// darts-usb.c // // DARTS USB driver 0.0-pre0 // // The DARTS USB driver recieves data from a radio direction finding unit, // timestamps each received datum, and makes the data available to use // user. // // Designed for Linux 2.4 // Supports devfs // // Copyright (c) 2003 Jeffrey M. Laughlin, n1ywb@arrl.org // // Based upon USB Skeleton driver - 0.7 // Copyright (c) 2001 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; either version 2 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CONFIG_USB_DEBUG #ifdef CONFIG_USB_DEBUG static int debug = 1; #else static int debug; #endif /* Use our own dbg macro */ #undef dbg #define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg); } while (0) /* Version Information */ #define DRIVER_VERSION "v0.0pre0" #define DRIVER_AUTHOR "Jeffrey M. Laughlin, n1ywb@arrl.org" #define DRIVER_DESC "DARTS USB Interface Driver" /* Module paramaters */ MODULE_PARM(debug, "i"); MODULE_PARM_DESC(debug, "Debug enabled or not"); /* Define these values to match your device */ #define DARTS_USB_VENDOR_ID 1240 // This is Microchips ID. Technically DARTS // needs to request a unique ID from the // USB organization. #define DARTS_USB_PRODUCT_ID 42 // The ultimate answer. /* table of devices that work with this driver */ static struct usb_device_id darts_usb_table [] = { { USB_DEVICE(DARTS_USB_VENDOR_ID, DARTS_USB_PRODUCT_ID) }, { } /* Terminating entry */ }; MODULE_DEVICE_TABLE (usb, darts_usb_table); // Technically, DARTS needs to request an assigned minor number range from the // USB kernel maintainer. For now we're using the skeleton's minor number. #define DARTS_USB_MINOR_BASE 192 /* we can have up to this number of device plugged in at once */ #define MAX_DEVICES 16 /* Structure to hold all of our device specific stuff */ struct darts_usb { struct usb_device * udev; /* save off the usb device pointer */ struct usb_interface * interface; /* the interface for this device */ devfs_handle_t devfs; /* devfs device node */ unsigned char minor; /* the starting minor number for this device */ unsigned char num_ports; /* the number of ports this device has */ char num_interrupt_in; /* number of interrupt in endpoints we have */ unsigned char * interrupt_in_buffer; /* the buffer to receive data */ int interrupt_in_size; /* the size of the receive buffer */ __u8 interrupt_in_endpointAddr; /* the address of the interrupt in endpoint */ struct urb * read_urb; /* the urb used to receive data */ unsigned char * userland_buffer; /* file data buffer */ int userland_size; /* the size of the file data buffer */ int open_count; /* number of times this port has been opened */ struct semaphore sem; /* locks this structure */ wait_queue_head_t read_queue; // Queue for processes blocked on read struct timeval tv; // Hold the timestamp }; /* the global usb devfs handle */ extern devfs_handle_t usb_devfs_handle; /* local function prototypes */ static ssize_t darts_usb_read (struct file *file, char *buffer, size_t count, loff_t *ppos); static int darts_usb_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); static int darts_usb_open (struct inode *inode, struct file *file); static int darts_usb_release (struct inode *inode, struct file *file); static void * darts_usb_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id); static void darts_usb_disconnect (struct usb_device *dev, void *ptr); static void darts_usb_irq (struct urb *urb); /* array of pointers to our devices that are currently connected */ static struct darts_usb *minor_table[MAX_DEVICES]; /* lock to protect the minor_table structure */ static DECLARE_MUTEX (minor_table_mutex); /* * File operations needed when we register this driver. * This assumes that this driver NEEDS file operations, * of course, which means that the driver is expected * to have a node in the /dev directory. If the USB * device were for a network interface then the driver * would use "struct net_driver" instead, and a serial * device would use "struct tty_driver". */ static struct file_operations darts_usb_fops = { /* * The owner field is part of the module-locking * mechanism. The idea is that the kernel knows * which module to increment the use-counter of * BEFORE it calls the device's open() function. * This also means that the kernel can decrement * the use-counter again before calling release() * or should the open() function fail. * * Not all device structures have an "owner" field * yet. "struct file_operations" and "struct net_device" * do, while "struct tty_driver" does not. If the struct * has an "owner" field, then initialize it to the value * THIS_MODULE and the kernel will handle all module * locking for you automatically. Otherwise, you must * increment the use-counter in the open() function * and decrement it again in the release() function * yourself. */ owner: THIS_MODULE, read: darts_usb_read, ioctl: darts_usb_ioctl, open: darts_usb_open, release: darts_usb_release, }; /* usb specific object needed to register this driver with the usb subsystem */ static struct usb_driver darts_usb_driver = { name: "darts-usb", probe: darts_usb_probe, disconnect: darts_usb_disconnect, fops: &darts_usb_fops, minor: DARTS_USB_MINOR_BASE, id_table: darts_usb_table, }; static inline void darts_usb_delete (struct darts_usb *dev) { dbg(__FUNCTION__); minor_table[dev->minor] = NULL; dbg(__FUNCTION__ " - if (dev->interrupt_in_buffer != NULL)"); if (dev->interrupt_in_buffer != NULL) { dbg(__FUNCTION__ " - kfree (dev->interrupt_in_buffer);"); kfree (dev->interrupt_in_buffer); } dbg(__FUNCTION__ " - if (dev->read_urb != NULL)"); if (dev->read_urb != NULL) { dbg(__FUNCTION__ " - usb_free_urb (dev->read_urb);"); usb_free_urb (dev->read_urb); } if (dev->userland_buffer != NULL) { dbg(__FUNCTION__ " - kfree (dev->userland_buffer);"); kfree (dev->userland_buffer); } dbg(__FUNCTION__ " - if (dev->read_urb != NULL)"); dbg(__FUNCTION__ " - kfree (dev);"); kfree (dev); } static int darts_usb_open (struct inode *inode, struct file *file) { struct darts_usb *dev = NULL; int subminor; int retval = 0; dbg(__FUNCTION__); subminor = MINOR (inode->i_rdev) - DARTS_USB_MINOR_BASE; if ((subminor < 0) || (subminor >= MAX_DEVICES)) { return -ENODEV; } /* Increment our usage count for the module. * This is redundant here, because "struct file_operations" * has an "owner" field. This line is included here soley as * a reference for drivers using lesser structures... ;-) */ MOD_INC_USE_COUNT; /* lock our minor table and get our local data for this minor */ down (&minor_table_mutex); dev = minor_table[subminor]; if (dev == NULL) { up (&minor_table_mutex); MOD_DEC_USE_COUNT; return -ENODEV; } /* lock this device */ down (&dev->sem); /* unlock the minor table */ up (&minor_table_mutex); /* increment our usage count for the driver */ ++dev->open_count; /* save our object in the file's private structure */ file->private_data = dev; /* unlock this device */ up (&dev->sem); return retval; } static int darts_usb_release (struct inode *inode, struct file *file) { struct darts_usb *dev; int retval = 0; dbg(__FUNCTION__); dev = (struct darts_usb *)file->private_data; if (dev == NULL) { dbg (__FUNCTION__ " - object is NULL"); return -ENODEV; } dbg(__FUNCTION__ " - minor %d", dev->minor); /* lock our minor table */ down (&minor_table_mutex); /* lock our device */ down (&dev->sem); if (dev->open_count <= 0) { dbg (__FUNCTION__ " - device not opened"); retval = -ENODEV; goto exit_not_opened; } if (dev->udev == NULL) { /* the device was unplugged before the file was released */ up (&dev->sem); darts_usb_delete (dev); up (&minor_table_mutex); MOD_DEC_USE_COUNT; return 0; } /* decrement our usage count for the device */ --dev->open_count; if (dev->open_count <= 0) { dev->open_count = 0; } /* decrement our usage count for the module */ MOD_DEC_USE_COUNT; exit_not_opened: up (&dev->sem); up (&minor_table_mutex); return retval; } // darts_usb_read always returns a fixed size data structure containing the // current bearing, and the timestamp of when the bearing was received. All // calls to read should request the exact number of bytes. static ssize_t darts_usb_read (struct file *file, char *buffer, size_t count, loff_t *ppos) { struct darts_usb *dev; // dbg(__FUNCTION__); dev = (struct darts_usb *)file->private_data; // dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count); // Go to sleep untill next datum is ready interruptible_sleep_on(&dev->read_queue); if (count < sizeof(long) * 2 + sizeof(unsigned char)) return -EINVAL; /* lock this object */ if (down_interruptible(&dev->sem)) return -ERESTARTSYS; /* verify that the device wasn't unplugged */ if (dev->udev == NULL) { up (&dev->sem); return -ENODEV; } // Get datum out of userland buffer and get it to the user somehow if (dev->interrupt_in_buffer == NULL) { up (&dev->sem); return -ENODEV; } if (copy_to_user (buffer, dev->interrupt_in_buffer, sizeof(unsigned char))) return -EFAULT; if (copy_to_user (buffer + sizeof(unsigned char), &dev->tv.tv_sec, sizeof(long))) return -EFAULT; if (copy_to_user (buffer + sizeof(unsigned char) + sizeof(long), &dev->tv.tv_usec, sizeof(long))) return -EFAULT; /* unlock the device */ up (&dev->sem); return (sizeof(unsigned char) + sizeof(long) * 2); } static int darts_usb_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct darts_usb *dev; dbg(__FUNCTION__); dev = (struct darts_usb *)file->private_data; /* lock this object */ down (&dev->sem); /* verify that the device wasn't unplugged */ if (dev->udev == NULL) { up (&dev->sem); return -ENODEV; } dbg(__FUNCTION__ " - minor %d, cmd 0x%.4x, arg %ld", dev->minor, cmd, arg); /* fill in your device specific stuff here */ /* unlock the device */ up (&dev->sem); /* return that we did not understand this ioctl call */ return -ENOTTY; } // The USB host controller periodically polls the DARTS device for data. When // data arrives the USB host issues an interrupt, puts the datum in the buffer, // and calls this function in interrupt context to let us know it happened. So // we take the opportunity to precisely timestamp the datum. static void darts_usb_irq(struct urb *urb) { struct darts_usb *dev = urb->context; // dbg(__FUNCTION__); // Check to make sure buffer still exists if (urb->status != USB_ST_NOERROR) { return; } do_gettimeofday(&dev->tv); // Update the timestamp // printk(KERN_DEBUG "darts-usb output: %d\n", *data ); wake_up_interruptible(&dev->read_queue); // Send wake up event to any processees sleeping on read } // The USB core driver calls this function when our device is plugged in. This // is where most of the initialization happens. static void * darts_usb_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id) { struct darts_usb *dev = NULL; struct usb_interface *interface; struct usb_interface_descriptor *iface_desc; struct usb_endpoint_descriptor *endpoint; int minor; int buffer_size; char name[10]; int pipe; dbg(__FUNCTION__); /* See if the device offered us matches what we can accept */ dbg(__FUNCTION__ " - See if the device offered us matches what we can accept"); if ((udev->descriptor.idVendor != DARTS_USB_VENDOR_ID) || (udev->descriptor.idProduct != DARTS_USB_PRODUCT_ID)) { return NULL; } /* select a "subminor" number (part of a minor number) */ dbg(__FUNCTION__ " - select a \"subminor\" number (part of a minor number) "); down (&minor_table_mutex); for (minor = 0; minor < MAX_DEVICES; ++minor) { if (minor_table[minor] == NULL) break; } if (minor >= MAX_DEVICES) { info ("Too many devices plugged in, can not handle this device."); goto exit; } /* allocate memory for our device state and intialize it */ dbg(__FUNCTION__ " - allocate memory for our device state and intialize it "); dev = kmalloc (sizeof(struct darts_usb), GFP_KERNEL); if (dev == NULL) { err ("Out of memory"); goto exit; } memset (dev, 0x00, sizeof (*dev)); minor_table[minor] = dev; interface = &udev->actconfig->interface[ifnum]; init_MUTEX (&dev->sem); dev->udev = udev; dev->interface = interface; dev->minor = minor; /* set up the endpoint information */ dbg(__FUNCTION__ " - set up the endpoint information"); iface_desc = &interface->altsetting[0]; endpoint = &iface_desc->endpoint[0]; // DARTS only has one endpoint. if (!(endpoint->bEndpointAddress & 0x80)) goto error; // See if this is an IN endpoint if ((endpoint->bmAttributes & 3) != 3) goto error; // See if this is an interrupt endpoint dbg(__FUNCTION__ " - dev->read_urb = usb_alloc_urb(0);"); dev->read_urb = usb_alloc_urb(0); if (!dev->read_urb) { err("No free URBs"); goto error; } // Set up some additional device parameters dbg(__FUNCTION__ " - fill the URB data structure using the FILL_INT_URB macro"); buffer_size = endpoint->wMaxPacketSize; dbg(__FUNCTION__ " - dev->interrupt_in_size = buffer_size;"); dev->interrupt_in_size = buffer_size; dbg(__FUNCTION__ " - dev->interrupt_in_endpointAddr = endpoint->bEndpointAddress;"); dev->interrupt_in_endpointAddr = endpoint->bEndpointAddress; dbg(__FUNCTION__ " - dev->interrupt_in_buffer = kmalloc (buffer_size, GFP_KERNEL);"); dev->interrupt_in_buffer = kmalloc (buffer_size, GFP_KERNEL); dbg(__FUNCTION__ " - if (!dev->interrupt_in_buffer)"); if (!dev->interrupt_in_buffer) { err("Couldn't allocate interrupt_in_buffer"); goto error; } // Create a buffer for users reading from our device dev->userland_size = buffer_size; dev->userland_buffer = kmalloc (buffer_size, GFP_KERNEL); if (!dev->userland_buffer) { err("Couldn't allocate userland_buffer"); goto error; } /* initialize the devfs node for this device and register it */ dbg(__FUNCTION__ " - initialize the devfs node for this device and register it"); sprintf(name, "darts-usb%d", dev->minor); dev->devfs = devfs_register (usb_devfs_handle, name, DEVFS_FL_DEFAULT, USB_MAJOR, DARTS_USB_MINOR_BASE + dev->minor, S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH, &darts_usb_fops, NULL); // Create a wait queue to allow reading process to block until the next datum is available init_waitqueue_head( &dev->read_queue ); /* fill the URB data structure using the usb_fill_int_urb function in usb.h */ dbg(__FUNCTION__ " - pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);"); pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress); dbg(__FUNCTION__ " - FILL_INT_URB"); usb_fill_int_urb(dev->read_urb, udev, pipe, dev->interrupt_in_buffer, buffer_size, darts_usb_irq, dev, endpoint->bInterval); dbg(__FUNCTION__ " - if (usb_submit_urb(dev->read_urb))"); // The second we submit the URB, the device may start to receive data. // It would be bad if darts_usb_irq were called before we were ready, // so call usb_submit_urb LAST after all buffers are allocated and all // parameters are set up. if (usb_submit_urb(dev->read_urb)) {dbg(__FUNCTION__ " - goto error"); goto error; } /* let the user know what node this device is now attached to */ info ("DARTS USB device now attached to usb/darts-usb%d", dev->minor); goto exit; error: darts_usb_delete (dev); dev = NULL; exit: up (&minor_table_mutex); return dev; } // The opposite of probe, this function is called by the usb core when // the device is removed from the system. static void darts_usb_disconnect(struct usb_device *udev, void *ptr) { struct darts_usb *dev; int minor; dbg(__FUNCTION__); dev = (struct darts_usb *)ptr; down (&minor_table_mutex); down (&dev->sem); minor = dev->minor; /* remove our devfs node */ devfs_unregister(dev->devfs); dbg(__FUNCTION__ "usb_unlink_urb(dev->read_urb);" ); usb_unlink_urb(dev->read_urb); /* if the device is not opened, then we clean up right now */ if (!dev->open_count) { up (&dev->sem); darts_usb_delete (dev); } else { dev->udev = NULL; up (&dev->sem); } info("DARTS USB #%d now disconnected", minor); up (&minor_table_mutex); dbg(__FUNCTION__ " - returning"); } static int __init darts_usb_init(void) { int result; dbg(__FUNCTION__); /* register this driver with the USB subsystem */ result = usb_register(&darts_usb_driver); if (result < 0) { err("usb_register failed for the "__FILE__" driver. Error number %d", result); return -1; } info(DRIVER_DESC " " DRIVER_VERSION); return 0; } static void __exit darts_usb_exit(void) { dbg(__FUNCTION__); /* deregister this driver with the USB subsystem */ usb_deregister(&darts_usb_driver); } module_init (darts_usb_init); module_exit (darts_usb_exit); MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL");