1 /* 2 * USB Skeleton driver - 2.0 3 * 4 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation, version 2. 9 * 10 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c 11 * but has been rewritten to be easy to read and use, as no locks are now 12 * needed anymore. 13 * 14 */ 15 16 #include <linux/config.h> 17 #include <linux/kernel.h> 18 #include <linux/errno.h> 19 #include <linux/init.h> 20 #include <linux/slab.h> 21 #include <linux/module.h> 22 #include <linux/kref.h> 23 #include <asm/uaccess.h> 24 #include <linux/usb.h> 25 26 27 /* Define these values to match your devices */ 28 #define USB_SKEL_VENDOR_ID 0xfff0 29 #define USB_SKEL_PRODUCT_ID 0xfff0 30 31 /* table of devices that work with this driver */ 32 static struct usb_device_id skel_table [] = { 33 { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) }, 34 { } /* Terminating entry */ 35 }; 36 MODULE_DEVICE_TABLE (usb, skel_table); 37 38 39 /* Get a minor range for your devices from the usb maintainer */ 40 #define USB_SKEL_MINOR_BASE 192 41 42 /* Structure to hold all of our device specific stuff */ 43 struct usb_skel { 44 struct usb_device * udev; /* the usb device for this device */ 45 struct usb_interface * interface; /* the interface for this device */ 46 unsigned char * bulk_in_buffer; /* the buffer to receive data */ 47 size_t bulk_in_size; /* the size of the receive buffer */ 48 __u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */ 49 __u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */ 50 struct kref kref; 51 }; 52 #define to_skel_dev(d) container_of(d, struct usb_skel, kref) 53 54 static struct usb_driver skel_driver; 55 56 static void skel_delete(struct kref *kref) 57 { 58 struct usb_skel *dev = to_skel_dev(kref); 59 60 usb_put_dev(dev->udev); 61 kfree (dev->bulk_in_buffer); 62 kfree (dev); 63 } 64 65 static int skel_open(struct inode *inode, struct file *file) 66 { 67 struct usb_skel *dev; 68 struct usb_interface *interface; 69 int subminor; 70 int retval = 0; 71 72 subminor = iminor(inode); 73 74 interface = usb_find_interface(&skel_driver, subminor); 75 if (!interface) { 76 err ("%s - error, can't find device for minor %d", 77 __FUNCTION__, subminor); 78 retval = -ENODEV; 79 goto exit; 80 } 81 82 dev = usb_get_intfdata(interface); 83 if (!dev) { 84 retval = -ENODEV; 85 goto exit; 86 } 87 88 /* increment our usage count for the device */ 89 kref_get(&dev->kref); 90 91 /* save our object in the file's private structure */ 92 file->private_data = dev; 93 94 exit: 95 return retval; 96 } 97 98 static int skel_release(struct inode *inode, struct file *file) 99 { 100 struct usb_skel *dev; 101 102 dev = (struct usb_skel *)file->private_data; 103 if (dev == NULL) 104 return -ENODEV; 105 106 /* decrement the count on our device */ 107 kref_put(&dev->kref, skel_delete); 108 return 0; 109 } 110 111 static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos) 112 { 113 struct usb_skel *dev; 114 int retval = 0; 115 int bytes_read; 116 117 dev = (struct usb_skel *)file->private_data; 118 119 /* do a blocking bulk read to get data from the device */ 120 retval = usb_bulk_msg(dev->udev, 121 usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr), 122 dev->bulk_in_buffer, 123 min(dev->bulk_in_size, count), 124 &bytes_read, 10000); 125 126 /* if the read was successful, copy the data to userspace */ 127 if (!retval) { 128 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read)) 129 retval = -EFAULT; 130 else 131 retval = bytes_read; 132 } 133 134 return retval; 135 } 136 137 static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs) 138 { 139 struct usb_skel *dev; 140 141 dev = (struct usb_skel *)urb->context; 142 143 /* sync/async unlink faults aren't errors */ 144 if (urb->status && 145 !(urb->status == -ENOENT || 146 urb->status == -ECONNRESET || 147 urb->status == -ESHUTDOWN)) { 148 dbg("%s - nonzero write bulk status received: %d", 149 __FUNCTION__, urb->status); 150 } 151 152 /* free up our allocated buffer */ 153 usb_buffer_free(urb->dev, urb->transfer_buffer_length, 154 urb->transfer_buffer, urb->transfer_dma); 155 } 156 157 static ssize_t skel_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos) 158 { 159 struct usb_skel *dev; 160 int retval = 0; 161 struct urb *urb = NULL; 162 char *buf = NULL; 163 164 dev = (struct usb_skel *)file->private_data; 165 166 /* verify that we actually have some data to write */ 167 if (count == 0) 168 goto exit; 169 170 /* create a urb, and a buffer for it, and copy the data to the urb */ 171 urb = usb_alloc_urb(0, GFP_KERNEL); 172 if (!urb) { 173 retval = -ENOMEM; 174 goto error; 175 } 176 177 buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma); 178 if (!buf) { 179 retval = -ENOMEM; 180 goto error; 181 } 182 183 if (copy_from_user(buf, user_buffer, count)) { 184 retval = -EFAULT; 185 goto error; 186 } 187 188 /* initialize the urb properly */ 189 usb_fill_bulk_urb(urb, dev->udev, 190 usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr), 191 buf, count, skel_write_bulk_callback, dev); 192 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; 193 194 /* send the data out the bulk port */ 195 retval = usb_submit_urb(urb, GFP_KERNEL); 196 if (retval) { 197 err("%s - failed submitting write urb, error %d", __FUNCTION__, retval); 198 goto error; 199 } 200 201 /* release our reference to this urb, the USB core will eventually free it entirely */ 202 usb_free_urb(urb); 203 204 exit: 205 return count; 206 207 error: 208 usb_buffer_free(dev->udev, count, buf, urb->transfer_dma); 209 usb_free_urb(urb); 210 return retval; 211 } 212 213 static struct file_operations skel_fops = { 214 .owner = THIS_MODULE, 215 .read = skel_read, 216 .write = skel_write, 217 .open = skel_open, 218 .release = skel_release, 219 }; 220 221 /* 222 * usb class driver info in order to get a minor number from the usb core, 223 * and to have the device registered with devfs and the driver core 224 */ 225 static struct usb_class_driver skel_class = { 226 .name = "skel%d", 227 .fops = &skel_fops, 228 .minor_base = USB_SKEL_MINOR_BASE, 229 }; 230 231 static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id) 232 { 233 struct usb_skel *dev = NULL; 234 struct usb_host_interface *iface_desc; 235 struct usb_endpoint_descriptor *endpoint; 236 size_t buffer_size; 237 int i; 238 int retval = -ENOMEM; 239 240 /* allocate memory for our device state and initialize it */ 241 dev = kmalloc(sizeof(*dev), GFP_KERNEL); 242 if (dev == NULL) { 243 err("Out of memory"); 244 goto error; 245 } 246 memset(dev, 0x00, sizeof(*dev)); 247 kref_init(&dev->kref); 248 249 dev->udev = usb_get_dev(interface_to_usbdev(interface)); 250 dev->interface = interface; 251 252 /* set up the endpoint information */ 253 /* use only the first bulk-in and bulk-out endpoints */ 254 iface_desc = interface->cur_altsetting; 255 for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) { 256 endpoint = &iface_desc->endpoint[i].desc; 257 258 if (!dev->bulk_in_endpointAddr && 259 ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) 260 == USB_DIR_IN) && 261 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) 262 == USB_ENDPOINT_XFER_BULK)) { 263 /* we found a bulk in endpoint */ 264 buffer_size = le16_to_cpu(endpoint->wMaxPacketSize); 265 dev->bulk_in_size = buffer_size; 266 dev->bulk_in_endpointAddr = endpoint->bEndpointAddress; 267 dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL); 268 if (!dev->bulk_in_buffer) { 269 err("Could not allocate bulk_in_buffer"); 270 goto error; 271 } 272 } 273 274 if (!dev->bulk_out_endpointAddr && 275 ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) 276 == USB_DIR_OUT) && 277 ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) 278 == USB_ENDPOINT_XFER_BULK)) { 279 /* we found a bulk out endpoint */ 280 dev->bulk_out_endpointAddr = endpoint->bEndpointAddress; 281 } 282 } 283 if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) { 284 err("Could not find both bulk-in and bulk-out endpoints"); 285 goto error; 286 } 287 288 /* save our data pointer in this interface device */ 289 usb_set_intfdata(interface, dev); 290 291 /* we can register the device now, as it is ready */ 292 retval = usb_register_dev(interface, &skel_class); 293 if (retval) { 294 /* something prevented us from registering this driver */ 295 err("Not able to get a minor for this device."); 296 usb_set_intfdata(interface, NULL); 297 goto error; 298 } 299 300 /* let the user know what node this device is now attached to */ 301 info("USB Skeleton device now attached to USBSkel-%d", interface->minor); 302 return 0; 303 304 error: 305 if (dev) 306 kref_put(&dev->kref, skel_delete); 307 return retval; 308 } 309 310 static void skel_disconnect(struct usb_interface *interface) 311 { 312 struct usb_skel *dev; 313 int minor = interface->minor; 314 315 /* prevent skel_open() from racing skel_disconnect() */ 316 lock_kernel(); 317 318 dev = usb_get_intfdata(interface); 319 usb_set_intfdata(interface, NULL); 320 321 /* give back our minor */ 322 usb_deregister_dev(interface, &skel_class); 323 324 unlock_kernel(); 325 326 /* decrement our usage count */ 327 kref_put(&dev->kref, skel_delete); 328 329 info("USB Skeleton #%d now disconnected", minor); 330 } 331 332 static struct usb_driver skel_driver = { 333 .owner = THIS_MODULE, 334 .name = "skeleton", 335 .probe = skel_probe, 336 .disconnect = skel_disconnect, 337 .id_table = skel_table, 338 }; 339 340 static int __init usb_skel_init(void) 341 { 342 int result; 343 344 /* register this driver with the USB subsystem */ 345 result = usb_register(&skel_driver); 346 if (result) 347 err("usb_register failed. Error number %d", result); 348 349 return result; 350 } 351 352 static void __exit usb_skel_exit(void) 353 { 354 /* deregister this driver with the USB subsystem */ 355 usb_deregister(&skel_driver); 356 } 357 358 module_init (usb_skel_init); 359 module_exit (usb_skel_exit); 360 361 MODULE_LICENSE("GPL"); 362