nosy.c

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/*
 * nosy - Snoop mode driver for TI PCILynx 1394 controllers
 * Copyright (C) 2002-2007 Kristian Høgsberg
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/sched.h> /* required for linux/wait.h */
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timex.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/dma-mapping.h>
#include <linux/atomic.h>
#include <asm/byteorder.h>

#include "nosy.h"
#include "nosy-user.h"

#define TCODE_PHY_PACKET        0x10
#define PCI_DEVICE_ID_TI_PCILYNX    0x8000

static char driver_name[] = KBUILD_MODNAME;

/* this is the physical layout of a PCL, its size is 128 bytes */
struct pcl {
    __le32 next;
    __le32 async_error_next;
    u32 user_data;
    __le32 pcl_status;
    __le32 remaining_transfer_count;
    __le32 next_data_buffer;
    struct {
        __le32 control;
        __le32 pointer;
    } buffer[13];
};

struct packet {
    unsigned int length;
    char data[0];
};

struct packet_buffer {
    char *data;
    size_t capacity;
    long total_packet_count, lost_packet_count;
    atomic_t size;
    struct packet *head, *tail;
    wait_queue_head_t wait;
};

struct pcilynx {
    struct pci_dev *pci_device;
    __iomem char *registers;

    struct pcl *rcv_start_pcl, *rcv_pcl;
    __le32 *rcv_buffer;

    dma_addr_t rcv_start_pcl_bus, rcv_pcl_bus, rcv_buffer_bus;

    spinlock_t client_list_lock;
    struct list_head client_list;

    struct miscdevice misc;
    struct list_head link;
    struct kref kref;
};

static inline struct pcilynx *
lynx_get(struct pcilynx *lynx)
{
    kref_get(&lynx->kref);

    return lynx;
}

static void
lynx_release(struct kref *kref)
{
    kfree(container_of(kref, struct pcilynx, kref));
}

static inline void
lynx_put(struct pcilynx *lynx)
{
    kref_put(&lynx->kref, lynx_release);
}

struct client {
    struct pcilynx *lynx;
    u32 tcode_mask;
    struct packet_buffer buffer;
    struct list_head link;
};

static DEFINE_MUTEX(card_mutex);
static LIST_HEAD(card_list);

static int
packet_buffer_init(struct packet_buffer *buffer, size_t capacity)
{
    buffer->data = kmalloc(capacity, GFP_KERNEL);
    if (buffer->data == NULL)
        return -ENOMEM;
    buffer->head = (struct packet *) buffer->data;
    buffer->tail = (struct packet *) buffer->data;
    buffer->capacity = capacity;
    buffer->lost_packet_count = 0;
    atomic_set(&buffer->size, 0);
    init_waitqueue_head(&buffer->wait);

    return 0;
}

static void
packet_buffer_destroy(struct packet_buffer *buffer)
{
    kfree(buffer->data);
}

static int
packet_buffer_get(struct client *client, char __user *data, size_t user_length)
{
    struct packet_buffer *buffer = &client->buffer;
    size_t length;
    char *end;

    if (wait_event_interruptible(buffer->wait,
                     atomic_read(&buffer->size) > 0) ||
                     list_empty(&client->lynx->link))
        return -ERESTARTSYS;

    if (atomic_read(&buffer->size) == 0)
        return -ENODEV;

    /* FIXME: Check length <= user_length. */

    end = buffer->data + buffer->capacity;
    length = buffer->head->length;

    if (&buffer->head->data[length] < end) {
        if (copy_to_user(data, buffer->head->data, length))
            return -EFAULT;
        buffer->head = (struct packet *) &buffer->head->data[length];
    } else {
        size_t split = end - buffer->head->data;

        if (copy_to_user(data, buffer->head->data, split))
            return -EFAULT;
        if (copy_to_user(data + split, buffer->data, length - split))
            return -EFAULT;
        buffer->head = (struct packet *) &buffer->data[length - split];
    }

    /*
     * Decrease buffer->size as the last thing, since this is what
     * keeps the interrupt from overwriting the packet we are
     * retrieving from the buffer.
     */
    atomic_sub(sizeof(struct packet) + length, &buffer->size);

    return length;
}

static void
packet_buffer_put(struct packet_buffer *buffer, void *data, size_t length)
{
    char *end;

    buffer->total_packet_count++;

    if (buffer->capacity <
        atomic_read(&buffer->size) + sizeof(struct packet) + length) {
        buffer->lost_packet_count++;
        return;
    }

    end = buffer->data + buffer->capacity;
    buffer->tail->length = length;

    if (&buffer->tail->data[length] < end) {
        memcpy(buffer->tail->data, data, length);
        buffer->tail = (struct packet *) &buffer->tail->data[length];
    } else {
        size_t split = end - buffer->tail->data;

        memcpy(buffer->tail->data, data, split);
        memcpy(buffer->data, data + split, length - split);
        buffer->tail = (struct packet *) &buffer->data[length - split];
    }

    /* Finally, adjust buffer size and wake up userspace reader. */

    atomic_add(sizeof(struct packet) + length, &buffer->size);
    wake_up_interruptible(&buffer->wait);
}

static inline void
reg_write(struct pcilynx *lynx, int offset, u32 data)
{
    writel(data, lynx->registers + offset);
}

static inline u32
reg_read(struct pcilynx *lynx, int offset)
{
    return readl(lynx->registers + offset);
}

static inline void
reg_set_bits(struct pcilynx *lynx, int offset, u32 mask)
{
    reg_write(lynx, offset, (reg_read(lynx, offset) | mask));
}

/*
 * Maybe the pcl programs could be set up to just append data instead
 * of using a whole packet.
 */
static inline void
run_pcl(struct pcilynx *lynx, dma_addr_t pcl_bus,
               int dmachan)
{
    reg_write(lynx, DMA0_CURRENT_PCL + dmachan * 0x20, pcl_bus);
    reg_write(lynx, DMA0_CHAN_CTRL + dmachan * 0x20,
          DMA_CHAN_CTRL_ENABLE | DMA_CHAN_CTRL_LINK);
}

static int
set_phy_reg(struct pcilynx *lynx, int addr, int val)
{
    if (addr > 15) {
        dev_err(&lynx->pci_device->dev,
            "PHY register address %d out of range\n", addr);
        return -1;
    }
    if (val > 0xff) {
        dev_err(&lynx->pci_device->dev,
            "PHY register value %d out of range\n", val);
        return -1;
    }
    reg_write(lynx, LINK_PHY, LINK_PHY_WRITE |
          LINK_PHY_ADDR(addr) | LINK_PHY_WDATA(val));

    return 0;
}

static int
nosy_open(struct inode *inode, struct file *file)
{
    int minor = iminor(inode);
    struct client *client;
    struct pcilynx *tmp, *lynx = NULL;

    mutex_lock(&card_mutex);
    list_for_each_entry(tmp, &card_list, link)
        if (tmp->misc.minor == minor) {
            lynx = lynx_get(tmp);
            break;
        }
    mutex_unlock(&card_mutex);
    if (lynx == NULL)
        return -ENODEV;

    client = kmalloc(sizeof *client, GFP_KERNEL);
    if (client == NULL)
        goto fail;

    client->tcode_mask = ~0;
    client->lynx = lynx;
    INIT_LIST_HEAD(&client->link);

    if (packet_buffer_init(&client->buffer, 128 * 1024) < 0)
        goto fail;

    file->private_data = client;

    return nonseekable_open(inode, file);
fail:
    kfree(client);
    lynx_put(lynx);

    return -ENOMEM;
}

static int
nosy_release(struct inode *inode, struct file *file)
{
    struct client *client = file->private_data;
    struct pcilynx *lynx = client->lynx;

    spin_lock_irq(&lynx->client_list_lock);
    list_del_init(&client->link);
    spin_unlock_irq(&lynx->client_list_lock);

    packet_buffer_destroy(&client->buffer);
    kfree(client);
    lynx_put(lynx);

    return 0;
}

static unsigned int
nosy_poll(struct file *file, poll_table *pt)
{
    struct client *client = file->private_data;
    unsigned int ret = 0;

    poll_wait(file, &client->buffer.wait, pt);

    if (atomic_read(&client->buffer.size) > 0)
        ret = POLLIN | POLLRDNORM;

    if (list_empty(&client->lynx->link))
        ret |= POLLHUP;

    return ret;
}

static ssize_t
nosy_read(struct file *file, char __user *buffer, size_t count, loff_t *offset)
{
    struct client *client = file->private_data;

    return packet_buffer_get(client, buffer, count);
}

static long
nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    struct client *client = file->private_data;
    spinlock_t *client_list_lock = &client->lynx->client_list_lock;
    struct nosy_stats stats;

    switch (cmd) {
    case NOSY_IOC_GET_STATS:
        spin_lock_irq(client_list_lock);
        stats.total_packet_count = client->buffer.total_packet_count;
        stats.lost_packet_count  = client->buffer.lost_packet_count;
        spin_unlock_irq(client_list_lock);

        if (copy_to_user((void __user *) arg, &stats, sizeof stats))
            return -EFAULT;
        else
            return 0;

    case NOSY_IOC_START:
        spin_lock_irq(client_list_lock);
        list_add_tail(&client->link, &client->lynx->client_list);
        spin_unlock_irq(client_list_lock);

        return 0;

    case NOSY_IOC_STOP:
        spin_lock_irq(client_list_lock);
        list_del_init(&client->link);
        spin_unlock_irq(client_list_lock);

        return 0;

    case NOSY_IOC_FILTER:
        spin_lock_irq(client_list_lock);
        client->tcode_mask = arg;
        spin_unlock_irq(client_list_lock);

        return 0;

    default:
        return -EINVAL;
        /* Flush buffer, configure filter. */
    }
}

static const struct file_operations nosy_ops = {
    .owner =        THIS_MODULE,
    .read =         nosy_read,
    .unlocked_ioctl =   nosy_ioctl,
    .poll =         nosy_poll,
    .open =         nosy_open,
    .release =      nosy_release,
};

#define PHY_PACKET_SIZE 12 /* 1 payload, 1 inverse, 1 ack = 3 quadlets */

static void
packet_irq_handler(struct pcilynx *lynx)
{
    struct client *client;
    u32 tcode_mask, tcode;
    size_t length;
    struct timeval tv;

    /* FIXME: Also report rcv_speed. */

    length = __le32_to_cpu(lynx->rcv_pcl->pcl_status) & 0x00001fff;
    tcode  = __le32_to_cpu(lynx->rcv_buffer[1]) >> 4 & 0xf;

    do_gettimeofday(&tv);
    lynx->rcv_buffer[0] = (__force __le32)tv.tv_usec;

    if (length == PHY_PACKET_SIZE)
        tcode_mask = 1 << TCODE_PHY_PACKET;
    else
        tcode_mask = 1 << tcode;

    spin_lock(&lynx->client_list_lock);

    list_for_each_entry(client, &lynx->client_list, link)
        if (client->tcode_mask & tcode_mask)
            packet_buffer_put(&client->buffer,
                      lynx->rcv_buffer, length + 4);

    spin_unlock(&lynx->client_list_lock);
}

static void
bus_reset_irq_handler(struct pcilynx *lynx)
{
    struct client *client;
    struct timeval tv;

    do_gettimeofday(&tv);

    spin_lock(&lynx->client_list_lock);

    list_for_each_entry(client, &lynx->client_list, link)
        packet_buffer_put(&client->buffer, &tv.tv_usec, 4);

    spin_unlock(&lynx->client_list_lock);
}

static irqreturn_t
irq_handler(int irq, void *device)
{
    struct pcilynx *lynx = device;
    u32 pci_int_status;

    pci_int_status = reg_read(lynx, PCI_INT_STATUS);

    if (pci_int_status == ~0)
        /* Card was ejected. */
        return IRQ_NONE;

    if ((pci_int_status & PCI_INT_INT_PEND) == 0)
        /* Not our interrupt, bail out quickly. */
        return IRQ_NONE;

    if ((pci_int_status & PCI_INT_P1394_INT) != 0) {
        u32 link_int_status;

        link_int_status = reg_read(lynx, LINK_INT_STATUS);
        reg_write(lynx, LINK_INT_STATUS, link_int_status);

        if ((link_int_status & LINK_INT_PHY_BUSRESET) > 0)
            bus_reset_irq_handler(lynx);
    }

    /* Clear the PCI_INT_STATUS register only after clearing the
     * LINK_INT_STATUS register; otherwise the PCI_INT_P1394 will
     * be set again immediately. */

    reg_write(lynx, PCI_INT_STATUS, pci_int_status);

    if ((pci_int_status & PCI_INT_DMA0_HLT) > 0) {
        packet_irq_handler(lynx);
        run_pcl(lynx, lynx->rcv_start_pcl_bus, 0);
    }

    return IRQ_HANDLED;
}

static void
remove_card(struct pci_dev *dev)
{
    struct pcilynx *lynx = pci_get_drvdata(dev);
    struct client *client;

    mutex_lock(&card_mutex);
    list_del_init(&lynx->link);
    misc_deregister(&lynx->misc);
    mutex_unlock(&card_mutex);

    reg_write(lynx, PCI_INT_ENABLE, 0);
    free_irq(lynx->pci_device->irq, lynx);

    spin_lock_irq(&lynx->client_list_lock);
    list_for_each_entry(client, &lynx->client_list, link)
        wake_up_interruptible(&client->buffer.wait);
    spin_unlock_irq(&lynx->client_list_lock);

    pci_free_consistent(lynx->pci_device, sizeof(struct pcl),
                lynx->rcv_start_pcl, lynx->rcv_start_pcl_bus);
    pci_free_consistent(lynx->pci_device, sizeof(struct pcl),
                lynx->rcv_pcl, lynx->rcv_pcl_bus);
    pci_free_consistent(lynx->pci_device, PAGE_SIZE,
                lynx->rcv_buffer, lynx->rcv_buffer_bus);

    iounmap(lynx->registers);
    pci_disable_device(dev);
    lynx_put(lynx);
}

#define RCV_BUFFER_SIZE (16 * 1024)

static int __devinit
add_card(struct pci_dev *dev, const struct pci_device_id *unused)
{
    struct pcilynx *lynx;
    u32 p, end;
    int ret, i;

    if (pci_set_dma_mask(dev, DMA_BIT_MASK(32))) {
        dev_err(&dev->dev,
            "DMA address limits not supported for PCILynx hardware\n");
        return -ENXIO;
    }
    if (pci_enable_device(dev)) {
        dev_err(&dev->dev, "Failed to enable PCILynx hardware\n");
        return -ENXIO;
    }
    pci_set_master(dev);

    lynx = kzalloc(sizeof *lynx, GFP_KERNEL);
    if (lynx == NULL) {
        dev_err(&dev->dev, "Failed to allocate control structure\n");
        ret = -ENOMEM;
        goto fail_disable;
    }
    lynx->pci_device = dev;
    pci_set_drvdata(dev, lynx);

    spin_lock_init(&lynx->client_list_lock);
    INIT_LIST_HEAD(&lynx->client_list);
    kref_init(&lynx->kref);

    lynx->registers = ioremap_nocache(pci_resource_start(dev, 0),
                      PCILYNX_MAX_REGISTER);

    lynx->rcv_start_pcl = pci_alloc_consistent(lynx->pci_device,
                sizeof(struct pcl), &lynx->rcv_start_pcl_bus);
    lynx->rcv_pcl = pci_alloc_consistent(lynx->pci_device,
                sizeof(struct pcl), &lynx->rcv_pcl_bus);
    lynx->rcv_buffer = pci_alloc_consistent(lynx->pci_device,
                RCV_BUFFER_SIZE, &lynx->rcv_buffer_bus);
    if (lynx->rcv_start_pcl == NULL ||
        lynx->rcv_pcl == NULL ||
        lynx->rcv_buffer == NULL) {
        dev_err(&dev->dev, "Failed to allocate receive buffer\n");
        ret = -ENOMEM;
        goto fail_deallocate;
    }
    lynx->rcv_start_pcl->next   = cpu_to_le32(lynx->rcv_pcl_bus);
    lynx->rcv_pcl->next     = cpu_to_le32(PCL_NEXT_INVALID);
    lynx->rcv_pcl->async_error_next = cpu_to_le32(PCL_NEXT_INVALID);

    lynx->rcv_pcl->buffer[0].control =
            cpu_to_le32(PCL_CMD_RCV | PCL_BIGENDIAN | 2044);
    lynx->rcv_pcl->buffer[0].pointer =
            cpu_to_le32(lynx->rcv_buffer_bus + 4);
    p = lynx->rcv_buffer_bus + 2048;
    end = lynx->rcv_buffer_bus + RCV_BUFFER_SIZE;
    for (i = 1; p < end; i++, p += 2048) {
        lynx->rcv_pcl->buffer[i].control =
            cpu_to_le32(PCL_CMD_RCV | PCL_BIGENDIAN | 2048);
        lynx->rcv_pcl->buffer[i].pointer = cpu_to_le32(p);
    }
    lynx->rcv_pcl->buffer[i - 1].control |= cpu_to_le32(PCL_LAST_BUFF);

    reg_set_bits(lynx, MISC_CONTROL, MISC_CONTROL_SWRESET);
    /* Fix buggy cards with autoboot pin not tied low: */
    reg_write(lynx, DMA0_CHAN_CTRL, 0);
    reg_write(lynx, DMA_GLOBAL_REGISTER, 0x00 << 24);

#if 0
    /* now, looking for PHY register set */
    if ((get_phy_reg(lynx, 2) & 0xe0) == 0xe0) {
        lynx->phyic.reg_1394a = 1;
        PRINT(KERN_INFO, lynx->id,
              "found 1394a conform PHY (using extended register set)");
        lynx->phyic.vendor = get_phy_vendorid(lynx);
        lynx->phyic.product = get_phy_productid(lynx);
    } else {
        lynx->phyic.reg_1394a = 0;
        PRINT(KERN_INFO, lynx->id, "found old 1394 PHY");
    }
#endif

    /* Setup the general receive FIFO max size. */
    reg_write(lynx, FIFO_SIZES, 255);

    reg_set_bits(lynx, PCI_INT_ENABLE, PCI_INT_DMA_ALL);

    reg_write(lynx, LINK_INT_ENABLE,
          LINK_INT_PHY_TIME_OUT | LINK_INT_PHY_REG_RCVD |
          LINK_INT_PHY_BUSRESET | LINK_INT_IT_STUCK |
          LINK_INT_AT_STUCK | LINK_INT_SNTRJ |
          LINK_INT_TC_ERR | LINK_INT_GRF_OVER_FLOW |
          LINK_INT_ITF_UNDER_FLOW | LINK_INT_ATF_UNDER_FLOW);

    /* Disable the L flag in self ID packets. */
    set_phy_reg(lynx, 4, 0);

    /* Put this baby into snoop mode */
    reg_set_bits(lynx, LINK_CONTROL, LINK_CONTROL_SNOOP_ENABLE);

    run_pcl(lynx, lynx->rcv_start_pcl_bus, 0);

    if (request_irq(dev->irq, irq_handler, IRQF_SHARED,
            driver_name, lynx)) {
        dev_err(&dev->dev,
            "Failed to allocate shared interrupt %d\n", dev->irq);
        ret = -EIO;
        goto fail_deallocate;
    }

    lynx->misc.parent = &dev->dev;
    lynx->misc.minor = MISC_DYNAMIC_MINOR;
    lynx->misc.name = "nosy";
    lynx->misc.fops = &nosy_ops;

    mutex_lock(&card_mutex);
    ret = misc_register(&lynx->misc);
    if (ret) {
        dev_err(&dev->dev, "Failed to register misc char device\n");
        mutex_unlock(&card_mutex);
        goto fail_free_irq;
    }
    list_add_tail(&lynx->link, &card_list);
    mutex_unlock(&card_mutex);

    dev_info(&dev->dev,
         "Initialized PCILynx IEEE1394 card, irq=%d\n", dev->irq);

    return 0;

fail_free_irq:
    reg_write(lynx, PCI_INT_ENABLE, 0);
    free_irq(lynx->pci_device->irq, lynx);

fail_deallocate:
    if (lynx->rcv_start_pcl)
        pci_free_consistent(lynx->pci_device, sizeof(struct pcl),
                lynx->rcv_start_pcl, lynx->rcv_start_pcl_bus);
    if (lynx->rcv_pcl)
        pci_free_consistent(lynx->pci_device, sizeof(struct pcl),
                lynx->rcv_pcl, lynx->rcv_pcl_bus);
    if (lynx->rcv_buffer)
        pci_free_consistent(lynx->pci_device, PAGE_SIZE,
                lynx->rcv_buffer, lynx->rcv_buffer_bus);
    iounmap(lynx->registers);
    kfree(lynx);

fail_disable:
    pci_disable_device(dev);

    return ret;
}

static struct pci_device_id pci_table[] __devinitdata = {
    {
        .vendor =    PCI_VENDOR_ID_TI,
        .device =    PCI_DEVICE_ID_TI_PCILYNX,
        .subvendor = PCI_ANY_ID,
        .subdevice = PCI_ANY_ID,
    },
    { } /* Terminating entry */
};

MODULE_DEVICE_TABLE(pci, pci_table);

static struct pci_driver lynx_pci_driver = {
    .name =     driver_name,
    .id_table = pci_table,
    .probe =    add_card,
    .remove =   remove_card,
};

module_pci_driver(lynx_pci_driver);

MODULE_AUTHOR("Kristian Hoegsberg");
MODULE_DESCRIPTION("Snoop mode driver for TI pcilynx 1394 controllers");
MODULE_LICENSE("GPL");