/**************************************************************************** * drivers/usbhost/usbhost_skeleton.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Configuration ************************************************************/ #ifndef CONFIG_SCHED_WORKQUEUE # warning "Worker thread support is required (CONFIG_SCHED_WORKQUEUE)" #endif /* Driver support ***********************************************************/ /* This format is used to construct the /dev/skel[n] device driver path. It * defined here so that it will be used consistently in all places. */ #define DEV_FORMAT "/dev/skel%c" #define DEV_NAMELEN 12 /* Used in usbhost_cfgdesc() */ #define USBHOST_IFFOUND 0x01 #define USBHOST_BINFOUND 0x02 #define USBHOST_BOUTFOUND 0x04 #define USBHOST_ALLFOUND 0x07 #define USBHOST_MAX_CREFS 0x7fff /**************************************************************************** * Private Types ****************************************************************************/ /* This structure contains the internal, private state of the USB host class * driver. */ struct usbhost_state_s { /* This is the externally visible portion of the state */ struct usbhost_class_s usbclass; /* The remainder of the fields are provide to the class driver */ char devchar; /* Character identifying the /dev/skel[n] device */ volatile bool disconnected; /* TRUE: Device has been disconnected */ uint8_t ifno; /* Interface number */ int16_t crefs; /* Reference count on the driver instance */ sem_t exclsem; /* Used to maintain mutual exclusive access */ struct work_s work; /* For interacting with the worker thread */ FAR uint8_t *tbuffer; /* The allocated transfer buffer */ size_t tbuflen; /* Size of the allocated transfer buffer */ usbhost_ep_t epin; /* IN endpoint */ usbhost_ep_t epout; /* OUT endpoint */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Semaphores */ static int usbhost_takesem(FAR sem_t *sem); static void usbhost_forcetake(FAR sem_t *sem); #define usbhost_givesem(s) nxsem_post(s); /* Memory allocation services */ static inline FAR struct usbhost_state_s *usbhost_allocclass(void); static inline void usbhost_freeclass(FAR struct usbhost_state_s *usbclass); /* Device name management */ static int usbhost_allocdevno(FAR struct usbhost_state_s *priv); static void usbhost_freedevno(FAR struct usbhost_state_s *priv); static inline void usbhost_mkdevname(FAR struct usbhost_state_s *priv, FAR char *devname); /* Worker thread actions */ static void usbhost_destroy(FAR void *arg); /* Helpers for usbhost_connect() */ static inline int usbhost_cfgdesc(FAR struct usbhost_state_s *priv, FAR const uint8_t *configdesc, int desclen); static inline int usbhost_devinit(FAR struct usbhost_state_s *priv); /* (Little Endian) Data helpers */ static inline uint16_t usbhost_getle16(const uint8_t *val); static inline void usbhost_putle16(uint8_t *dest, uint16_t val); static inline uint32_t usbhost_getle32(const uint8_t *val); static void usbhost_putle32(uint8_t *dest, uint32_t val); /* Transfer descriptor memory management */ static inline int usbhost_talloc(FAR struct usbhost_state_s *priv); static inline int usbhost_tfree(FAR struct usbhost_state_s *priv); /* struct usbhost_registry_s methods */ static struct usbhost_class_s * usbhost_create(FAR struct usbhost_hubport_s *hport, FAR const struct usbhost_id_s *id); /* struct usbhost_class_s methods */ static int usbhost_connect(FAR struct usbhost_class_s *usbclass, FAR const uint8_t *configdesc, int desclen); static int usbhost_disconnected(FAR struct usbhost_class_s *usbclass); /* Driver methods -- depend upon the type of NuttX driver interface exported */ /**************************************************************************** * Private Data ****************************************************************************/ /* This structure provides the registry entry ID information that will be * used to associate the USB class driver to a connected USB device. */ static const struct usbhost_id_s g_id = { 0, /* base -- Must be one of the USB_CLASS_* definitions in usb.h */ 0, /* subclass -- depends on the device */ 0, /* proto -- depends on the device */ 0, /* vid */ 0 /* pid */ }; /* This is the USB host storage class's registry entry */ static struct usbhost_registry_s g_skeleton = { NULL, /* flink */ usbhost_create, /* create */ 1, /* nids */ &g_id /* id[] */ }; /* This is a bitmap that is used to allocate device names /dev/skela-z. */ static uint32_t g_devinuse; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: usbhost_takesem * * Description: * This is just a wrapper to handle the annoying behavior of semaphore * waits that return due to the receipt of a signal. * ****************************************************************************/ static int usbhost_takesem(FAR sem_t *sem) { return nxsem_wait_uninterruptible(sem); } /**************************************************************************** * Name: usbhost_forcetake * * Description: * This is just another wrapper but this one continues even if the thread * is canceled. This must be done in certain conditions where were must * continue in order to clean-up resources. * ****************************************************************************/ static void usbhost_forcetake(FAR sem_t *sem) { int ret; do { ret = nxsem_wait_uninterruptible(sem); /* The only expected error would -ECANCELED meaning that the * parent thread has been canceled. We have to continue and * terminate the poll in this case. */ DEBUGASSERT(ret == OK || ret == -ECANCELED); } while (ret < 0); } /**************************************************************************** * Name: usbhost_allocclass * * Description: * This is really part of the logic that implements the create() method * of struct usbhost_registry_s. This function allocates memory for one * new class instance. * * Input Parameters: * None * * Returned Value: * On success, this function will return a non-NULL instance of struct * usbhost_class_s. NULL is returned on failure; this function will * will fail only if there are insufficient resources to create another * USB host class instance. * ****************************************************************************/ static inline FAR struct usbhost_state_s *usbhost_allocclass(void) { FAR struct usbhost_state_s *priv; DEBUGASSERT(!up_interrupt_context()); priv = (FAR struct usbhost_state_s *) kmm_malloc(sizeof(struct usbhost_state_s)); uinfo("Allocated: %p\n", priv); return priv; } /**************************************************************************** * Name: usbhost_freeclass * * Description: * Free a class instance previously allocated by usbhost_allocclass(). * * Input Parameters: * usbclass - A reference to the class instance to be freed. * * Returned Value: * None * ****************************************************************************/ static inline void usbhost_freeclass(FAR struct usbhost_state_s *usbclass) { DEBUGASSERT(usbclass != NULL); /* Free the class instance (perhaps calling sched_kmm_free() in case we are * executing from an interrupt handler. */ uinfo("Freeing: %p\n", usbclass); kmm_free(usbclass); } /**************************************************************************** * Name: Device name management * * Description: * Some tiny functions to coordinate management of device names. * ****************************************************************************/ static int usbhost_allocdevno(FAR struct usbhost_state_s *priv) { irqstate_t flags; int devno; flags = enter_critical_section(); for (devno = 0; devno < 26; devno++) { uint32_t bitno = 1 << devno; if ((g_devinuse & bitno) == 0) { g_devinuse |= bitno; priv->devchar = 'a' + devno; leave_critical_section(flags); return OK; } } leave_critical_section(flags); return -EMFILE; } static void usbhost_freedevno(FAR struct usbhost_state_s *priv) { int devno = 'a' - priv->devchar; if (devno >= 0 && devno < 26) { irqstate_t flags = enter_critical_section(); g_devinuse &= ~(1 << devno); leave_critical_section(flags); } } static inline void usbhost_mkdevname(FAR struct usbhost_state_s *priv, FAR char *devname) { snprintf(devname, DEV_NAMELEN, DEV_FORMAT, priv->devchar); } /**************************************************************************** * Name: usbhost_destroy * * Description: * The USB device has been disconnected and the reference count on the USB * host class instance has gone to 1.. Time to destroy the USB host class * instance. * * Input Parameters: * arg - A reference to the class instance to be destroyed. * * Returned Value: * None * ****************************************************************************/ static void usbhost_destroy(FAR void *arg) { FAR struct usbhost_state_s *priv = (FAR struct usbhost_state_s *)arg; FAR struct usbhost_hubport_s *hport; FAR struct usbhost_driver_s *drvr; DEBUGASSERT(priv != NULL && priv->usbclass.hport != NULL); hport = priv->usbclass.hport; DEBUGASSERT(hport->drvr); drvr = hport->drvr; uinfo("crefs: %d\n", priv->crefs); /* Unregister the driver */ /* Release the device name used by this connection */ usbhost_freedevno(priv); /* Free the endpoints */ /* Free any transfer buffers */ /* Free the function address assigned to this device */ usbhost_devaddr_destroy(hport, hport->funcaddr); hport->funcaddr = 0; /* Destroy the semaphores */ /* Disconnect the USB host device */ DRVR_DISCONNECT(drvr, hport); /* And free the class instance. Hmmm.. this may execute on the worker * thread and the work structure is part of what is getting freed. That * should be okay because once the work contained is removed from the * queue, it should not longer be accessed by the worker thread. */ usbhost_freeclass(priv); } /**************************************************************************** * Name: usbhost_cfgdesc * * Description: * This function implements the connect() method of struct * usbhost_class_s. This method is a callback into the class * implementation. It is used to provide the device's configuration * descriptor to the class so that the class may initialize properly * * Input Parameters: * priv - The USB host class instance. * configdesc - A pointer to a uint8_t buffer container the configuration * descriptor. * desclen - The length in bytes of the configuration descriptor. * * Returned Value: * On success, zero (OK) is returned. On a failure, a negated errno value * is returned indicating the nature of the failure * * Assumptions: * This function will *not* be called from an interrupt handler. * ****************************************************************************/ static inline int usbhost_cfgdesc(FAR struct usbhost_state_s *priv, FAR const uint8_t *configdesc, int desclen) { FAR struct usbhost_hubport_s *hport; FAR struct usb_cfgdesc_s *cfgdesc; FAR struct usb_desc_s *desc; FAR struct usbhost_epdesc_s bindesc; FAR struct usbhost_epdesc_s boutdesc; int remaining; uint8_t found = 0; int ret; DEBUGASSERT(priv != NULL && priv->usbclass.hport && configdesc != NULL && desclen >= sizeof(struct usb_cfgdesc_s)); hport = priv->usbclass.hport; /* Verify that we were passed a configuration descriptor */ cfgdesc = (FAR struct usb_cfgdesc_s *)configdesc; if (cfgdesc->type != USB_DESC_TYPE_CONFIG) { return -EINVAL; } /* Get the total length of the configuration descriptor (little endian). * It might be a good check to get the number of interfaces here too. */ remaining = (int)usbhost_getle16(cfgdesc->totallen); /* Skip to the next entry descriptor */ configdesc += cfgdesc->len; remaining -= cfgdesc->len; /* Loop where there are more dscriptors to examine */ while (remaining >= sizeof(struct usb_desc_s)) { /* What is the next descriptor? */ desc = (FAR struct usb_desc_s *)configdesc; switch (desc->type) { /* Interface descriptor. We really should get the number of endpoints * from this descriptor too. */ case USB_DESC_TYPE_INTERFACE: { FAR struct usb_ifdesc_s *ifdesc = (FAR struct usb_ifdesc_s *)configdesc; uinfo("Interface descriptor\n"); DEBUGASSERT(remaining >= USB_SIZEOF_IFDESC); /* Save the interface number and mark ONLY the interface found */ priv->ifno = ifdesc->ifno; found = USBHOST_IFFOUND; } break; /* Endpoint descriptor. Here, we expect two bulk endpoints, an IN * and an OUT. */ case USB_DESC_TYPE_ENDPOINT: { FAR struct usb_epdesc_s *epdesc = (FAR struct usb_epdesc_s *)configdesc; uinfo("Endpoint descriptor\n"); DEBUGASSERT(remaining >= USB_SIZEOF_EPDESC); /* Check for a bulk endpoint. */ if ((epdesc->attr & USB_EP_ATTR_XFERTYPE_MASK) == USB_EP_ATTR_XFER_BULK) { /* Yes.. it is a bulk endpoint. IN or OUT? */ if (USB_ISEPOUT(epdesc->addr)) { /* It is an OUT bulk endpoint. There should be only one * bulk OUT endpoint. */ if ((found & USBHOST_BOUTFOUND) != 0) { /* Oops.. more than one endpoint. We don't know * what to do with this. */ return -EINVAL; } found |= USBHOST_BOUTFOUND; /* Save the bulk OUT endpoint information */ boutdesc.hport = hport; boutdesc.addr = epdesc->addr & USB_EP_ADDR_NUMBER_MASK; boutdesc.in = false; boutdesc.xfrtype = USB_EP_ATTR_XFER_BULK; boutdesc.interval = epdesc->interval; boutdesc.mxpacketsize = usbhost_getle16(epdesc->mxpacketsize); uinfo("Bulk OUT EP addr:%d mxpacketsize:%d\n", boutdesc.addr, boutdesc.mxpacketsize); } else { /* It is an IN bulk endpoint. There should be only one * bulk IN endpoint. */ if ((found & USBHOST_BINFOUND) != 0) { /* Oops.. more than one endpoint. We don't know * what to do with this. */ return -EINVAL; } found |= USBHOST_BINFOUND; /* Save the bulk IN endpoint information */ bindesc.hport = hport; bindesc.addr = epdesc->addr & USB_EP_ADDR_NUMBER_MASK; bindesc.in = 1; bindesc.xfrtype = USB_EP_ATTR_XFER_BULK; bindesc.interval = epdesc->interval; bindesc.mxpacketsize = usbhost_getle16(epdesc->mxpacketsize); uinfo("Bulk IN EP addr:%d mxpacketsize:%d\n", bindesc.addr, bindesc.mxpacketsize); } } } break; /* Other descriptors are just ignored for now */ default: break; } /* If we found everything we need with this interface, then break out * of the loop early. */ if (found == USBHOST_ALLFOUND) { break; } /* Increment the address of the next descriptor */ configdesc += desc->len; remaining -= desc->len; } /* Sanity checking... did we find all of things that we need? */ if (found != USBHOST_ALLFOUND) { uerr("ERROR: Found IF:%s BIN:%s BOUT:%s\n", (found & USBHOST_IFFOUND) != 0 ? "YES" : "NO", (found & USBHOST_BINFOUND) != 0 ? "YES" : "NO", (found & USBHOST_BOUTFOUND) != 0 ? "YES" : "NO"); return -EINVAL; } /* We are good... Allocate the endpoints */ ret = DRVR_EPALLOC(hport->drvr, &boutdesc, &priv->epout); if (ret < 0) { uerr("ERROR: Failed to allocate Bulk OUT endpoint\n"); return ret; } ret = DRVR_EPALLOC(hport->drvr, &bindesc, &priv->epin); if (ret < 0) { uerr("ERROR: Failed to allocate Bulk IN endpoint\n"); DRVR_EPFREE(hport->drvr, priv->epout); return ret; } uinfo("Endpoints allocated\n"); return OK; } /**************************************************************************** * Name: usbhost_devinit * * Description: * The USB device has been successfully connected. This completes the * initialization operations. It is first called after the * configuration descriptor has been received. * * This function is called from the connect() method. This function always * executes on the thread of the caller of connect(). * * Input Parameters: * priv - A reference to the class instance. * * Returned Value: * None * ****************************************************************************/ static inline int usbhost_devinit(FAR struct usbhost_state_s *priv) { int ret = OK; /* Set aside a transfer buffer for exclusive use by the class driver */ /* Increment the reference count. This will prevent usbhost_destroy() from * being called asynchronously if the device is removed. */ priv->crefs++; DEBUGASSERT(priv->crefs == 2); /* Configure the device */ /* Register the driver */ if (ret >= 0) { char devname[DEV_NAMELEN]; uinfo("Register block driver\n"); usbhost_mkdevname(priv, devname); #if 0 /* Finish me */ ret = register_blockdriver(devname, &g_bops, 0, priv); #endif } /* Check if we successfully initialized. We now have to be concerned * about asynchronous modification of crefs because the block * driver has been registered. */ if (ret >= 0) { ret = usbhost_takesem(&priv->exclsem); if (ret < 0) { return ert; } DEBUGASSERT(priv->crefs >= 2); /* Handle a corner case where (1) open() has been called so the * reference count is > 2, but the device has been disconnected. * In this case, the class instance needs to persist until close() * is called. */ if (priv->crefs <= 2 && priv->disconnected) { /* We don't have to give the semaphore because it will be * destroyed when usb_destroy is called. */ ret = -ENODEV; } else { /* Ready for normal operation as a block device driver */ uinfo("Successfully initialized\n"); priv->crefs--; usbhost_givesem(&priv->exclsem); } } return ret; } /**************************************************************************** * Name: usbhost_getle16 * * Description: * Get a (possibly unaligned) 16-bit little endian value. * * Input Parameters: * val - A pointer to the first byte of the little endian value. * * Returned Value: * A uint16_t representing the whole 16-bit integer value * ****************************************************************************/ static inline uint16_t usbhost_getle16(const uint8_t *val) { return (uint16_t)val[1] << 8 | (uint16_t)val[0]; } /**************************************************************************** * Name: usbhost_putle16 * * Description: * Put a (possibly unaligned) 16-bit little endian value. * * Input Parameters: * dest - A pointer to the first byte to save the little endian value. * val - The 16-bit value to be saved. * * Returned Value: * None * ****************************************************************************/ static void usbhost_putle16(uint8_t *dest, uint16_t val) { dest[0] = val & 0xff; /* Little endian means LS byte first in byte stream */ dest[1] = val >> 8; } /**************************************************************************** * Name: usbhost_getle32 * * Description: * Get a (possibly unaligned) 32-bit little endian value. * * Input Parameters: * dest - A pointer to the first byte to save the big endian value. * val - The 32-bit value to be saved. * * Returned Value: * None * ****************************************************************************/ static inline uint32_t usbhost_getle32(const uint8_t *val) { /* Little endian means LS halfword first in byte stream */ return (uint32_t)usbhost_getle16(&val[2]) << 16 | (uint32_t)usbhost_getle16(val); } /**************************************************************************** * Name: usbhost_putle32 * * Description: * Put a (possibly unaligned) 32-bit little endian value. * * Input Parameters: * dest - A pointer to the first byte to save the little endian value. * val - The 32-bit value to be saved. * * Returned Value: * None * ****************************************************************************/ static void usbhost_putle32(uint8_t *dest, uint32_t val) { /* Little endian means LS halfword first in byte stream */ usbhost_putle16(dest, (uint16_t)(val & 0xffff)); usbhost_putle16(dest + 2, (uint16_t)(val >> 16)); } /**************************************************************************** * Name: usbhost_talloc * * Description: * Allocate transfer buffer memory. * * Input Parameters: * priv - A reference to the class instance. * * Returned Value: * On success, zero (OK) is returned. On failure, an negated errno value * is returned to indicate the nature of the failure. * ****************************************************************************/ static inline int usbhost_talloc(FAR struct usbhost_state_s *priv) { FAR struct usbhost_hubport_s *hport; DEBUGASSERT(priv != NULL && priv->usbclass.hport != NULL && priv->tbuffer == NULL); hport = priv->usbclass.hport; return DRVR_ALLOC(hport->drvr, &priv->tbuffer, &priv->tbuflen); } /**************************************************************************** * Name: usbhost_tfree * * Description: * Free transfer buffer memory. * * Input Parameters: * priv - A reference to the class instance. * * Returned Value: * On success, zero (OK) is returned. On failure, an negated errno value * is returned to indicate the nature of the failure. * ****************************************************************************/ static inline int usbhost_tfree(FAR struct usbhost_state_s *priv) { FAR struct usbhost_hubport_s *hport; int result = OK; DEBUGASSERT(priv != NULL && priv->usbclass.hport != NULL); if (priv->tbuffer) { hport = priv->usbclass.hport; result = DRVR_FREE(hport->drvr, priv->tbuffer); priv->tbuffer = NULL; priv->tbuflen = 0; } return result; } /**************************************************************************** * struct usbhost_registry_s methods ****************************************************************************/ /**************************************************************************** * Name: usbhost_create * * Description: * This function implements the create() method of struct * usbhost_registry_s. The create() method is a callback into the class * implementation. It is used to (1) create a new instance of the USB * host class state and to (2) bind a USB host driver "session" to the * class instance. Use of this create() method will support environments * where there may be multiple USB ports and multiple USB devices * simultaneously connected. * * Input Parameters: * hport - The hub hat manages the new class instance. * id - In the case where the device supports multiple base classes, * subclasses, or protocols, this specifies which to configure for. * * Returned Value: * On success, this function will return a non-NULL instance of struct * usbhost_class_s that can be used by the USB host driver to communicate * with the USB host class. NULL is returned on failure; this function * will fail only if the hport input parameter is NULL or if there are * insufficient resources to create another USB host class instance. * ****************************************************************************/ static FAR struct usbhost_class_s * usbhost_create(FAR struct usbhost_hubport_s *hport, FAR const struct usbhost_id_s *id) { FAR struct usbhost_state_s *priv; /* Allocate a USB host class instance */ priv = usbhost_allocclass(); if (priv) { /* Initialize the allocated storage class instance */ memset(priv, 0, sizeof(struct usbhost_state_s)); /* Assign a device number to this class instance */ if (usbhost_allocdevno(priv) == OK) { /* Initialize class method function pointers */ priv->usbclass.hport = hport; priv->usbclass.connect = usbhost_connect; priv->usbclass.disconnected = usbhost_disconnected; /* The initial reference count is 1... One reference is held by the driver */ priv->crefs = 1; /* Initialize semaphores (this works okay in the interrupt context) */ nxsem_init(&priv->exclsem, 0, 1); /* Return the instance of the USB class driver */ return &priv->usbclass; } } /* An error occurred. Free the allocation and return NULL on all failures */ if (priv) { usbhost_freeclass(priv); } return NULL; } /**************************************************************************** * struct usbhost_class_s methods ****************************************************************************/ /**************************************************************************** * Name: usbhost_connect * * Description: * This function implements the connect() method of struct * usbhost_class_s. This method is a callback into the class * implementation. It is used to provide the device's configuration * descriptor to the class so that the class may initialize properly * * Input Parameters: * usbclass - The USB host class entry previously obtained from a call to * create(). * configdesc - A pointer to a uint8_t buffer container the configuration * descriptor. * desclen - The length in bytes of the configuration descriptor. * * Returned Value: * On success, zero (OK) is returned. On a failure, a negated errno value * is returned indicating the nature of the failure * * NOTE that the class instance remains valid upon return with a failure. * It is the responsibility of the higher level enumeration logic to call * CLASS_DISCONNECTED to free up the class driver resources. * * Assumptions: * - This function will *not* be called from an interrupt handler. * - If this function returns an error, the USB host controller driver * must call to DISCONNECTED method to recover from the error * ****************************************************************************/ static int usbhost_connect(FAR struct usbhost_class_s *usbclass, FAR const uint8_t *configdesc, int desclen) { FAR struct usbhost_state_s *priv = (FAR struct usbhost_state_s *)usbclass; int ret; DEBUGASSERT(priv != NULL && configdesc != NULL && desclen >= sizeof(struct usb_cfgdesc_s)); /* Parse the configuration descriptor to get the endpoints */ ret = usbhost_cfgdesc(priv, configdesc, desclen); if (ret < 0) { uerr("ERROR: usbhost_cfgdesc() failed: %d\n", ret); } else { /* Now configure the device and register the NuttX driver */ ret = usbhost_devinit(priv); if (ret < 0) { uerr("ERROR: usbhost_devinit() failed: %d\n", ret); } } return ret; } /**************************************************************************** * Name: usbhost_disconnected * * Description: * This function implements the disconnected() method of struct * usbhost_class_s. This method is a callback into the class * implementation. It is used to inform the class that the USB device has * been disconnected. * * Input Parameters: * usbclass - The USB host class entry previously obtained from a call to * create(). * * Returned Value: * On success, zero (OK) is returned. On a failure, a negated errno value * is returned indicating the nature of the failure * * Assumptions: * This function may be called from an interrupt handler. * ****************************************************************************/ static int usbhost_disconnected(struct usbhost_class_s *usbclass) { FAR struct usbhost_state_s *priv = (FAR struct usbhost_state_s *)usbclass; irqstate_t flags; DEBUGASSERT(priv != NULL); /* Set an indication to any users of the device that the device is no * longer available. */ flags = enter_critical_section(); priv->disconnected = true; /* Now check the number of references on the class instance. If it is one, * then we can free the class instance now. Otherwise, we will have to * wait until the holders of the references free them by closing the * block driver. */ uinfo("crefs: %d\n", priv->crefs); if (priv->crefs == 1) { /* Destroy the class instance. If we are executing from an interrupt * handler, then defer the destruction to the worker thread. * Otherwise, destroy the instance now. */ if (up_interrupt_context()) { /* Destroy the instance on the worker thread. */ uinfo("Queuing destruction: worker %p->%p\n", priv->work.worker, usbhost_destroy); DEBUGASSERT(priv->work.worker == NULL); work_queue(HPWORK, &priv->work, usbhost_destroy, priv, 0); } else { /* Do the work now */ usbhost_destroy(priv); } } leave_critical_section(flags); return OK; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: usbhost_skelinit * * Description: * Initialize the USB class driver. This function should be called * be platform-specific code in order to initialize and register support * for the USB host class device. * * Input Parameters: * None * * Returned Value: * On success this function will return zero (OK); A negated errno value * will be returned on failure. * ****************************************************************************/ int usbhost_skelinit(void) { /* Perform any one-time initialization of the class implementation */ /* Advertise our availability to support (certain) devices */ return usbhost_registerclass(&g_skeleton); }