Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[linux-2.6-omap-h63xx.git] / drivers / usb / misc / ldusb.c

diff --git a/drivers/usb/misc/ldusb.c b/drivers/usb/misc/ldusb.c
index 11555bde655bf16c6fc2b049aea6910b1a808fba..c730d20eec66cc6c3f4517626b74c696c4e15731 100644 (file)
--- a/drivers/usb/misc/ldusb.c
+++ b/drivers/usb/misc/ldusb.c
@@ -61,6 +61,7 @@
 #define USB_DEVICE_ID_VERNIER_GOTEMP   0x0002
 #define USB_DEVICE_ID_VERNIER_SKIP     0x0003
 #define USB_DEVICE_ID_VERNIER_CYCLOPS  0x0004
+#define USB_DEVICE_ID_VERNIER_LCSPEC   0x0006
 
 #define USB_VENDOR_ID_MICROCHIP                0x04d8
 #define USB_DEVICE_ID_PICDEM           0x000c
@@ -92,6 +93,7 @@ static struct usb_device_id ld_usb_table [] = {
        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_SKIP) },
        { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_CYCLOPS) },
        { USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_PICDEM) },
+       { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_LCSPEC) },
        { }                                     /* Terminating entry */
 };
 MODULE_DEVICE_TABLE(usb, ld_usb_table);
@@ -165,6 +167,8 @@ struct ld_usb {
        size_t                  interrupt_in_endpoint_size;
        int                     interrupt_in_running;
        int                     interrupt_in_done;
+       int                     buffer_overflow;
+       spinlock_t              rbsl;
 
        char*                   interrupt_out_buffer;
        struct usb_endpoint_descriptor* interrupt_out_endpoint;
@@ -174,9 +178,6 @@ struct ld_usb {
        int                     interrupt_out_busy;
 };
 
-/* prevent races between open() and disconnect() */
-static DEFINE_MUTEX(disconnect_mutex);
-
 static struct usb_driver ld_usb_driver;
 
 /**
@@ -220,20 +221,23 @@ static void ld_usb_interrupt_in_callback(struct urb *urb)
        struct ld_usb *dev = urb->context;
        size_t *actual_buffer;
        unsigned int next_ring_head;
+       int status = urb->status;
        int retval;
 
-       if (urb->status) {
-               if (urb->status == -ENOENT ||
-                   urb->status == -ECONNRESET ||
-                   urb->status == -ESHUTDOWN) {
+       if (status) {
+               if (status == -ENOENT ||
+                   status == -ECONNRESET ||
+                   status == -ESHUTDOWN) {
                        goto exit;
                } else {
                        dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
-                                __FUNCTION__, urb->status);
+                                __FUNCTION__, status);
+                       spin_lock(&dev->rbsl);
                        goto resubmit; /* maybe we can recover */
                }
        }
 
+       spin_lock(&dev->rbsl);
        if (urb->actual_length > 0) {
                next_ring_head = (dev->ring_head+1) % ring_buffer_size;
                if (next_ring_head != dev->ring_tail) {
@@ -244,21 +248,25 @@ static void ld_usb_interrupt_in_callback(struct urb *urb)
                        dev->ring_head = next_ring_head;
                        dbg_info(&dev->intf->dev, "%s: received %d bytes\n",
                                 __FUNCTION__, urb->actual_length);
-               } else
+               } else {
                        dev_warn(&dev->intf->dev,
                                 "Ring buffer overflow, %d bytes dropped\n",
                                 urb->actual_length);
+                       dev->buffer_overflow = 1;
+               }
        }
 
 resubmit:
        /* resubmit if we're still running */
-       if (dev->interrupt_in_running && dev->intf) {
+       if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
                retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
-               if (retval)
+               if (retval) {
                        dev_err(&dev->intf->dev,
                                "usb_submit_urb failed (%d)\n", retval);
+                       dev->buffer_overflow = 1;
+               }
        }
-
+       spin_unlock(&dev->rbsl);
 exit:
        dev->interrupt_in_done = 1;
        wake_up_interruptible(&dev->read_wait);
@@ -270,14 +278,15 @@ exit:
 static void ld_usb_interrupt_out_callback(struct urb *urb)
 {
        struct ld_usb *dev = urb->context;
+       int status = urb->status;
 
        /* sync/async unlink faults aren't errors */
-       if (urb->status && !(urb->status == -ENOENT ||
-                            urb->status == -ECONNRESET ||
-                            urb->status == -ESHUTDOWN))
+       if (status && !(status == -ENOENT ||
+                       status == -ECONNRESET ||
+                       status == -ESHUTDOWN))
                dbg_info(&dev->intf->dev,
                         "%s - nonzero write interrupt status received: %d\n",
-                        __FUNCTION__, urb->status);
+                        __FUNCTION__, status);
 
        dev->interrupt_out_busy = 0;
        wake_up_interruptible(&dev->write_wait);
@@ -290,35 +299,28 @@ static int ld_usb_open(struct inode *inode, struct file *file)
 {
        struct ld_usb *dev;
        int subminor;
-       int retval = 0;
+       int retval;
        struct usb_interface *interface;
 
        nonseekable_open(inode, file);
        subminor = iminor(inode);
 
-       mutex_lock(&disconnect_mutex);
-
        interface = usb_find_interface(&ld_usb_driver, subminor);
 
        if (!interface) {
                err("%s - error, can't find device for minor %d\n",
                     __FUNCTION__, subminor);
-               retval = -ENODEV;
-               goto unlock_disconnect_exit;
+               return -ENODEV;
        }
 
        dev = usb_get_intfdata(interface);
 
-       if (!dev) {
-               retval = -ENODEV;
-               goto unlock_disconnect_exit;
-       }
+       if (!dev)
+               return -ENODEV;
 
        /* lock this device */
-       if (down_interruptible(&dev->sem)) {
-               retval = -ERESTARTSYS;
-               goto unlock_disconnect_exit;
-       }
+       if (down_interruptible(&dev->sem))
+               return -ERESTARTSYS;
 
        /* allow opening only once */
        if (dev->open_count) {
@@ -330,6 +332,7 @@ static int ld_usb_open(struct inode *inode, struct file *file)
        /* initialize in direction */
        dev->ring_head = 0;
        dev->ring_tail = 0;
+       dev->buffer_overflow = 0;
        usb_fill_int_urb(dev->interrupt_in_urb,
                         interface_to_usbdev(interface),
                         usb_rcvintpipe(interface_to_usbdev(interface),
@@ -357,9 +360,6 @@ static int ld_usb_open(struct inode *inode, struct file *file)
 unlock_exit:
        up(&dev->sem);
 
-unlock_disconnect_exit:
-       mutex_unlock(&disconnect_mutex);
-
        return retval;
 }
 
@@ -439,6 +439,7 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
        size_t *actual_buffer;
        size_t bytes_to_read;
        int retval = 0;
+       int rv;
 
        dev = file->private_data;
 
@@ -460,7 +461,10 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
        }
 
        /* wait for data */
+       spin_lock_irq(&dev->rbsl);
        if (dev->ring_head == dev->ring_tail) {
+               dev->interrupt_in_done = 0;
+               spin_unlock_irq(&dev->rbsl);
                if (file->f_flags & O_NONBLOCK) {
                        retval = -EAGAIN;
                        goto unlock_exit;
@@ -468,6 +472,8 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
                retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
                if (retval < 0)
                        goto unlock_exit;
+       } else {
+               spin_unlock_irq(&dev->rbsl);
        }
 
        /* actual_buffer contains actual_length + interrupt_in_buffer */
@@ -486,6 +492,17 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
 
        retval = bytes_to_read;
 
+       spin_lock_irq(&dev->rbsl);
+       if (dev->buffer_overflow) {
+               dev->buffer_overflow = 0;
+               spin_unlock_irq(&dev->rbsl);
+               rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
+               if (rv < 0)
+                       dev->buffer_overflow = 1;
+       } else {
+               spin_unlock_irq(&dev->rbsl);
+       }
+
 unlock_exit:
        /* unlock the device */
        up(&dev->sem);
@@ -635,6 +652,7 @@ static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *
                goto exit;
        }
        init_MUTEX(&dev->sem);
+       spin_lock_init(&dev->rbsl);
        dev->intf = intf;
        init_waitqueue_head(&dev->read_wait);
        init_waitqueue_head(&dev->write_wait);
@@ -739,18 +757,16 @@ static void ld_usb_disconnect(struct usb_interface *intf)
        struct ld_usb *dev;
        int minor;
 
-       mutex_lock(&disconnect_mutex);
-
        dev = usb_get_intfdata(intf);
        usb_set_intfdata(intf, NULL);
 
-       down(&dev->sem);
-
        minor = intf->minor;
 
        /* give back our minor */
        usb_deregister_dev(intf, &ld_usb_class);
 
+       down(&dev->sem);
+
        /* if the device is not opened, then we clean up right now */
        if (!dev->open_count) {
                up(&dev->sem);
@@ -760,8 +776,6 @@ static void ld_usb_disconnect(struct usb_interface *intf)
                up(&dev->sem);
        }
 
-       mutex_unlock(&disconnect_mutex);
-
        dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
                 (minor - USB_LD_MINOR_BASE));
 }