// SPDX-License-Identifier: GPL-2.0 /***************************************************************************** * USBLCD Kernel Driver * * Version 1.05 * * (C) 2005 Georges Toth <g.toth@e-biz.lu> * * * * This file is licensed under the GPL. See COPYING in the package. * * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com) * * * * * * 28.02.05 Complete rewrite of the original usblcd.c driver, * * based on usb_skeleton.c. * * This new driver allows more than one USB-LCD to be connected * * and controlled, at once * *****************************************************************************/ #include <linux/module.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/mutex.h> #include <linux/rwsem.h> #include <linux/uaccess.h> #include <linux/usb.h> #define DRIVER_VERSION "USBLCD Driver Version 1.05" #define USBLCD_MINOR 144 #define IOCTL_GET_HARD_VERSION 1 #define IOCTL_GET_DRV_VERSION 2 static const struct usb_device_id id_table[] = { { .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, }, { }, }; MODULE_DEVICE_TABLE(usb, id_table); struct usb_lcd { struct usb_device *udev; /* init: probe_lcd */ struct usb_interface *interface; /* the interface for this device */ unsigned char *bulk_in_buffer; /* the buffer to receive data */ size_t bulk_in_size; /* the size of the receive buffer */ __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */ __u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */ struct kref kref; struct semaphore limit_sem; /* to stop writes at full throttle from using up all RAM */ struct usb_anchor submitted; /* URBs to wait for before suspend */ struct rw_semaphore io_rwsem; unsigned long disconnected:1; }; #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref) #define USB_LCD_CONCURRENT_WRITES 5 static struct usb_driver lcd_driver; static void lcd_delete(struct kref *kref) { struct usb_lcd *dev = to_lcd_dev(kref); usb_put_dev(dev->udev); kfree(dev->bulk_in_buffer); kfree(dev); } static int lcd_open(struct inode *inode, struct file *file) { struct usb_lcd *dev; struct usb_interface *interface; int subminor, r; subminor = iminor(inode); interface = usb_find_interface(&lcd_driver, subminor); if (!interface) { pr_err("USBLCD: %s - error, can't find device for minor %d\n", __func__, subminor); return -ENODEV; } dev = usb_get_intfdata(interface); /* increment our usage count for the device */ kref_get(&dev->kref); /* grab a power reference */ r = usb_autopm_get_interface(interface); if (r < 0) { kref_put(&dev->kref, lcd_delete); return r; } /* save our object in the file's private structure */ file->private_data = dev; return 0; } static int lcd_release(struct inode *inode, struct file *file) { struct usb_lcd *dev; dev = file->private_data; if (dev == NULL) return -ENODEV; /* decrement the count on our device */ usb_autopm_put_interface(dev->interface); kref_put(&dev->kref, lcd_delete); return 0; } static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, loff_t *ppos) { struct usb_lcd *dev; int retval = 0; int bytes_read; dev = file->private_data; down_read(&dev->io_rwsem); if (dev->disconnected) { retval = -ENODEV; goto out_up_io; } /* do a blocking bulk read to get data from the device */ retval = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr), dev->bulk_in_buffer, min(dev->bulk_in_size, count), &bytes_read, 10000); /* if the read was successful, copy the data to userspace */ if (!retval) { if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read)) retval = -EFAULT; else retval = bytes_read; } out_up_io: up_read(&dev->io_rwsem); return retval; } static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct usb_lcd *dev; u16 bcdDevice; char buf[30]; dev = file->private_data; if (dev == NULL) return -ENODEV; switch (cmd) { case IOCTL_GET_HARD_VERSION: bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice); sprintf(buf, "%1d%1d.%1d%1d", (bcdDevice & 0xF000)>>12, (bcdDevice & 0xF00)>>8, (bcdDevice & 0xF0)>>4, (bcdDevice & 0xF)); if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) return -EFAULT; break; case IOCTL_GET_DRV_VERSION: sprintf(buf, DRIVER_VERSION); if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) return -EFAULT; break; default: return -ENOTTY; } return 0; } static void lcd_write_bulk_callback(struct urb *urb) { struct usb_lcd *dev; int status = urb->status; dev = urb->context; /* sync/async unlink faults aren't errors */ if (status && !(status == -ENOENT || status == -ECONNRESET || status == -ESHUTDOWN)) { dev_dbg(&dev->interface->dev, "nonzero write bulk status received: %d\n", status); } /* free up our allocated buffer */ usb_free_coherent(urb->dev, urb->transfer_buffer_length, urb->transfer_buffer, urb->transfer_dma); up(&dev->limit_sem); } static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos) { struct usb_lcd *dev; int retval = 0, r; struct urb *urb = NULL; char *buf = NULL; dev = file->private_data; /* verify that we actually have some data to write */ if (count == 0) goto exit; r = down_interruptible(&dev->limit_sem); if (r < 0) return -EINTR; down_read(&dev->io_rwsem); if (dev->disconnected) { retval = -ENODEV; goto err_up_io; } /* 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 err_up_io; } buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, &urb->transfer_dma); if (!buf) { retval = -ENOMEM; goto error; } if (copy_from_user(buf, user_buffer, count)) { retval = -EFAULT; goto error; } /* initialize the urb properly */ usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr), buf, count, lcd_write_bulk_callback, dev); urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; usb_anchor_urb(urb, &dev->submitted); /* send the data out the bulk port */ retval = usb_submit_urb(urb, GFP_KERNEL); if (retval) { dev_err(&dev->udev->dev, "%s - failed submitting write urb, error %d\n", __func__, retval); goto error_unanchor; } /* release our reference to this urb, the USB core will eventually free it entirely */ usb_free_urb(urb); up_read(&dev->io_rwsem); exit: return count; error_unanchor: usb_unanchor_urb(urb); error: usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); usb_free_urb(urb); err_up_io: up_read(&dev->io_rwsem); up(&dev->limit_sem); return retval; } static const struct file_operations lcd_fops = { .owner = THIS_MODULE, .read = lcd_read, .write = lcd_write, .open = lcd_open, .unlocked_ioctl = lcd_ioctl, .release = lcd_release, .llseek = noop_llseek, }; /* * 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 lcd_class = { .name = "lcd%d", .fops = &lcd_fops, .minor_base = USBLCD_MINOR, }; static int lcd_probe(struct usb_interface *interface, const struct usb_device_id *id) { struct usb_lcd *dev = NULL; struct usb_endpoint_descriptor *bulk_in, *bulk_out; int i; int retval; /* allocate memory for our device state and initialize it */ dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) return -ENOMEM; kref_init(&dev->kref); sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); init_rwsem(&dev->io_rwsem); init_usb_anchor(&dev->submitted); dev->udev = usb_get_dev(interface_to_usbdev(interface)); dev->interface = interface; if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) { dev_warn(&interface->dev, "USBLCD model not supported.\n"); retval = -ENODEV; goto error; } /* set up the endpoint information */ /* use only the first bulk-in and bulk-out endpoints */ retval = usb_find_common_endpoints(interface->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL); if (retval) { dev_err(&interface->dev, "Could not find both bulk-in and bulk-out endpoints\n"); goto error; } dev->bulk_in_size = usb_endpoint_maxp(bulk_in); dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress; dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL); if (!dev->bulk_in_buffer) { retval = -ENOMEM; goto error; } dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress; /* 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, &lcd_class); if (retval) { /* something prevented us from registering this driver */ dev_err(&interface->dev, "Not able to get a minor for this device.\n"); goto error; } i = le16_to_cpu(dev->udev->descriptor.bcdDevice); dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found " "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8, (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum); /* let the user know what node this device is now attached to */ dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n", interface->minor); return 0; error: kref_put(&dev->kref, lcd_delete); return retval; } static void lcd_draw_down(struct usb_lcd *dev) { int time; time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000); if (!time) usb_kill_anchored_urbs(&dev->submitted); } static int lcd_suspend(struct usb_interface *intf, pm_message_t message) { struct usb_lcd *dev = usb_get_intfdata(intf); if (!dev) return 0; lcd_draw_down(dev); return 0; } static int lcd_resume(struct usb_interface *intf) { return 0; } static void lcd_disconnect(struct usb_interface *interface) { struct usb_lcd *dev = usb_get_intfdata(interface); int minor = interface->minor; /* give back our minor */ usb_deregister_dev(interface, &lcd_class); down_write(&dev->io_rwsem); dev->disconnected = 1; up_write(&dev->io_rwsem); usb_kill_anchored_urbs(&dev->submitted); /* decrement our usage count */ kref_put(&dev->kref, lcd_delete); dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor); } static struct usb_driver lcd_driver = { .name = "usblcd", .probe = lcd_probe, .disconnect = lcd_disconnect, .suspend = lcd_suspend, .resume = lcd_resume, .id_table = id_table, .supports_autosuspend = 1, }; module_usb_driver(lcd_driver); MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>"); MODULE_DESCRIPTION(DRIVER_VERSION); MODULE_LICENSE("GPL");