->events[0] < 0 || ring->events[1] < 0)
                goto out_flags;

        pasemi_dma_clear_flag(ring->events[0]);
        pasemi_dma_clear_flag(ring->events[1]);

        ring->fun = pasemi_dma_alloc_fun();
        if (ring->fun < 0)
                goto out_fun;

        cfg = PAS_DMA_TXCHAN_CFG_TY_FUNC | PAS_DMA_TXCHAN_CFG_UP |
              PAS_DMA_TXCHAN_CFG_TATTR(ring->fun) |
              PAS_DMA_TXCHAN_CFG_LPSQ | PAS_DMA_TXCHAN_CFG_LPDQ;

        if (translation_enabled())
                cfg |= PAS_DMA_TXCHAN_CFG_TRD | PAS_DMA_TXCHAN_CFG_TRR;

        write_dma_reg(PAS_DMA_TXCHAN_CFG(chno), cfg);

        /* enable channel */
        pasemi_dma_start_chan(&ring->chan, PAS_DMA_TXCHAN_TCMDSTA_SZ |
                                           PAS_DMA_TXCHAN_TCMDSTA_DB |
                                           PAS_DMA_TXCHAN_TCMDSTA_DE |
                                           PAS_DMA_TXCHAN_TCMDSTA_DA);

        return ring;

out_fun:
out_flags:
        if (ring->events[0] >= 0)
                pasemi_dma_free_flag(ring->events[0]);
        if (ring->events[1] >= 0)
                pasemi_dma_free_flag(ring->events[1]);
        pasemi_dma_free_ring(&ring->chan);
out_ring_desc:
        pasemi_dma_free_chan(&ring->chan);
out_chan:

        return NULL;
}

static void pasemi_mac_setup_csrings(struct pasemi_mac *mac)
{
        int i;
        mac->cs[0] = pasemi_mac_setup_csring(mac);
        if (mac->type == MAC_TYPE_XAUI)
                mac->cs[1] = pasemi_mac_setup_csring(mac);
        else
                mac->cs[1] = 0;

        for (i = 0; i < MAX_CS; i++)
                if (mac->cs[i])
                        mac->num_cs++;
}

static void pasemi_mac_free_csring(struct pasemi_mac_csring *csring)
{
        pasemi_dma_stop_chan(&csring->chan);
        pasemi_dma_free_flag(csring->events[0]);
        pasemi_dma_free_flag(csring->events[1]);
        pasemi_dma_free_ring(&csring->chan);
        pasemi_dma_free_chan(&csring->chan);
        pasemi_dma_free_fun(csring->fun);
}

static int pasemi_mac_setup_rx_resources(const struct net_device *dev)
{
        struct pasemi_mac_rxring *ring;
        struct pasemi_mac *mac = netdev_priv(dev);
        int chno;
        unsigned int cfg;

        ring = pasemi_dma_alloc_chan(RXCHAN, sizeof(struct pasemi_mac_rxring),
                                     offsetof(struct pasemi_mac_rxring, chan));

        if (!ring) {
                dev_err(&mac->pdev->dev, "Can't allocate RX channel\n");
                goto out_chan;
        }
        chno = ring->chan.chno;

        spin_lock_init(&ring->lock);

        ring->size = RX_RING_SIZE;
        ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
                                  RX_RING_SIZE, GFP_KERNEL);

        if (!ring->ring_info)
                goto out_ring_info;

        /* Allocate descriptors */
        if (pasemi_dma_alloc_ring(&ring->chan, RX_RING_SIZE))
                goto out_ring_desc;

        ring->buffers = dma_alloc_coherent(&mac->dma_pdev->dev,
                                           RX_RING_SIZE * sizeof(u64),
                                           &ring->buf_dma, GFP_KERNEL);
        if (!ring->buffers)
                goto out_ring_desc;

        memset(ring->buffers, 0, RX_RING_SIZE * sizeof(u64));

        write_dma_reg(PAS_DMA_RXCHAN_BASEL(chno),
                      PAS_DMA_RXCHAN_BASEL_BRBL(ring->chan.ring_dma));

        write_dma_reg(PAS_DMA_RXCHAN_BASEU(chno),
                      PAS_DMA_RXCHAN_BASEU_BRBH(ring->chan.ring_dma >> 32) |
                      PAS_DMA_RXCHAN_BASEU_SIZ(RX_RING_SIZE >> 3));

        cfg = PAS_DMA_RXCHAN_CFG_HBU(2);

        if (translation_enabled())
                cfg |= PAS_DMA_RXCHAN_CFG_CTR;

        write_dma_reg(PAS_DMA_RXCHAN_CFG(chno), cfg);

        write_dma_reg(PAS_DMA_RXINT_BASEL(mac->dma_if),
                      PAS_DMA_RXINT_BASEL_BRBL(ring->buf_dma));

        write_dma_reg(PAS_DMA_RXINT_BASEU(mac->dma_if),
                      PAS_DMA_RXINT_BASEU_BRBH(ring->buf_dma >> 32) |
                      PAS_DMA_RXINT_BASEU_SIZ(RX_RING_SIZE >> 3));

        cfg = PAS_DMA_RXINT_CFG_DHL(2) | PAS_DMA_RXINT_CFG_L2 |
              PAS_DMA_RXINT_CFG_LW | PAS_DMA_RXINT_CFG_RBP |
              PAS_DMA_RXINT_CFG_HEN;

        if (translation_enabled())
                cfg |= PAS_DMA_RXINT_CFG_ITRR | PAS_DMA_RXINT_CFG_ITR;

        write_dma_reg(PAS_DMA_RXINT_CFG(mac->dma_if), cfg);

        ring->next_to_fill = 0;
        ring->next_to_clean = 0;
        ring->mac = mac;
        mac->rx = ring;

        return 0;

out_ring_desc:
        kfree(ring->ring_info);
out_ring_info:
        pasemi_dma_free_chan(&ring->chan);
out_chan:
        return -ENOMEM;
}

static struct pasemi_mac_txring *
pasemi_mac_setup_tx_resources(const struct net_device *dev)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        u32 val;
        struct pasemi_mac_txring *ring;
        unsigned int cfg;
        int chno;

        ring = pasemi_dma_alloc_chan(TXCHAN, sizeof(struct pasemi_mac_txring),
                                     offsetof(struct pasemi_mac_txring, chan));

        if (!ring) {
                dev_err(&mac->pdev->dev, "Can't allocate TX channel\n");
                goto out_chan;
        }

        chno = ring->chan.chno;

        spin_lock_init(&ring->lock);

        ring->size = TX_RING_SIZE;
        ring->ring_info = kzalloc(sizeof(struct pasemi_mac_buffer) *
                                  TX_RING_SIZE, GFP_KERNEL);
        if (!ring->ring_info)
                goto out_ring_info;

        /* Allocate descriptors */
        if (pasemi_dma_alloc_ring(&ring->chan, TX_RING_SIZE))
                goto out_ring_desc;

        write_dma_reg(PAS_DMA_TXCHAN_BASEL(chno),
                      PAS_DMA_TXCHAN_BASEL_BRBL(ring->chan.ring_dma));
        val = PAS_DMA_TXCHAN_BASEU_BRBH(ring->chan.ring_dma >> 32);
        val |= PAS_DMA_TXCHAN_BASEU_SIZ(TX_RING_SIZE >> 3);

        write_dma_reg(PAS_DMA_TXCHAN_BASEU(chno), val);

        cfg = PAS_DMA_TXCHAN_CFG_TY_IFACE |
              PAS_DMA_TXCHAN_CFG_TATTR(mac->dma_if) |
              PAS_DMA_TXCHAN_CFG_UP |
              PAS_DMA_TXCHAN_CFG_WT(4);

        if (translation_enabled())
                cfg |= PAS_DMA_TXCHAN_CFG_TRD | PAS_DMA_TXCHAN_CFG_TRR;

        write_dma_reg(PAS_DMA_TXCHAN_CFG(chno), cfg);

        ring->next_to_fill = 0;
        ring->next_to_clean = 0;
        ring->mac = mac;

        return ring;

out_ring_desc:
        kfree(ring->ring_info);
out_ring_info:
        pasemi_dma_free_chan(&ring->chan);
out_chan:
        return NULL;
}

static void pasemi_mac_free_tx_resources(struct pasemi_mac *mac)
{
        struct pasemi_mac_txring *txring = tx_ring(mac);
        unsigned int i, j;
        struct pasemi_mac_buffer *info;
        dma_addr_t dmas[MAX_SKB_FRAGS+1];
        int freed, nfrags;
        int start, limit;

        start = txring->next_to_clean;
        limit = txring->next_to_fill;

        /* Compensate for when fill has wrapped and clean has not */
        if (start > limit)
                limit += TX_RING_SIZE;

        for (i = start; i < limit; i += freed) {
                info = &txring->ring_info[(i+1) & (TX_RING_SIZE-1)];
                if (info->dma && info->skb) {
                        nfrags = skb_shinfo(info->skb)->nr_frags;
                        for (j = 0; j <= nfrags; j++)
                                dmas[j] = txring->ring_info[(i+1+j) &
                                                (TX_RING_SIZE-1)].dma;
                        freed = pasemi_mac_unmap_tx_skb(mac, nfrags,
                                                        info->skb, dmas);
                } else
                        freed = 2;
        }

        kfree(txring->ring_info);
        pasemi_dma_free_chan(&txring->chan);

}

static void pasemi_mac_free_rx_buffers(struct pasemi_mac *mac)
{
        struct pasemi_mac_rxring *rx = rx_ring(mac);
        unsigned int i;
        struct pasemi_mac_buffer *info;

        for (i = 0; i < RX_RING_SIZE; i++) {
                info = &RX_DESC_INFO(rx, i);
                if (info->skb && info->dma) {
                        pci_unmap_single(mac->dma_pdev,
                                         info->dma,
                                         info->skb->len,
                                         PCI_DMA_FROMDEVICE);
                        dev_kfree_skb_any(info->skb);
                }
                info->dma = 0;
                info->skb = NULL;
        }

        for (i = 0; i < RX_RING_SIZE; i++)
                RX_BUFF(rx, i) = 0;
}

static void pasemi_mac_free_rx_resources(struct pasemi_mac *mac)
{
        pasemi_mac_free_rx_buffers(mac);

        dma_free_coherent(&mac->dma_pdev->dev, RX_RING_SIZE * sizeof(u64),
                          rx_ring(mac)->buffers, rx_ring(mac)->buf_dma);

        kfree(rx_ring(mac)->ring_info);
        pasemi_dma_free_chan(&rx_ring(mac)->chan);
        mac->rx = NULL;
}

static void pasemi_mac_replenish_rx_ring(const struct net_device *dev,
                                         const int limit)
{
        const struct pasemi_mac *mac = netdev_priv(dev);
        struct pasemi_mac_rxring *rx = rx_ring(mac);
        int fill, count;

        if (limit <= 0)
                return;

        fill = rx_ring(mac)->next_to_fill;
        for (count = 0; count < limit; count++) {
                struct pasemi_mac_buffer *info = &RX_DESC_INFO(rx, fill);
                u64 *buff = &RX_BUFF(rx, fill);
                struct sk_buff *skb;
                dma_addr_t dma;

                /* Entry in use? */
                WARN_ON(*buff);

                skb = dev_alloc_skb(mac->bufsz);
                skb_reserve(skb, LOCAL_SKB_ALIGN);

                if (unlikely(!skb))
                        break;

                dma = pci_map_single(mac->dma_pdev, skb->data,
                                     mac->bufsz - LOCAL_SKB_ALIGN,
                                     PCI_DMA_FROMDEVICE);

                if (unlikely(pci_dma_mapping_error(mac->dma_pdev, dma))) {
                        dev_kfree_skb_irq(info->skb);
                        break;
                }

                info->skb = skb;
                info->dma = dma;
                *buff = XCT_RXB_LEN(mac->bufsz) | XCT_RXB_ADDR(dma);
                fill++;
        }

        wmb();

        write_dma_reg(PAS_DMA_RXINT_INCR(mac->dma_if), count);

        rx_ring(mac)->next_to_fill = (rx_ring(mac)->next_to_fill + count) &
                                (RX_RING_SIZE - 1);
}

static void pasemi_mac_restart_rx_intr(const struct pasemi_mac *mac)
{
        struct pasemi_mac_rxring *rx = rx_ring(mac);
        unsigned int reg, pcnt;
        /* Re-enable packet count interrupts: finally
         * ack the packet count interrupt we got in rx_intr.
         */

        pcnt = *rx->chan.status & PAS_STATUS_PCNT_M;

        reg = PAS_IOB_DMA_RXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_RXCH_RESET_PINTC;

        if (*rx->chan.status & PAS_STATUS_TIMER)
                reg |= PAS_IOB_DMA_RXCH_RESET_TINTC;

        write_iob_reg(PAS_IOB_DMA_RXCH_RESET(mac->rx->chan.chno), reg);
}

static void pasemi_mac_restart_tx_intr(const struct pasemi_mac *mac)
{
        unsigned int reg, pcnt;

        /* Re-enable packet count interrupts */
        pcnt = *tx_ring(mac)->chan.status & PAS_STATUS_PCNT_M;

        reg = PAS_IOB_DMA_TXCH_RESET_PCNT(pcnt) | PAS_IOB_DMA_TXCH_RESET_PINTC;

        write_iob_reg(PAS_IOB_DMA_TXCH_RESET(tx_ring(mac)->chan.chno), reg);
}


static inline void pasemi_mac_rx_error(const struct pasemi_mac *mac,
                                       const u64 macrx)
{
        unsigned int rcmdsta, ccmdsta;
        struct pasemi_dmachan *chan = &rx_ring(mac)->chan;

        if (!netif_msg_rx_err(mac))
                return;

        rcmdsta = read_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
        ccmdsta = read_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(chan->chno));

        printk(KERN_ERR "pasemi_mac: rx error. macrx %016llx, rx status %llx\n",
                macrx, *chan->status);

        printk(KERN_ERR "pasemi_mac: rcmdsta %08x ccmdsta %08x\n",
                rcmdsta, ccmdsta);
}

static inline void pasemi_mac_tx_error(const struct pasemi_mac *mac,
                                       const u64 mactx)
{
        unsigned int cmdsta;
        struct pasemi_dmachan *chan = &tx_ring(mac)->chan;

        if (!netif_msg_tx_err(mac))
                return;

        cmdsta = read_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(chan->chno));

        printk(KERN_ERR "pasemi_mac: tx error. mactx 0x%016llx, "\
                "tx status 0x%016llx\n", mactx, *chan->status);

        printk(KERN_ERR "pasemi_mac: tcmdsta 0x%08x\n", cmdsta);
}

static int pasemi_mac_clean_rx(struct pasemi_mac_rxring *rx,
                               const int limit)
{
        const struct pasemi_dmachan *chan = &rx->chan;
        struct pasemi_mac *mac = rx->mac;
        struct pci_dev *pdev = mac->dma_pdev;
        unsigned int n;
        int count, buf_index, tot_bytes, packets;
        struct pasemi_mac_buffer *info;
        struct sk_buff *skb;
        unsigned int len;
        u64 macrx, eval;
        dma_addr_t dma;

        tot_bytes = 0;
        packets = 0;

        spin_lock(&rx->lock);

        n = rx->next_to_clean;

        prefetch(&RX_DESC(rx, n));

        for (count = 0; count < limit; count++) {
                macrx = RX_DESC(rx, n);
                prefetch(&RX_DESC(rx, n+4));

                if ((macrx & XCT_MACRX_E) ||
                    (*chan->status & PAS_STATUS_ERROR))
                        pasemi_mac_rx_error(mac, macrx);

                if (!(macrx & XCT_MACRX_O))
                        break;

                info = NULL;

                BUG_ON(!(macrx & XCT_MACRX_RR_8BRES));

                eval = (RX_DESC(rx, n+1) & XCT_RXRES_8B_EVAL_M) >>
                        XCT_RXRES_8B_EVAL_S;
                buf_index = eval-1;

                dma = (RX_DESC(rx, n+2) & XCT_PTR_ADDR_M);
                info = &RX_DESC_INFO(rx, buf_index);

                skb = info->skb;

                prefetch_skb(skb);

                len = (macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;

                pci_unmap_single(pdev, dma, mac->bufsz - LOCAL_SKB_ALIGN,
                                 PCI_DMA_FROMDEVICE);

                if (macrx & XCT_MACRX_CRC) {
                        /* CRC error flagged */
                        mac->netdev->stats.rx_errors++;
                        mac->netdev->stats.rx_crc_errors++;
                        /* No need to free skb, it'll be reused */
                        goto next;
                }

                info->skb = NULL;
                info->dma = 0;

                if (likely((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK)) {
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
                        skb->csum = (macrx & XCT_MACRX_CSUM_M) >>
                                           XCT_MACRX_CSUM_S;
                } else
                        skb->ip_summed = CHECKSUM_NONE;

                packets++;
                tot_bytes += len;

                /* Don't include CRC */
                skb_put(skb, len-4);

                skb->protocol = eth_type_trans(skb, mac->netdev);
                lro_receive_skb(&mac->lro_mgr, skb, (void *)macrx);

next:
                RX_DESC(rx, n) = 0;
                RX_DESC(rx, n+1) = 0;

                /* Need to zero it out since hardware doesn't, since the
                 * replenish loop uses it to tell when it's done.
                 */
                RX_BUFF(rx, buf_index) = 0;

                n += 4;
        }

        if (n > RX_RING_SIZE) {
                /* Errata 5971 workaround: L2 target of headers */
                write_iob_reg(PAS_IOB_COM_PKTHDRCNT, 0);
                n &= (RX_RING_SIZE-1);
        }

        rx_ring(mac)->next_to_clean = n;

        lro_flush_all(&mac->lro_mgr);

        /* Increase is in number of 16-byte entries, and since each descriptor
         * with an 8BRES takes up 3x8 bytes (padded to 4x8), increase with
         * count*2.
         */
        write_dma_reg(PAS_DMA_RXCHAN_INCR(mac->rx->chan.chno), count << 1);

        pasemi_mac_replenish_rx_ring(mac->netdev, count);

        mac->netdev->stats.rx_bytes += tot_bytes;
        mac->netdev->stats.rx_packets += packets;

        spin_unlock(&rx_ring(mac)->lock);

        return count;
}

/* Can't make this too large or we blow the kernel stack limits */
#define TX_CLEAN_BATCHSIZE (128/MAX_SKB_FRAGS)

static int pasemi_mac_clean_tx(struct pasemi_mac_txring *txring)
{
        struct pasemi_dmachan *chan = &txring->chan;
        struct pasemi_mac *mac = txring->mac;
        int i, j;
        unsigned int start, descr_count, buf_count, batch_limit;
        unsigned int ring_limit;
        unsigned int total_count;
        unsigned long flags;
        struct sk_buff *skbs[TX_CLEAN_BATCHSIZE];
        dma_addr_t dmas[TX_CLEAN_BATCHSIZE][MAX_SKB_FRAGS+1];
        int nf[TX_CLEAN_BATCHSIZE];
        int nr_frags;

        total_count = 0;
        batch_limit = TX_CLEAN_BATCHSIZE;
restart:
        spin_lock_irqsave(&txring->lock, flags);

        start = txring->next_to_clean;
        ring_limit = txring->next_to_fill;

        prefetch(&TX_DESC_INFO(txring, start+1).skb);

        /* Compensate for when fill has wrapped but clean has not */
        if (start > ring_limit)
                ring_limit += TX_RING_SIZE;

        buf_count = 0;
        descr_count = 0;

        for (i = start;
             descr_count < batch_limit && i < ring_limit;
             i += buf_count) {
                u64 mactx = TX_DESC(txring, i);
                struct sk_buff *skb;

                if ((mactx  & XCT_MACTX_E) ||
                    (*chan->status & PAS_STATUS_ERROR))
                        pasemi_mac_tx_error(mac, mactx);

                /* Skip over control descriptors */
                if (!(mactx & XCT_MACTX_LLEN_M)) {
                        TX_DESC(txring, i) = 0;
                        TX_DESC(txring, i+1) = 0;
                        buf_count = 2;
                        continue;
                }

                skb = TX_DESC_INFO(txring, i+1).skb;
                nr_frags = TX_DESC_INFO(txring, i).dma;

                if (unlikely(mactx & XCT_MACTX_O))
                        /* Not yet transmitted */
                        break;

                buf_count = 2 + nr_frags;
                /* Since we always fill with an even number of entries, make
                 * sure we skip any unused one at the end as well.
                 */
                if (buf_count & 1)
                        buf_count++;

                for (j = 0; j <= nr_frags; j++)
                        dmas[descr_count][j] = TX_DESC_INFO(txring, i+1+j).dma;

                skbs[descr_count] = skb;
                nf[descr_count] = nr_frags;

                TX_DESC(txring, i) = 0;
                TX_DESC(txring, i+1) = 0;

                descr_count++;
        }
        txring->next_to_clean = i & (TX_RING_SIZE-1);

        spin_unlock_irqrestore(&txring->lock, flags);
        netif_wake_queue(mac->netdev);

        for (i = 0; i < descr_count; i++)
                pasemi_mac_unmap_tx_skb(mac, nf[i], skbs[i], dmas[i]);

        total_count += descr_count;

        /* If the batch was full, try to clean more */
        if (descr_count == batch_limit)
                goto restart;

        return total_count;
}


static irqreturn_t pasemi_mac_rx_intr(int irq, void *data)
{
        const struct pasemi_mac_rxring *rxring = data;
        struct pasemi_mac *mac = rxring->mac;
        const struct pasemi_dmachan *chan = &rxring->chan;
        unsigned int reg;

        if (!(*chan->status & PAS_STATUS_CAUSE_M))
                return IRQ_NONE;

        /* Don't reset packet count so it won't fire again but clear
         * all others.
         */

        reg = 0;
        if (*chan->status & PAS_STATUS_SOFT)
                reg |= PAS_IOB_DMA_RXCH_RESET_SINTC;
        if (*chan->status & PAS_STATUS_ERROR)
                reg |= PAS_IOB_DMA_RXCH_RESET_DINTC;

        napi_schedule(&mac->napi);

        write_iob_reg(PAS_IOB_DMA_RXCH_RESET(chan->chno), reg);

        return IRQ_HANDLED;
}

#define TX_CLEAN_INTERVAL HZ

static void pasemi_mac_tx_timer(unsigned long data)
{
        struct pasemi_mac_txring *txring = (struct pasemi_mac_txring *)data;
        struct pasemi_mac *mac = txring->mac;

        pasemi_mac_clean_tx(txring);

        mod_timer(&txring->clean_timer, jiffies + TX_CLEAN_INTERVAL);

        pasemi_mac_restart_tx_intr(mac);
}

static irqreturn_t pasemi_mac_tx_intr(int irq, void *data)
{
        struct pasemi_mac_txring *txring = data;
        const struct pasemi_dmachan *chan = &txring->chan;
        struct pasemi_mac *mac = txring->mac;
        unsigned int reg;

        if (!(*chan->status & PAS_STATUS_CAUSE_M))
                return IRQ_NONE;

        reg = 0;

        if (*chan->status & PAS_STATUS_SOFT)
                reg |= PAS_IOB_DMA_TXCH_RESET_SINTC;
        if (*chan->status & PAS_STATUS_ERROR)
                reg |= PAS_IOB_DMA_TXCH_RESET_DINTC;

        mod_timer(&txring->clean_timer, jiffies + (TX_CLEAN_INTERVAL)*2);

        napi_schedule(&mac->napi);

        if (reg)
                write_iob_reg(PAS_IOB_DMA_TXCH_RESET(chan->chno), reg);

        return IRQ_HANDLED;
}

static void pasemi_adjust_link(struct net_device *dev)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        int msg;
        unsigned int flags;
        unsigned int new_flags;

        if (!mac->phydev->link) {
                /* If no link, MAC speed settings don't matter. Just report
                 * link down and return.
                 */
                if (mac->link && netif_msg_link(mac))
                        printk(KERN_INFO "%s: Link is down.\n", dev->name);

                netif_carrier_off(dev);
                pasemi_mac_intf_disable(mac);
                mac->link = 0;

                return;
        } else {
                pasemi_mac_intf_enable(mac);
                netif_carrier_on(dev);
        }

        flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);
        new_flags = flags & ~(PAS_MAC_CFG_PCFG_HD | PAS_MAC_CFG_PCFG_SPD_M |
                              PAS_MAC_CFG_PCFG_TSR_M);

        if (!mac->phydev->duplex)
                new_flags |= PAS_MAC_CFG_PCFG_HD;

        switch (mac->phydev->speed) {
        case 1000:
                new_flags |= PAS_MAC_CFG_PCFG_SPD_1G |
                             PAS_MAC_CFG_PCFG_TSR_1G;
                break;
        case 100:
                new_flags |= PAS_MAC_CFG_PCFG_SPD_100M |
                             PAS_MAC_CFG_PCFG_TSR_100M;
                break;
        case 10:
                new_flags |= PAS_MAC_CFG_PCFG_SPD_10M |
                             PAS_MAC_CFG_PCFG_TSR_10M;
                break;
        default:
                printk("Unsupported speed %d\n", mac->phydev->speed);
        }

        /* Print on link or speed/duplex change */
        msg = mac->link != mac->phydev->link || flags != new_flags;

        mac->duplex = mac->phydev->duplex;
        mac->speed = mac->phydev->speed;
        mac->link = mac->phydev->link;

        if (new_flags != flags)
                write_mac_reg(mac, PAS_MAC_CFG_PCFG, new_flags);

        if (msg && netif_msg_link(mac))
                printk(KERN_INFO "%s: Link is up at %d Mbps, %s duplex.\n",
                       dev->name, mac->speed, mac->duplex ? "full" : "half");
}

static int pasemi_mac_phy_init(struct net_device *dev)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        struct device_node *dn, *phy_dn;
        struct phy_device *phydev;

        dn = pci_device_to_OF_node(mac->pdev);
        phy_dn = of_parse_phandle(dn, "phy-handle", 0);
        of_node_put(phy_dn);

        mac->link = 0;
        mac->speed = 0;
        mac->duplex = -1;

        phydev = of_phy_connect(dev, phy_dn, &pasemi_adjust_link, 0,
                                PHY_INTERFACE_MODE_SGMII);

        if (IS_ERR(phydev)) {
                printk(KERN_ERR "%s: Could not attach to phy\n", dev->name);
                return PTR_ERR(phydev);
        }

        mac->phydev = phydev;

        return 0;
}


static int pasemi_mac_open(struct net_device *dev)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        unsigned int flags;
        int i, ret;

        flags = PAS_MAC_CFG_TXP_FCE | PAS_MAC_CFG_TXP_FPC(3) |
                PAS_MAC_CFG_TXP_SL(3) | PAS_MAC_CFG_TXP_COB(0xf) |
                PAS_MAC_CFG_TXP_TIFT(8) | PAS_MAC_CFG_TXP_TIFG(12);

        write_mac_reg(mac, PAS_MAC_CFG_TXP, flags);

        ret = pasemi_mac_setup_rx_resources(dev);
        if (ret)
                goto out_rx_resources;

        mac->tx = pasemi_mac_setup_tx_resources(dev);

        if (!mac->tx)
                goto out_tx_ring;

        /* We might already have allocated rings in case mtu was changed
         * before interface was brought up.
         */
        if (dev->mtu > 1500 && !mac->num_cs) {
                pasemi_mac_setup_csrings(mac);
                if (!mac->num_cs)
                        goto out_tx_ring;
        }

        /* Zero out rmon counters */
        for (i = 0; i < 32; i++)
                write_mac_reg(mac, PAS_MAC_RMON(i), 0);

        /* 0x3ff with 33MHz clock is about 31us */
        write_iob_reg(PAS_IOB_DMA_COM_TIMEOUTCFG,
                      PAS_IOB_DMA_COM_TIMEOUTCFG_TCNT(0x3ff));

        write_iob_reg(PAS_IOB_DMA_RXCH_CFG(mac->rx->chan.chno),
                      PAS_IOB_DMA_RXCH_CFG_CNTTH(256));

        write_iob_reg(PAS_IOB_DMA_TXCH_CFG(mac->tx->chan.chno),
                      PAS_IOB_DMA_TXCH_CFG_CNTTH(32));

        write_mac_reg(mac, PAS_MAC_IPC_CHNL,
                      PAS_MAC_IPC_CHNL_DCHNO(mac->rx->chan.chno) |
                      PAS_MAC_IPC_CHNL_BCH(mac->rx->chan.chno));

        /* enable rx if */
        write_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if),
                      PAS_DMA_RXINT_RCMDSTA_EN |
                      PAS_DMA_RXINT_RCMDSTA_DROPS_M |
                      PAS_DMA_RXINT_RCMDSTA_BP |
                      PAS_DMA_RXINT_RCMDSTA_OO |
                      PAS_DMA_RXINT_RCMDSTA_BT);

        /* enable rx channel */
        pasemi_dma_start_chan(&rx_ring(mac)->chan, PAS_DMA_RXCHAN_CCMDSTA_DU |
                                                   PAS_DMA_RXCHAN_CCMDSTA_OD |
                                                   PAS_DMA_RXCHAN_CCMDSTA_FD |
                                                   PAS_DMA_RXCHAN_CCMDSTA_DT);

        /* enable tx channel */
        pasemi_dma_start_chan(&tx_ring(mac)->chan, PAS_DMA_TXCHAN_TCMDSTA_SZ |
                                                   PAS_DMA_TXCHAN_TCMDSTA_DB |
                                                   PAS_DMA_TXCHAN_TCMDSTA_DE |
                                                   PAS_DMA_TXCHAN_TCMDSTA_DA);

        pasemi_mac_replenish_rx_ring(dev, RX_RING_SIZE);

        write_dma_reg(PAS_DMA_RXCHAN_INCR(rx_ring(mac)->chan.chno),
                      RX_RING_SIZE>>1);

        /* Clear out any residual packet count state from firmware */
        pasemi_mac_restart_rx_intr(mac);
        pasemi_mac_restart_tx_intr(mac);

        flags = PAS_MAC_CFG_PCFG_S1 | PAS_MAC_CFG_PCFG_PR | PAS_MAC_CFG_PCFG_CE;

        if (mac->type == MAC_TYPE_GMAC)
                flags |= PAS_MAC_CFG_PCFG_TSR_1G | PAS_MAC_CFG_PCFG_SPD_1G;
        else
                flags |= PAS_MAC_CFG_PCFG_TSR_10G | PAS_MAC_CFG_PCFG_SPD_10G;

        /* Enable interface in MAC */
        write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);

        ret = pasemi_mac_phy_init(dev);
        if (ret) {
                /* Since we won't get link notification, just enable RX */
                pasemi_mac_intf_enable(mac);
                if (mac->type == MAC_TYPE_GMAC) {
                        /* Warn for missing PHY on SGMII (1Gig) ports */
                        dev_warn(&mac->pdev->dev,
                                 "PHY init failed: %d.\n", ret);
                        dev_warn(&mac->pdev->dev,
                                 "Defaulting to 1Gbit full duplex\n");
                }
        }

        netif_start_queue(dev);
        napi_enable(&mac->napi);

        snprintf(mac->tx_irq_name, sizeof(mac->tx_irq_name), "%s tx",
                 dev->name);

        ret = request_irq(mac->tx->chan.irq, &pasemi_mac_tx_intr, IRQF_DISABLED,
                          mac->tx_irq_name, mac->tx);
        if (ret) {
                dev_err(&mac->pdev->dev, "request_irq of irq %d failed: %d\n",
                        mac->tx->chan.irq, ret);
                goto out_tx_int;
        }

        snprintf(mac->rx_irq_name, sizeof(mac->rx_irq_name), "%s rx",
                 dev->name);

        ret = request_irq(mac->rx->chan.irq, &pasemi_mac_rx_intr, IRQF_DISABLED,
                          mac->rx_irq_name, mac->rx);
        if (ret) {
                dev_err(&mac->pdev->dev, "request_irq of irq %d failed: %d\n",
                        mac->rx->chan.irq, ret);
                goto out_rx_int;
        }

        if (mac->phydev)
                phy_start(mac->phydev);

        init_timer(&mac->tx->clean_timer);
        mac->tx->clean_timer.function = pasemi_mac_tx_timer;
        mac->tx->clean_timer.data = (unsigned long)mac->tx;
        mac->tx->clean_timer.expires = jiffies+HZ;
        add_timer(&mac->tx->clean_timer);

        return 0;

out_rx_int:
        free_irq(mac->tx->chan.irq, mac->tx);
out_tx_int:
        napi_disable(&mac->napi);
        netif_stop_queue(dev);
out_tx_ring:
        if (mac->tx)
                pasemi_mac_free_tx_resources(mac);
        pasemi_mac_free_rx_resources(mac);
out_rx_resources:

        return ret;
}

#define MAX_RETRIES 5000

static void pasemi_mac_pause_txchan(struct pasemi_mac *mac)
{
        unsigned int sta, retries;
        int txch = tx_ring(mac)->chan.chno;

        write_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(txch),
                      PAS_DMA_TXCHAN_TCMDSTA_ST);

        for (retries = 0; retries < MAX_RETRIES; retries++) {
                sta = read_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(txch));
                if (!(sta & PAS_DMA_TXCHAN_TCMDSTA_ACT))
                        break;
                cond_resched();
        }

        if (sta & PAS_DMA_TXCHAN_TCMDSTA_ACT)
                dev_err(&mac->dma_pdev->dev,
                        "Failed to stop tx channel, tcmdsta %08x\n", sta);

        write_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(txch), 0);
}

static void pasemi_mac_pause_rxchan(struct pasemi_mac *mac)
{
        unsigned int sta, retries;
        int rxch = rx_ring(mac)->chan.chno;

        write_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(rxch),
                      PAS_DMA_RXCHAN_CCMDSTA_ST);
        for (retries = 0; retries < MAX_RETRIES; retries++) {
                sta = read_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(rxch));
                if (!(sta & PAS_DMA_RXCHAN_CCMDSTA_ACT))
                        break;
                cond_resched();
        }

        if (sta & PAS_DMA_RXCHAN_CCMDSTA_ACT)
                dev_err(&mac->dma_pdev->dev,
                        "Failed to stop rx channel, ccmdsta 08%x\n", sta);
        write_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(rxch), 0);
}

static void pasemi_mac_pause_rxint(struct pasemi_mac *mac)
{
        unsigned int sta, retries;

        write_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if),
                      PAS_DMA_RXINT_RCMDSTA_ST);
        for (retries = 0; retries < MAX_RETRIES; retries++) {
                sta = read_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
                if (!(sta & PAS_DMA_RXINT_RCMDSTA_ACT))
                        break;
                cond_resched();
        }

        if (sta & PAS_DMA_RXINT_RCMDSTA_ACT)
                dev_err(&mac->dma_pdev->dev,
                        "Failed to stop rx interface, rcmdsta %08x\n", sta);
        write_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if), 0);
}

static int pasemi_mac_close(struct net_device *dev)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        unsigned int sta;
        int rxch, txch, i;

        rxch = rx_ring(mac)->chan.chno;
        txch = tx_ring(mac)->chan.chno;

        if (mac->phydev) {
                phy_stop(mac->phydev);
                phy_disconnect(mac->phydev);
        }

        del_timer_sync(&mac->tx->clean_timer);

        netif_stop_queue(dev);
        napi_disable(&mac->napi);

        sta = read_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
        if (sta & (PAS_DMA_RXINT_RCMDSTA_BP |
                      PAS_DMA_RXINT_RCMDSTA_OO |
                      PAS_DMA_RXINT_RCMDSTA_BT))
                printk(KERN_DEBUG "pasemi_mac: rcmdsta error: 0x%08x\n", sta);

        sta = read_dma_reg(PAS_DMA_RXCHAN_CCMDSTA(rxch));
        if (sta & (PAS_DMA_RXCHAN_CCMDSTA_DU |
                     PAS_DMA_RXCHAN_CCMDSTA_OD |
                     PAS_DMA_RXCHAN_CCMDSTA_FD |
                     PAS_DMA_RXCHAN_CCMDSTA_DT))
                printk(KERN_DEBUG "pasemi_mac: ccmdsta error: 0x%08x\n", sta);

        sta = read_dma_reg(PAS_DMA_TXCHAN_TCMDSTA(txch));
        if (sta & (PAS_DMA_TXCHAN_TCMDSTA_SZ | PAS_DMA_TXCHAN_TCMDSTA_DB |
                      PAS_DMA_TXCHAN_TCMDSTA_DE | PAS_DMA_TXCHAN_TCMDSTA_DA))
                printk(KERN_DEBUG "pasemi_mac: tcmdsta error: 0x%08x\n", sta);

        /* Clean out any pending buffers */
        pasemi_mac_clean_tx(tx_ring(mac));
        pasemi_mac_clean_rx(rx_ring(mac), RX_RING_SIZE);

        pasemi_mac_pause_txchan(mac);
        pasemi_mac_pause_rxint(mac);
        pasemi_mac_pause_rxchan(mac);
        pasemi_mac_intf_disable(mac);

        free_irq(mac->tx->chan.irq, mac->tx);
        free_irq(mac->rx->chan.irq, mac->rx);

        for (i = 0; i < mac->num_cs; i++) {
                pasemi_mac_free_csring(mac->cs[i]);
                mac->cs[i] = NULL;
        }

        mac->num_cs = 0;

        /* Free resources */
        pasemi_mac_free_rx_resources(mac);
        pasemi_mac_free_tx_resources(mac);

        return 0;
}

static void pasemi_mac_queue_csdesc(const struct sk_buff *skb,
                                    const dma_addr_t *map,
                                    const unsigned int *map_size,
                                    struct pasemi_mac_txring *txring,
                                    struct pasemi_mac_csring *csring)
{
        u64 fund;
        dma_addr_t cs_dest;
        const int nh_off = skb_network_offset(skb);
        const int nh_len = skb_network_header_len(skb);
        const int nfrags = skb_shinfo(skb)->nr_frags;
        int cs_size, i, fill, hdr, cpyhdr, evt;
        dma_addr_t csdma;

        fund = XCT_FUN_ST | XCT_FUN_RR_8BRES |
               XCT_FUN_O | XCT_FUN_FUN(csring->fun) |
               XCT_FUN_CRM_SIG | XCT_FUN_LLEN(skb->len - nh_off) |
               XCT_FUN_SHL(nh_len >> 2) | XCT_FUN_SE;

        switch (ip_hdr(skb)->protocol) {
        case IPPROTO_TCP:
                fund |= XCT_FUN_SIG_TCP4;
                /* TCP checksum is 16 bytes into the header */
                cs_dest = map[0] + skb_transport_offset(skb) + 16;
                break;
        case IPPROTO_UDP:
                fund |= XCT_FUN_SIG_UDP4;
                /* UDP checksum is 6 bytes into the header */
                cs_dest = map[0] + skb_transport_offset(skb) + 6;
                break;
        default:
                BUG();
        }

        /* Do the checksum offloaded */
        fill = csring->next_to_fill;
        hdr = fill;

        CS_DESC(csring, fill++) = fund;
        /* Room for 8BRES. Checksum result is really 2 bytes into it */
        csdma = csring->chan.ring_dma + (fill & (CS_RING_SIZE-1)) * 8 + 2;
        CS_DESC(csring, fill++) = 0;

        CS_DESC(csring, fill) = XCT_PTR_LEN(map_size[0]-nh_off) | XCT_PTR_ADDR(map[0]+nh_off);
        for (i = 1; i <= nfrags; i++)
                CS_DESC(csring, fill+i) = XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);

        fill += i;
        if (fill & 1)
                fill++;

        /* Copy the result into the TCP packet */
        cpyhdr = fill;
        CS_DESC(csring, fill++) = XCT_FUN_O | XCT_FUN_FUN(csring->fun) |
                                  XCT_FUN_LLEN(2) | XCT_FUN_SE;
        CS_DESC(csring, fill++) = XCT_PTR_LEN(2) | XCT_PTR_ADDR(cs_dest) | XCT_PTR_T;
        CS_DESC(csring, fill++) = XCT_PTR_LEN(2) | XCT_PTR_ADDR(csdma);
        fill++;

        evt = !csring->last_event;
        csring->last_event = evt;

        /* Event handshaking with MAC TX */
        CS_DESC(csring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
                                  CTRL_CMD_ETYPE_SET | CTRL_CMD_REG(csring->events[evt]);
        CS_DESC(csring, fill++) = 0;
        CS_DESC(csring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
                                  CTRL_CMD_ETYPE_WCLR | CTRL_CMD_REG(csring->events[!evt]);
        CS_DESC(csring, fill++) = 0;
        csring->next_to_fill = fill & (CS_RING_SIZE-1);

        cs_size = fill - hdr;
        write_dma_reg(PAS_DMA_TXCHAN_INCR(csring->chan.chno), (cs_size) >> 1);

        /* TX-side event handshaking */
        fill = txring->next_to_fill;
        TX_DESC(txring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
                                  CTRL_CMD_ETYPE_WSET | CTRL_CMD_REG(csring->events[evt]);
        TX_DESC(txring, fill++) = 0;
        TX_DESC(txring, fill++) = CTRL_CMD_T | CTRL_CMD_META_EVT | CTRL_CMD_O |
                                  CTRL_CMD_ETYPE_CLR | CTRL_CMD_REG(csring->events[!evt]);
        TX_DESC(txring, fill++) = 0;
        txring->next_to_fill = fill;

        write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), 2);

        return;
}

static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
{
        struct pasemi_mac * const mac = netdev_priv(dev);
        struct pasemi_mac_txring * const txring = tx_ring(mac);
        struct pasemi_mac_csring *csring;
        u64 dflags = 0;
        u64 mactx;
        dma_addr_t map[MAX_SKB_FRAGS+1];
        unsigned int map_size[MAX_SKB_FRAGS+1];
        unsigned long flags;
        int i, nfrags;
        int fill;
        const int nh_off = skb_network_offset(skb);
        const int nh_len = skb_network_header_len(skb);

        prefetch(&txring->ring_info);

        dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_CRC_PAD;

        nfrags = skb_shinfo(skb)->nr_frags;

        map[0] = pci_map_single(mac->dma_pdev, skb->data, skb_headlen(skb),
                                PCI_DMA_TODEVICE);
        map_size[0] = skb_headlen(skb);
        if (pci_dma_mapping_error(mac->dma_pdev, map[0]))
                goto out_err_nolock;

        for (i = 0; i < nfrags; i++) {
                skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

                map[i+1] = pci_map_page(mac->dma_pdev, frag->page,
                                        frag->page_offset, frag->size,
                                        PCI_DMA_TODEVICE);
                map_size[i+1] = frag->size;
                if (pci_dma_mapping_error(mac->dma_pdev, map[i+1])) {
                        nfrags = i;
                        goto out_err_nolock;
                }
        }

        if (skb->ip_summed == CHECKSUM_PARTIAL && skb->len <= 1540) {
                switch (ip_hdr(skb)->protocol) {
                case IPPROTO_TCP:
                        dflags |= XCT_MACTX_CSUM_TCP;
                        dflags |= XCT_MACTX_IPH(nh_len >> 2);
                        dflags |= XCT_MACTX_IPO(nh_off);
                        break;
                case IPPROTO_UDP:
                        dflags |= XCT_MACTX_CSUM_UDP;
                        dflags |= XCT_MACTX_IPH(nh_len >> 2);
                        dflags |= XCT_MACTX_IPO(nh_off);
                        break;
                default:
                        WARN_ON(1);
                }
        }

        mactx = dflags | XCT_MACTX_LLEN(skb->len);

        spin_lock_irqsave(&txring->lock, flags);

        /* Avoid stepping on the same cache line that the DMA controller
         * is currently about to send, so leave at least 8 words available.
         * Total free space needed is mactx + fragments + 8
         */
        if (RING_AVAIL(txring) < nfrags + 14) {
                /* no room -- stop the queue and wait for tx intr */
                netif_stop_queue(dev);
                goto out_err;
        }

        /* Queue up checksum + event descriptors, if needed */
        if (mac->num_cs && skb->ip_summed == CHECKSUM_PARTIAL && skb->len > 1540) {
                csring = mac->cs[mac->last_cs];
                mac->last_cs = (mac->last_cs + 1) % mac->num_cs;

                pasemi_mac_queue_csdesc(skb, map, map_size, txring, csring);
        }

        fill = txring->next_to_fill;
        TX_DESC(txring, fill) = mactx;
        TX_DESC_INFO(txring, fill).dma = nfrags;
        fill++;
        TX_DESC_INFO(txring, fill).skb = skb;
        for (i = 0; i <= nfrags; i++) {
                TX_DESC(txring, fill+i) =
                        XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);
                TX_DESC_INFO(txring, fill+i).dma = map[i];
        }

        /* We have to add an even number of 8-byte entries to the ring
         * even if the last one is unused. That means always an odd number
         * of pointers + one mactx descriptor.
         */
        if (nfrags & 1)
                nfrags++;

        txring->next_to_fill = (fill + nfrags + 1) & (TX_RING_SIZE-1);

        dev->stats.tx_packets++;
        dev->stats.tx_bytes += skb->len;

        spin_unlock_irqrestore(&txring->lock, flags);

        write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), (nfrags+2) >> 1);

        return NETDEV_TX_OK;

out_err:
        spin_unlock_irqrestore(&txring->lock, flags);
out_err_nolock:
        while (nfrags--)
                pci_unmap_single(mac->dma_pdev, map[nfrags], map_size[nfrags],
                                 PCI_DMA_TODEVICE);

        return NETDEV_TX_BUSY;
}

static void pasemi_mac_set_rx_mode(struct net_device *dev)
{
        const struct pasemi_mac *mac = netdev_priv(dev);
        unsigned int flags;

        flags = read_mac_reg(mac, PAS_MAC_CFG_PCFG);

        /* Set promiscuous */
        if (dev->flags & IFF_PROMISC)
                flags |= PAS_MAC_CFG_PCFG_PR;
        else
                flags &= ~PAS_MAC_CFG_PCFG_PR;

        write_mac_reg(mac, PAS_MAC_CFG_PCFG, flags);
}


static int pasemi_mac_poll(struct napi_struct *napi, int budget)
{
        struct pasemi_mac *mac = container_of(napi, struct pasemi_mac, napi);
        int pkts;

        pasemi_mac_clean_tx(tx_ring(mac));
        pkts = pasemi_mac_clean_rx(rx_ring(mac), budget);
        if (pkts < budget) {
                /* all done, no more packets present */
                napi_complete(napi);

                pasemi_mac_restart_rx_intr(mac);
                pasemi_mac_restart_tx_intr(mac);
        }
        return pkts;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/*
 * Polling 'interrupt' - used by things like netconsole to send skbs
 * without having to re-enable interrupts. It's not called while
 * the interrupt routine is executing.
 */
static void pasemi_mac_netpoll(struct net_device *dev)
{
        const struct pasemi_mac *mac = netdev_priv(dev);

        disable_irq(mac->tx->chan.irq);
        pasemi_mac_tx_intr(mac->tx->chan.irq, mac->tx);
        enable_irq(mac->tx->chan.irq);

        disable_irq(mac->rx->chan.irq);
        pasemi_mac_rx_intr(mac->rx->chan.irq, mac->rx);
        enable_irq(mac->rx->chan.irq);
}
#endif

static int pasemi_mac_change_mtu(struct net_device *dev, int new_mtu)
{
        struct pasemi_mac *mac = netdev_priv(dev);
        unsigned int reg;
        unsigned int rcmdsta = 0;
        int running;
        int ret = 0;

        if (new_mtu < PE_MIN_MTU || new_mtu > PE_MAX_MTU)
                return -EINVAL;

        running = netif_running(dev);

        if (running) {
                /* Need to stop the interface, clean out all already
                 * received buffers, free all unused buffers on the RX
                 * interface ring, then finally re-fill the rx ring with
                 * the new-size buffers and restart.
                 */

                napi_disable(&mac->napi);
                netif_tx_disable(dev);
                pasemi_mac_intf_disable(mac);

                rcmdsta = read_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if));
                pasemi_mac_pause_rxint(mac);
                pasemi_mac_clean_rx(rx_ring(mac), RX_RING_SIZE);
                pasemi_mac_free_rx_buffers(mac);

        }

        /* Setup checksum channels if large MTU and none already allocated */
        if (new_mtu > 1500 && !mac->num_cs) {
                pasemi_mac_setup_csrings(mac);
                if (!mac->num_cs) {
                        ret = -ENOMEM;
                        goto out;
                }
        }

        /* Change maxf, i.e. what size frames are accepted.
         * Need room for ethernet header and CRC word
         */
        reg = read_mac_reg(mac, PAS_MAC_CFG_MACCFG);
        reg &= ~PAS_MAC_CFG_MACCFG_MAXF_M;
        reg |= PAS_MAC_CFG_MACCFG_MAXF(new_mtu + ETH_HLEN + 4);
        write_mac_reg(mac, PAS_MAC_CFG_MACCFG, reg);

        dev->mtu = new_mtu;
        /* MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */
        mac->bufsz = new_mtu + ETH_HLEN + ETH_FCS_LEN + LOCAL_SKB_ALIGN + 128;

out:
        if (running) {
                write_dma_reg(PAS_DMA_RXINT_RCMDSTA(mac->dma_if),
                              rcmdsta | PAS_DMA_RXINT_RCMDSTA_EN);

                rx_ring(mac)->next_to_fill = 0;
                pasemi_mac_replenish_rx_ring(dev, RX_RING_SIZE-1);

                napi_enable(&mac->napi);
                netif_start_queue(dev);
                pasemi_mac_intf_enable(mac);
        }

        return ret;
}

static const struct net_device_ops pasemi_netdev_ops = {
        .ndo_open               = pasemi_mac_open,
        .ndo_stop               = pasemi_mac_close,
        .ndo_start_xmit         = pasemi_mac_start_tx,
        .ndo_set_multicast_list = pasemi_mac_set_rx_mode,
        .ndo_set_mac_address    = pasemi_mac_set_mac_addr,
        .ndo_change_mtu         = pasemi_mac_change_mtu,
        .ndo_validate_addr      = eth_validate_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = pasemi_mac_netpoll,
#endif
};

static int __devinit
pasemi_mac_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        struct net_device *dev;
        struct pasemi_mac *mac;
        int err, ret;

        err = pci_enable_device(pdev);
        if (err)
                return err;

        dev = alloc_etherdev(sizeof(struct pasemi_mac));
        if (dev == NULL) {
                dev_err(&pdev->dev,
                        "pasemi_mac: Could not allocate ethernet device.\n");
                err = -ENOMEM;
                goto out_disable_device;
        }

        pci_set_drvdata(pdev, dev);
        SET_NETDEV_DEV(dev, &pdev->dev);

        mac = netdev_priv(dev);

        mac->pdev = pdev;
        mac->netdev = dev;

        netif_napi_add(dev, &mac->napi, pasemi_mac_poll, 64);

        dev->features = NETIF_F_IP_CSUM | NETIF_F_LLTX | NETIF_F_SG |
                        NETIF_F_HIGHDMA | NETIF_F_GSO;

        mac->lro_mgr.max_aggr = LRO_MAX_AGGR;
        mac->lro_mgr.max_desc = MAX_LRO_DESCRIPTORS;
        mac->lro_mgr.lro_arr = mac->lro_desc;
        mac->lro_mgr.get_skb_header = get_skb_hdr;
        mac->lro_mgr.features = LRO_F_NAPI | LRO_F_EXTRACT_VLAN_ID;
        mac->lro_mgr.dev = mac->netdev;
        mac->lro_mgr.ip_summed = CHECKSUM_UNNECESSARY;
        mac->lro_mgr.ip_summed_aggr = CHECKSUM_UNNECESSARY;


        mac->dma_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa007, NULL);
        if (!mac->dma_pdev) {
                dev_err(&mac->pdev->dev, "Can't find DMA Controller\n");
                err = -ENODEV;
                goto out;
        }

        mac->iob_pdev = pci_get_device(PCI_VENDOR_ID_PASEMI, 0xa001, NULL);
        if (!mac->iob_pdev) {
                dev_err(&mac->pdev->dev, "Can't find I/O Bridge\n");
                err = -ENODEV;
                goto out;
        }

        /* get mac addr from device tree */
        if (pasemi_get_mac_addr(mac) || !is_valid_ether_addr(mac->mac_addr)) {
                err = -ENODEV;
                goto out;
        }
        memcpy(dev->dev_addr, mac->mac_addr, sizeof(mac->mac_addr));

        ret = mac_to_intf(mac);
        if (ret < 0) {
                dev_err(&mac->pdev->dev, "Can't map DMA interface\n");
                err = -ENODEV;
                goto out;
        }
        mac->dma_if = ret;

        switch (pdev->device) {
        case 0xa005:
                mac->type = MAC_TYPE_GMAC;
                break;
        case 0xa006:
                mac->type = MAC_TYPE_XAUI;
                break;
        default:
                err = -ENODEV;
                goto out;
        }

        dev->netdev_ops = &pasemi_netdev_ops;
        dev->mtu = PE_DEF_MTU;
        /* 1500 MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */
        mac->bufsz = dev->mtu + ETH_HLEN + ETH_FCS_LEN + LOCAL_SKB_ALIGN + 128;

        dev->ethtool_ops = &pasemi_mac_ethtool_ops;

        if (err)
                goto out;

        mac->msg_enable = netif_msg_init(debug, DEFAULT_MSG_ENABLE);

        /* Enable most messages by default */
        mac->msg_enable = (NETIF_MSG_IFUP << 1 ) - 1;

        err = register_netdev(dev);

        if (err) {
                dev_err(&mac->pdev->dev, "register_netdev failed with error %d\n",
                        err);
                goto out;
        } else if netif_msg_probe(mac)
                printk(KERN_INFO "%s: PA Semi %s: intf %d, hw addr %pM\n",
                       dev->name, mac->type == MAC_TYPE_GMAC ? "GMAC" : "XAUI",
                       mac->dma_if, dev->dev_addr);

        return err;

out:
        if (mac->iob_pdev)
                pci_dev_put(mac->iob_pdev);
        if (mac->dma_pdev)
                pci_dev_put(mac->dma_pdev);

        free_netdev(dev);
out_disable_device:
        pci_disable_device(pdev);
        return err;

}

static void __devexit pasemi_mac_remove(struct pci_dev *pdev)
{
        struct net_device *netdev = pci_get_drvdata(pdev);
        struct pasemi_mac *mac;

        if (!netdev)
                return;

        mac = netdev_priv(netdev);

        unregister_netdev(netdev);

        pci_disable_device(pdev);
        pci_dev_put(mac->dma_pdev);
        pci_dev_put(mac->iob_pdev);

        pasemi_dma_free_chan(&mac->tx->chan);
        pasemi_dma_free_chan(&mac->rx->chan);

        pci_set_drvdata(pdev, NULL);
        free_netdev(netdev);
}

static struct pci_device_id pasemi_mac_pci_tbl[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_PASEMI, 0xa005) },
        { PCI_DEVICE(PCI_VENDOR_ID_PASEMI, 0xa006) },
        { },
};

MODULE_DEVICE_TABLE(pci, pasemi_mac_pci_tbl);

static struct pci_driver pasemi_mac_driver = {
        .name           = "pasemi_mac",
        .id_table       = pasemi_mac_pci_tbl,
        .probe          = pasemi_mac_probe,
        .remove         = __devexit_p(pasemi_mac_remove),
};

static void __exit pasemi_mac_cleanup_module(void)
{
        pci_unregister_driver(&pasemi_mac_driver);
}

int pasemi_mac_init_module(void)
{
        int err;

        err = pasemi_dma_init();
        if (err)
                return err;

        return pci_register_driver(&pasemi_mac_driver);
}

module_init(pasemi_mac_init_module);
module_exit(pasemi_mac_cleanup_module);