From a00828e9ac62caed7b830d631914d7748817ccd1 Mon Sep 17 00:00:00 2001 From: Pete Zaitcev Date: Sat, 22 Oct 2005 20:15:09 -0700 Subject: [PATCH] USB: drivers/usb/storage/libusual This patch adds a shim driver libusual, which routes devices between usb-storage and ub according to the common table, based on unusual_devs.h. The help and example syntax is in Kconfig. Signed-off-by: Pete Zaitcev Signed-off-by: Greg Kroah-Hartman --- drivers/usb/storage/libusual.c | 266 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 266 insertions(+) create mode 100644 drivers/usb/storage/libusual.c (limited to 'drivers/usb/storage/libusual.c') diff --git a/drivers/usb/storage/libusual.c b/drivers/usb/storage/libusual.c new file mode 100644 index 0000000..61f73d8 --- /dev/null +++ b/drivers/usb/storage/libusual.c @@ -0,0 +1,266 @@ +/* + * libusual + * + * The libusual contains the table of devices common for ub and usb-storage. + */ +#include +#include +#include +#include +#include + +/* + */ +#define USU_MOD_FL_THREAD 1 /* Thread is running */ +#define USU_MOD_FL_PRESENT 2 /* The module is loaded */ + +struct mod_status { + unsigned long fls; +}; + +static struct mod_status stat[3]; +static DEFINE_SPINLOCK(usu_lock); + +/* + */ +#define USB_US_DEFAULT_BIAS USB_US_TYPE_STOR + +#define BIAS_NAME_SIZE (sizeof("usb-storage")) +static char bias[BIAS_NAME_SIZE]; +static int usb_usual_bias; +static const char *bias_names[3] = { "none", "usb-storage", "ub" }; + +static DECLARE_MUTEX_LOCKED(usu_init_notify); +static DECLARE_COMPLETION(usu_end_notify); +static atomic_t total_threads = ATOMIC_INIT(0); + +static int usu_probe_thread(void *arg); +static int parse_bias(const char *bias_s); + +/* + * The table. + */ +#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \ + vendorName, productName,useProtocol, useTransport, \ + initFunction, flags) \ +{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \ + .driver_info = (flags)|(USB_US_TYPE_STOR<<24) } + +#define USUAL_DEV(useProto, useTrans, useType) \ +{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \ + .driver_info = ((useType)<<24) } + +struct usb_device_id storage_usb_ids [] = { +# include "unusual_devs.h" + { } /* Terminating entry */ +}; + +#undef USUAL_DEV +#undef UNUSUAL_DEV + +MODULE_DEVICE_TABLE(usb, storage_usb_ids); +EXPORT_SYMBOL_GPL(storage_usb_ids); + +/* + * @type: the module type as an integer + */ +void usb_usual_set_present(int type) +{ + struct mod_status *st; + unsigned long flags; + + if (type <= 0 || type >= 3) + return; + st = &stat[type]; + spin_lock_irqsave(&usu_lock, flags); + st->fls |= USU_MOD_FL_PRESENT; + spin_unlock_irqrestore(&usu_lock, flags); +} +EXPORT_SYMBOL_GPL(usb_usual_set_present); + +void usb_usual_clear_present(int type) +{ + struct mod_status *st; + unsigned long flags; + + if (type <= 0 || type >= 3) + return; + st = &stat[type]; + spin_lock_irqsave(&usu_lock, flags); + st->fls &= ~USU_MOD_FL_PRESENT; + spin_unlock_irqrestore(&usu_lock, flags); +} +EXPORT_SYMBOL_GPL(usb_usual_clear_present); + +/* + * Match the calling driver type against the table. + * Returns: 0 if the device matches. + */ +int usb_usual_check_type(const struct usb_device_id *id, int caller_type) +{ + int id_type = USB_US_TYPE(id->driver_info); + + if (caller_type <= 0 || caller_type >= 3) + return -EINVAL; + + /* Drivers grab fixed assignment devices */ + if (id_type == caller_type) + return 0; + /* Drivers grab devices biased to them */ + if (id_type == USB_US_TYPE_NONE && caller_type == usb_usual_bias) + return 0; + return -ENODEV; +} +EXPORT_SYMBOL_GPL(usb_usual_check_type); + +/* + */ +static int usu_probe(struct usb_interface *intf, + const struct usb_device_id *id) +{ + int type; + int rc; + unsigned long flags; + + type = USB_US_TYPE(id->driver_info); + if (type == 0) + type = usb_usual_bias; + + spin_lock_irqsave(&usu_lock, flags); + if ((stat[type].fls & (USU_MOD_FL_THREAD|USU_MOD_FL_PRESENT)) != 0) { + spin_unlock_irqrestore(&usu_lock, flags); + return -ENXIO; + } + stat[type].fls |= USU_MOD_FL_THREAD; + spin_unlock_irqrestore(&usu_lock, flags); + + rc = kernel_thread(usu_probe_thread, (void*)type, CLONE_VM); + if (rc < 0) { + printk(KERN_WARNING "libusual: " + "Unable to start the thread for %s: %d\n", + bias_names[type], rc); + spin_lock_irqsave(&usu_lock, flags); + stat[type].fls &= ~USU_MOD_FL_THREAD; + spin_unlock_irqrestore(&usu_lock, flags); + return rc; /* Not being -ENXIO causes a message printed */ + } + atomic_inc(&total_threads); + + return -ENXIO; +} + +static void usu_disconnect(struct usb_interface *intf) +{ + ; /* We should not be here. */ +} + +static struct usb_driver usu_driver = { + .owner = THIS_MODULE, + .name = "libusual", + .probe = usu_probe, + .disconnect = usu_disconnect, + .id_table = storage_usb_ids, +}; + +/* + * A whole new thread for a purpose of request_module seems quite stupid. + * The request_module forks once inside again. However, if we attempt + * to load a storage module from our own modprobe thread, that module + * references our symbols, which cannot be resolved until our module is + * initialized. I wish there was a way to wait for the end of initialization. + * The module notifier reports MODULE_STATE_COMING only. + * So, we wait until module->init ends as the next best thing. + */ +static int usu_probe_thread(void *arg) +{ + int type = (unsigned long) arg; + struct mod_status *st = &stat[type]; + int rc; + unsigned long flags; + + daemonize("libusual_%d", type); /* "usb-storage" is kinda too long */ + + /* A completion does not work here because it's counted. */ + down(&usu_init_notify); + up(&usu_init_notify); + + rc = request_module(bias_names[type]); + spin_lock_irqsave(&usu_lock, flags); + if (rc == 0 && (st->fls & USU_MOD_FL_PRESENT) == 0) { + /* + * This should not happen, but let us keep tabs on it. + */ + printk(KERN_NOTICE "libusual: " + "modprobe for %s succeeded, but module is not present\n", + bias_names[type]); + } + st->fls &= ~USU_MOD_FL_THREAD; + spin_unlock_irqrestore(&usu_lock, flags); + + complete_and_exit(&usu_end_notify, 0); +} + +/* + */ +static int __init usb_usual_init(void) +{ + int rc; + + bias[BIAS_NAME_SIZE-1] = 0; + usb_usual_bias = parse_bias(bias); + + rc = usb_register(&usu_driver); + up(&usu_init_notify); + return rc; +} + +static void __exit usb_usual_exit(void) +{ + /* + * We do not check for any drivers present, because + * they keep us pinned with symbol references. + */ + + usb_deregister(&usu_driver); + + while (atomic_read(&total_threads) > 0) { + wait_for_completion(&usu_end_notify); + atomic_dec(&total_threads); + } +} + +/* + * Validate and accept the bias parameter. + * Maybe make an sysfs method later. XXX + */ +static int parse_bias(const char *bias_s) +{ + int i; + int bias_n = 0; + + if (bias_s[0] == 0 || bias_s[0] == ' ') { + bias_n = USB_US_DEFAULT_BIAS; + } else { + for (i = 1; i < 3; i++) { + if (strcmp(bias_s, bias_names[i]) == 0) { + bias_n = i; + break; + } + } + if (bias_n == 0) { + bias_n = USB_US_DEFAULT_BIAS; + printk(KERN_INFO + "libusual: unknown bias \"%s\", using \"%s\"\n", + bias_s, bias_names[bias_n]); + } + } + return bias_n; +} + +module_init(usb_usual_init); +module_exit(usb_usual_exit); + +module_param_string(bias, bias, BIAS_NAME_SIZE, S_IRUGO|S_IWUSR); +MODULE_PARM_DESC(bias, "Bias to usb-storage or ub"); + +MODULE_LICENSE("GPL"); -- cgit v1.1