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Diffstat (limited to 'kernel/drivers/usb/gadget/function/f_printer.c')
-rw-r--r--kernel/drivers/usb/gadget/function/f_printer.c1471
1 files changed, 1471 insertions, 0 deletions
diff --git a/kernel/drivers/usb/gadget/function/f_printer.c b/kernel/drivers/usb/gadget/function/f_printer.c
new file mode 100644
index 000000000..44173df27
--- /dev/null
+++ b/kernel/drivers/usb/gadget/function/f_printer.c
@@ -0,0 +1,1471 @@
+/*
+ * f_printer.c - USB printer function driver
+ *
+ * Copied from drivers/usb/gadget/legacy/printer.c,
+ * which was:
+ *
+ * printer.c -- Printer gadget driver
+ *
+ * Copyright (C) 2003-2005 David Brownell
+ * Copyright (C) 2006 Craig W. Nadler
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/timer.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/moduleparam.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/cdev.h>
+
+#include <asm/byteorder.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/uaccess.h>
+#include <asm/unaligned.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/g_printer.h>
+
+#include "u_printer.h"
+
+#define PNP_STRING_LEN 1024
+#define PRINTER_MINORS 4
+#define GET_DEVICE_ID 0
+#define GET_PORT_STATUS 1
+#define SOFT_RESET 2
+
+static int major, minors;
+static struct class *usb_gadget_class;
+static DEFINE_IDA(printer_ida);
+static DEFINE_MUTEX(printer_ida_lock); /* protects access do printer_ida */
+
+/*-------------------------------------------------------------------------*/
+
+struct printer_dev {
+ spinlock_t lock; /* lock this structure */
+ /* lock buffer lists during read/write calls */
+ struct mutex lock_printer_io;
+ struct usb_gadget *gadget;
+ s8 interface;
+ struct usb_ep *in_ep, *out_ep;
+
+ struct list_head rx_reqs; /* List of free RX structs */
+ struct list_head rx_reqs_active; /* List of Active RX xfers */
+ struct list_head rx_buffers; /* List of completed xfers */
+ /* wait until there is data to be read. */
+ wait_queue_head_t rx_wait;
+ struct list_head tx_reqs; /* List of free TX structs */
+ struct list_head tx_reqs_active; /* List of Active TX xfers */
+ /* Wait until there are write buffers available to use. */
+ wait_queue_head_t tx_wait;
+ /* Wait until all write buffers have been sent. */
+ wait_queue_head_t tx_flush_wait;
+ struct usb_request *current_rx_req;
+ size_t current_rx_bytes;
+ u8 *current_rx_buf;
+ u8 printer_status;
+ u8 reset_printer;
+ int minor;
+ struct cdev printer_cdev;
+ u8 printer_cdev_open;
+ wait_queue_head_t wait;
+ unsigned q_len;
+ char *pnp_string; /* We don't own memory! */
+ struct usb_function function;
+};
+
+static inline struct printer_dev *func_to_printer(struct usb_function *f)
+{
+ return container_of(f, struct printer_dev, function);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * DESCRIPTORS ... most are static, but strings and (full) configuration
+ * descriptors are built on demand.
+ */
+
+/* holds our biggest descriptor */
+#define USB_DESC_BUFSIZE 256
+#define USB_BUFSIZE 8192
+
+static struct usb_interface_descriptor intf_desc = {
+ .bLength = sizeof(intf_desc),
+ .bDescriptorType = USB_DT_INTERFACE,
+ .bNumEndpoints = 2,
+ .bInterfaceClass = USB_CLASS_PRINTER,
+ .bInterfaceSubClass = 1, /* Printer Sub-Class */
+ .bInterfaceProtocol = 2, /* Bi-Directional */
+ .iInterface = 0
+};
+
+static struct usb_endpoint_descriptor fs_ep_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK
+};
+
+static struct usb_endpoint_descriptor fs_ep_out_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = USB_DIR_OUT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK
+};
+
+static struct usb_descriptor_header *fs_printer_function[] = {
+ (struct usb_descriptor_header *) &intf_desc,
+ (struct usb_descriptor_header *) &fs_ep_in_desc,
+ (struct usb_descriptor_header *) &fs_ep_out_desc,
+ NULL
+};
+
+/*
+ * usb 2.0 devices need to expose both high speed and full speed
+ * descriptors, unless they only run at full speed.
+ */
+
+static struct usb_endpoint_descriptor hs_ep_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(512)
+};
+
+static struct usb_endpoint_descriptor hs_ep_out_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(512)
+};
+
+static struct usb_qualifier_descriptor dev_qualifier = {
+ .bLength = sizeof(dev_qualifier),
+ .bDescriptorType = USB_DT_DEVICE_QUALIFIER,
+ .bcdUSB = cpu_to_le16(0x0200),
+ .bDeviceClass = USB_CLASS_PRINTER,
+ .bNumConfigurations = 1
+};
+
+static struct usb_descriptor_header *hs_printer_function[] = {
+ (struct usb_descriptor_header *) &intf_desc,
+ (struct usb_descriptor_header *) &hs_ep_in_desc,
+ (struct usb_descriptor_header *) &hs_ep_out_desc,
+ NULL
+};
+
+/*
+ * Added endpoint descriptors for 3.0 devices
+ */
+
+static struct usb_endpoint_descriptor ss_ep_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_ep_in_comp_desc = {
+ .bLength = sizeof(ss_ep_in_comp_desc),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+};
+
+static struct usb_endpoint_descriptor ss_ep_out_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_ep_out_comp_desc = {
+ .bLength = sizeof(ss_ep_out_comp_desc),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+};
+
+static struct usb_descriptor_header *ss_printer_function[] = {
+ (struct usb_descriptor_header *) &intf_desc,
+ (struct usb_descriptor_header *) &ss_ep_in_desc,
+ (struct usb_descriptor_header *) &ss_ep_in_comp_desc,
+ (struct usb_descriptor_header *) &ss_ep_out_desc,
+ (struct usb_descriptor_header *) &ss_ep_out_comp_desc,
+ NULL
+};
+
+/* maxpacket and other transfer characteristics vary by speed. */
+static inline struct usb_endpoint_descriptor *ep_desc(struct usb_gadget *gadget,
+ struct usb_endpoint_descriptor *fs,
+ struct usb_endpoint_descriptor *hs,
+ struct usb_endpoint_descriptor *ss)
+{
+ switch (gadget->speed) {
+ case USB_SPEED_SUPER:
+ return ss;
+ case USB_SPEED_HIGH:
+ return hs;
+ default:
+ return fs;
+ }
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_request *
+printer_req_alloc(struct usb_ep *ep, unsigned len, gfp_t gfp_flags)
+{
+ struct usb_request *req;
+
+ req = usb_ep_alloc_request(ep, gfp_flags);
+
+ if (req != NULL) {
+ req->length = len;
+ req->buf = kmalloc(len, gfp_flags);
+ if (req->buf == NULL) {
+ usb_ep_free_request(ep, req);
+ return NULL;
+ }
+ }
+
+ return req;
+}
+
+static void
+printer_req_free(struct usb_ep *ep, struct usb_request *req)
+{
+ if (ep != NULL && req != NULL) {
+ kfree(req->buf);
+ usb_ep_free_request(ep, req);
+ }
+}
+
+/*-------------------------------------------------------------------------*/
+
+static void rx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct printer_dev *dev = ep->driver_data;
+ int status = req->status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ list_del_init(&req->list); /* Remode from Active List */
+
+ switch (status) {
+
+ /* normal completion */
+ case 0:
+ if (req->actual > 0) {
+ list_add_tail(&req->list, &dev->rx_buffers);
+ DBG(dev, "G_Printer : rx length %d\n", req->actual);
+ } else {
+ list_add(&req->list, &dev->rx_reqs);
+ }
+ break;
+
+ /* software-driven interface shutdown */
+ case -ECONNRESET: /* unlink */
+ case -ESHUTDOWN: /* disconnect etc */
+ VDBG(dev, "rx shutdown, code %d\n", status);
+ list_add(&req->list, &dev->rx_reqs);
+ break;
+
+ /* for hardware automagic (such as pxa) */
+ case -ECONNABORTED: /* endpoint reset */
+ DBG(dev, "rx %s reset\n", ep->name);
+ list_add(&req->list, &dev->rx_reqs);
+ break;
+
+ /* data overrun */
+ case -EOVERFLOW:
+ /* FALLTHROUGH */
+
+ default:
+ DBG(dev, "rx status %d\n", status);
+ list_add(&req->list, &dev->rx_reqs);
+ break;
+ }
+
+ wake_up_interruptible(&dev->rx_wait);
+ spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+static void tx_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct printer_dev *dev = ep->driver_data;
+
+ switch (req->status) {
+ default:
+ VDBG(dev, "tx err %d\n", req->status);
+ /* FALLTHROUGH */
+ case -ECONNRESET: /* unlink */
+ case -ESHUTDOWN: /* disconnect etc */
+ break;
+ case 0:
+ break;
+ }
+
+ spin_lock(&dev->lock);
+ /* Take the request struct off the active list and put it on the
+ * free list.
+ */
+ list_del_init(&req->list);
+ list_add(&req->list, &dev->tx_reqs);
+ wake_up_interruptible(&dev->tx_wait);
+ if (likely(list_empty(&dev->tx_reqs_active)))
+ wake_up_interruptible(&dev->tx_flush_wait);
+
+ spin_unlock(&dev->lock);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int
+printer_open(struct inode *inode, struct file *fd)
+{
+ struct printer_dev *dev;
+ unsigned long flags;
+ int ret = -EBUSY;
+
+ dev = container_of(inode->i_cdev, struct printer_dev, printer_cdev);
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ if (!dev->printer_cdev_open) {
+ dev->printer_cdev_open = 1;
+ fd->private_data = dev;
+ ret = 0;
+ /* Change the printer status to show that it's on-line. */
+ dev->printer_status |= PRINTER_SELECTED;
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ DBG(dev, "printer_open returned %x\n", ret);
+ return ret;
+}
+
+static int
+printer_close(struct inode *inode, struct file *fd)
+{
+ struct printer_dev *dev = fd->private_data;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->lock, flags);
+ dev->printer_cdev_open = 0;
+ fd->private_data = NULL;
+ /* Change printer status to show that the printer is off-line. */
+ dev->printer_status &= ~PRINTER_SELECTED;
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ DBG(dev, "printer_close\n");
+
+ return 0;
+}
+
+/* This function must be called with interrupts turned off. */
+static void
+setup_rx_reqs(struct printer_dev *dev)
+{
+ struct usb_request *req;
+
+ while (likely(!list_empty(&dev->rx_reqs))) {
+ int error;
+
+ req = container_of(dev->rx_reqs.next,
+ struct usb_request, list);
+ list_del_init(&req->list);
+
+ /* The USB Host sends us whatever amount of data it wants to
+ * so we always set the length field to the full USB_BUFSIZE.
+ * If the amount of data is more than the read() caller asked
+ * for it will be stored in the request buffer until it is
+ * asked for by read().
+ */
+ req->length = USB_BUFSIZE;
+ req->complete = rx_complete;
+
+ /* here, we unlock, and only unlock, to avoid deadlock. */
+ spin_unlock(&dev->lock);
+ error = usb_ep_queue(dev->out_ep, req, GFP_ATOMIC);
+ spin_lock(&dev->lock);
+ if (error) {
+ DBG(dev, "rx submit --> %d\n", error);
+ list_add(&req->list, &dev->rx_reqs);
+ break;
+ }
+ /* if the req is empty, then add it into dev->rx_reqs_active. */
+ else if (list_empty(&req->list))
+ list_add(&req->list, &dev->rx_reqs_active);
+ }
+}
+
+static ssize_t
+printer_read(struct file *fd, char __user *buf, size_t len, loff_t *ptr)
+{
+ struct printer_dev *dev = fd->private_data;
+ unsigned long flags;
+ size_t size;
+ size_t bytes_copied;
+ struct usb_request *req;
+ /* This is a pointer to the current USB rx request. */
+ struct usb_request *current_rx_req;
+ /* This is the number of bytes in the current rx buffer. */
+ size_t current_rx_bytes;
+ /* This is a pointer to the current rx buffer. */
+ u8 *current_rx_buf;
+
+ if (len == 0)
+ return -EINVAL;
+
+ DBG(dev, "printer_read trying to read %d bytes\n", (int)len);
+
+ mutex_lock(&dev->lock_printer_io);
+ spin_lock_irqsave(&dev->lock, flags);
+
+ /* We will use this flag later to check if a printer reset happened
+ * after we turn interrupts back on.
+ */
+ dev->reset_printer = 0;
+
+ setup_rx_reqs(dev);
+
+ bytes_copied = 0;
+ current_rx_req = dev->current_rx_req;
+ current_rx_bytes = dev->current_rx_bytes;
+ current_rx_buf = dev->current_rx_buf;
+ dev->current_rx_req = NULL;
+ dev->current_rx_bytes = 0;
+ dev->current_rx_buf = NULL;
+
+ /* Check if there is any data in the read buffers. Please note that
+ * current_rx_bytes is the number of bytes in the current rx buffer.
+ * If it is zero then check if there are any other rx_buffers that
+ * are on the completed list. We are only out of data if all rx
+ * buffers are empty.
+ */
+ if ((current_rx_bytes == 0) &&
+ (likely(list_empty(&dev->rx_buffers)))) {
+ /* Turn interrupts back on before sleeping. */
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ /*
+ * If no data is available check if this is a NON-Blocking
+ * call or not.
+ */
+ if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
+ mutex_unlock(&dev->lock_printer_io);
+ return -EAGAIN;
+ }
+
+ /* Sleep until data is available */
+ wait_event_interruptible(dev->rx_wait,
+ (likely(!list_empty(&dev->rx_buffers))));
+ spin_lock_irqsave(&dev->lock, flags);
+ }
+
+ /* We have data to return then copy it to the caller's buffer.*/
+ while ((current_rx_bytes || likely(!list_empty(&dev->rx_buffers)))
+ && len) {
+ if (current_rx_bytes == 0) {
+ req = container_of(dev->rx_buffers.next,
+ struct usb_request, list);
+ list_del_init(&req->list);
+
+ if (req->actual && req->buf) {
+ current_rx_req = req;
+ current_rx_bytes = req->actual;
+ current_rx_buf = req->buf;
+ } else {
+ list_add(&req->list, &dev->rx_reqs);
+ continue;
+ }
+ }
+
+ /* Don't leave irqs off while doing memory copies */
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (len > current_rx_bytes)
+ size = current_rx_bytes;
+ else
+ size = len;
+
+ size -= copy_to_user(buf, current_rx_buf, size);
+ bytes_copied += size;
+ len -= size;
+ buf += size;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ /* We've disconnected or reset so return. */
+ if (dev->reset_printer) {
+ list_add(&current_rx_req->list, &dev->rx_reqs);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+ return -EAGAIN;
+ }
+
+ /* If we not returning all the data left in this RX request
+ * buffer then adjust the amount of data left in the buffer.
+ * Othewise if we are done with this RX request buffer then
+ * requeue it to get any incoming data from the USB host.
+ */
+ if (size < current_rx_bytes) {
+ current_rx_bytes -= size;
+ current_rx_buf += size;
+ } else {
+ list_add(&current_rx_req->list, &dev->rx_reqs);
+ current_rx_bytes = 0;
+ current_rx_buf = NULL;
+ current_rx_req = NULL;
+ }
+ }
+
+ dev->current_rx_req = current_rx_req;
+ dev->current_rx_bytes = current_rx_bytes;
+ dev->current_rx_buf = current_rx_buf;
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+
+ DBG(dev, "printer_read returned %d bytes\n", (int)bytes_copied);
+
+ if (bytes_copied)
+ return bytes_copied;
+ else
+ return -EAGAIN;
+}
+
+static ssize_t
+printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
+{
+ struct printer_dev *dev = fd->private_data;
+ unsigned long flags;
+ size_t size; /* Amount of data in a TX request. */
+ size_t bytes_copied = 0;
+ struct usb_request *req;
+
+ DBG(dev, "printer_write trying to send %d bytes\n", (int)len);
+
+ if (len == 0)
+ return -EINVAL;
+
+ mutex_lock(&dev->lock_printer_io);
+ spin_lock_irqsave(&dev->lock, flags);
+
+ /* Check if a printer reset happens while we have interrupts on */
+ dev->reset_printer = 0;
+
+ /* Check if there is any available write buffers */
+ if (likely(list_empty(&dev->tx_reqs))) {
+ /* Turn interrupts back on before sleeping. */
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ /*
+ * If write buffers are available check if this is
+ * a NON-Blocking call or not.
+ */
+ if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
+ mutex_unlock(&dev->lock_printer_io);
+ return -EAGAIN;
+ }
+
+ /* Sleep until a write buffer is available */
+ wait_event_interruptible(dev->tx_wait,
+ (likely(!list_empty(&dev->tx_reqs))));
+ spin_lock_irqsave(&dev->lock, flags);
+ }
+
+ while (likely(!list_empty(&dev->tx_reqs)) && len) {
+
+ if (len > USB_BUFSIZE)
+ size = USB_BUFSIZE;
+ else
+ size = len;
+
+ req = container_of(dev->tx_reqs.next, struct usb_request,
+ list);
+ list_del_init(&req->list);
+
+ req->complete = tx_complete;
+ req->length = size;
+
+ /* Check if we need to send a zero length packet. */
+ if (len > size)
+ /* They will be more TX requests so no yet. */
+ req->zero = 0;
+ else
+ /* If the data amount is not a multiple of the
+ * maxpacket size then send a zero length packet.
+ */
+ req->zero = ((len % dev->in_ep->maxpacket) == 0);
+
+ /* Don't leave irqs off while doing memory copies */
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (copy_from_user(req->buf, buf, size)) {
+ list_add(&req->list, &dev->tx_reqs);
+ mutex_unlock(&dev->lock_printer_io);
+ return bytes_copied;
+ }
+
+ bytes_copied += size;
+ len -= size;
+ buf += size;
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ /* We've disconnected or reset so free the req and buffer */
+ if (dev->reset_printer) {
+ list_add(&req->list, &dev->tx_reqs);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+ return -EAGAIN;
+ }
+
+ if (usb_ep_queue(dev->in_ep, req, GFP_ATOMIC)) {
+ list_add(&req->list, &dev->tx_reqs);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+ return -EAGAIN;
+ }
+
+ list_add(&req->list, &dev->tx_reqs_active);
+
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+
+ DBG(dev, "printer_write sent %d bytes\n", (int)bytes_copied);
+
+ if (bytes_copied)
+ return bytes_copied;
+ else
+ return -EAGAIN;
+}
+
+static int
+printer_fsync(struct file *fd, loff_t start, loff_t end, int datasync)
+{
+ struct printer_dev *dev = fd->private_data;
+ struct inode *inode = file_inode(fd);
+ unsigned long flags;
+ int tx_list_empty;
+
+ mutex_lock(&inode->i_mutex);
+ spin_lock_irqsave(&dev->lock, flags);
+ tx_list_empty = (likely(list_empty(&dev->tx_reqs)));
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ if (!tx_list_empty) {
+ /* Sleep until all data has been sent */
+ wait_event_interruptible(dev->tx_flush_wait,
+ (likely(list_empty(&dev->tx_reqs_active))));
+ }
+ mutex_unlock(&inode->i_mutex);
+
+ return 0;
+}
+
+static unsigned int
+printer_poll(struct file *fd, poll_table *wait)
+{
+ struct printer_dev *dev = fd->private_data;
+ unsigned long flags;
+ int status = 0;
+
+ mutex_lock(&dev->lock_printer_io);
+ spin_lock_irqsave(&dev->lock, flags);
+ setup_rx_reqs(dev);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ mutex_unlock(&dev->lock_printer_io);
+
+ poll_wait(fd, &dev->rx_wait, wait);
+ poll_wait(fd, &dev->tx_wait, wait);
+
+ spin_lock_irqsave(&dev->lock, flags);
+ if (likely(!list_empty(&dev->tx_reqs)))
+ status |= POLLOUT | POLLWRNORM;
+
+ if (likely(dev->current_rx_bytes) ||
+ likely(!list_empty(&dev->rx_buffers)))
+ status |= POLLIN | POLLRDNORM;
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return status;
+}
+
+static long
+printer_ioctl(struct file *fd, unsigned int code, unsigned long arg)
+{
+ struct printer_dev *dev = fd->private_data;
+ unsigned long flags;
+ int status = 0;
+
+ DBG(dev, "printer_ioctl: cmd=0x%4.4x, arg=%lu\n", code, arg);
+
+ /* handle ioctls */
+
+ spin_lock_irqsave(&dev->lock, flags);
+
+ switch (code) {
+ case GADGET_GET_PRINTER_STATUS:
+ status = (int)dev->printer_status;
+ break;
+ case GADGET_SET_PRINTER_STATUS:
+ dev->printer_status = (u8)arg;
+ break;
+ default:
+ /* could not handle ioctl */
+ DBG(dev, "printer_ioctl: ERROR cmd=0x%4.4xis not supported\n",
+ code);
+ status = -ENOTTY;
+ }
+
+ spin_unlock_irqrestore(&dev->lock, flags);
+
+ return status;
+}
+
+/* used after endpoint configuration */
+static const struct file_operations printer_io_operations = {
+ .owner = THIS_MODULE,
+ .open = printer_open,
+ .read = printer_read,
+ .write = printer_write,
+ .fsync = printer_fsync,
+ .poll = printer_poll,
+ .unlocked_ioctl = printer_ioctl,
+ .release = printer_close,
+ .llseek = noop_llseek,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int
+set_printer_interface(struct printer_dev *dev)
+{
+ int result = 0;
+
+ dev->in_ep->desc = ep_desc(dev->gadget, &fs_ep_in_desc, &hs_ep_in_desc,
+ &ss_ep_in_desc);
+ dev->in_ep->driver_data = dev;
+
+ dev->out_ep->desc = ep_desc(dev->gadget, &fs_ep_out_desc,
+ &hs_ep_out_desc, &ss_ep_out_desc);
+ dev->out_ep->driver_data = dev;
+
+ result = usb_ep_enable(dev->in_ep);
+ if (result != 0) {
+ DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
+ goto done;
+ }
+
+ result = usb_ep_enable(dev->out_ep);
+ if (result != 0) {
+ DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
+ goto done;
+ }
+
+done:
+ /* on error, disable any endpoints */
+ if (result != 0) {
+ (void) usb_ep_disable(dev->in_ep);
+ (void) usb_ep_disable(dev->out_ep);
+ dev->in_ep->desc = NULL;
+ dev->out_ep->desc = NULL;
+ }
+
+ /* caller is responsible for cleanup on error */
+ return result;
+}
+
+static void printer_reset_interface(struct printer_dev *dev)
+{
+ if (dev->interface < 0)
+ return;
+
+ DBG(dev, "%s\n", __func__);
+
+ if (dev->in_ep->desc)
+ usb_ep_disable(dev->in_ep);
+
+ if (dev->out_ep->desc)
+ usb_ep_disable(dev->out_ep);
+
+ dev->in_ep->desc = NULL;
+ dev->out_ep->desc = NULL;
+ dev->interface = -1;
+}
+
+/* Change our operational Interface. */
+static int set_interface(struct printer_dev *dev, unsigned number)
+{
+ int result = 0;
+
+ /* Free the current interface */
+ printer_reset_interface(dev);
+
+ result = set_printer_interface(dev);
+ if (result)
+ printer_reset_interface(dev);
+ else
+ dev->interface = number;
+
+ if (!result)
+ INFO(dev, "Using interface %x\n", number);
+
+ return result;
+}
+
+static void printer_soft_reset(struct printer_dev *dev)
+{
+ struct usb_request *req;
+
+ INFO(dev, "Received Printer Reset Request\n");
+
+ if (usb_ep_disable(dev->in_ep))
+ DBG(dev, "Failed to disable USB in_ep\n");
+ if (usb_ep_disable(dev->out_ep))
+ DBG(dev, "Failed to disable USB out_ep\n");
+
+ if (dev->current_rx_req != NULL) {
+ list_add(&dev->current_rx_req->list, &dev->rx_reqs);
+ dev->current_rx_req = NULL;
+ }
+ dev->current_rx_bytes = 0;
+ dev->current_rx_buf = NULL;
+ dev->reset_printer = 1;
+
+ while (likely(!(list_empty(&dev->rx_buffers)))) {
+ req = container_of(dev->rx_buffers.next, struct usb_request,
+ list);
+ list_del_init(&req->list);
+ list_add(&req->list, &dev->rx_reqs);
+ }
+
+ while (likely(!(list_empty(&dev->rx_reqs_active)))) {
+ req = container_of(dev->rx_buffers.next, struct usb_request,
+ list);
+ list_del_init(&req->list);
+ list_add(&req->list, &dev->rx_reqs);
+ }
+
+ while (likely(!(list_empty(&dev->tx_reqs_active)))) {
+ req = container_of(dev->tx_reqs_active.next,
+ struct usb_request, list);
+ list_del_init(&req->list);
+ list_add(&req->list, &dev->tx_reqs);
+ }
+
+ if (usb_ep_enable(dev->in_ep))
+ DBG(dev, "Failed to enable USB in_ep\n");
+ if (usb_ep_enable(dev->out_ep))
+ DBG(dev, "Failed to enable USB out_ep\n");
+
+ wake_up_interruptible(&dev->rx_wait);
+ wake_up_interruptible(&dev->tx_wait);
+ wake_up_interruptible(&dev->tx_flush_wait);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static bool gprinter_req_match(struct usb_function *f,
+ const struct usb_ctrlrequest *ctrl)
+{
+ struct printer_dev *dev = func_to_printer(f);
+ u16 w_index = le16_to_cpu(ctrl->wIndex);
+ u16 w_value = le16_to_cpu(ctrl->wValue);
+ u16 w_length = le16_to_cpu(ctrl->wLength);
+
+ if ((ctrl->bRequestType & USB_RECIP_MASK) != USB_RECIP_INTERFACE ||
+ (ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
+ return false;
+
+ switch (ctrl->bRequest) {
+ case GET_DEVICE_ID:
+ w_index >>= 8;
+ if (w_length <= PNP_STRING_LEN &&
+ (USB_DIR_IN & ctrl->bRequestType))
+ break;
+ return false;
+ case GET_PORT_STATUS:
+ if (!w_value && w_length == 1 &&
+ (USB_DIR_IN & ctrl->bRequestType))
+ break;
+ return false;
+ case SOFT_RESET:
+ if (!w_value && !w_length &&
+ !(USB_DIR_IN & ctrl->bRequestType))
+ break;
+ /* fall through */
+ default:
+ return false;
+ }
+ return w_index == dev->interface;
+}
+
+/*
+ * The setup() callback implements all the ep0 functionality that's not
+ * handled lower down.
+ */
+static int printer_func_setup(struct usb_function *f,
+ const struct usb_ctrlrequest *ctrl)
+{
+ struct printer_dev *dev = func_to_printer(f);
+ struct usb_composite_dev *cdev = f->config->cdev;
+ struct usb_request *req = cdev->req;
+ int value = -EOPNOTSUPP;
+ u16 wIndex = le16_to_cpu(ctrl->wIndex);
+ u16 wValue = le16_to_cpu(ctrl->wValue);
+ u16 wLength = le16_to_cpu(ctrl->wLength);
+
+ DBG(dev, "ctrl req%02x.%02x v%04x i%04x l%d\n",
+ ctrl->bRequestType, ctrl->bRequest, wValue, wIndex, wLength);
+
+ switch (ctrl->bRequestType&USB_TYPE_MASK) {
+ case USB_TYPE_CLASS:
+ switch (ctrl->bRequest) {
+ case GET_DEVICE_ID: /* Get the IEEE-1284 PNP String */
+ /* Only one printer interface is supported. */
+ if ((wIndex>>8) != dev->interface)
+ break;
+
+ value = (dev->pnp_string[0] << 8) | dev->pnp_string[1];
+ memcpy(req->buf, dev->pnp_string, value);
+ DBG(dev, "1284 PNP String: %x %s\n", value,
+ &dev->pnp_string[2]);
+ break;
+
+ case GET_PORT_STATUS: /* Get Port Status */
+ /* Only one printer interface is supported. */
+ if (wIndex != dev->interface)
+ break;
+
+ *(u8 *)req->buf = dev->printer_status;
+ value = min_t(u16, wLength, 1);
+ break;
+
+ case SOFT_RESET: /* Soft Reset */
+ /* Only one printer interface is supported. */
+ if (wIndex != dev->interface)
+ break;
+
+ printer_soft_reset(dev);
+
+ value = 0;
+ break;
+
+ default:
+ goto unknown;
+ }
+ break;
+
+ default:
+unknown:
+ VDBG(dev,
+ "unknown ctrl req%02x.%02x v%04x i%04x l%d\n",
+ ctrl->bRequestType, ctrl->bRequest,
+ wValue, wIndex, wLength);
+ break;
+ }
+ /* host either stalls (value < 0) or reports success */
+ if (value >= 0) {
+ req->length = value;
+ req->zero = value < wLength;
+ value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
+ if (value < 0) {
+ ERROR(dev, "%s:%d Error!\n", __func__, __LINE__);
+ req->status = 0;
+ }
+ }
+ return value;
+}
+
+static int printer_func_bind(struct usb_configuration *c,
+ struct usb_function *f)
+{
+ struct usb_gadget *gadget = c->cdev->gadget;
+ struct printer_dev *dev = func_to_printer(f);
+ struct device *pdev;
+ struct usb_composite_dev *cdev = c->cdev;
+ struct usb_ep *in_ep;
+ struct usb_ep *out_ep = NULL;
+ struct usb_request *req;
+ dev_t devt;
+ int id;
+ int ret;
+ u32 i;
+
+ id = usb_interface_id(c, f);
+ if (id < 0)
+ return id;
+ intf_desc.bInterfaceNumber = id;
+
+ /* finish hookup to lower layer ... */
+ dev->gadget = gadget;
+
+ /* all we really need is bulk IN/OUT */
+ in_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_in_desc);
+ if (!in_ep) {
+autoconf_fail:
+ dev_err(&cdev->gadget->dev, "can't autoconfigure on %s\n",
+ cdev->gadget->name);
+ return -ENODEV;
+ }
+ in_ep->driver_data = in_ep; /* claim */
+
+ out_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_out_desc);
+ if (!out_ep)
+ goto autoconf_fail;
+ out_ep->driver_data = out_ep; /* claim */
+
+ /* assumes that all endpoints are dual-speed */
+ hs_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
+ hs_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
+ ss_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
+ ss_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
+
+ ret = usb_assign_descriptors(f, fs_printer_function,
+ hs_printer_function, ss_printer_function);
+ if (ret)
+ return ret;
+
+ dev->in_ep = in_ep;
+ dev->out_ep = out_ep;
+
+ ret = -ENOMEM;
+ for (i = 0; i < dev->q_len; i++) {
+ req = printer_req_alloc(dev->in_ep, USB_BUFSIZE, GFP_KERNEL);
+ if (!req)
+ goto fail_tx_reqs;
+ list_add(&req->list, &dev->tx_reqs);
+ }
+
+ for (i = 0; i < dev->q_len; i++) {
+ req = printer_req_alloc(dev->out_ep, USB_BUFSIZE, GFP_KERNEL);
+ if (!req)
+ goto fail_rx_reqs;
+ list_add(&req->list, &dev->rx_reqs);
+ }
+
+ /* Setup the sysfs files for the printer gadget. */
+ devt = MKDEV(major, dev->minor);
+ pdev = device_create(usb_gadget_class, NULL, devt,
+ NULL, "g_printer%d", dev->minor);
+ if (IS_ERR(pdev)) {
+ ERROR(dev, "Failed to create device: g_printer\n");
+ ret = PTR_ERR(pdev);
+ goto fail_rx_reqs;
+ }
+
+ /*
+ * Register a character device as an interface to a user mode
+ * program that handles the printer specific functionality.
+ */
+ cdev_init(&dev->printer_cdev, &printer_io_operations);
+ dev->printer_cdev.owner = THIS_MODULE;
+ ret = cdev_add(&dev->printer_cdev, devt, 1);
+ if (ret) {
+ ERROR(dev, "Failed to open char device\n");
+ goto fail_cdev_add;
+ }
+
+ return 0;
+
+fail_cdev_add:
+ device_destroy(usb_gadget_class, devt);
+
+fail_rx_reqs:
+ while (!list_empty(&dev->rx_reqs)) {
+ req = container_of(dev->rx_reqs.next, struct usb_request, list);
+ list_del(&req->list);
+ printer_req_free(dev->out_ep, req);
+ }
+
+fail_tx_reqs:
+ while (!list_empty(&dev->tx_reqs)) {
+ req = container_of(dev->tx_reqs.next, struct usb_request, list);
+ list_del(&req->list);
+ printer_req_free(dev->in_ep, req);
+ }
+
+ return ret;
+
+}
+
+static int printer_func_set_alt(struct usb_function *f,
+ unsigned intf, unsigned alt)
+{
+ struct printer_dev *dev = func_to_printer(f);
+ int ret = -ENOTSUPP;
+
+ if (!alt)
+ ret = set_interface(dev, intf);
+
+ return ret;
+}
+
+static void printer_func_disable(struct usb_function *f)
+{
+ struct printer_dev *dev = func_to_printer(f);
+ unsigned long flags;
+
+ DBG(dev, "%s\n", __func__);
+
+ spin_lock_irqsave(&dev->lock, flags);
+ printer_reset_interface(dev);
+ spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+static inline struct f_printer_opts
+*to_f_printer_opts(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct f_printer_opts,
+ func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_printer_opts);
+CONFIGFS_ATTR_OPS(f_printer_opts);
+
+static void printer_attr_release(struct config_item *item)
+{
+ struct f_printer_opts *opts = to_f_printer_opts(item);
+
+ usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations printer_item_ops = {
+ .release = printer_attr_release,
+ .show_attribute = f_printer_opts_attr_show,
+ .store_attribute = f_printer_opts_attr_store,
+};
+
+static ssize_t f_printer_opts_pnp_string_show(struct f_printer_opts *opts,
+ char *page)
+{
+ int result;
+
+ mutex_lock(&opts->lock);
+ result = strlcpy(page, opts->pnp_string + 2, PNP_STRING_LEN - 2);
+ mutex_unlock(&opts->lock);
+
+ return result;
+}
+
+static ssize_t f_printer_opts_pnp_string_store(struct f_printer_opts *opts,
+ const char *page, size_t len)
+{
+ int result, l;
+
+ mutex_lock(&opts->lock);
+ result = strlcpy(opts->pnp_string + 2, page, PNP_STRING_LEN - 2);
+ l = strlen(opts->pnp_string + 2) + 2;
+ opts->pnp_string[0] = (l >> 8) & 0xFF;
+ opts->pnp_string[1] = l & 0xFF;
+ mutex_unlock(&opts->lock);
+
+ return result;
+}
+
+static struct f_printer_opts_attribute f_printer_opts_pnp_string =
+ __CONFIGFS_ATTR(pnp_string, S_IRUGO | S_IWUSR,
+ f_printer_opts_pnp_string_show,
+ f_printer_opts_pnp_string_store);
+
+static ssize_t f_printer_opts_q_len_show(struct f_printer_opts *opts,
+ char *page)
+{
+ int result;
+
+ mutex_lock(&opts->lock);
+ result = sprintf(page, "%d\n", opts->q_len);
+ mutex_unlock(&opts->lock);
+
+ return result;
+}
+
+static ssize_t f_printer_opts_q_len_store(struct f_printer_opts *opts,
+ const char *page, size_t len)
+{
+ int ret;
+ u16 num;
+
+ mutex_lock(&opts->lock);
+ if (opts->refcnt) {
+ ret = -EBUSY;
+ goto end;
+ }
+
+ ret = kstrtou16(page, 0, &num);
+ if (ret)
+ goto end;
+
+ opts->q_len = (unsigned)num;
+ ret = len;
+end:
+ mutex_unlock(&opts->lock);
+ return ret;
+}
+
+static struct f_printer_opts_attribute f_printer_opts_q_len =
+ __CONFIGFS_ATTR(q_len, S_IRUGO | S_IWUSR, f_printer_opts_q_len_show,
+ f_printer_opts_q_len_store);
+
+static struct configfs_attribute *printer_attrs[] = {
+ &f_printer_opts_pnp_string.attr,
+ &f_printer_opts_q_len.attr,
+ NULL,
+};
+
+static struct config_item_type printer_func_type = {
+ .ct_item_ops = &printer_item_ops,
+ .ct_attrs = printer_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static inline int gprinter_get_minor(void)
+{
+ return ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL);
+}
+
+static inline void gprinter_put_minor(int minor)
+{
+ ida_simple_remove(&printer_ida, minor);
+}
+
+static int gprinter_setup(int);
+static void gprinter_cleanup(void);
+
+static void gprinter_free_inst(struct usb_function_instance *f)
+{
+ struct f_printer_opts *opts;
+
+ opts = container_of(f, struct f_printer_opts, func_inst);
+
+ mutex_lock(&printer_ida_lock);
+
+ gprinter_put_minor(opts->minor);
+ if (idr_is_empty(&printer_ida.idr))
+ gprinter_cleanup();
+
+ mutex_unlock(&printer_ida_lock);
+
+ kfree(opts);
+}
+
+static struct usb_function_instance *gprinter_alloc_inst(void)
+{
+ struct f_printer_opts *opts;
+ struct usb_function_instance *ret;
+ int status = 0;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_init(&opts->lock);
+ opts->func_inst.free_func_inst = gprinter_free_inst;
+ ret = &opts->func_inst;
+
+ mutex_lock(&printer_ida_lock);
+
+ if (idr_is_empty(&printer_ida.idr)) {
+ status = gprinter_setup(PRINTER_MINORS);
+ if (status) {
+ ret = ERR_PTR(status);
+ kfree(opts);
+ goto unlock;
+ }
+ }
+
+ opts->minor = gprinter_get_minor();
+ if (opts->minor < 0) {
+ ret = ERR_PTR(opts->minor);
+ kfree(opts);
+ if (idr_is_empty(&printer_ida.idr))
+ gprinter_cleanup();
+ goto unlock;
+ }
+ config_group_init_type_name(&opts->func_inst.group, "",
+ &printer_func_type);
+
+unlock:
+ mutex_unlock(&printer_ida_lock);
+ return ret;
+}
+
+static void gprinter_free(struct usb_function *f)
+{
+ struct printer_dev *dev = func_to_printer(f);
+ struct f_printer_opts *opts;
+
+ opts = container_of(f->fi, struct f_printer_opts, func_inst);
+ kfree(dev);
+ mutex_lock(&opts->lock);
+ --opts->refcnt;
+ mutex_unlock(&opts->lock);
+}
+
+static void printer_func_unbind(struct usb_configuration *c,
+ struct usb_function *f)
+{
+ struct printer_dev *dev;
+ struct usb_request *req;
+
+ dev = func_to_printer(f);
+
+ device_destroy(usb_gadget_class, MKDEV(major, dev->minor));
+
+ /* Remove Character Device */
+ cdev_del(&dev->printer_cdev);
+
+ /* we must already have been disconnected ... no i/o may be active */
+ WARN_ON(!list_empty(&dev->tx_reqs_active));
+ WARN_ON(!list_empty(&dev->rx_reqs_active));
+
+ /* Free all memory for this driver. */
+ while (!list_empty(&dev->tx_reqs)) {
+ req = container_of(dev->tx_reqs.next, struct usb_request,
+ list);
+ list_del(&req->list);
+ printer_req_free(dev->in_ep, req);
+ }
+
+ if (dev->current_rx_req != NULL)
+ printer_req_free(dev->out_ep, dev->current_rx_req);
+
+ while (!list_empty(&dev->rx_reqs)) {
+ req = container_of(dev->rx_reqs.next,
+ struct usb_request, list);
+ list_del(&req->list);
+ printer_req_free(dev->out_ep, req);
+ }
+
+ while (!list_empty(&dev->rx_buffers)) {
+ req = container_of(dev->rx_buffers.next,
+ struct usb_request, list);
+ list_del(&req->list);
+ printer_req_free(dev->out_ep, req);
+ }
+ usb_free_all_descriptors(f);
+}
+
+static struct usb_function *gprinter_alloc(struct usb_function_instance *fi)
+{
+ struct printer_dev *dev;
+ struct f_printer_opts *opts;
+
+ opts = container_of(fi, struct f_printer_opts, func_inst);
+
+ mutex_lock(&opts->lock);
+ if (opts->minor >= minors) {
+ mutex_unlock(&opts->lock);
+ return ERR_PTR(-ENOENT);
+ }
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
+ mutex_unlock(&opts->lock);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ ++opts->refcnt;
+ dev->minor = opts->minor;
+ dev->pnp_string = opts->pnp_string;
+ dev->q_len = opts->q_len;
+ mutex_unlock(&opts->lock);
+
+ dev->function.name = "printer";
+ dev->function.bind = printer_func_bind;
+ dev->function.setup = printer_func_setup;
+ dev->function.unbind = printer_func_unbind;
+ dev->function.set_alt = printer_func_set_alt;
+ dev->function.disable = printer_func_disable;
+ dev->function.req_match = gprinter_req_match;
+ dev->function.free_func = gprinter_free;
+
+ INIT_LIST_HEAD(&dev->tx_reqs);
+ INIT_LIST_HEAD(&dev->rx_reqs);
+ INIT_LIST_HEAD(&dev->rx_buffers);
+ INIT_LIST_HEAD(&dev->tx_reqs_active);
+ INIT_LIST_HEAD(&dev->rx_reqs_active);
+
+ spin_lock_init(&dev->lock);
+ mutex_init(&dev->lock_printer_io);
+ init_waitqueue_head(&dev->rx_wait);
+ init_waitqueue_head(&dev->tx_wait);
+ init_waitqueue_head(&dev->tx_flush_wait);
+
+ dev->interface = -1;
+ dev->printer_cdev_open = 0;
+ dev->printer_status = PRINTER_NOT_ERROR;
+ dev->current_rx_req = NULL;
+ dev->current_rx_bytes = 0;
+ dev->current_rx_buf = NULL;
+
+ return &dev->function;
+}
+
+DECLARE_USB_FUNCTION_INIT(printer, gprinter_alloc_inst, gprinter_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Craig Nadler");
+
+static int gprinter_setup(int count)
+{
+ int status;
+ dev_t devt;
+
+ usb_gadget_class = class_create(THIS_MODULE, "usb_printer_gadget");
+ if (IS_ERR(usb_gadget_class)) {
+ status = PTR_ERR(usb_gadget_class);
+ usb_gadget_class = NULL;
+ pr_err("unable to create usb_gadget class %d\n", status);
+ return status;
+ }
+
+ status = alloc_chrdev_region(&devt, 0, count, "USB printer gadget");
+ if (status) {
+ pr_err("alloc_chrdev_region %d\n", status);
+ class_destroy(usb_gadget_class);
+ usb_gadget_class = NULL;
+ return status;
+ }
+
+ major = MAJOR(devt);
+ minors = count;
+
+ return status;
+}
+
+static void gprinter_cleanup(void)
+{
+ if (major) {
+ unregister_chrdev_region(MKDEV(major, 0), minors);
+ major = minors = 0;
+ }
+ class_destroy(usb_gadget_class);
+ usb_gadget_class = NULL;
+}