267 lines
6.3 KiB
C
267 lines
6.3 KiB
C
/*
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* libusual
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*
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* The libusual contains the table of devices common for ub and usb-storage.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/usb_usual.h>
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#include <linux/vmalloc.h>
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/*
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*/
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#define USU_MOD_FL_THREAD 1 /* Thread is running */
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#define USU_MOD_FL_PRESENT 2 /* The module is loaded */
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struct mod_status {
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unsigned long fls;
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};
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static struct mod_status stat[3];
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static DEFINE_SPINLOCK(usu_lock);
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/*
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*/
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#define USB_US_DEFAULT_BIAS USB_US_TYPE_STOR
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static atomic_t usu_bias = ATOMIC_INIT(USB_US_DEFAULT_BIAS);
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#define BIAS_NAME_SIZE (sizeof("usb-storage"))
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static const char *bias_names[3] = { "none", "usb-storage", "ub" };
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static DECLARE_MUTEX_LOCKED(usu_init_notify);
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static DECLARE_COMPLETION(usu_end_notify);
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static atomic_t total_threads = ATOMIC_INIT(0);
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static int usu_probe_thread(void *arg);
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/*
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* The table.
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*/
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#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
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vendorName, productName,useProtocol, useTransport, \
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initFunction, flags) \
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{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \
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.driver_info = (flags)|(USB_US_TYPE_STOR<<24) }
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#define USUAL_DEV(useProto, useTrans, useType) \
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{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \
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.driver_info = ((useType)<<24) }
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struct usb_device_id storage_usb_ids [] = {
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# include "unusual_devs.h"
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{ } /* Terminating entry */
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};
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#undef USUAL_DEV
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#undef UNUSUAL_DEV
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MODULE_DEVICE_TABLE(usb, storage_usb_ids);
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EXPORT_SYMBOL_GPL(storage_usb_ids);
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/*
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* @type: the module type as an integer
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*/
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void usb_usual_set_present(int type)
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{
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struct mod_status *st;
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unsigned long flags;
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if (type <= 0 || type >= 3)
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return;
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st = &stat[type];
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spin_lock_irqsave(&usu_lock, flags);
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st->fls |= USU_MOD_FL_PRESENT;
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spin_unlock_irqrestore(&usu_lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_usual_set_present);
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void usb_usual_clear_present(int type)
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{
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struct mod_status *st;
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unsigned long flags;
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if (type <= 0 || type >= 3)
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return;
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st = &stat[type];
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spin_lock_irqsave(&usu_lock, flags);
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st->fls &= ~USU_MOD_FL_PRESENT;
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spin_unlock_irqrestore(&usu_lock, flags);
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}
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EXPORT_SYMBOL_GPL(usb_usual_clear_present);
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/*
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* Match the calling driver type against the table.
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* Returns: 0 if the device matches.
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*/
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int usb_usual_check_type(const struct usb_device_id *id, int caller_type)
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{
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int id_type = USB_US_TYPE(id->driver_info);
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if (caller_type <= 0 || caller_type >= 3)
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return -EINVAL;
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/* Drivers grab fixed assignment devices */
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if (id_type == caller_type)
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return 0;
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/* Drivers grab devices biased to them */
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if (id_type == USB_US_TYPE_NONE && caller_type == atomic_read(&usu_bias))
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return 0;
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return -ENODEV;
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}
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EXPORT_SYMBOL_GPL(usb_usual_check_type);
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/*
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*/
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static int usu_probe(struct usb_interface *intf,
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const struct usb_device_id *id)
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{
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unsigned long type;
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int rc;
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unsigned long flags;
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type = USB_US_TYPE(id->driver_info);
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if (type == 0)
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type = atomic_read(&usu_bias);
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spin_lock_irqsave(&usu_lock, flags);
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if ((stat[type].fls & (USU_MOD_FL_THREAD|USU_MOD_FL_PRESENT)) != 0) {
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spin_unlock_irqrestore(&usu_lock, flags);
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return -ENXIO;
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}
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stat[type].fls |= USU_MOD_FL_THREAD;
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spin_unlock_irqrestore(&usu_lock, flags);
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rc = kernel_thread(usu_probe_thread, (void*)type, CLONE_VM);
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if (rc < 0) {
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printk(KERN_WARNING "libusual: "
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"Unable to start the thread for %s: %d\n",
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bias_names[type], rc);
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spin_lock_irqsave(&usu_lock, flags);
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stat[type].fls &= ~USU_MOD_FL_THREAD;
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spin_unlock_irqrestore(&usu_lock, flags);
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return rc; /* Not being -ENXIO causes a message printed */
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}
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atomic_inc(&total_threads);
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return -ENXIO;
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}
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static void usu_disconnect(struct usb_interface *intf)
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{
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; /* We should not be here. */
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}
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static struct usb_driver usu_driver = {
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.name = "libusual",
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.probe = usu_probe,
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.disconnect = usu_disconnect,
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.id_table = storage_usb_ids,
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};
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/*
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* A whole new thread for a purpose of request_module seems quite stupid.
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* The request_module forks once inside again. However, if we attempt
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* to load a storage module from our own modprobe thread, that module
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* references our symbols, which cannot be resolved until our module is
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* initialized. I wish there was a way to wait for the end of initialization.
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* The module notifier reports MODULE_STATE_COMING only.
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* So, we wait until module->init ends as the next best thing.
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*/
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static int usu_probe_thread(void *arg)
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{
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int type = (unsigned long) arg;
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struct mod_status *st = &stat[type];
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int rc;
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unsigned long flags;
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daemonize("libusual_%d", type); /* "usb-storage" is kinda too long */
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/* A completion does not work here because it's counted. */
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down(&usu_init_notify);
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up(&usu_init_notify);
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rc = request_module(bias_names[type]);
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spin_lock_irqsave(&usu_lock, flags);
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if (rc == 0 && (st->fls & USU_MOD_FL_PRESENT) == 0) {
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/*
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* This should not happen, but let us keep tabs on it.
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*/
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printk(KERN_NOTICE "libusual: "
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"modprobe for %s succeeded, but module is not present\n",
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bias_names[type]);
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}
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st->fls &= ~USU_MOD_FL_THREAD;
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spin_unlock_irqrestore(&usu_lock, flags);
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complete_and_exit(&usu_end_notify, 0);
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}
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/*
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*/
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static int __init usb_usual_init(void)
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{
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int rc;
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rc = usb_register(&usu_driver);
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up(&usu_init_notify);
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return rc;
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}
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static void __exit usb_usual_exit(void)
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{
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/*
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* We do not check for any drivers present, because
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* they keep us pinned with symbol references.
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*/
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usb_deregister(&usu_driver);
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while (atomic_read(&total_threads) > 0) {
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wait_for_completion(&usu_end_notify);
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atomic_dec(&total_threads);
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}
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}
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/*
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* Validate and accept the bias parameter.
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*/
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static int usu_set_bias(const char *bias_s, struct kernel_param *kp)
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{
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int i;
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int len;
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int bias_n = 0;
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len = strlen(bias_s);
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if (len == 0)
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return -EDOM;
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if (bias_s[len-1] == '\n')
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--len;
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for (i = 1; i < 3; i++) {
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if (strncmp(bias_s, bias_names[i], len) == 0) {
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bias_n = i;
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break;
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}
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}
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if (bias_n == 0)
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return -EINVAL;
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atomic_set(&usu_bias, bias_n);
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return 0;
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}
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static int usu_get_bias(char *buffer, struct kernel_param *kp)
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{
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return strlen(strcpy(buffer, bias_names[atomic_read(&usu_bias)]));
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}
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module_init(usb_usual_init);
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module_exit(usb_usual_exit);
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module_param_call(bias, usu_set_bias, usu_get_bias, NULL, S_IRUGO|S_IWUSR);
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__MODULE_PARM_TYPE(bias, "string");
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MODULE_PARM_DESC(bias, "Bias to usb-storage or ub");
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MODULE_LICENSE("GPL");
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