drivers.c

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/*
    module/drivers.c
    functions for manipulating drivers

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1997-2000 David A. Schleef <[email protected]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#define _GNU_SOURCE

#define __NO_VERSION__
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/usb.h>
#include <linux/errno.h>
#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/highmem.h>  /* for SuSE brokenness */
#include <linux/vmalloc.h>
#include <linux/cdev.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>

#include "comedidev.h"
#include "comedi_internal.h"

static int postconfig(struct comedi_device *dev);
static int insn_rw_emulate_bits(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data);
static void *comedi_recognize(struct comedi_driver *driv, const char *name);
static void comedi_report_boards(struct comedi_driver *driv);
static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s);

struct comedi_driver *comedi_drivers;

int comedi_alloc_subdevices(struct comedi_device *dev, int num_subdevices)
{
    struct comedi_subdevice *s;
    int i;

    if (num_subdevices < 1)
        return -EINVAL;

    s = kcalloc(num_subdevices, sizeof(*s), GFP_KERNEL);
    if (!s)
        return -ENOMEM;
    dev->subdevices = s;
    dev->n_subdevices = num_subdevices;

    for (i = 0; i < num_subdevices; ++i) {
        s = &dev->subdevices[i];
        s->device = dev;
        s->async_dma_dir = DMA_NONE;
        spin_lock_init(&s->spin_lock);
        s->minor = -1;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(comedi_alloc_subdevices);

static void cleanup_device(struct comedi_device *dev)
{
    int i;
    struct comedi_subdevice *s;

    if (dev->subdevices) {
        for (i = 0; i < dev->n_subdevices; i++) {
            s = &dev->subdevices[i];
            comedi_free_subdevice_minor(s);
            if (s->async) {
                comedi_buf_alloc(dev, s, 0);
                kfree(s->async);
            }
        }
        kfree(dev->subdevices);
        dev->subdevices = NULL;
        dev->n_subdevices = 0;
    }
    kfree(dev->private);
    dev->private = NULL;
    dev->driver = NULL;
    dev->board_name = NULL;
    dev->board_ptr = NULL;
    dev->iobase = 0;
    dev->irq = 0;
    dev->read_subdev = NULL;
    dev->write_subdev = NULL;
    dev->open = NULL;
    dev->close = NULL;
    comedi_set_hw_dev(dev, NULL);
}

static void __comedi_device_detach(struct comedi_device *dev)
{
    dev->attached = 0;
    if (dev->driver)
        dev->driver->detach(dev);
    else
        dev_warn(dev->class_dev,
             "BUG: dev->driver=NULL in comedi_device_detach()\n");
    cleanup_device(dev);
}

void comedi_device_detach(struct comedi_device *dev)
{
    if (!dev->attached)
        return;
    __comedi_device_detach(dev);
}

/* do a little post-config cleanup */
/* called with module refcount incremented, decrements it */
static int comedi_device_postconfig(struct comedi_device *dev)
{
    int ret = postconfig(dev);
    module_put(dev->driver->module);
    if (ret < 0) {
        __comedi_device_detach(dev);
        return ret;
    }
    if (!dev->board_name) {
        dev_warn(dev->class_dev, "BUG: dev->board_name=NULL\n");
        dev->board_name = "BUG";
    }
    smp_wmb();
    dev->attached = 1;
    return 0;
}

int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
    struct comedi_driver *driv;
    int ret;

    if (dev->attached)
        return -EBUSY;

    for (driv = comedi_drivers; driv; driv = driv->next) {
        if (!try_module_get(driv->module))
            continue;
        if (driv->num_names) {
            dev->board_ptr = comedi_recognize(driv, it->board_name);
            if (dev->board_ptr)
                break;
        } else if (strcmp(driv->driver_name, it->board_name) == 0)
            break;
        module_put(driv->module);
    }
    if (driv == NULL) {
        /*  recognize has failed if we get here */
        /*  report valid board names before returning error */
        for (driv = comedi_drivers; driv; driv = driv->next) {
            if (!try_module_get(driv->module))
                continue;
            comedi_report_boards(driv);
            module_put(driv->module);
        }
        return -EIO;
    }
    if (driv->attach == NULL) {
        /* driver does not support manual configuration */
        dev_warn(dev->class_dev,
             "driver '%s' does not support attach using comedi_config\n",
             driv->driver_name);
        module_put(driv->module);
        return -ENOSYS;
    }
    /* initialize dev->driver here so
     * comedi_error() can be called from attach */
    dev->driver = driv;
    ret = driv->attach(dev, it);
    if (ret < 0) {
        module_put(dev->driver->module);
        __comedi_device_detach(dev);
        return ret;
    }
    return comedi_device_postconfig(dev);
}

int comedi_driver_register(struct comedi_driver *driver)
{
    driver->next = comedi_drivers;
    comedi_drivers = driver;

    return 0;
}
EXPORT_SYMBOL(comedi_driver_register);

int comedi_driver_unregister(struct comedi_driver *driver)
{
    struct comedi_driver *prev;
    int i;

    /* check for devices using this driver */
    for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) {
        struct comedi_device_file_info *dev_file_info =
            comedi_get_device_file_info(i);
        struct comedi_device *dev;

        if (dev_file_info == NULL)
            continue;
        dev = dev_file_info->device;

        mutex_lock(&dev->mutex);
        if (dev->attached && dev->driver == driver) {
            if (dev->use_count)
                dev_warn(dev->class_dev,
                     "BUG! detaching device with use_count=%d\n",
                     dev->use_count);
            comedi_device_detach(dev);
        }
        mutex_unlock(&dev->mutex);
    }

    if (comedi_drivers == driver) {
        comedi_drivers = driver->next;
        return 0;
    }

    for (prev = comedi_drivers; prev->next; prev = prev->next) {
        if (prev->next == driver) {
            prev->next = driver->next;
            return 0;
        }
    }
    return -EINVAL;
}
EXPORT_SYMBOL(comedi_driver_unregister);

static int postconfig(struct comedi_device *dev)
{
    int i;
    struct comedi_subdevice *s;
    struct comedi_async *async = NULL;
    int ret;

    for (i = 0; i < dev->n_subdevices; i++) {
        s = &dev->subdevices[i];

        if (s->type == COMEDI_SUBD_UNUSED)
            continue;

        if (s->len_chanlist == 0)
            s->len_chanlist = 1;

        if (s->do_cmd) {
            unsigned int buf_size;

            BUG_ON((s->subdev_flags & (SDF_CMD_READ |
                           SDF_CMD_WRITE)) == 0);
            BUG_ON(!s->do_cmdtest);

            async =
                kzalloc(sizeof(struct comedi_async), GFP_KERNEL);
            if (async == NULL) {
                dev_warn(dev->class_dev,
                     "failed to allocate async struct\n");
                return -ENOMEM;
            }
            init_waitqueue_head(&async->wait_head);
            async->subdevice = s;
            s->async = async;

            async->max_bufsize =
                comedi_default_buf_maxsize_kb * 1024;
            buf_size = comedi_default_buf_size_kb * 1024;
            if (buf_size > async->max_bufsize)
                buf_size = async->max_bufsize;

            async->prealloc_buf = NULL;
            async->prealloc_bufsz = 0;
            if (comedi_buf_alloc(dev, s, buf_size) < 0) {
                dev_warn(dev->class_dev,
                     "Buffer allocation failed\n");
                return -ENOMEM;
            }
            if (s->buf_change) {
                ret = s->buf_change(dev, s, buf_size);
                if (ret < 0)
                    return ret;
            }
            comedi_alloc_subdevice_minor(dev, s);
        }

        if (!s->range_table && !s->range_table_list)
            s->range_table = &range_unknown;

        if (!s->insn_read && s->insn_bits)
            s->insn_read = insn_rw_emulate_bits;
        if (!s->insn_write && s->insn_bits)
            s->insn_write = insn_rw_emulate_bits;

        if (!s->insn_read)
            s->insn_read = insn_inval;
        if (!s->insn_write)
            s->insn_write = insn_inval;
        if (!s->insn_bits)
            s->insn_bits = insn_inval;
        if (!s->insn_config)
            s->insn_config = insn_inval;

        if (!s->poll)
            s->poll = poll_invalid;
    }

    return 0;
}

/*
 * Generic recognize function for drivers that register their supported
 * board names.
 *
 * 'driv->board_name' points to a 'const char *' member within the
 * zeroth element of an array of some private board information
 * structure, say 'struct foo_board' containing a member 'const char
 * *board_name' that is initialized to point to a board name string that
 * is one of the candidates matched against this function's 'name'
 * parameter.
 *
 * 'driv->offset' is the size of the private board information
 * structure, say 'sizeof(struct foo_board)', and 'driv->num_names' is
 * the length of the array of private board information structures.
 *
 * If one of the board names in the array of private board information
 * structures matches the name supplied to this function, the function
 * returns a pointer to the pointer to the board name, otherwise it
 * returns NULL.  The return value ends up in the 'board_ptr' member of
 * a 'struct comedi_device' that the low-level comedi driver's
 * 'attach()' hook can convert to a point to a particular element of its
 * array of private board information structures by subtracting the
 * offset of the member that points to the board name.  (No subtraction
 * is required if the board name pointer is the first member of the
 * private board information structure, which is generally the case.)
 */
static void *comedi_recognize(struct comedi_driver *driv, const char *name)
{
    char **name_ptr = (char **)driv->board_name;
    int i;

    for (i = 0; i < driv->num_names; i++) {
        if (strcmp(*name_ptr, name) == 0)
            return name_ptr;
        name_ptr = (void *)name_ptr + driv->offset;
    }

    return NULL;
}

static void comedi_report_boards(struct comedi_driver *driv)
{
    unsigned int i;
    const char *const *name_ptr;

    pr_info("comedi: valid board names for %s driver are:\n",
        driv->driver_name);

    name_ptr = driv->board_name;
    for (i = 0; i < driv->num_names; i++) {
        pr_info(" %s\n", *name_ptr);
        name_ptr = (const char **)((char *)name_ptr + driv->offset);
    }

    if (driv->num_names == 0)
        pr_info(" %s\n", driv->driver_name);
}

static int poll_invalid(struct comedi_device *dev, struct comedi_subdevice *s)
{
    return -EINVAL;
}

int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s,
           struct comedi_insn *insn, unsigned int *data)
{
    return -EINVAL;
}

static int insn_rw_emulate_bits(struct comedi_device *dev,
                struct comedi_subdevice *s,
                struct comedi_insn *insn, unsigned int *data)
{
    struct comedi_insn new_insn;
    int ret;
    static const unsigned channels_per_bitfield = 32;

    unsigned chan = CR_CHAN(insn->chanspec);
    const unsigned base_bitfield_channel =
        (chan < channels_per_bitfield) ? 0 : chan;
    unsigned int new_data[2];
    memset(new_data, 0, sizeof(new_data));
    memset(&new_insn, 0, sizeof(new_insn));
    new_insn.insn = INSN_BITS;
    new_insn.chanspec = base_bitfield_channel;
    new_insn.n = 2;
    new_insn.subdev = insn->subdev;

    if (insn->insn == INSN_WRITE) {
        if (!(s->subdev_flags & SDF_WRITABLE))
            return -EINVAL;
        new_data[0] = 1 << (chan - base_bitfield_channel); /* mask */
        new_data[1] = data[0] ? (1 << (chan - base_bitfield_channel))
                  : 0; /* bits */
    }

    ret = s->insn_bits(dev, s, &new_insn, new_data);
    if (ret < 0)
        return ret;

    if (insn->insn == INSN_READ)
        data[0] = (new_data[1] >> (chan - base_bitfield_channel)) & 1;

    return 1;
}

int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
             unsigned long new_size)
{
    struct comedi_async *async = s->async;

    /* Round up new_size to multiple of PAGE_SIZE */
    new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;

    /* if no change is required, do nothing */
    if (async->prealloc_buf && async->prealloc_bufsz == new_size)
        return 0;

    /*  deallocate old buffer */
    if (async->prealloc_buf) {
        vunmap(async->prealloc_buf);
        async->prealloc_buf = NULL;
        async->prealloc_bufsz = 0;
    }
    if (async->buf_page_list) {
        unsigned i;
        for (i = 0; i < async->n_buf_pages; ++i) {
            if (async->buf_page_list[i].virt_addr) {
                clear_bit(PG_reserved,
                    &(virt_to_page(async->buf_page_list[i].
                            virt_addr)->flags));
                if (s->async_dma_dir != DMA_NONE) {
                    dma_free_coherent(dev->hw_dev,
                              PAGE_SIZE,
                              async->
                              buf_page_list
                              [i].virt_addr,
                              async->
                              buf_page_list
                              [i].dma_addr);
                } else {
                    free_page((unsigned long)
                          async->buf_page_list[i].
                          virt_addr);
                }
            }
        }
        vfree(async->buf_page_list);
        async->buf_page_list = NULL;
        async->n_buf_pages = 0;
    }
    /*  allocate new buffer */
    if (new_size) {
        unsigned i = 0;
        unsigned n_pages = new_size >> PAGE_SHIFT;
        struct page **pages = NULL;

        async->buf_page_list =
            vzalloc(sizeof(struct comedi_buf_page) * n_pages);
        if (async->buf_page_list)
            pages = vmalloc(sizeof(struct page *) * n_pages);

        if (pages) {
            for (i = 0; i < n_pages; i++) {
                if (s->async_dma_dir != DMA_NONE) {
                    async->buf_page_list[i].virt_addr =
                        dma_alloc_coherent(dev->hw_dev,
                                   PAGE_SIZE,
                                   &async->
                                   buf_page_list
                                   [i].dma_addr,
                                   GFP_KERNEL |
                                   __GFP_COMP);
                } else {
                    async->buf_page_list[i].virt_addr =
                        (void *)
                        get_zeroed_page(GFP_KERNEL);
                }
                if (async->buf_page_list[i].virt_addr == NULL)
                    break;

                set_bit(PG_reserved,
                    &(virt_to_page(async->buf_page_list[i].
                            virt_addr)->flags));
                pages[i] = virt_to_page(async->buf_page_list[i].
                                virt_addr);
            }
        }
        if (i == n_pages) {
            async->prealloc_buf =
#ifdef PAGE_KERNEL_NOCACHE
                vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);
#else
                vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
#endif
        }
        vfree(pages);

        if (async->prealloc_buf == NULL) {
            /* Some allocation failed above. */
            if (async->buf_page_list) {
                for (i = 0; i < n_pages; i++) {
                    if (async->buf_page_list[i].virt_addr ==
                        NULL) {
                        break;
                    }
                    clear_bit(PG_reserved,
                        &(virt_to_page(async->
                            buf_page_list[i].
                            virt_addr)->flags));
                    if (s->async_dma_dir != DMA_NONE) {
                        dma_free_coherent(dev->hw_dev,
                                  PAGE_SIZE,
                                  async->
                                  buf_page_list
                                  [i].virt_addr,
                                  async->
                                  buf_page_list
                                  [i].dma_addr);
                    } else {
                        free_page((unsigned long)
                              async->buf_page_list
                              [i].virt_addr);
                    }
                }
                vfree(async->buf_page_list);
                async->buf_page_list = NULL;
            }
            return -ENOMEM;
        }
        async->n_buf_pages = n_pages;
    }
    async->prealloc_bufsz = new_size;

    return 0;
}

/* munging is applied to data by core as it passes between user
 * and kernel space */
static unsigned int comedi_buf_munge(struct comedi_async *async,
                     unsigned int num_bytes)
{
    struct comedi_subdevice *s = async->subdevice;
    unsigned int count = 0;
    const unsigned num_sample_bytes = bytes_per_sample(s);

    if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) {
        async->munge_count += num_bytes;
        BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
        return num_bytes;
    }
    /* don't munge partial samples */
    num_bytes -= num_bytes % num_sample_bytes;
    while (count < num_bytes) {
        int block_size;

        block_size = num_bytes - count;
        if (block_size < 0) {
            dev_warn(s->device->class_dev,
                 "%s: %s: bug! block_size is negative\n",
                 __FILE__, __func__);
            break;
        }
        if ((int)(async->munge_ptr + block_size -
              async->prealloc_bufsz) > 0)
            block_size = async->prealloc_bufsz - async->munge_ptr;

        s->munge(s->device, s, async->prealloc_buf + async->munge_ptr,
             block_size, async->munge_chan);

        smp_wmb();  /* barrier insures data is munged in buffer
                 * before munge_count is incremented */

        async->munge_chan += block_size / num_sample_bytes;
        async->munge_chan %= async->cmd.chanlist_len;
        async->munge_count += block_size;
        async->munge_ptr += block_size;
        async->munge_ptr %= async->prealloc_bufsz;
        count += block_size;
    }
    BUG_ON((int)(async->munge_count - async->buf_write_count) > 0);
    return count;
}

unsigned int comedi_buf_write_n_available(struct comedi_async *async)
{
    unsigned int free_end;
    unsigned int nbytes;

    if (async == NULL)
        return 0;

    free_end = async->buf_read_count + async->prealloc_bufsz;
    nbytes = free_end - async->buf_write_alloc_count;
    nbytes -= nbytes % bytes_per_sample(async->subdevice);
    /* barrier insures the read of buf_read_count in this
       query occurs before any following writes to the buffer which
       might be based on the return value from this query.
     */
    smp_mb();
    return nbytes;
}

/* allocates chunk for the writer from free buffer space */
unsigned int comedi_buf_write_alloc(struct comedi_async *async,
                    unsigned int nbytes)
{
    unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;

    if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
        nbytes = free_end - async->buf_write_alloc_count;

    async->buf_write_alloc_count += nbytes;
    /* barrier insures the read of buf_read_count above occurs before
       we write data to the write-alloc'ed buffer space */
    smp_mb();
    return nbytes;
}
EXPORT_SYMBOL(comedi_buf_write_alloc);

/* allocates nothing unless it can completely fulfill the request */
unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async,
                       unsigned int nbytes)
{
    unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;

    if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0)
        nbytes = 0;

    async->buf_write_alloc_count += nbytes;
    /* barrier insures the read of buf_read_count above occurs before
       we write data to the write-alloc'ed buffer space */
    smp_mb();
    return nbytes;
}

/* transfers a chunk from writer to filled buffer space */
unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes)
{
    if ((int)(async->buf_write_count + nbytes -
          async->buf_write_alloc_count) > 0) {
        dev_info(async->subdevice->device->class_dev,
             "attempted to write-free more bytes than have been write-allocated.\n");
        nbytes = async->buf_write_alloc_count - async->buf_write_count;
    }
    async->buf_write_count += nbytes;
    async->buf_write_ptr += nbytes;
    comedi_buf_munge(async, async->buf_write_count - async->munge_count);
    if (async->buf_write_ptr >= async->prealloc_bufsz)
        async->buf_write_ptr %= async->prealloc_bufsz;

    return nbytes;
}
EXPORT_SYMBOL(comedi_buf_write_free);

/* allocates a chunk for the reader from filled (and munged) buffer space */
unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes)
{
    if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) >
        0) {
        nbytes = async->munge_count - async->buf_read_alloc_count;
    }
    async->buf_read_alloc_count += nbytes;
    /* barrier insures read of munge_count occurs before we actually read
       data out of buffer */
    smp_rmb();
    return nbytes;
}
EXPORT_SYMBOL(comedi_buf_read_alloc);

/* transfers control of a chunk from reader to free buffer space */
unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes)
{
    /* barrier insures data has been read out of
     * buffer before read count is incremented */
    smp_mb();
    if ((int)(async->buf_read_count + nbytes -
          async->buf_read_alloc_count) > 0) {
        dev_info(async->subdevice->device->class_dev,
             "attempted to read-free more bytes than have been read-allocated.\n");
        nbytes = async->buf_read_alloc_count - async->buf_read_count;
    }
    async->buf_read_count += nbytes;
    async->buf_read_ptr += nbytes;
    async->buf_read_ptr %= async->prealloc_bufsz;
    return nbytes;
}
EXPORT_SYMBOL(comedi_buf_read_free);

void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset,
              const void *data, unsigned int num_bytes)
{
    unsigned int write_ptr = async->buf_write_ptr + offset;

    if (write_ptr >= async->prealloc_bufsz)
        write_ptr %= async->prealloc_bufsz;

    while (num_bytes) {
        unsigned int block_size;

        if (write_ptr + num_bytes > async->prealloc_bufsz)
            block_size = async->prealloc_bufsz - write_ptr;
        else
            block_size = num_bytes;

        memcpy(async->prealloc_buf + write_ptr, data, block_size);

        data += block_size;
        num_bytes -= block_size;

        write_ptr = 0;
    }
}
EXPORT_SYMBOL(comedi_buf_memcpy_to);

void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset,
                void *dest, unsigned int nbytes)
{
    void *src;
    unsigned int read_ptr = async->buf_read_ptr + offset;

    if (read_ptr >= async->prealloc_bufsz)
        read_ptr %= async->prealloc_bufsz;

    while (nbytes) {
        unsigned int block_size;

        src = async->prealloc_buf + read_ptr;

        if (nbytes >= async->prealloc_bufsz - read_ptr)
            block_size = async->prealloc_bufsz - read_ptr;
        else
            block_size = nbytes;

        memcpy(dest, src, block_size);
        nbytes -= block_size;
        dest += block_size;
        read_ptr = 0;
    }
}
EXPORT_SYMBOL(comedi_buf_memcpy_from);

unsigned int comedi_buf_read_n_available(struct comedi_async *async)
{
    unsigned num_bytes;

    if (async == NULL)
        return 0;
    num_bytes = async->munge_count - async->buf_read_count;
    /* barrier insures the read of munge_count in this
       query occurs before any following reads of the buffer which
       might be based on the return value from this query.
     */
    smp_rmb();
    return num_bytes;
}
EXPORT_SYMBOL(comedi_buf_read_n_available);

int comedi_buf_get(struct comedi_async *async, short *x)
{
    unsigned int n = comedi_buf_read_n_available(async);

    if (n < sizeof(short))
        return 0;
    comedi_buf_read_alloc(async, sizeof(short));
    *x = *(short *)(async->prealloc_buf + async->buf_read_ptr);
    comedi_buf_read_free(async, sizeof(short));
    return 1;
}
EXPORT_SYMBOL(comedi_buf_get);

int comedi_buf_put(struct comedi_async *async, short x)
{
    unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short));

    if (n < sizeof(short)) {
        async->events |= COMEDI_CB_ERROR;
        return 0;
    }
    *(short *)(async->prealloc_buf + async->buf_write_ptr) = x;
    comedi_buf_write_free(async, sizeof(short));
    return 1;
}
EXPORT_SYMBOL(comedi_buf_put);

void comedi_reset_async_buf(struct comedi_async *async)
{
    async->buf_write_alloc_count = 0;
    async->buf_write_count = 0;
    async->buf_read_alloc_count = 0;
    async->buf_read_count = 0;

    async->buf_write_ptr = 0;
    async->buf_read_ptr = 0;

    async->cur_chan = 0;
    async->scan_progress = 0;
    async->munge_chan = 0;
    async->munge_count = 0;
    async->munge_ptr = 0;

    async->events = 0;
}

static int
comedi_auto_config_helper(struct device *hardware_device,
              struct comedi_driver *driver,
              int (*attach_wrapper) (struct comedi_device *,
                         void *), void *context)
{
    int minor;
    struct comedi_device_file_info *dev_file_info;
    struct comedi_device *comedi_dev;
    int ret;

    if (!comedi_autoconfig)
        return 0;

    minor = comedi_alloc_board_minor(hardware_device);
    if (minor < 0)
        return minor;

    dev_file_info = comedi_get_device_file_info(minor);
    comedi_dev = dev_file_info->device;

    mutex_lock(&comedi_dev->mutex);
    if (comedi_dev->attached)
        ret = -EBUSY;
    else if (!try_module_get(driver->module))
        ret = -EIO;
    else {
        /* set comedi_dev->driver here for attach wrapper */
        comedi_dev->driver = driver;
        ret = (*attach_wrapper)(comedi_dev, context);
        if (ret < 0) {
            module_put(driver->module);
            __comedi_device_detach(comedi_dev);
        } else {
            ret = comedi_device_postconfig(comedi_dev);
        }
    }
    mutex_unlock(&comedi_dev->mutex);

    if (ret < 0)
        comedi_free_board_minor(minor);
    return ret;
}

static int comedi_auto_config_wrapper(struct comedi_device *dev, void *context)
{
    struct comedi_devconfig *it = context;
    struct comedi_driver *driv = dev->driver;

    if (driv->num_names) {
        /* look for generic board entry matching driver name, which
         * has already been copied to it->board_name */
        dev->board_ptr = comedi_recognize(driv, it->board_name);
        if (dev->board_ptr == NULL) {
            dev_warn(dev->class_dev,
                 "auto config failed to find board entry '%s' for driver '%s'\n",
                 it->board_name, driv->driver_name);
            comedi_report_boards(driv);
            return -EINVAL;
        }
    }
    if (!driv->attach) {
        dev_warn(dev->class_dev,
             "BUG! driver '%s' using old-style auto config but has no attach handler\n",
             driv->driver_name);
        return -EINVAL;
    }
    return driv->attach(dev, it);
}

static int comedi_auto_config(struct device *hardware_device,
                  struct comedi_driver *driver, const int *options,
                  unsigned num_options)
{
    struct comedi_devconfig it;

    memset(&it, 0, sizeof(it));
    strncpy(it.board_name, driver->driver_name, COMEDI_NAMELEN);
    it.board_name[COMEDI_NAMELEN - 1] = '\0';
    BUG_ON(num_options > COMEDI_NDEVCONFOPTS);
    memcpy(it.options, options, num_options * sizeof(int));
    return comedi_auto_config_helper(hardware_device, driver,
                     comedi_auto_config_wrapper, &it);
}

static void comedi_auto_unconfig(struct device *hardware_device)
{
    int minor;

    if (hardware_device == NULL)
        return;
    minor = comedi_find_board_minor(hardware_device);
    if (minor < 0)
        return;
    BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);
    comedi_free_board_minor(minor);
}

int comedi_pci_enable(struct pci_dev *pdev, const char *res_name)
{
    int rc;

    rc = pci_enable_device(pdev);
    if (rc < 0)
        return rc;

    rc = pci_request_regions(pdev, res_name);
    if (rc < 0)
        pci_disable_device(pdev);

    return rc;
}
EXPORT_SYMBOL_GPL(comedi_pci_enable);

void comedi_pci_disable(struct pci_dev *pdev)
{
    pci_release_regions(pdev);
    pci_disable_device(pdev);
}
EXPORT_SYMBOL_GPL(comedi_pci_disable);

static int comedi_old_pci_auto_config(struct pci_dev *pcidev,
                      struct comedi_driver *driver)
{
    int options[2];

    /*  pci bus */
    options[0] = pcidev->bus->number;
    /*  pci slot */
    options[1] = PCI_SLOT(pcidev->devfn);

    return comedi_auto_config(&pcidev->dev, driver,
                  options, ARRAY_SIZE(options));
}

static int comedi_pci_attach_wrapper(struct comedi_device *dev, void *pcidev)
{
    return dev->driver->attach_pci(dev, pcidev);
}

static int comedi_new_pci_auto_config(struct pci_dev *pcidev,
                      struct comedi_driver *driver)
{
    return comedi_auto_config_helper(&pcidev->dev, driver,
                     comedi_pci_attach_wrapper, pcidev);
}

int comedi_pci_auto_config(struct pci_dev *pcidev, struct comedi_driver *driver)
{

    if (driver->attach_pci)
        return comedi_new_pci_auto_config(pcidev, driver);
    else
        return comedi_old_pci_auto_config(pcidev, driver);
}
EXPORT_SYMBOL_GPL(comedi_pci_auto_config);

void comedi_pci_auto_unconfig(struct pci_dev *pcidev)
{
    comedi_auto_unconfig(&pcidev->dev);
}
EXPORT_SYMBOL_GPL(comedi_pci_auto_unconfig);

int comedi_pci_driver_register(struct comedi_driver *comedi_driver,
        struct pci_driver *pci_driver)
{
    int ret;

    ret = comedi_driver_register(comedi_driver);
    if (ret < 0)
        return ret;

    /* FIXME: Remove this test after auditing all comedi pci drivers */
    if (!pci_driver->name)
        pci_driver->name = comedi_driver->driver_name;

    ret = pci_register_driver(pci_driver);
    if (ret < 0) {
        comedi_driver_unregister(comedi_driver);
        return ret;
    }

    return 0;
}
EXPORT_SYMBOL_GPL(comedi_pci_driver_register);

void comedi_pci_driver_unregister(struct comedi_driver *comedi_driver,
        struct pci_driver *pci_driver)
{
    pci_unregister_driver(pci_driver);
    comedi_driver_unregister(comedi_driver);
}
EXPORT_SYMBOL_GPL(comedi_pci_driver_unregister);

#if IS_ENABLED(CONFIG_USB)

static int comedi_old_usb_auto_config(struct usb_interface *intf,
                      struct comedi_driver *driver)
{
    return comedi_auto_config(&intf->dev, driver, NULL, 0);
}

static int comedi_usb_attach_wrapper(struct comedi_device *dev, void *intf)
{
    return dev->driver->attach_usb(dev, intf);
}

static int comedi_new_usb_auto_config(struct usb_interface *intf,
                      struct comedi_driver *driver)
{
    return comedi_auto_config_helper(&intf->dev, driver,
                     comedi_usb_attach_wrapper, intf);
}

int comedi_usb_auto_config(struct usb_interface *intf,
               struct comedi_driver *driver)
{
    BUG_ON(intf == NULL);
    if (driver->attach_usb)
        return comedi_new_usb_auto_config(intf, driver);
    else
        return comedi_old_usb_auto_config(intf, driver);
}
EXPORT_SYMBOL_GPL(comedi_usb_auto_config);

void comedi_usb_auto_unconfig(struct usb_interface *intf)
{
    BUG_ON(intf == NULL);
    comedi_auto_unconfig(&intf->dev);
}
EXPORT_SYMBOL_GPL(comedi_usb_auto_unconfig);

int comedi_usb_driver_register(struct comedi_driver *comedi_driver,
        struct usb_driver *usb_driver)
{
    int ret;

    ret = comedi_driver_register(comedi_driver);
    if (ret < 0)
        return ret;

    ret = usb_register(usb_driver);
    if (ret < 0) {
        comedi_driver_unregister(comedi_driver);
        return ret;
    }

    return 0;
}
EXPORT_SYMBOL_GPL(comedi_usb_driver_register);

void comedi_usb_driver_unregister(struct comedi_driver *comedi_driver,
        struct usb_driver *usb_driver)
{
    usb_deregister(usb_driver);
    comedi_driver_unregister(comedi_driver);
}
EXPORT_SYMBOL_GPL(comedi_usb_driver_unregister);

#endif