/*********************************************************************
 *
 *      vlsi_ir.c:      VLSI82C147 PCI IrDA controller driver for Linux
 *
 *      Copyright (c) 2001-2003 Martin Diehl
 *
 *      This program is free software; you can redistribute it and/or 
 *      modify it under the terms of the GNU General Public License as 
 *      published by the Free Software Foundation; either version 2 of 
 *      the License, or (at your option) any later version.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License 
 *      along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 ********************************************************************/

#include <linux/module.h>
 
#define DRIVER_NAME             "vlsi_ir"
#define DRIVER_VERSION          "v0.5"
#define DRIVER_DESCRIPTION      "IrDA SIR/MIR/FIR driver for VLSI 82C147"
#define DRIVER_AUTHOR           "Martin Diehl <info@mdiehl.de>"

MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_LICENSE("GPL");

/********************************************************/

#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/math64.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>

#include <net/irda/irda.h>
#include <net/irda/irda_device.h>
#include <net/irda/wrapper.h>
#include <net/irda/crc.h>

#include "vlsi_ir.h"

/********************************************************/

static /* const */ char drivername[] = DRIVER_NAME;

static const struct pci_device_id vlsi_irda_table[] = {
        {
                .class =        PCI_CLASS_WIRELESS_IRDA << 8,
                .class_mask =   PCI_CLASS_SUBCLASS_MASK << 8, 
                .vendor =       PCI_VENDOR_ID_VLSI,
                .device =       PCI_DEVICE_ID_VLSI_82C147,
                .subvendor =    PCI_ANY_ID,
                .subdevice =    PCI_ANY_ID,
        },
        { /* all zeroes */ }
};

MODULE_DEVICE_TABLE(pci, vlsi_irda_table);

/********************************************************/

/*      clksrc: which clock source to be used
 *              0: auto - try PLL, fallback to 40MHz XCLK
 *              1: on-chip 48MHz PLL
 *              2: external 48MHz XCLK
 *              3: external 40MHz XCLK (HP OB-800)
 */

static int clksrc = 0;                  /* default is 0(auto) */
module_param(clksrc, int, 0);
MODULE_PARM_DESC(clksrc, "clock input source selection");

/*      ringsize: size of the tx and rx descriptor rings
 *              independent for tx and rx
 *              specify as ringsize=tx[,rx]
 *              allowed values: 4, 8, 16, 32, 64
 *              Due to the IrDA 1.x max. allowed window size=7,
 *              there should be no gain when using rings larger than 8
 */

static int ringsize[] = {8,8};          /* default is tx=8 / rx=8 */
module_param_array(ringsize, int, NULL, 0);
MODULE_PARM_DESC(ringsize, "TX, RX ring descriptor size");

/*      sirpulse: tuning of the SIR pulse width within IrPHY 1.3 limits
 *              0: very short, 1.5us (exception: 6us at 2.4 kbaud)
 *              1: nominal 3/16 bittime width
 *      note: IrDA compliant peer devices should be happy regardless
 *              which one is used. Primary goal is to save some power
 *              on the sender's side - at 9.6kbaud for example the short
 *              pulse width saves more than 90% of the transmitted IR power.
 */

static int sirpulse = 1;                /* default is 3/16 bittime */
module_param(sirpulse, int, 0);
MODULE_PARM_DESC(sirpulse, "SIR pulse width tuning");

/*      qos_mtt_bits: encoded min-turn-time value we require the peer device
 *               to use before transmitting to us. "Type 1" (per-station)
 *               bitfield according to IrLAP definition (section 6.6.8)
 *               Don't know which transceiver is used by my OB800 - the
 *               pretty common HP HDLS-1100 requires 1 msec - so lets use this.
 */

static int qos_mtt_bits = 0x07;         /* default is 1 ms or more */
module_param(qos_mtt_bits, int, 0);
MODULE_PARM_DESC(qos_mtt_bits, "IrLAP bitfield representing min-turn-time");

/********************************************************/

static void vlsi_reg_debug(unsigned iobase, const char *s)
{
        int     i;

        printk(KERN_DEBUG "%s: ", s);
        for (i = 0; i < 0x20; i++)
                printk("%02x", (unsigned)inb((iobase+i)));
        printk("\n");
}

static void vlsi_ring_debug(struct vlsi_ring *r)
{
        struct ring_descr *rd;
        unsigned i;

        printk(KERN_DEBUG "%s - ring %p / size %u / mask 0x%04x / len %u / dir %d / hw %p\n",
                __func__, r, r->size, r->mask, r->len, r->dir, r->rd[0].hw);
        printk(KERN_DEBUG "%s - head = %d / tail = %d\n", __func__,
                atomic_read(&r->head) & r->mask, atomic_read(&r->tail) & r->mask);
        for (i = 0; i < r->size; i++) {
                rd = &r->rd[i];
                printk(KERN_DEBUG "%s - ring descr %u: ", __func__, i);
                printk("skb=%p data=%p hw=%p\n", rd->skb, rd->buf, rd->hw);
                printk(KERN_DEBUG "%s - hw: status=%02x count=%u addr=0x%08x\n",
                        __func__, (unsigned) rd_get_status(rd),
                        (unsigned) rd_get_count(rd), (unsigned) rd_get_addr(rd));
        }
}

/********************************************************/

/* needed regardless of CONFIG_PROC_FS */
static struct proc_dir_entry *vlsi_proc_root = NULL;

#ifdef CONFIG_PROC_FS

static void vlsi_proc_pdev(struct seq_file *seq, struct pci_dev *pdev)
{
        unsigned iobase = pci_resource_start(pdev, 0);
        unsigned i;

        seq_printf(seq, "\n%s (vid/did: [%04x:%04x])\n",
                   pci_name(pdev), (int)pdev->vendor, (int)pdev->device);
        seq_printf(seq, "pci-power-state: %u\n", (unsigned) pdev->current_state);
        seq_printf(seq, "resources: irq=%u / io=0x%04x / dma_mask=0x%016Lx\n",
                   pdev->irq, (unsigned)pci_resource_start(pdev, 0), (unsigned long long)pdev->dma_mask);
        seq_printf(seq, "hw registers: ");
        for (i = 0; i < 0x20; i++)
                seq_printf(seq, "%02x", (unsigned)inb((iobase+i)));
        seq_printf(seq, "\n");
}
                
static void vlsi_proc_ndev(struct seq_file *seq, struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        u8 byte;
        u16 word;
        s32 sec, usec;
        unsigned iobase = ndev->base_addr;

        seq_printf(seq, "\n%s link state: %s / %s / %s / %s\n", ndev->name,
                netif_device_present(ndev) ? "attached" : "detached", 
                netif_running(ndev) ? "running" : "not running",
                netif_carrier_ok(ndev) ? "carrier ok" : "no carrier",
                netif_queue_stopped(ndev) ? "queue stopped" : "queue running");

        if (!netif_running(ndev))
                return;

        seq_printf(seq, "\nhw-state:\n");
        pci_read_config_byte(idev->pdev, VLSI_PCI_IRMISC, &byte);
        seq_printf(seq, "IRMISC:%s%s%s uart%s",
                (byte&IRMISC_IRRAIL) ? " irrail" : "",
                (byte&IRMISC_IRPD) ? " irpd" : "",
                (byte&IRMISC_UARTTST) ? " uarttest" : "",
                (byte&IRMISC_UARTEN) ? "@" : " disabled\n");
        if (byte&IRMISC_UARTEN) {
                seq_printf(seq, "0x%s\n",
                        (byte&2) ? ((byte&1) ? "3e8" : "2e8")
                                 : ((byte&1) ? "3f8" : "2f8"));
        }
        pci_read_config_byte(idev->pdev, VLSI_PCI_CLKCTL, &byte);
        seq_printf(seq, "CLKCTL: PLL %s%s%s / clock %s / wakeup %s\n",
                (byte&CLKCTL_PD_INV) ? "powered" : "down",
                (byte&CLKCTL_LOCK) ? " locked" : "",
                (byte&CLKCTL_EXTCLK) ? ((byte&CLKCTL_XCKSEL)?" / 40 MHz XCLK":" / 48 MHz XCLK") : "",
                (byte&CLKCTL_CLKSTP) ? "stopped" : "running",
                (byte&CLKCTL_WAKE) ? "enabled" : "disabled");
        pci_read_config_byte(idev->pdev, VLSI_PCI_MSTRPAGE, &byte);
        seq_printf(seq, "MSTRPAGE: 0x%02x\n", (unsigned)byte);

        byte = inb(iobase+VLSI_PIO_IRINTR);
        seq_printf(seq, "IRINTR:%s%s%s%s%s%s%s%s\n",
                (byte&IRINTR_ACTEN) ? " ACTEN" : "",
                (byte&IRINTR_RPKTEN) ? " RPKTEN" : "",
                (byte&IRINTR_TPKTEN) ? " TPKTEN" : "",
                (byte&IRINTR_OE_EN) ? " OE_EN" : "",
                (byte&IRINTR_ACTIVITY) ? " ACTIVITY" : "",
                (byte&IRINTR_RPKTINT) ? " RPKTINT" : "",
                (byte&IRINTR_TPKTINT) ? " TPKTINT" : "",
                (byte&IRINTR_OE_INT) ? " OE_INT" : "");
        word = inw(iobase+VLSI_PIO_RINGPTR);
        seq_printf(seq, "RINGPTR: rx=%u / tx=%u\n", RINGPTR_GET_RX(word), RINGPTR_GET_TX(word));
        word = inw(iobase+VLSI_PIO_RINGBASE);
        seq_printf(seq, "RINGBASE: busmap=0x%08x\n",
                ((unsigned)word << 10)|(MSTRPAGE_VALUE<<24));
        word = inw(iobase+VLSI_PIO_RINGSIZE);
        seq_printf(seq, "RINGSIZE: rx=%u / tx=%u\n", RINGSIZE_TO_RXSIZE(word),
                RINGSIZE_TO_TXSIZE(word));

        word = inw(iobase+VLSI_PIO_IRCFG);
        seq_printf(seq, "IRCFG:%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
                (word&IRCFG_LOOP) ? " LOOP" : "",
                (word&IRCFG_ENTX) ? " ENTX" : "",
                (word&IRCFG_ENRX) ? " ENRX" : "",
                (word&IRCFG_MSTR) ? " MSTR" : "",
                (word&IRCFG_RXANY) ? " RXANY" : "",
                (word&IRCFG_CRC16) ? " CRC16" : "",
                (word&IRCFG_FIR) ? " FIR" : "",
                (word&IRCFG_MIR) ? " MIR" : "",
                (word&IRCFG_SIR) ? " SIR" : "",
                (word&IRCFG_SIRFILT) ? " SIRFILT" : "",
                (word&IRCFG_SIRTEST) ? " SIRTEST" : "",
                (word&IRCFG_TXPOL) ? " TXPOL" : "",
                (word&IRCFG_RXPOL) ? " RXPOL" : "");
        word = inw(iobase+VLSI_PIO_IRENABLE);
        seq_printf(seq, "IRENABLE:%s%s%s%s%s%s%s%s\n",
                (word&IRENABLE_PHYANDCLOCK) ? " PHYANDCLOCK" : "",
                (word&IRENABLE_CFGER) ? " CFGERR" : "",
                (word&IRENABLE_FIR_ON) ? " FIR_ON" : "",
                (word&IRENABLE_MIR_ON) ? " MIR_ON" : "",
                (word&IRENABLE_SIR_ON) ? " SIR_ON" : "",
                (word&IRENABLE_ENTXST) ? " ENTXST" : "",
                (word&IRENABLE_ENRXST) ? " ENRXST" : "",
                (word&IRENABLE_CRC16_ON) ? " CRC16_ON" : "");
        word = inw(iobase+VLSI_PIO_PHYCTL);
        seq_printf(seq, "PHYCTL: baud-divisor=%u / pulsewidth=%u / preamble=%u\n",
                (unsigned)PHYCTL_TO_BAUD(word),
                (unsigned)PHYCTL_TO_PLSWID(word),
                (unsigned)PHYCTL_TO_PREAMB(word));
        word = inw(iobase+VLSI_PIO_NPHYCTL);
        seq_printf(seq, "NPHYCTL: baud-divisor=%u / pulsewidth=%u / preamble=%u\n",
                (unsigned)PHYCTL_TO_BAUD(word),
                (unsigned)PHYCTL_TO_PLSWID(word),
                (unsigned)PHYCTL_TO_PREAMB(word));
        word = inw(iobase+VLSI_PIO_MAXPKT);
        seq_printf(seq, "MAXPKT: max. rx packet size = %u\n", word);
        word = inw(iobase+VLSI_PIO_RCVBCNT) & RCVBCNT_MASK;
        seq_printf(seq, "RCVBCNT: rx-fifo filling level = %u\n", word);

        seq_printf(seq, "\nsw-state:\n");
        seq_printf(seq, "IrPHY setup: %d baud - %s encoding\n", idev->baud, 
                (idev->mode==IFF_SIR)?"SIR":((idev->mode==IFF_MIR)?"MIR":"FIR"));
        sec = div_s64_rem(ktime_us_delta(ktime_get(), idev->last_rx),
                          USEC_PER_SEC, &usec);
        seq_printf(seq, "last rx: %ul.%06u sec\n", sec, usec);

        seq_printf(seq, "RX: packets=%lu / bytes=%lu / errors=%lu / dropped=%lu",
                ndev->stats.rx_packets, ndev->stats.rx_bytes, ndev->stats.rx_errors,
                ndev->stats.rx_dropped);
        seq_printf(seq, " / overrun=%lu / length=%lu / frame=%lu / crc=%lu\n",
                ndev->stats.rx_over_errors, ndev->stats.rx_length_errors,
                ndev->stats.rx_frame_errors, ndev->stats.rx_crc_errors);
        seq_printf(seq, "TX: packets=%lu / bytes=%lu / errors=%lu / dropped=%lu / fifo=%lu\n",
                ndev->stats.tx_packets, ndev->stats.tx_bytes, ndev->stats.tx_errors,
                ndev->stats.tx_dropped, ndev->stats.tx_fifo_errors);

}
                
static void vlsi_proc_ring(struct seq_file *seq, struct vlsi_ring *r)
{
        struct ring_descr *rd;
        unsigned i, j;
        int h, t;

        seq_printf(seq, "size %u / mask 0x%04x / len %u / dir %d / hw %p\n",
                r->size, r->mask, r->len, r->dir, r->rd[0].hw);
        h = atomic_read(&r->head) & r->mask;
        t = atomic_read(&r->tail) & r->mask;
        seq_printf(seq, "head = %d / tail = %d ", h, t);
        if (h == t)
                seq_printf(seq, "(empty)\n");
        else {
                if (((t+1)&r->mask) == h)
                        seq_printf(seq, "(full)\n");
                else
                        seq_printf(seq, "(level = %d)\n", ((unsigned)(t-h) & r->mask)); 
                rd = &r->rd[h];
                j = (unsigned) rd_get_count(rd);
                seq_printf(seq, "current: rd = %d / status = %02x / len = %u\n",
                                h, (unsigned)rd_get_status(rd), j);
                if (j > 0) {
                        seq_printf(seq, "   data: %*ph\n",
                                   min_t(unsigned, j, 20), rd->buf);
                }
        }
        for (i = 0; i < r->size; i++) {
                rd = &r->rd[i];
                seq_printf(seq, "> ring descr %u: ", i);
                seq_printf(seq, "skb=%p data=%p hw=%p\n", rd->skb, rd->buf, rd->hw);
                seq_printf(seq, "  hw: status=%02x count=%u busaddr=0x%08x\n",
                        (unsigned) rd_get_status(rd),
                        (unsigned) rd_get_count(rd), (unsigned) rd_get_addr(rd));
        }
}

static int vlsi_seq_show(struct seq_file *seq, void *v)
{
        struct net_device *ndev = seq->private;
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        unsigned long flags;

        seq_printf(seq, "\n%s %s\n\n", DRIVER_NAME, DRIVER_VERSION);
        seq_printf(seq, "clksrc: %s\n", 
                (clksrc>=2) ? ((clksrc==3)?"40MHz XCLK":"48MHz XCLK")
                            : ((clksrc==1)?"48MHz PLL":"autodetect"));
        seq_printf(seq, "ringsize: tx=%d / rx=%d\n",
                ringsize[0], ringsize[1]);
        seq_printf(seq, "sirpulse: %s\n", (sirpulse)?"3/16 bittime":"short");
        seq_printf(seq, "qos_mtt_bits: 0x%02x\n", (unsigned)qos_mtt_bits);

        spin_lock_irqsave(&idev->lock, flags);
        if (idev->pdev != NULL) {
                vlsi_proc_pdev(seq, idev->pdev);

                if (idev->pdev->current_state == 0)
                        vlsi_proc_ndev(seq, ndev);
                else
                        seq_printf(seq, "\nPCI controller down - resume_ok = %d\n",
                                idev->resume_ok);
                if (netif_running(ndev) && idev->rx_ring && idev->tx_ring) {
                        seq_printf(seq, "\n--------- RX ring -----------\n\n");
                        vlsi_proc_ring(seq, idev->rx_ring);
                        seq_printf(seq, "\n--------- TX ring -----------\n\n");
                        vlsi_proc_ring(seq, idev->tx_ring);
                }
        }
        seq_printf(seq, "\n");
        spin_unlock_irqrestore(&idev->lock, flags);

        return 0;
}

static int vlsi_seq_open(struct inode *inode, struct file *file)
{
        return single_open(file, vlsi_seq_show, PDE_DATA(inode));
}

static const struct file_operations vlsi_proc_fops = {
        .owner   = THIS_MODULE,
        .open    = vlsi_seq_open,
        .read    = seq_read,
        .llseek  = seq_lseek,
        .release = single_release,
};

#define VLSI_PROC_FOPS          (&vlsi_proc_fops)

#else   /* CONFIG_PROC_FS */
#define VLSI_PROC_FOPS          NULL
#endif

/********************************************************/

static struct vlsi_ring *vlsi_alloc_ring(struct pci_dev *pdev, struct ring_descr_hw *hwmap,
                                                unsigned size, unsigned len, int dir)
{
        struct vlsi_ring *r;
        struct ring_descr *rd;
        unsigned        i, j;
        dma_addr_t      busaddr;

        if (!size  ||  ((size-1)&size)!=0)      /* must be >0 and power of 2 */
                return NULL;

        r = kmalloc(sizeof(*r) + size * sizeof(struct ring_descr), GFP_KERNEL);
        if (!r)
                return NULL;
        memset(r, 0, sizeof(*r));

        r->pdev = pdev;
        r->dir = dir;
        r->len = len;
        r->rd = (struct ring_descr *)(r+1);
        r->mask = size - 1;
        r->size = size;
        atomic_set(&r->head, 0);
        atomic_set(&r->tail, 0);

        for (i = 0; i < size; i++) {
                rd = r->rd + i;
                memset(rd, 0, sizeof(*rd));
                rd->hw = hwmap + i;
                rd->buf = kmalloc(len, GFP_KERNEL|GFP_DMA);
                if (rd->buf == NULL ||
                    !(busaddr = pci_map_single(pdev, rd->buf, len, dir))) {
                        if (rd->buf) {
                                net_err_ratelimited("%s: failed to create PCI-MAP for %p\n",
                                                    __func__, rd->buf);
                                kfree(rd->buf);
                                rd->buf = NULL;
                        }
                        for (j = 0; j < i; j++) {
                                rd = r->rd + j;
                                busaddr = rd_get_addr(rd);
                                rd_set_addr_status(rd, 0, 0);
                                if (busaddr)
                                        pci_unmap_single(pdev, busaddr, len, dir);
                                kfree(rd->buf);
                                rd->buf = NULL;
                        }
                        kfree(r);
                        return NULL;
                }
                rd_set_addr_status(rd, busaddr, 0);
                /* initially, the dma buffer is owned by the CPU */
                rd->skb = NULL;
        }
        return r;
}

static int vlsi_free_ring(struct vlsi_ring *r)
{
        struct ring_descr *rd;
        unsigned        i;
        dma_addr_t      busaddr;

        for (i = 0; i < r->size; i++) {
                rd = r->rd + i;
                if (rd->skb)
                        dev_kfree_skb_any(rd->skb);
                busaddr = rd_get_addr(rd);
                rd_set_addr_status(rd, 0, 0);
                if (busaddr)
                        pci_unmap_single(r->pdev, busaddr, r->len, r->dir);
                kfree(rd->buf);
        }
        kfree(r);
        return 0;
}

static int vlsi_create_hwif(vlsi_irda_dev_t *idev)
{
        char                    *ringarea;
        struct ring_descr_hw    *hwmap;

        idev->virtaddr = NULL;
        idev->busaddr = 0;

        ringarea = pci_zalloc_consistent(idev->pdev, HW_RING_AREA_SIZE,
                                         &idev->busaddr);
        if (!ringarea)
                goto out;

        hwmap = (struct ring_descr_hw *)ringarea;
        idev->rx_ring = vlsi_alloc_ring(idev->pdev, hwmap, ringsize[1],
                                        XFER_BUF_SIZE, PCI_DMA_FROMDEVICE);
        if (idev->rx_ring == NULL)
                goto out_unmap;

        hwmap += MAX_RING_DESCR;
        idev->tx_ring = vlsi_alloc_ring(idev->pdev, hwmap, ringsize[0],
                                        XFER_BUF_SIZE, PCI_DMA_TODEVICE);
        if (idev->tx_ring == NULL)
                goto out_free_rx;

        idev->virtaddr = ringarea;
        return 0;

out_free_rx:
        vlsi_free_ring(idev->rx_ring);
out_unmap:
        idev->rx_ring = idev->tx_ring = NULL;
        pci_free_consistent(idev->pdev, HW_RING_AREA_SIZE, ringarea, idev->busaddr);
        idev->busaddr = 0;
out:
        return -ENOMEM;
}

static int vlsi_destroy_hwif(vlsi_irda_dev_t *idev)
{
        vlsi_free_ring(idev->rx_ring);
        vlsi_free_ring(idev->tx_ring);
        idev->rx_ring = idev->tx_ring = NULL;

        if (idev->busaddr)
                pci_free_consistent(idev->pdev,HW_RING_AREA_SIZE,idev->virtaddr,idev->busaddr);

        idev->virtaddr = NULL;
        idev->busaddr = 0;

        return 0;
}

/********************************************************/

static int vlsi_process_rx(struct vlsi_ring *r, struct ring_descr *rd)
{
        u16             status;
        int             crclen, len = 0;
        struct sk_buff  *skb;
        int             ret = 0;
        struct net_device *ndev = pci_get_drvdata(r->pdev);
        vlsi_irda_dev_t *idev = netdev_priv(ndev);

        pci_dma_sync_single_for_cpu(r->pdev, rd_get_addr(rd), r->len, r->dir);
        /* dma buffer now owned by the CPU */
        status = rd_get_status(rd);
        if (status & RD_RX_ERROR) {
                if (status & RD_RX_OVER)  
                        ret |= VLSI_RX_OVER;
                if (status & RD_RX_LENGTH)  
                        ret |= VLSI_RX_LENGTH;
                if (status & RD_RX_PHYERR)  
                        ret |= VLSI_RX_FRAME;
                if (status & RD_RX_CRCERR)  
                        ret |= VLSI_RX_CRC;
                goto done;
        }

        len = rd_get_count(rd);
        crclen = (idev->mode==IFF_FIR) ? sizeof(u32) : sizeof(u16);
        len -= crclen;          /* remove trailing CRC */
        if (len <= 0) {
                pr_debug("%s: strange frame (len=%d)\n", __func__, len);
                ret |= VLSI_RX_DROP;
                goto done;
        }

        if (idev->mode == IFF_SIR) {    /* hw checks CRC in MIR, FIR mode */

                /* rd->buf is a streaming PCI_DMA_FROMDEVICE map. Doing the
                 * endian-adjustment there just in place will dirty a cache line
                 * which belongs to the map and thus we must be sure it will
                 * get flushed before giving the buffer back to hardware.
                 * vlsi_fill_rx() will do this anyway - but here we rely on.
                 */
                le16_to_cpus(rd->buf+len);
                if (irda_calc_crc16(INIT_FCS,rd->buf,len+crclen) != GOOD_FCS) {
                        pr_debug("%s: crc error\n", __func__);
                        ret |= VLSI_RX_CRC;
                        goto done;
                }
        }

        if (!rd->skb) {
                net_warn_ratelimited("%s: rx packet lost\n", __func__);
                ret |= VLSI_RX_DROP;
                goto done;
        }

        skb = rd->skb;
        rd->skb = NULL;
        skb->dev = ndev;
        memcpy(skb_put(skb,len), rd->buf, len);
        skb_reset_mac_header(skb);
        if (in_interrupt())
                netif_rx(skb);
        else
                netif_rx_ni(skb);

done:
        rd_set_status(rd, 0);
        rd_set_count(rd, 0);
        /* buffer still owned by CPU */

        return (ret) ? -ret : len;
}

static void vlsi_fill_rx(struct vlsi_ring *r)
{
        struct ring_descr *rd;

        for (rd = ring_last(r); rd != NULL; rd = ring_put(r)) {
                if (rd_is_active(rd)) {
                        net_warn_ratelimited("%s: driver bug: rx descr race with hw\n",
                                             __func__);
                        vlsi_ring_debug(r);
                        break;
                }
                if (!rd->skb) {
                        rd->skb = dev_alloc_skb(IRLAP_SKB_ALLOCSIZE);
                        if (rd->skb) {
                                skb_reserve(rd->skb,1);
                                rd->skb->protocol = htons(ETH_P_IRDA);
                        }
                        else
                                break;  /* probably not worth logging? */
                }
                /* give dma buffer back to busmaster */
                pci_dma_sync_single_for_device(r->pdev, rd_get_addr(rd), r->len, r->dir);
                rd_activate(rd);
        }
}

static void vlsi_rx_interrupt(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        struct vlsi_ring *r = idev->rx_ring;
        struct ring_descr *rd;
        int ret;

        for (rd = ring_first(r); rd != NULL; rd = ring_get(r)) {

                if (rd_is_active(rd))
                        break;

                ret = vlsi_process_rx(r, rd);

                if (ret < 0) {
                        ret = -ret;
                        ndev->stats.rx_errors++;
                        if (ret & VLSI_RX_DROP)  
                                ndev->stats.rx_dropped++;
                        if (ret & VLSI_RX_OVER)  
                                ndev->stats.rx_over_errors++;
                        if (ret & VLSI_RX_LENGTH)  
                                ndev->stats.rx_length_errors++;
                        if (ret & VLSI_RX_FRAME)  
                                ndev->stats.rx_frame_errors++;
                        if (ret & VLSI_RX_CRC)  
                                ndev->stats.rx_crc_errors++;
                }
                else if (ret > 0) {
                        ndev->stats.rx_packets++;
                        ndev->stats.rx_bytes += ret;
                }
        }

        idev->last_rx = ktime_get(); /* remember "now" for later mtt delay */

        vlsi_fill_rx(r);

        if (ring_first(r) == NULL) {
                /* we are in big trouble, if this should ever happen */
                net_err_ratelimited("%s: rx ring exhausted!\n", __func__);
                vlsi_ring_debug(r);
        }
        else
                outw(0, ndev->base_addr+VLSI_PIO_PROMPT);
}

/* caller must have stopped the controller from busmastering */

static void vlsi_unarm_rx(vlsi_irda_dev_t *idev)
{
        struct net_device *ndev = pci_get_drvdata(idev->pdev);
        struct vlsi_ring *r = idev->rx_ring;
        struct ring_descr *rd;
        int ret;

        for (rd = ring_first(r); rd != NULL; rd = ring_get(r)) {

                ret = 0;
                if (rd_is_active(rd)) {
                        rd_set_status(rd, 0);
                        if (rd_get_count(rd)) {
                                pr_debug("%s - dropping rx packet\n", __func__);
                                ret = -VLSI_RX_DROP;
                        }
                        rd_set_count(rd, 0);
                        pci_dma_sync_single_for_cpu(r->pdev, rd_get_addr(rd), r->len, r->dir);
                        if (rd->skb) {
                                dev_kfree_skb_any(rd->skb);
                                rd->skb = NULL;
                        }
                }
                else
                        ret = vlsi_process_rx(r, rd);

                if (ret < 0) {
                        ret = -ret;
                        ndev->stats.rx_errors++;
                        if (ret & VLSI_RX_DROP)  
                                ndev->stats.rx_dropped++;
                        if (ret & VLSI_RX_OVER)  
                                ndev->stats.rx_over_errors++;
                        if (ret & VLSI_RX_LENGTH)  
                                ndev->stats.rx_length_errors++;
                        if (ret & VLSI_RX_FRAME)  
                                ndev->stats.rx_frame_errors++;
                        if (ret & VLSI_RX_CRC)  
                                ndev->stats.rx_crc_errors++;
                }
                else if (ret > 0) {
                        ndev->stats.rx_packets++;
                        ndev->stats.rx_bytes += ret;
                }
        }
}

/********************************************************/

static int vlsi_process_tx(struct vlsi_ring *r, struct ring_descr *rd)
{
        u16             status;
        int             len;
        int             ret;

        pci_dma_sync_single_for_cpu(r->pdev, rd_get_addr(rd), r->len, r->dir);
        /* dma buffer now owned by the CPU */
        status = rd_get_status(rd);
        if (status & RD_TX_UNDRN)
                ret = VLSI_TX_FIFO;
        else
                ret = 0;
        rd_set_status(rd, 0);

        if (rd->skb) {
                len = rd->skb->len;
                dev_kfree_skb_any(rd->skb);
                rd->skb = NULL;
        }
        else    /* tx-skb already freed? - should never happen */
                len = rd_get_count(rd);         /* incorrect for SIR! (due to wrapping) */

        rd_set_count(rd, 0);
        /* dma buffer still owned by the CPU */

        return (ret) ? -ret : len;
}

static int vlsi_set_baud(vlsi_irda_dev_t *idev, unsigned iobase)
{
        u16 nphyctl;
        u16 config;
        unsigned mode;
        int     ret;
        int     baudrate;
        int     fifocnt;

        baudrate = idev->new_baud;
        pr_debug("%s: %d -> %d\n", __func__, idev->baud, idev->new_baud);
        if (baudrate == 4000000) {
                mode = IFF_FIR;
                config = IRCFG_FIR;
                nphyctl = PHYCTL_FIR;
        }
        else if (baudrate == 1152000) {
                mode = IFF_MIR;
                config = IRCFG_MIR | IRCFG_CRC16;
                nphyctl = PHYCTL_MIR(clksrc==3);
        }
        else {
                mode = IFF_SIR;
                config = IRCFG_SIR | IRCFG_SIRFILT  | IRCFG_RXANY;
                switch(baudrate) {
                        default:
                                net_warn_ratelimited("%s: undefined baudrate %d - fallback to 9600!\n",
                                                     __func__, baudrate);
                                baudrate = 9600;
                                /* fallthru */
                        case 2400:
                        case 9600:
                        case 19200:
                        case 38400:
                        case 57600:
                        case 115200:
                                nphyctl = PHYCTL_SIR(baudrate,sirpulse,clksrc==3);
                                break;
                }
        }
        config |= IRCFG_MSTR | IRCFG_ENRX;

        fifocnt = inw(iobase+VLSI_PIO_RCVBCNT) & RCVBCNT_MASK;
        if (fifocnt != 0) {
                pr_debug("%s: rx fifo not empty(%d)\n", __func__, fifocnt);
        }

        outw(0, iobase+VLSI_PIO_IRENABLE);
        outw(config, iobase+VLSI_PIO_IRCFG);
        outw(nphyctl, iobase+VLSI_PIO_NPHYCTL);
        wmb();
        outw(IRENABLE_PHYANDCLOCK, iobase+VLSI_PIO_IRENABLE);
        mb();

        udelay(1);      /* chip applies IRCFG on next rising edge of its 8MHz clock */

        /* read back settings for validation */

        config = inw(iobase+VLSI_PIO_IRENABLE) & IRENABLE_MASK;

        if (mode == IFF_FIR)
                config ^= IRENABLE_FIR_ON;
        else if (mode == IFF_MIR)
                config ^= (IRENABLE_MIR_ON|IRENABLE_CRC16_ON);
        else
                config ^= IRENABLE_SIR_ON;

        if (config != (IRENABLE_PHYANDCLOCK|IRENABLE_ENRXST)) {
                net_warn_ratelimited("%s: failed to set %s mode!\n",
                                     __func__,
                                     mode == IFF_SIR ? "SIR" :
                                     mode == IFF_MIR ? "MIR" : "FIR");
                ret = -1;
        }
        else {
                if (inw(iobase+VLSI_PIO_PHYCTL) != nphyctl) {
                        net_warn_ratelimited("%s: failed to apply baudrate %d\n",
                                             __func__, baudrate);
                        ret = -1;
                }
                else {
                        idev->mode = mode;
                        idev->baud = baudrate;
                        idev->new_baud = 0;
                        ret = 0;
                }
        }

        if (ret)
                vlsi_reg_debug(iobase,__func__);

        return ret;
}

static netdev_tx_t vlsi_hard_start_xmit(struct sk_buff *skb,
                                              struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        struct vlsi_ring        *r = idev->tx_ring;
        struct ring_descr *rd;
        unsigned long flags;
        unsigned iobase = ndev->base_addr;
        u8 status;
        u16 config;
        int mtt, diff;
        int len, speed;
        char *msg = NULL;

        speed = irda_get_next_speed(skb);
        spin_lock_irqsave(&idev->lock, flags);
        if (speed != -1  &&  speed != idev->baud) {
                netif_stop_queue(ndev);
                idev->new_baud = speed;
                status = RD_TX_CLRENTX;  /* stop tx-ring after this frame */
        }
        else
                status = 0;

        if (skb->len == 0) {
                /* handle zero packets - should be speed change */
                if (status == 0) {
                        msg = "bogus zero-length packet";
                        goto drop_unlock;
                }

                /* due to the completely asynch tx operation we might have
                 * IrLAP racing with the hardware here, f.e. if the controller
                 * is just sending the last packet with current speed while
                 * the LAP is already switching the speed using synchronous
                 * len=0 packet. Immediate execution would lead to hw lockup
                 * requiring a powercycle to reset. Good candidate to trigger
                 * this is the final UA:RSP packet after receiving a DISC:CMD
                 * when getting the LAP down.
                 * Note that we are not protected by the queue_stop approach
                 * because the final UA:RSP arrives _without_ request to apply
                 * new-speed-after-this-packet - hence the driver doesn't know
                 * this was the last packet and doesn't stop the queue. So the
                 * forced switch to default speed from LAP gets through as fast
                 * as only some 10 usec later while the UA:RSP is still processed
                 * by the hardware and we would get screwed.
                 */

                if (ring_first(idev->tx_ring) == NULL) {
                        /* no race - tx-ring already empty */
                        vlsi_set_baud(idev, iobase);
                        netif_wake_queue(ndev);
                }
                else
                        ;
                        /* keep the speed change pending like it would
                         * for any len>0 packet. tx completion interrupt
                         * will apply it when the tx ring becomes empty.
                         */
                spin_unlock_irqrestore(&idev->lock, flags);
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        /* sanity checks - simply drop the packet */

        rd = ring_last(r);
        if (!rd) {
                msg = "ring full, but queue wasn't stopped";
                goto drop_unlock;
        }

        if (rd_is_active(rd)) {
                msg = "entry still owned by hw";
                goto drop_unlock;
        }

        if (!rd->buf) {
                msg = "tx ring entry without pci buffer";
                goto drop_unlock;
        }

        if (rd->skb) {
                msg = "ring entry with old skb still attached";
                goto drop_unlock;
        }

        /* no need for serialization or interrupt disable during mtt */
        spin_unlock_irqrestore(&idev->lock, flags);

        if ((mtt = irda_get_mtt(skb)) > 0) {
                diff = ktime_us_delta(ktime_get(), idev->last_rx);
                if (mtt > diff)
                        udelay(mtt - diff);
                        /* must not sleep here - called under netif_tx_lock! */
        }

        /* tx buffer already owned by CPU due to pci_dma_sync_single_for_cpu()
         * after subsequent tx-completion
         */

        if (idev->mode == IFF_SIR) {
                status |= RD_TX_DISCRC;         /* no hw-crc creation */
                len = async_wrap_skb(skb, rd->buf, r->len);

                /* Some rare worst case situation in SIR mode might lead to
                 * potential buffer overflow. The wrapper detects this, returns
                 * with a shortened frame (without FCS/EOF) but doesn't provide
                 * any error indication about the invalid packet which we are
                 * going to transmit.
                 * Therefore we log if the buffer got filled to the point, where the
                 * wrapper would abort, i.e. when there are less than 5 bytes left to
                 * allow appending the FCS/EOF.
                 */

                if (len >= r->len-5)
                        net_warn_ratelimited("%s: possible buffer overflow with SIR wrapping!\n",
                                             __func__);
        }
        else {
                /* hw deals with MIR/FIR mode wrapping */
                status |= RD_TX_PULSE;          /* send 2 us highspeed indication pulse */
                len = skb->len;
                if (len > r->len) {
                        msg = "frame exceeds tx buffer length";
                        goto drop;
                }
                else
                        skb_copy_from_linear_data(skb, rd->buf, len);
        }

        rd->skb = skb;                  /* remember skb for tx-complete stats */

        rd_set_count(rd, len);
        rd_set_status(rd, status);      /* not yet active! */

        /* give dma buffer back to busmaster-hw (flush caches to make
         * CPU-driven changes visible from the pci bus).
         */

        pci_dma_sync_single_for_device(r->pdev, rd_get_addr(rd), r->len, r->dir);

/*      Switching to TX mode here races with the controller
 *      which may stop TX at any time when fetching an inactive descriptor
 *      or one with CLR_ENTX set. So we switch on TX only, if TX was not running
 *      _after_ the new descriptor was activated on the ring. This ensures
 *      we will either find TX already stopped or we can be sure, there
 *      will be a TX-complete interrupt even if the chip stopped doing
 *      TX just after we found it still running. The ISR will then find
 *      the non-empty ring and restart TX processing. The enclosing
 *      spinlock provides the correct serialization to prevent race with isr.
 */

        spin_lock_irqsave(&idev->lock,flags);

        rd_activate(rd);

        if (!(inw(iobase+VLSI_PIO_IRENABLE) & IRENABLE_ENTXST)) {

                int fifocnt;

                fifocnt = inw(ndev->base_addr+VLSI_PIO_RCVBCNT) & RCVBCNT_MASK;
                if (fifocnt != 0) {
                        pr_debug("%s: rx fifo not empty(%d)\n",
                                 __func__, fifocnt);
                }

                config = inw(iobase+VLSI_PIO_IRCFG);
                mb();
                outw(config | IRCFG_ENTX, iobase+VLSI_PIO_IRCFG);
                wmb();
                outw(0, iobase+VLSI_PIO_PROMPT);
        }

        if (ring_put(r) == NULL) {
                netif_stop_queue(ndev);
                pr_debug("%s: tx ring full - queue stopped\n", __func__);
        }
        spin_unlock_irqrestore(&idev->lock, flags);

        return NETDEV_TX_OK;

drop_unlock:
        spin_unlock_irqrestore(&idev->lock, flags);
drop:
        net_warn_ratelimited("%s: dropping packet - %s\n", __func__, msg);
        dev_kfree_skb_any(skb);
        ndev->stats.tx_errors++;
        ndev->stats.tx_dropped++;
        /* Don't even think about returning NET_XMIT_DROP (=1) here!
         * In fact any retval!=0 causes the packet scheduler to requeue the
         * packet for later retry of transmission - which isn't exactly
         * what we want after we've just called dev_kfree_skb_any ;-)
         */
        return NETDEV_TX_OK;
}

static void vlsi_tx_interrupt(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        struct vlsi_ring        *r = idev->tx_ring;
        struct ring_descr       *rd;
        unsigned        iobase;
        int     ret;
        u16     config;

        for (rd = ring_first(r); rd != NULL; rd = ring_get(r)) {

                if (rd_is_active(rd))
                        break;

                ret = vlsi_process_tx(r, rd);

                if (ret < 0) {
                        ret = -ret;
                        ndev->stats.tx_errors++;
                        if (ret & VLSI_TX_DROP)
                                ndev->stats.tx_dropped++;
                        if (ret & VLSI_TX_FIFO)
                                ndev->stats.tx_fifo_errors++;
                }
                else if (ret > 0){
                        ndev->stats.tx_packets++;
                        ndev->stats.tx_bytes += ret;
                }
        }

        iobase = ndev->base_addr;

        if (idev->new_baud  &&  rd == NULL)     /* tx ring empty and speed change pending */
                vlsi_set_baud(idev, iobase);

        config = inw(iobase+VLSI_PIO_IRCFG);
        if (rd == NULL)                 /* tx ring empty: re-enable rx */
                outw((config & ~IRCFG_ENTX) | IRCFG_ENRX, iobase+VLSI_PIO_IRCFG);

        else if (!(inw(iobase+VLSI_PIO_IRENABLE) & IRENABLE_ENTXST)) {
                int fifocnt;

                fifocnt = inw(iobase+VLSI_PIO_RCVBCNT) & RCVBCNT_MASK;
                if (fifocnt != 0) {
                        pr_debug("%s: rx fifo not empty(%d)\n",
                                 __func__, fifocnt);
                }
                outw(config | IRCFG_ENTX, iobase+VLSI_PIO_IRCFG);
        }

        outw(0, iobase+VLSI_PIO_PROMPT);

        if (netif_queue_stopped(ndev)  &&  !idev->new_baud) {
                netif_wake_queue(ndev);
                pr_debug("%s: queue awoken\n", __func__);
        }
}

/* caller must have stopped the controller from busmastering */

static void vlsi_unarm_tx(vlsi_irda_dev_t *idev)
{
        struct net_device *ndev = pci_get_drvdata(idev->pdev);
        struct vlsi_ring *r = idev->tx_ring;
        struct ring_descr *rd;
        int ret;

        for (rd = ring_first(r); rd != NULL; rd = ring_get(r)) {

                ret = 0;
                if (rd_is_active(rd)) {
                        rd_set_status(rd, 0);
                        rd_set_count(rd, 0);
                        pci_dma_sync_single_for_cpu(r->pdev, rd_get_addr(rd), r->len, r->dir);
                        if (rd->skb) {
                                dev_kfree_skb_any(rd->skb);
                                rd->skb = NULL;
                        }
                        pr_debug("%s - dropping tx packet\n", __func__);
                        ret = -VLSI_TX_DROP;
                }
                else
                        ret = vlsi_process_tx(r, rd);

                if (ret < 0) {
                        ret = -ret;
                        ndev->stats.tx_errors++;
                        if (ret & VLSI_TX_DROP)
                                ndev->stats.tx_dropped++;
                        if (ret & VLSI_TX_FIFO)
                                ndev->stats.tx_fifo_errors++;
                }
                else if (ret > 0){
                        ndev->stats.tx_packets++;
                        ndev->stats.tx_bytes += ret;
                }
        }

}

/********************************************************/

static int vlsi_start_clock(struct pci_dev *pdev)
{
        u8      clkctl, lock;
        int     i, count;

        if (clksrc < 2) { /* auto or PLL: try PLL */
                clkctl = CLKCTL_PD_INV | CLKCTL_CLKSTP;
                pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);

                /* procedure to detect PLL lock synchronisation:
                 * after 0.5 msec initial delay we expect to find 3 PLL lock
                 * indications within 10 msec for successful PLL detection.
                 */
                udelay(500);
                count = 0;
                for (i = 500; i <= 10000; i += 50) { /* max 10 msec */
                        pci_read_config_byte(pdev, VLSI_PCI_CLKCTL, &lock);
                        if (lock&CLKCTL_LOCK) {
                                if (++count >= 3)
                                        break;
                        }
                        udelay(50);
                }
                if (count < 3) {
                        if (clksrc == 1) { /* explicitly asked for PLL hence bail out */
                                net_err_ratelimited("%s: no PLL or failed to lock!\n",
                                                    __func__);
                                clkctl = CLKCTL_CLKSTP;
                                pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);
                                return -1;
                        }
                        else                    /* was: clksrc=0(auto) */
                                clksrc = 3;     /* fallback to 40MHz XCLK (OB800) */

                        pr_debug("%s: PLL not locked, fallback to clksrc=%d\n",
                                 __func__, clksrc);
                }
                else
                        clksrc = 1;     /* got successful PLL lock */
        }

        if (clksrc != 1) {
                /* we get here if either no PLL detected in auto-mode or
                   an external clock source was explicitly specified */

                clkctl = CLKCTL_EXTCLK | CLKCTL_CLKSTP;
                if (clksrc == 3)
                        clkctl |= CLKCTL_XCKSEL;        
                pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);

                /* no way to test for working XCLK */
        }
        else
                pci_read_config_byte(pdev, VLSI_PCI_CLKCTL, &clkctl);

        /* ok, now going to connect the chip with the clock source */

        clkctl &= ~CLKCTL_CLKSTP;
        pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);

        return 0;
}

static void vlsi_stop_clock(struct pci_dev *pdev)
{
        u8      clkctl;

        /* disconnect chip from clock source */
        pci_read_config_byte(pdev, VLSI_PCI_CLKCTL, &clkctl);
        clkctl |= CLKCTL_CLKSTP;
        pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);

        /* disable all clock sources */
        clkctl &= ~(CLKCTL_EXTCLK | CLKCTL_PD_INV);
        pci_write_config_byte(pdev, VLSI_PCI_CLKCTL, clkctl);
}

/********************************************************/

/* writing all-zero to the VLSI PCI IO register area seems to prevent
 * some occasional situations where the hardware fails (symptoms are 
 * what appears as stalled tx/rx state machines, i.e. everything ok for
 * receive or transmit but hw makes no progress or is unable to access
 * the bus memory locations).
 * Best place to call this is immediately after/before the internal clock
 * gets started/stopped.
 */

static inline void vlsi_clear_regs(unsigned iobase)
{
        unsigned        i;
        const unsigned  chip_io_extent = 32;

        for (i = 0; i < chip_io_extent; i += sizeof(u16))
                outw(0, iobase + i);
}

static int vlsi_init_chip(struct pci_dev *pdev)
{
        struct net_device *ndev = pci_get_drvdata(pdev);
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        unsigned        iobase;
        u16 ptr;

        /* start the clock and clean the registers */

        if (vlsi_start_clock(pdev)) {
                net_err_ratelimited("%s: no valid clock source\n", __func__);
                return -1;
        }
        iobase = ndev->base_addr;
        vlsi_clear_regs(iobase);

        outb(IRINTR_INT_MASK, iobase+VLSI_PIO_IRINTR); /* w/c pending IRQ, disable all INT */

        outw(0, iobase+VLSI_PIO_IRENABLE);      /* disable IrPHY-interface */

        /* disable everything, particularly IRCFG_MSTR - (also resetting the RING_PTR) */

        outw(0, iobase+VLSI_PIO_IRCFG);
        wmb();

        outw(MAX_PACKET_LENGTH, iobase+VLSI_PIO_MAXPKT);  /* max possible value=0x0fff */

        outw(BUS_TO_RINGBASE(idev->busaddr), iobase+VLSI_PIO_RINGBASE);

        outw(TX_RX_TO_RINGSIZE(idev->tx_ring->size, idev->rx_ring->size),
                iobase+VLSI_PIO_RINGSIZE);      

        ptr = inw(iobase+VLSI_PIO_RINGPTR);
        atomic_set(&idev->rx_ring->head, RINGPTR_GET_RX(ptr));
        atomic_set(&idev->rx_ring->tail, RINGPTR_GET_RX(ptr));
        atomic_set(&idev->tx_ring->head, RINGPTR_GET_TX(ptr));
        atomic_set(&idev->tx_ring->tail, RINGPTR_GET_TX(ptr));

        vlsi_set_baud(idev, iobase);    /* idev->new_baud used as provided by caller */

        outb(IRINTR_INT_MASK, iobase+VLSI_PIO_IRINTR);  /* just in case - w/c pending IRQ's */
        wmb();

        /* DO NOT BLINDLY ENABLE IRINTR_ACTEN!
         * basically every received pulse fires an ACTIVITY-INT
         * leading to >>1000 INT's per second instead of few 10
         */

        outb(IRINTR_RPKTEN|IRINTR_TPKTEN, iobase+VLSI_PIO_IRINTR);

        return 0;
}

static int vlsi_start_hw(vlsi_irda_dev_t *idev)
{
        struct pci_dev *pdev = idev->pdev;
        struct net_device *ndev = pci_get_drvdata(pdev);
        unsigned iobase = ndev->base_addr;
        u8 byte;

        /* we don't use the legacy UART, disable its address decoding */

        pci_read_config_byte(pdev, VLSI_PCI_IRMISC, &byte);
        byte &= ~(IRMISC_UARTEN | IRMISC_UARTTST);
        pci_write_config_byte(pdev, VLSI_PCI_IRMISC, byte);

        /* enable PCI busmaster access to our 16MB page */

        pci_write_config_byte(pdev, VLSI_PCI_MSTRPAGE, MSTRPAGE_VALUE);
        pci_set_master(pdev);

        if (vlsi_init_chip(pdev) < 0) {
                pci_disable_device(pdev);
                return -1;
        }

        vlsi_fill_rx(idev->rx_ring);

        idev->last_rx = ktime_get();    /* first mtt may start from now on */

        outw(0, iobase+VLSI_PIO_PROMPT);        /* kick hw state machine */

        return 0;
}

static int vlsi_stop_hw(vlsi_irda_dev_t *idev)
{
        struct pci_dev *pdev = idev->pdev;
        struct net_device *ndev = pci_get_drvdata(pdev);
        unsigned iobase = ndev->base_addr;
        unsigned long flags;

        spin_lock_irqsave(&idev->lock,flags);
        outw(0, iobase+VLSI_PIO_IRENABLE);
        outw(0, iobase+VLSI_PIO_IRCFG);                 /* disable everything */

        /* disable and w/c irqs */
        outb(0, iobase+VLSI_PIO_IRINTR);
        wmb();
        outb(IRINTR_INT_MASK, iobase+VLSI_PIO_IRINTR);
        spin_unlock_irqrestore(&idev->lock,flags);

        vlsi_unarm_tx(idev);
        vlsi_unarm_rx(idev);

        vlsi_clear_regs(iobase);
        vlsi_stop_clock(pdev);

        pci_disable_device(pdev);

        return 0;
}

/**************************************************************/

static void vlsi_tx_timeout(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);


        vlsi_reg_debug(ndev->base_addr, __func__);
        vlsi_ring_debug(idev->tx_ring);

        if (netif_running(ndev))
                netif_stop_queue(ndev);

        vlsi_stop_hw(idev);

        /* now simply restart the whole thing */

        if (!idev->new_baud)
                idev->new_baud = idev->baud;            /* keep current baudrate */

        if (vlsi_start_hw(idev))
                net_err_ratelimited("%s: failed to restart hw - %s(%s) unusable!\n",
                                    __func__, pci_name(idev->pdev), ndev->name);
        else
                netif_start_queue(ndev);
}

static int vlsi_ioctl(struct net_device *ndev, struct ifreq *rq, int cmd)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        struct if_irda_req *irq = (struct if_irda_req *) rq;
        unsigned long flags;
        u16 fifocnt;
        int ret = 0;

        switch (cmd) {
                case SIOCSBANDWIDTH:
                        if (!capable(CAP_NET_ADMIN)) {
                                ret = -EPERM;
                                break;
                        }
                        spin_lock_irqsave(&idev->lock, flags);
                        idev->new_baud = irq->ifr_baudrate;
                        /* when called from userland there might be a minor race window here
                         * if the stack tries to change speed concurrently - which would be
                         * pretty strange anyway with the userland having full control...
                         */
                        vlsi_set_baud(idev, ndev->base_addr);
                        spin_unlock_irqrestore(&idev->lock, flags);
                        break;
                case SIOCSMEDIABUSY:
                        if (!capable(CAP_NET_ADMIN)) {
                                ret = -EPERM;
                                break;
                        }
                        irda_device_set_media_busy(ndev, TRUE);
                        break;
                case SIOCGRECEIVING:
                        /* the best we can do: check whether there are any bytes in rx fifo.
                         * The trustable window (in case some data arrives just afterwards)
                         * may be as short as 1usec or so at 4Mbps.
                         */
                        fifocnt = inw(ndev->base_addr+VLSI_PIO_RCVBCNT) & RCVBCNT_MASK;
                        irq->ifr_receiving = (fifocnt!=0) ? 1 : 0;
                        break;
                default:
                        net_warn_ratelimited("%s: notsupp - cmd=%04x\n",
                                             __func__, cmd);
                        ret = -EOPNOTSUPP;
        }       
        
        return ret;
}

/********************************************************/

static irqreturn_t vlsi_interrupt(int irq, void *dev_instance)
{
        struct net_device *ndev = dev_instance;
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        unsigned        iobase;
        u8              irintr;
        int             boguscount = 5;
        unsigned long   flags;
        int             handled = 0;

        iobase = ndev->base_addr;
        spin_lock_irqsave(&idev->lock,flags);
        do {
                irintr = inb(iobase+VLSI_PIO_IRINTR);
                mb();
                outb(irintr, iobase+VLSI_PIO_IRINTR);   /* acknowledge asap */

                if (!(irintr&=IRINTR_INT_MASK))         /* not our INT - probably shared */
                        break;

                handled = 1;

                if (unlikely(!(irintr & ~IRINTR_ACTIVITY)))
                        break;                          /* nothing todo if only activity */

                if (irintr&IRINTR_RPKTINT)
                        vlsi_rx_interrupt(ndev);

                if (irintr&IRINTR_TPKTINT)
                        vlsi_tx_interrupt(ndev);

        } while (--boguscount > 0);
        spin_unlock_irqrestore(&idev->lock,flags);

        if (boguscount <= 0)
                net_info_ratelimited("%s: too much work in interrupt!\n",
                                     __func__);
        return IRQ_RETVAL(handled);
}

/********************************************************/

static int vlsi_open(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        int     err = -EAGAIN;
        char    hwname[32];

        if (pci_request_regions(idev->pdev, drivername)) {
                net_warn_ratelimited("%s: io resource busy\n", __func__);
                goto errout;
        }
        ndev->base_addr = pci_resource_start(idev->pdev,0);
        ndev->irq = idev->pdev->irq;

        /* under some rare occasions the chip apparently comes up with
         * IRQ's pending. We better w/c pending IRQ and disable them all
         */

        outb(IRINTR_INT_MASK, ndev->base_addr+VLSI_PIO_IRINTR);

        if (request_irq(ndev->irq, vlsi_interrupt, IRQF_SHARED,
                        drivername, ndev)) {
                net_warn_ratelimited("%s: couldn't get IRQ: %d\n",
                                     __func__, ndev->irq);
                goto errout_io;
        }

        if ((err = vlsi_create_hwif(idev)) != 0)
                goto errout_irq;

        sprintf(hwname, "VLSI-FIR @ 0x%04x", (unsigned)ndev->base_addr);
        idev->irlap = irlap_open(ndev,&idev->qos,hwname);
        if (!idev->irlap)
                goto errout_free_ring;

        idev->last_rx = ktime_get();  /* first mtt may start from now on */

        idev->new_baud = 9600;          /* start with IrPHY using 9600(SIR) mode */

        if ((err = vlsi_start_hw(idev)) != 0)
                goto errout_close_irlap;

        netif_start_queue(ndev);

        net_info_ratelimited("%s: device %s operational\n",
                             __func__, ndev->name);

        return 0;

errout_close_irlap:
        irlap_close(idev->irlap);
errout_free_ring:
        vlsi_destroy_hwif(idev);
errout_irq:
        free_irq(ndev->irq,ndev);
errout_io:
        pci_release_regions(idev->pdev);
errout:
        return err;
}

static int vlsi_close(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);

        netif_stop_queue(ndev);

        if (idev->irlap)
                irlap_close(idev->irlap);
        idev->irlap = NULL;

        vlsi_stop_hw(idev);

        vlsi_destroy_hwif(idev);

        free_irq(ndev->irq,ndev);

        pci_release_regions(idev->pdev);

        net_info_ratelimited("%s: device %s stopped\n", __func__, ndev->name);

        return 0;
}

static const struct net_device_ops vlsi_netdev_ops = {
        .ndo_open       = vlsi_open,
        .ndo_stop       = vlsi_close,
        .ndo_start_xmit = vlsi_hard_start_xmit,
        .ndo_do_ioctl   = vlsi_ioctl,
        .ndo_tx_timeout = vlsi_tx_timeout,
};

static int vlsi_irda_init(struct net_device *ndev)
{
        vlsi_irda_dev_t *idev = netdev_priv(ndev);
        struct pci_dev *pdev = idev->pdev;

        ndev->irq = pdev->irq;
        ndev->base_addr = pci_resource_start(pdev,0);

        /* PCI busmastering
         * see include file for details why we need these 2 masks, in this order!
         */

        if (pci_set_dma_mask(pdev,DMA_MASK_USED_BY_HW) ||
            pci_set_dma_mask(pdev,DMA_MASK_MSTRPAGE)) {
                net_err_ratelimited("%s: aborting due to PCI BM-DMA address limitations\n",
                                    __func__);
                return -1;
        }

        irda_init_max_qos_capabilies(&idev->qos);

        /* the VLSI82C147 does not support 576000! */

        idev->qos.baud_rate.bits = IR_2400 | IR_9600
                | IR_19200 | IR_38400 | IR_57600 | IR_115200
                | IR_1152000 | (IR_4000000 << 8);

        idev->qos.min_turn_time.bits = qos_mtt_bits;

        irda_qos_bits_to_value(&idev->qos);

        /* currently no public media definitions for IrDA */

        ndev->flags |= IFF_PORTSEL | IFF_AUTOMEDIA;
        ndev->if_port = IF_PORT_UNKNOWN;
 
        ndev->netdev_ops = &vlsi_netdev_ops;
        ndev->watchdog_timeo  = 500*HZ/1000;    /* max. allowed turn time for IrLAP */

        SET_NETDEV_DEV(ndev, &pdev->dev);

        return 0;
}       

/**************************************************************/

static int
vlsi_irda_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct net_device       *ndev;
        vlsi_irda_dev_t         *idev;

        if (pci_enable_device(pdev))
                goto out;
        else
                pdev->current_state = 0; /* hw must be running now */

        net_info_ratelimited("%s: IrDA PCI controller %s detected\n",
                             drivername, pci_name(pdev));

        if ( !pci_resource_start(pdev,0) ||
             !(pci_resource_flags(pdev,0) & IORESOURCE_IO) ) {
                net_err_ratelimited("%s: bar 0 invalid", __func__);
                goto out_disable;
        }

        ndev = alloc_irdadev(sizeof(*idev));
        if (ndev==NULL) {
                net_err_ratelimited("%s: Unable to allocate device memory.\n",
                                    __func__);
                goto out_disable;
        }

        idev = netdev_priv(ndev);

        spin_lock_init(&idev->lock);
        mutex_init(&idev->mtx);
        mutex_lock(&idev->mtx);
        idev->pdev = pdev;

        if (vlsi_irda_init(ndev) < 0)
                goto out_freedev;

        if (register_netdev(ndev) < 0) {
                net_err_ratelimited("%s: register_netdev failed\n", __func__);
                goto out_freedev;
        }

        if (vlsi_proc_root != NULL) {
                struct proc_dir_entry *ent;

                ent = proc_create_data(ndev->name, S_IFREG|S_IRUGO,
                                       vlsi_proc_root, VLSI_PROC_FOPS, ndev);
                if (!ent) {
                        net_warn_ratelimited("%s: failed to create proc entry\n",
                                             __func__);
                } else {
                        proc_set_size(ent, 0);
                }
                idev->proc_entry = ent;
        }
        net_info_ratelimited("%s: registered device %s\n",
                             drivername, ndev->name);

        pci_set_drvdata(pdev, ndev);
        mutex_unlock(&idev->mtx);

        return 0;

out_freedev:
        mutex_unlock(&idev->mtx);
        free_netdev(ndev);
out_disable:
        pci_disable_device(pdev);
out:
        return -ENODEV;
}

static void vlsi_irda_remove(struct pci_dev *pdev)
{
        struct net_device *ndev = pci_get_drvdata(pdev);
        vlsi_irda_dev_t *idev;

        if (!ndev) {
                net_err_ratelimited("%s: lost netdevice?\n", drivername);
                return;
        }

        unregister_netdev(ndev);

        idev = netdev_priv(ndev);
        mutex_lock(&idev->mtx);
        if (idev->proc_entry) {
                remove_proc_entry(ndev->name, vlsi_proc_root);
                idev->proc_entry = NULL;
        }
        mutex_unlock(&idev->mtx);

        free_netdev(ndev);

        net_info_ratelimited("%s: %s removed\n", drivername, pci_name(pdev));
}

#ifdef CONFIG_PM

/* The Controller doesn't provide PCI PM capabilities as defined by PCI specs.
 * Some of the Linux PCI-PM code however depends on this, for example in
 * pci_set_power_state(). So we have to take care to perform the required
 * operations on our own (particularly reflecting the pdev->current_state)
 * otherwise we might get cheated by pci-pm.
 */


static int vlsi_irda_suspend(struct pci_dev *pdev, pm_message_t state)
{
        struct net_device *ndev = pci_get_drvdata(pdev);
        vlsi_irda_dev_t *idev;

        if (!ndev) {
                net_err_ratelimited("%s - %s: no netdevice\n",
                                    __func__, pci_name(pdev));
                return 0;
        }
        idev = netdev_priv(ndev);
        mutex_lock(&idev->mtx);
        if (pdev->current_state != 0) {                 /* already suspended */
                if (state.event > pdev->current_state) {        /* simply go deeper */
                        pci_set_power_state(pdev, pci_choose_state(pdev, state));
                        pdev->current_state = state.event;
                }
                else
                        net_err_ratelimited("%s - %s: invalid suspend request %u -> %u\n",
                                            __func__, pci_name(pdev),
                                            pdev->current_state, state.event);
                mutex_unlock(&idev->mtx);
                return 0;
        }

        if (netif_running(ndev)) {
                netif_device_detach(ndev);
                vlsi_stop_hw(idev);
                pci_save_state(pdev);
                if (!idev->new_baud)
                        /* remember speed settings to restore on resume */
                        idev->new_baud = idev->baud;
        }

        pci_set_power_state(pdev, pci_choose_state(pdev, state));
        pdev->current_state = state.event;
        idev->resume_ok = 1;
        mutex_unlock(&idev->mtx);
        return 0;
}

static int vlsi_irda_resume(struct pci_dev *pdev)
{
        struct net_device *ndev = pci_get_drvdata(pdev);
        vlsi_irda_dev_t *idev;

        if (!ndev) {
                net_err_ratelimited("%s - %s: no netdevice\n",
                                    __func__, pci_name(pdev));
                return 0;
        }
        idev = netdev_priv(ndev);
        mutex_lock(&idev->mtx);
        if (pdev->current_state == 0) {
                mutex_unlock(&idev->mtx);
                net_warn_ratelimited("%s - %s: already resumed\n",
                                     __func__, pci_name(pdev));
                return 0;
        }
        
        pci_set_power_state(pdev, PCI_D0);
        pdev->current_state = PM_EVENT_ON;

        if (!idev->resume_ok) {
                /* should be obsolete now - but used to happen due to:
                 * - pci layer initially setting pdev->current_state = 4 (unknown)
                 * - pci layer did not walk the save_state-tree (might be APM problem)
                 *   so we could not refuse to suspend from undefined state
                 * - vlsi_irda_suspend detected invalid state and refused to save
                 *   configuration for resume - but was too late to stop suspending
                 * - vlsi_irda_resume got screwed when trying to resume from garbage
                 *
                 * now we explicitly set pdev->current_state = 0 after enabling the
                 * device and independently resume_ok should catch any garbage config.
                 */
                net_warn_ratelimited("%s - hm, nothing to resume?\n", __func__);
                mutex_unlock(&idev->mtx);
                return 0;
        }

        if (netif_running(ndev)) {
                pci_restore_state(pdev);
                vlsi_start_hw(idev);
                netif_device_attach(ndev);
        }
        idev->resume_ok = 0;
        mutex_unlock(&idev->mtx);
        return 0;
}

#endif /* CONFIG_PM */

/*********************************************************/

static struct pci_driver vlsi_irda_driver = {
        .name           = drivername,
        .id_table       = vlsi_irda_table,
        .probe          = vlsi_irda_probe,
        .remove         = vlsi_irda_remove,
#ifdef CONFIG_PM
        .suspend        = vlsi_irda_suspend,
        .resume         = vlsi_irda_resume,
#endif
};

#define PROC_DIR ("driver/" DRIVER_NAME)

static int __init vlsi_mod_init(void)
{
        int     i, ret;

        if (clksrc < 0  ||  clksrc > 3) {
                net_err_ratelimited("%s: invalid clksrc=%d\n",
                                    drivername, clksrc);
                return -1;
        }

        for (i = 0; i < 2; i++) {
                switch(ringsize[i]) {
                        case 4:
                        case 8:
                        case 16:
                        case 32:
                        case 64:
                                break;
                        default:
                                net_warn_ratelimited("%s: invalid %s ringsize %d, using default=8\n",
                                                     drivername,
                                                     i ? "rx" : "tx",
                                                     ringsize[i]);
                                ringsize[i] = 8;
                                break;
                }
        } 

        sirpulse = !!sirpulse;

        /* proc_mkdir returns NULL if !CONFIG_PROC_FS.
         * Failure to create the procfs entry is handled like running
         * without procfs - it's not required for the driver to work.
         */
        vlsi_proc_root = proc_mkdir(PROC_DIR, NULL);

        ret = pci_register_driver(&vlsi_irda_driver);

        if (ret && vlsi_proc_root)
                remove_proc_entry(PROC_DIR, NULL);
        return ret;

}

static void __exit vlsi_mod_exit(void)
{
        pci_unregister_driver(&vlsi_irda_driver);
        if (vlsi_proc_root)
                remove_proc_entry(PROC_DIR, NULL);
}

module_init(vlsi_mod_init);
module_exit(vlsi_mod_exit);