urbtc.c

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/*
 * USB H8 based motor controller driver 
 *
 * based on USB Skeleton driver.
 */
/*
 * USB Skeleton driver - 2.0
 *
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 *
 *      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, version 2.
 *
 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c 
 * but has been rewritten to be easy to read and use, as no locks are now
 * needed anymore.
 *
 */

#define DEBUG

//#include <linux/config.h>
//#include <linux/autoconf.h>                   //chg t.miyo
//#include "/usr/src/linux-headers-3.2.0-4-amd64/include/generated/autoconf.h"
#include "/usr/src/linux-headers-3.13.0-34-generic/include/generated/autoconf.h"
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>

#include "urbtc.h"
#include "urobotc.h"

static struct usb_device_id urbtc_table [] = {
        { USB_DEVICE(0x8da, 0xfc00) },  /* base version */
        { USB_DEVICE(0xff8, 0x001) },   /* iXs Reserch version */
        { }                                     /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, urbtc_table);

#define USB_URBTC_MINOR_BASE    100

/* our private defines. if this grows any larger, use your own .h file */
#define MAX_TRANSFER            (PAGE_SIZE - 512)
#define WRITES_IN_FLIGHT        8

#define EP_READREQ      1
#define EP_SCMD         2
#define EP_READ         5
#define EP_CCMD         6

/* Structure to hold all of our device specific stuff */
struct usb_urbtc {
        struct usb_device *udev;
        struct usb_interface *interface;
        struct semaphore limit_sem;

        int read_status;
        unsigned char *readreq_buffer;
        size_t readreq_size;

        int readbuf_enabled;
        wait_queue_head_t readbuf_wait;
        struct urb *readbuf_urb;
        struct uin *readbuf_work;
        struct semaphore readbuf_sem;
        struct uin *readbuf_buffered;
        size_t readbuf_size;
        unsigned short readbuf_last_buffered; /* same to uin.time */
        unsigned short readbuf_last_read; /* same to uin.time */

        int write_status;
        unsigned char *write_counter_buffer;
        size_t write_counter_size;

        struct kref             kref;
};
#define to_urbtc_dev(d) container_of(d, struct usb_urbtc, kref)

static struct usb_driver urbtc_driver;

static void urbtc_delete(struct kref *kref)
{       
        struct usb_urbtc *dev = to_urbtc_dev(kref);

        usb_put_dev(dev->udev);
        kfree (dev->readreq_buffer);
        usb_free_urb(dev->readbuf_urb);
        kfree (dev->readbuf_work);
        kfree (dev->readbuf_buffered);
        kfree (dev);
}

static int urbtc_open(struct inode *inode, struct file *file)
{
        struct usb_urbtc *dev;
        struct usb_interface *interface;
        int subminor;
        int retval = 0;

        subminor = iminor(inode);

        interface = usb_find_interface(&urbtc_driver, subminor);
        if (!interface) {
                /* err ("%s - error, can't find device for minor %d", */
                /*      __FUNCTION__, subminor); */
                retval = -ENODEV;
                goto exit;
        }

        dev = usb_get_intfdata(interface);
        if (!dev) {
                retval = -ENODEV;
                goto exit;
        }

        dev->read_status = URBTC_STATUS_READ_REQUEST;
        dev->readbuf_enabled = 0;
        dev->write_status = URBTC_STATUS_WRITE_DESIRE;

        /* increment our usage count for the device */
        kref_get(&dev->kref);

        /* save our object in the file's private structure */
        file->private_data = dev;

exit:
        return retval;
}

static int urbtc_release(struct inode *inode, struct file *file)
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;

        if (dev == NULL)
                return -ENODEV;

        if (dev->interface) {
                if (dev->readbuf_enabled)
                        usb_kill_urb(dev->readbuf_urb);
        }
                
        /* decrement the count on our device */
        kref_put(&dev->kref, urbtc_delete);
        return 0;
}

//static void urbtc_read_bulk_callback(struct urb *urb, struct pt_regs *regs)
static void urbtc_read_bulk_callback(struct urb *urb)                   //chg t.miyo
{
        struct usb_urbtc *dev = (struct usb_urbtc *)urb->context;
        int res;

        /* sync/async unlink faults aren't errors */
        if (urb->status && 
            !(urb->status == -ENOENT || 
              urb->status == -ECONNRESET ||
              urb->status == -ESHUTDOWN)) {
                /* dbg("%s - nonzero read bulk status received: %d", */
                /*     __FUNCTION__, urb->status); */
                dev->readbuf_enabled = 0;
                return;
        }
        if (urb->actual_length > 0) {
                if (down_trylock(&dev->readbuf_sem) == 0) {
                        memcpy(dev->readbuf_buffered, dev->readbuf_work, urb->actual_length);
                        dev->readbuf_last_buffered = dev->readbuf_work->time;
                        up(&dev->readbuf_sem);
                        wake_up(&dev->readbuf_wait);
                }
        }
        if (dev->readbuf_enabled) {
                usb_fill_bulk_urb(dev->readbuf_urb, dev->udev,
                                  usb_rcvbulkpipe(dev->udev, EP_READ),
                                  dev->readbuf_urb->transfer_buffer,
                                  dev->readbuf_urb->transfer_buffer_length,
                                  urbtc_read_bulk_callback, dev);
                if ((res = usb_submit_urb(dev->readbuf_urb, GFP_ATOMIC))) {
                        dev->readbuf_enabled = 0;
                }
        }
}

static ssize_t urbtc_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;
        int retval = 0;
        int bytes_read;
        
        if (count != sizeof(struct uin))
                return -EINVAL;

        switch (dev->read_status) {
        case URBTC_STATUS_READ_REQUEST:
                /* do a blocking bulk read to get data from the device */
                retval = usb_bulk_msg(dev->udev,
                                      usb_rcvbulkpipe(dev->udev, EP_READREQ),
                                      dev->readreq_buffer,
                                      min(dev->readreq_size, count),
                                      &bytes_read, 10000);

                /* if the read was successful, copy the data to userspace */
                if (!retval) {
                        if (copy_to_user(buffer, dev->readreq_buffer, bytes_read))
                                retval = -EFAULT;
                        else
                                retval = bytes_read;
                }
                break;
        case URBTC_STATUS_READ_CONTINUOUS:
                if (dev->readbuf_enabled) {
                        wait_event_interruptible(dev->readbuf_wait,
                                                 dev->readbuf_last_read != dev->readbuf_last_buffered || !dev->udev);
                        if (signal_pending(current)) {
                                retval = -EINTR;
                                goto out;
                        }
                        if (!dev->udev) {
                                retval = -ENODEV;
                                goto out;
                        }
                        dev->readbuf_last_read = dev->readbuf_last_buffered;
                        down(&dev->readbuf_sem);
                        if (copy_to_user(buffer, dev->readbuf_buffered, dev->readbuf_size))
                                retval = -EFAULT;
                        else
                                retval = dev->readbuf_size;
                        up(&dev->readbuf_sem);
                } else {
                        /* do a blocking bulk read to get data from the device */
                        down(&dev->readbuf_sem);
                        retval = usb_bulk_msg(dev->udev,
                                              usb_rcvbulkpipe(dev->udev, EP_READ),
                                              dev->readbuf_buffered,
                                              min(dev->readbuf_size, count),
                                              &bytes_read, 10000);

                        /* if the read was successful, copy the data to userspace */
                        if (!retval) {
                                if (copy_to_user(buffer, dev->readbuf_buffered, bytes_read))
                                        retval = -EFAULT;
                                else
                                        retval = bytes_read;
                        }
                        up(&dev->readbuf_sem);
                }
                break;
        default:
                /* should not occur */
                retval = -EINVAL;
                break;
        }
out:
        return retval;
}

//static void urbtc_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
static void urbtc_write_bulk_callback(struct urb *urb)                  //chg t.miyo
{
        struct usb_urbtc *dev = (struct usb_urbtc *)urb->context;

        /* sync/async unlink faults aren't errors */
        if (urb->status && 
            !(urb->status == -ENOENT || 
              urb->status == -ECONNRESET ||
              urb->status == -ESHUTDOWN)) {
                /* dbg("%s - nonzero write bulk status received: %d", */
                /*     __FUNCTION__, urb->status); */
        }

        /* free up our allocated buffer */
        /*usb_buffer_free(urb->dev, urb->transfer_buffer_length, 
                        urb->transfer_buffer, urb->transfer_dma);*/
        usb_free_coherent(urb->dev, urb->transfer_buffer_length, urb->transfer_buffer, urb->transfer_dma);                      //chg t.miyo
        up(&dev->limit_sem);
}

static ssize_t urbtc_write_sync(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;
        int retval = 0;
        size_t writesize = min(count, dev->write_counter_size);
        int bytes_written;

        if (copy_from_user(dev->write_counter_buffer, user_buffer, writesize)) {
                retval = -EFAULT;
                goto error;
        }

        /* do a blocking bulk write to the device */
        retval = usb_bulk_msg(dev->udev,
                              usb_sndbulkpipe(dev->udev, EP_CCMD),
                              dev->write_counter_buffer,
                              writesize,
                              &bytes_written, 10000);

        if (!retval)
                retval = bytes_written;

error:
        return retval;
}

static ssize_t urbtc_write_async(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;
        int retval = 0;
        struct urb *urb = NULL;
        char *buf = NULL;
        size_t writesize = min(count, (size_t)MAX_TRANSFER);

        /* limit the number of URBs in flight to stop a user from using up all RAM */
        if (down_interruptible(&dev->limit_sem)) {
                retval = -ERESTARTSYS;
                goto exit;
        }

        /* create a urb, and a buffer for it, and copy the data to the urb */
        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!urb) {
                retval = -ENOMEM;
                goto error;
        }

        //buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
        buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
        if (!buf) {
                retval = -ENOMEM;
                goto error;
        }

        if (copy_from_user(buf, user_buffer, writesize)) {
                retval = -EFAULT;
                goto error;
        }

        /* initialize the urb properly */
        usb_fill_bulk_urb(urb, dev->udev,
                          usb_sndbulkpipe(dev->udev, EP_SCMD),
                          buf, writesize, urbtc_write_bulk_callback, dev);
        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

        /* send the data out the bulk port */
        retval = usb_submit_urb(urb, GFP_KERNEL);
        if (retval) {
                /* err("%s - failed submitting write urb, error %d", __FUNCTION__, retval); */
                goto error;
        }

        /* release our reference to this urb, the USB core will eventually free it entirely */
        usb_free_urb(urb);

exit:
        return writesize;

error:
        //usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
        usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);                        //chg t.miyo
        usb_free_urb(urb);
        up(&dev->limit_sem);
        return retval;
}

static ssize_t urbtc_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;

        /* verify that we actually have some data to write */
        if (count == 0)
                return 0;

        switch (dev->write_status) {
        case URBTC_STATUS_WRITE_COUNTER:
                return urbtc_write_sync(file, user_buffer, count, ppos);
        case URBTC_STATUS_WRITE_DESIRE:
                return urbtc_write_async(file, user_buffer, count, ppos);
        default:
                /* should not occur */
                return -EINVAL;
        }
}

/*static int
urbtc_ioctl(struct inode *inode, struct file *file,
            unsigned int cmd, unsigned long arg)*/
static long
urbtc_ioctl(struct file *file,
            unsigned int cmd, unsigned long arg)                        //chg t.miyo
{
        struct usb_urbtc *dev = (struct usb_urbtc *)file->private_data;
        struct usb_device *udev = dev->udev;
        int retval = 0;

        switch(cmd) {
        case URBTC_GET_VENDOR:
                if(copy_to_user((int*)arg, &udev->descriptor.idVendor, sizeof(int)))
                        return -EFAULT;
                break;
        case URBTC_GET_PRODUCT:
                if(copy_to_user((int*)arg, &udev->descriptor.idProduct, sizeof(int)))
                        return -EFAULT;
                break;
        case URBTC_REQUEST_READ:
                dev->read_status = URBTC_STATUS_READ_REQUEST;
                break;
        case URBTC_CONTINUOUS_READ:
                dev->read_status = URBTC_STATUS_READ_CONTINUOUS;
                break;
        case URBTC_BUFREAD:
                if (dev->read_status != URBTC_STATUS_READ_CONTINUOUS)
                        return -EINVAL;
                if (!dev->readbuf_enabled) {
                        usb_fill_bulk_urb(dev->readbuf_urb, dev->udev,
                                          usb_rcvbulkpipe(dev->udev, EP_READ),
                                          dev->readbuf_urb->transfer_buffer,
                                          dev->readbuf_urb->transfer_buffer_length,
                                          urbtc_read_bulk_callback, dev);
                        if (!(retval = usb_submit_urb(dev->readbuf_urb, GFP_KERNEL)))
                                dev->readbuf_enabled = 1;
                }
                break;
        case URBTC_WAITREAD:
                dev->readbuf_enabled = 0;
                break;
        case URBTC_GET_READ_STATUS:
                if (copy_to_user((int*)arg, &dev->read_status, sizeof(int)))
                        return -EFAULT;
                break;

        case URBTC_COUNTER_SET:
                dev->write_status = URBTC_STATUS_WRITE_COUNTER;
                break;
        case URBTC_DESIRE_SET:
                dev->write_status = URBTC_STATUS_WRITE_DESIRE;
                break;
        case URBTC_GET_WRITE_STATUS:
                if (copy_to_user((int*)arg, &dev->write_status, sizeof(int)))
                        return -EFAULT;
                break;
        default:
                return -ENOIOCTLCMD;
        }

        return retval;
}

static struct file_operations urbtc_fops = {
        .owner =        THIS_MODULE,
        .read =         urbtc_read,
        .write =        urbtc_write,
        //.ioctl =      urbtc_ioctl,
        .unlocked_ioctl =       urbtc_ioctl,            //chg t.miyo
        .open =         urbtc_open,
        .release =      urbtc_release,
};

/* 
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with the driver core
 */
static struct usb_class_driver urbtc_class = {
        .name =         "urbtc%d",
        .fops =         &urbtc_fops,
        .minor_base =   USB_URBTC_MINOR_BASE,
};

static int urbtc_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
        struct usb_urbtc *dev = NULL;
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
        size_t buffer_size;
        int i;
        int retval = -ENOMEM;

        /* allocate memory for our device state and initialize it */
        dev = kmalloc(sizeof(*dev), GFP_KERNEL);
        if (dev == NULL) {
                /* err("Out of memory"); */
                goto error;
        }
        memset(dev, 0, sizeof(*dev));
        kref_init(&dev->kref);
        sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
        //init_MUTEX(&dev->readbuf_sem);
        sema_init(&dev->readbuf_sem,1);                 //chg t.miyo
        init_waitqueue_head(&dev->readbuf_wait);

        dev->udev = usb_get_dev(interface_to_usbdev(interface));
        dev->interface = interface;

        dev->readreq_buffer = NULL;
        dev->readbuf_urb = NULL;
        dev->readbuf_work = NULL;
        dev->readbuf_buffered = NULL;
        dev->readbuf_last_read = 0;
        dev->readbuf_last_buffered = 0;

        iface_desc = interface->cur_altsetting;
        for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
                endpoint = &iface_desc->endpoint[i].desc;

                /* dbg("endpoint %d(%d) %s", */
                /*     endpoint->bEndpointAddress, */
                /*     endpoint->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK, */
                /*     endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK? "in": "out"); */
                if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
                     == USB_DIR_IN) &&
                    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
                     == USB_ENDPOINT_XFER_BULK)) {
                        switch (endpoint->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK) {
                        case EP_READREQ:
                                buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                                dev->readreq_size = buffer_size;
                                dev->readreq_buffer = kmalloc(buffer_size, GFP_KERNEL);
                                if (!dev->readreq_buffer) {
                                        /* err("Could not allocate readreq_buffer"); */
                                        goto error;
                                }
                                break;
                        case EP_READ:
                                buffer_size = sizeof(struct uin);
                                dev->readbuf_urb = usb_alloc_urb(0, GFP_KERNEL);
                                if (!dev->readbuf_urb) {
                                        /* err("Could not allocate readbuf_urb"); */
                                        goto error;
                                }
                                dev->readbuf_size = buffer_size;
                                dev->readbuf_work = kmalloc(buffer_size, GFP_KERNEL);
                                if (!dev->readbuf_work) {
                                        /* err("Could not allocate readbuf_work"); */
                                        goto error;
                                }
                                dev->readbuf_buffered = kmalloc(buffer_size, GFP_KERNEL);
                                if (!dev->readbuf_buffered) {
                                        /* err("Could not allocate readbuf_buffer"); */
                                        goto error;
                                }
                                usb_fill_bulk_urb(dev->readbuf_urb, dev->udev,
                                                  usb_rcvbulkpipe(dev->udev, endpoint->bEndpointAddress),
                                                  dev->readbuf_work, dev->readbuf_size,
                                                  urbtc_read_bulk_callback, dev);
                                break;
                        default:
                                break;
                        }
                }

                if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)
                     == USB_DIR_OUT) &&
                    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
                     == USB_ENDPOINT_XFER_BULK)) {
                        switch (endpoint->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK) {
                        case EP_CCMD:
                                buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
                                dev->write_counter_size = buffer_size;
                                dev->write_counter_buffer = kmalloc(buffer_size, GFP_KERNEL);
                                if (!dev->write_counter_buffer) {
                                        /* err("Could not allocate write_counter_buffer"); */
                                        goto error;
                                }
                                break;
                        case EP_SCMD:
                        default:
                                break;
                        }
                }
        }

        /* save our data pointer in this interface device */
        usb_set_intfdata(interface, dev);

        /* we can register the device now, as it is ready */
        retval = usb_register_dev(interface, &urbtc_class);
        if (retval) {
                /* something prevented us from registering this driver */
                /* err("Not able to get a minor for this device."); */
                usb_set_intfdata(interface, NULL);
                goto error;
        }

        /* let the user know what node this device is now attached to */
        //info("USB Robot device now attached to urbtc - %d", interface->minor);
        //chg t.miyo
        dev_info(&interface->dev,"USB Robot device now attached to urbtc - %d", interface->minor);
        return 0;

error:
        if (dev) {
                if (dev->readreq_buffer)
                        kfree(dev->readreq_buffer);
                if (dev->readbuf_urb)
                        usb_free_urb(dev->readbuf_urb);
                if (dev->readbuf_work)
                        kfree(dev->readbuf_work);
                if (dev->readbuf_buffered)
                        kfree(dev->readbuf_buffered);
                kref_put(&dev->kref, urbtc_delete);
        }
        return retval;
}

static void urbtc_disconnect(struct usb_interface *interface)
{
        struct usb_urbtc *dev;
        int minor = interface->minor;

        /* prevent urbtc_open() from racing urbtc_disconnect() */
        //lock_kernel();                //debug t.miyo

        dev = usb_get_intfdata(interface);
        usb_set_intfdata(interface, NULL);

        /* give back our minor */
        usb_deregister_dev(interface, &urbtc_class);

        //unlock_kernel();              //debug t.miyo

        /* decrement our usage count */
        kref_put(&dev->kref, urbtc_delete);
        wake_up(&dev->readbuf_wait);

        //info("USB Robot #%d now disconnected", minor);
        //chg t.miyo
        dev_info(&interface->dev,"USB Robot #%d now disconnected", minor);
}

static struct usb_driver urbtc_driver = {
        .name =         "urbtc",
        .probe =        urbtc_probe,
        .disconnect =   urbtc_disconnect,
        .id_table =     urbtc_table,
};

static int __init usb_urbtc_init(void)
{
        int result;

        /* register this driver with the USB subsystem */
        result = usb_register(&urbtc_driver);
        if (result){}
                /* err("usb_register failed. Error number %d", result); */

        return result;
}

static void __exit usb_urbtc_exit(void)
{
        /* deregister this driver with the USB subsystem */
        usb_deregister(&urbtc_driver);
}

module_init (usb_urbtc_init);
module_exit (usb_urbtc_exit);

MODULE_LICENSE("GPL");
/*
  Local Variables:
  c-file-style: "linux"
  End:
*/