/* * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet * Copyright (C) 2001 O'Reilly & Associates * * The source code in this file can be freely used, adapted, * and redistributed in source or binary form, so long as an * acknowledgment appears in derived source files.  The citation * should list that the code comes from the book "Linux Device * Drivers" by Alessandro Rubini and Jonathan Corbet, published * by O'Reilly & Associates.   No warranty is attached; * we cannot take responsibility for errors or fitness for use. * * * This sample driver implements USB protocol decoding for both an USB * keyboard and an USB mouse. You can test it using either device, provided * they are not already managed by the official drivers. If you want * to only experiment with one device, pass the nokbd=1 or the * no_mouse=1 option to the command line of insmod */#ifndef __KERNEL__#  define __KERNEL__#endif#ifndef MODULE#  define MODULE#endif#include <linux/config.h>#include <linux/module.h>/* No USB with 2.0, make an explicit error and avoid strange ones */#if LINUX_VERSION_CODE < 0x020200#  error "This module needs kmod, so it won't run with 2.0"#else#include <linux/kernel.h>#include <linux/malloc.h>#include <linux/init.h>#include <linux/usb.h>/* * Note: <linux/usb.h> in 2.2 includes <linux/kcomp.h> that breaks * our sysdep.h . You can't disable kcomp.h from entering the game, * so "sysdep.h" can't be included here. If you write a backward-portable * driver with both USB and something-else support, you need to separate * the USB stuff in order not to rely on sysdep.h in USB-related  files */#if 0  #include "sysdep.h"#else  #include "usb-sysdep.h"#endif/* * We need a local data structure, as it must be allocated for each new * mouse device plugged in the USB bus */struct sample_device {    unsigned char data[8];   /* enough for keyboard and mouse protocols */    char *name;              /* either "kdb" or "mouse" */    struct urb urb;          /* USB Request block, to get USB data*/    int maxp;                /* packet len */    char output[80];         /* used for printk at irq time */};/* * Handler for data sent in by the device. The function is called by * the USB kernel subsystem whenever a device spits out new data */static void sample_irq(struct urb *urb){    struct sample_device *sample = urb->context;    char *pos = sample->output;    int i;    if (urb->status != USB_ST_NOERROR) return;    pos += sprintf(pos, "usbsample: data from %-8s =",		   sample->name);    for (i=0; i<sample->maxp; i++) {	pos += sprintf(pos, " %02x", sample->data[i]);    }    printk(KERN_INFO "%s\n", sample->output);}/* * These two callbacks are invoked when an USB device is detached or attached * to the bus */static void sample_disconnect(struct usb_device *udev, void *clientdata){    /* the clientdata is the sample_device we passed originally */    struct sample_device *sample = clientdata;    /* remove the URB, remove the input device, free memory */    usb_unlink_urb(&sample->urb);    kfree(sample);    printk(KERN_INFO "sample: USB %s disconnected\n", sample->name);    /*     * here you might MOD_DEC_USE_COUNT, but only if you increment     * the count in sample_probe() below     */    return;}static void *sample_probe(struct usb_device *udev, unsigned int ifnum,			  const struct usb_device_id *id){    /*     * The probe procedure is pretty standard. Device matching has already     * been performed based on the id_table structure (defined later)     */    struct usb_interface *iface;    struct usb_interface_descriptor *interface;    struct usb_endpoint_descriptor *endpoint;    struct sample_device *sample;    printk(KERN_INFO "usbsample: probe called for %s device\n",	   (char *)id->driver_info /* "mouse" or "keyboard" */ );    iface = &udev->actconfig->interface[ifnum];    interface = &iface->altsetting[iface->act_altsetting];    if (interface->bNumEndpoints != 1) return NULL;    endpoint = interface->endpoint + 0;    if (!(endpoint->bEndpointAddress & 0x80)) return NULL;    if ((endpoint->bmAttributes & 3) != 3) return NULL;    usb_set_protocol(udev, interface->bInterfaceNumber, 0);    usb_set_idle(udev, interface->bInterfaceNumber, 0, 0);    /* allocate and zero a new data structure for the new device */    sample = kmalloc(sizeof(struct sample_device), GFP_KERNEL);    if (!sample) return NULL; /* failure */    memset(sample, 0, sizeof(*sample));    sample->name = (char *)id->driver_info;    /* fill the URB data structure using the FILL_INT_URB macro */    {	int pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);	int maxp = usb_maxpacket(udev, pipe, usb_pipeout(pipe));		if (maxp > 8) maxp = 8; sample->maxp = maxp; /* remember for later */	FILL_INT_URB(&sample->urb, udev, pipe, sample->data, maxp,		      sample_irq, sample, endpoint->bInterval);    }    /* register the URB within the USB subsystem */    if (usb_submit_urb(&sample->urb)) {	kfree(sample);	return NULL;    }    /* announce yourself */    printk(KERN_INFO "usbsample: probe successful for %s (maxp is %i)\n",	   sample->name, sample->maxp);    /*     * here you might MOD_INC_USE_COUNT; if you do, you'll need to unplug     * the device or the devices before being able to unload the module     */    /* and return the new structure */    return sample;}/* * The id_table, lists all devices that can be handled by this driver. * The three numbers are class, subclass, protocol. <linux/usb.h> has * more details about interface mathces and vendor/device matches. * This feature is not there in version 2.2, see below, sample_probe_22() * for details. Here we use a fake usb_device_id structure defined in  * ./usb-sysdep.h */static struct usb_device_id sample_id_table [] = {    {	USB_INTERFACE_INFO(3, 1, 1),	driver_info: (unsigned long)"keyboard"    },    {	USB_INTERFACE_INFO(3, 1, 2),	driver_info: (unsigned long)"mouse"    },    {	0, /* no more matches */    }};/* * The callbacks are registered within the USB subsystem using the * usb_driver data structure */#ifdef LINUX_24static struct usb_driver sample_usb_driver = {        name:        "sample",        probe:       sample_probe,        disconnect:  sample_disconnect,        id_table:    sample_id_table,};#else /* 2.2 *//* * With version 2.2, there is no device_id support: the probe function * is called for every device being plugged, and it must select whether * the device is going to be handled or not. Here we extract the identification * phase (based on class/subclass/protocol in this case) and rely on * sample_probe() above for the interesting part of the game. Note * that a 2.4 driver can use this approach as well, by not defining an * id table (and achieving a 2.2 and 2.4 source with less ifdef). We think * the id_table way is much cleaner, so we chose to exploit it where available */static void *sample_probe_22(struct usb_device *udev, unsigned int ifnum){    struct usb_device_id *id;    struct usb_interface_descriptor *interface;    printk(KERN_INFO "sample_probe_22 called\n");    if (udev->descriptor.bNumConfigurations != 1) return NULL;    interface = udev->config[0].interface[ifnum].altsetting;    for (id = sample_id_table; id->driver_info; id++) {        if (interface->bInterfaceClass !=    id->class)    continue;        if (interface->bInterfaceSubClass != id->subclass) continue;        if (interface->bInterfaceProtocol != id->protocol) continue;	break; /* found */    }    if (!id->driver_info)	return NULL; /* not ours */    return sample_probe(udev, ifnum, id);}static struct usb_driver sample_usb_driver = {        name:        "sample",        probe:       sample_probe_22,        disconnect:  sample_disconnect,	/* no id_table field here */};#endif /* 2.2 *//* * Functions called at module load and unload time: only register and * unregister the USB callbacks */int sample_init(void){    /* just register it, returns 0 or error code */    return usb_register(&sample_usb_driver);}void sample_exit(void){    usb_deregister(&sample_usb_driver);}module_init(sample_init);module_exit(sample_exit);#endif /* no 2.0 */