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Интерактивная система просмотра системных руководств (man-ов)

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usbd_transfer (9)
  • >> usbd_transfer (9) ( FreeBSD man: Ядро )

  • BSD mandoc
     

    NAME

    usb_detach_wait
    
     
    usb_detach_wakeup
    
     
    usb_find_desc
    
     
    usbd_abort_default_pipe
    
     
    usbd_abort_pipe
    
     
    usbd_alloc_buffer
    
     
    usbd_alloc_xfer
    
     
    usbd_bulk_transfer
    
     
    usbd_clear_endpoint_stall
    
     
    usbd_clear_endpoint_stall_async
    
     
    usbd_clear_endpoint_toggle
    
     
    usbd_close_pipe
    
     
    usbd_device2interface_handle
    
     
    usbd_devinfo
    
     
    usbd_do_request
    
     
    usbd_do_request_async
    
     
    usbd_do_request_flags
    
     
    usbd_do_request_flags_pipe
    
     
    usbd_dopoll
    
     
    usbd_endpoint_count
    
     
    usbd_errstr
    
     
    usbd_fill_deviceinfo
    
     
    usbd_find_edesc
    
     
    usbd_find_idesc
    
     
    usbd_free_buffer
    
     
    usbd_free_xfer
    
     
    usbd_get_buffer
    
     
    usbd_get_config
    
     
    usbd_get_config_desc
    
     
    usbd_get_config_desc_full
    
     
    usbd_get_config_descriptor
    
     
    usbd_get_device_descriptor
    
     
    usbd_get_endpoint_descriptor
    
     
    usbd_get_interface_altindex
    
     
    usbd_get_interface_descriptor
    
     
    usbd_get_no_alts
    
     
    usbd_get_quirks
    
     
    usbd_get_speed
    
     
    usbd_get_string
    
     
    usbd_get_string_desc
    
     
    usbd_get_xfer_status
    
     
    usbd_interface2device_handle
    
     
    usbd_interface2endpoint_descriptor
    
     
    usbd_interface_count
    
     
    usbd_intr_transfer
    
     
    usbd_open_pipe
    
     
    usbd_open_pipe_intr
    
     
    usbd_pipe2device_handle
    
     
    usbd_ratecheck
    
     
    usbd_set_config_index
    
     
    usbd_set_config_no
    
     
    usbd_set_interface
    
     
    usbd_set_polling
    
     
    usbd_setup_default_xfer
    
     
    usbd_setup_isoc_xfer
    
     
    usbd_setup_xfer
    
     
    usbd_sync_transfer
    
     
    usbd_transfer
    
     - Universal Serial Bus driver programming interface
    
     
    

    SYNOPSIS

       #include <dev/usb/usb.h>
       #include <dev/usb/usbdi.h>
       #include <dev/usb/usbdi_util.h>

    void usb_detach_wait (device_ptr_t dv);
    void usb_detach_wakeup (device_ptr_t dv);
    const usb_descriptor_t * usb_find_desc (usbd_device_handle dev int type int subtype);
    usbd_status usbd_abort_default_pipe (usbd_device_handle dev);
    usbd_status usbd_abort_pipe (usbd_pipe_handle pipe);
    void * usbd_alloc_buffer (usbd_xfer_handle xfer u_int32_t size);
    usbd_xfer_handle usbd_alloc_xfer (usbd_device_handle dev);
    usbd_status Fo usbd_bulk_transfer Fa usbd_xfer_handle xfer Fa usbd_pipe_handle pipe Fa u_int16_t flags Fa u_int32_t timeout Fa void *buf Fa u_int32_t *size Fa char *lbl Fc Ft usbd_status usbd_clear_endpoint_stall (usbd_pipe_handle pipe);
    usbd_status usbd_clear_endpoint_stall_async (usbd_pipe_handle);
    void usbd_clear_endpoint_toggle (usbd_pipe_handle pipe);
    usbd_status usbd_close_pipe (usbd_pipe_handle pipe);
    usbd_status Fo usbd_device2interface_handle Fa usbd_device_handle dev Fa u_int8_t ifaceno Fa usbd_interface_handle *iface Fc Ft void usbd_devinfo (usbd_device_handle dev int showclass char *cp);
    usbd_status Fo usbd_do_request Fa usbd_device_handle dev Fa usb_device_request_t *req Fa void *data Fc Ft usbd_status Fo usbd_do_request_async Fa usbd_device_handle dev Fa usb_device_request_t *req Fa void *data Fc Ft usbd_status Fo usbd_do_request_flags Fa usbd_device_handle dev Fa usb_device_request_t *req Fa void *data Fa u_int16_t flags Fa int *actlen Fa u_int32_t timo Fc Ft usbd_status Fo usbd_do_request_flags_pipe Fa usbd_device_handle dev Fa usbd_pipe_handle pipe Fa usb_device_request_t *req Fa void *data Fa u_int16_t flags Fa int *actlen Fa u_int32_t timeout Fc Ft void usbd_dopoll (usbd_interface_handle iface);
    usbd_status usbd_endpoint_count (usbd_interface_handle iface u_int8_t *count);
    const char * usbd_errstr (usbd_status err);
    void Fo usbd_fill_deviceinfo Fa usbd_device_handle dev Fa struct usb_device_info *di Fa int usedev Fc Ft usb_endpoint_descriptor_t * Fo usbd_find_edesc Fa usb_config_descriptor_t *cd Fa int ifaceidx Fa int altidx Fa int endptidx Fc Ft usb_interface_descriptor_t * usbd_find_idesc (usb_config_descriptor_t *cd int ifaceidx int altidx);
    void usbd_free_buffer (usbd_xfer_handle xfer);
    usbd_status usbd_free_xfer (usbd_xfer_handle xfer);
    void * usbd_get_buffer (usbd_xfer_handle xfer);
    usbd_status usbd_get_config (usbd_device_handle dev u_int8_t *conf);
    usbd_status Fo usbd_get_config_desc Fa usbd_device_handle dev Fa int confidx Fa usb_config_descriptor_t *d Fc Ft usbd_status Fo usbd_get_config_desc_full Fa usbd_device_handle dev Fa int conf Fa void *d Fa int size Fc Ft usb_config_descriptor_t * usbd_get_config_descriptor (usbd_device_handle dev);
    usb_device_descriptor_t * usbd_get_device_descriptor (usbd_device_handle dev);
    usb_endpoint_descriptor_t * Fo usbd_get_endpoint_descriptor Fa usbd_interface_handle iface Fa u_int8_t address Fc Ft int usbd_get_interface_altindex (usbd_interface_handle iface);
    usb_interface_descriptor_t * usbd_get_interface_descriptor (usbd_interface_handle iface);
    int usbd_get_no_alts (usb_config_descriptor_t *cdesc int ifaceno);
    const struct usbd_quirks * usbd_get_quirks (usbd_device_handle dev);
    int usbd_get_speed (usbd_device_handle dev);
    usbd_status usbd_get_string (usbd_device_handle dev int si char *buf);
    usbd_status Fo usbd_get_string_desc Fa usbd_device_handle dev Fa int sindex Fa int langid Fa usb_string_descriptor_t *sdesc Fa int *sizep Fc Ft void Fo usbd_get_xfer_status Fa usbd_xfer_handle xfer Fa usbd_private_handle *priv Fa void **buffer Fa u_int32_t *count Fa usbd_status *status Fc Ft void Fo usbd_interface2device_handle Fa usbd_interface_handle iface Fa usbd_device_handle *dev Fc Ft usb_endpoint_descriptor_t * Fo usbd_interface2endpoint_descriptor Fa usbd_interface_handle iface Fa u_int8_t index Fc Ft usbd_status usbd_interface_count (usbd_device_handle dev u_int8_t *count);
    usbd_status Fo usbd_intr_transfer Fa usbd_xfer_handle xfer Fa usbd_pipe_handle pipe Fa u_int16_t flags Fa u_int32_t timeout Fa void *buf Fa u_int32_t *size Fa char *lbl Fc Ft usbd_status Fo usbd_open_pipe Fa usbd_interface_handle iface Fa u_int8_t address Fa u_int8_t flags Fa usbd_pipe_handle *pipe Fc Ft usbd_status Fo usbd_open_pipe_intr Fa usbd_interface_handle iface Fa u_int8_t address Fa u_int8_t flags Fa usbd_pipe_handle *pipe Fa usbd_private_handle priv Fa void *buffer Fa u_int32_t len Fa usbd_callback cb Fa int ival Fc Ft usbd_device_handle usbd_pipe2device_handle (usbd_pipe_handle pipe);
    int usbd_ratecheck (struct timeval *last);
    usbd_status usbd_set_config_index (usbd_device_handle dev int index int msg);
    usbd_status usbd_set_config_no (usbd_device_handle dev int no int msg);
    usbd_status usbd_set_interface (usbd_interface_handle iface int altidx);
    void usbd_set_polling (usbd_device_handle dev int on);
    void Fo usbd_setup_default_xfer Fa usbd_xfer_handle xfer Fa usbd_device_handle dev Fa usbd_private_handle priv Fa u_int32_t timeout Fa usb_device_request_t *req Fa void *buffer Fa u_int32_t length Fa u_int16_t flags Fa usbd_callback callback Fc Ft void Fo usbd_setup_isoc_xfer Fa usbd_xfer_handle xfer Fa usbd_pipe_handle pipe Fa usbd_private_handle priv Fa u_int16_t *frlengths Fa u_int32_t nframes Fa u_int16_t flags Fa usbd_callback callback Fc Ft void Fo usbd_setup_xfer Fa usbd_xfer_handle xfer Fa usbd_pipe_handle pipe Fa usbd_private_handle priv Fa void *buffer Fa u_int32_t length Fa u_int16_t flags Fa u_int32_t timeout Fa usbd_callback callback Fc Ft usbd_status usbd_sync_transfer (usbd_xfer_handle xfer);
    usbd_status usbd_transfer (usbd_xfer_handle xfer);
     

    DESCRIPTION

    The Universal Serial Bus (USB) driver programming interface provides USB peripheral drivers with a host controller independent API for controlling and communicating with USB peripherals.

    Typically, drivers will first use some combination of the functions usbd_set_config_no (,);
    usbd_get_config_descriptor (,);
    usbd_set_interface (,);
    usbd_get_interface_descriptor (,);
    usbd_device2interface_handle (,);
    usbd_endpoint_count ();
    and usbd_interface2endpoint_descriptor ();
    to query the device's properties and prepare it for use. Drivers can then perform requests on the USB control pipe using usbd_do_request (,);
    they can open pipes using the functions usbd_open_pipe ();
    and usbd_open_pipe_intr (,);
    and perform transfers over these pipes using usbd_alloc_xfer (,);
    usbd_setup_xfer ();
    and usbd_transfer (.);
    Finally, the functions usbd_abort_pipe (,);
    usbd_close_pipe ();
    and usbd_free_xfer ();
    are used to cancel outstanding transfers, close open pipes and deallocate transfer structures.

    The usbd_get_device_descriptor ();
    function returns a pointer to the USB device descriptor for Fa dev . See Sx USB Descriptors below for information about the USB device descriptor.

    The usbd_get_config_desc ();
    function retrieves the specified configuration descriptor from the device. The Fa confidx parameter specifies the configuration descriptor index, which must be less than the Fa bNumConfigurations value in the device descriptor. The function usbd_get_config_desc_full ();
    retrieves a full configuration descriptor, which has all related interface and endpoint descriptors appended to a normal configuration descriptor. The parameter Fa d should point to memory that is at least Fa size bytes in length, and this should be at least as long as the Fa wTotalLength value from the configuration descriptor. See Sx USB Descriptors below for information about the USB configuration descriptor.

    The usbd_get_config ();
    function retrieves the current configuration number from the device, i.e. the Fa bConfigurationValue value from the configuration that is active. If the device is unconfigured then USB_UNCONFIG_NO is returned. The current configuration can be changed by calling either usbd_set_config_index ();
    or usbd_set_config_no (.);
    The difference between these functions is that usbd_set_config_index ();
    accepts a configuration index number that is less than the Fa bNumConfigurations value from the device descriptor, whereas usbd_set_config_no ();
    requires the Fa bConfigurationValue value of the desired configuration to be provided instead. To unconfigure the device, supply a configuration index of USB_UNCONFIG_INDEX to usbd_set_config_index (,);
    or else specify a configuration number of USB_UNCONFIG_NO to usbd_set_config_no (.);

    The usbd_get_config_descriptor ();
    function returns a pointer to an in-memory copy of the full configuration descriptor of the configuration that is currently active. The returned pointer remains valid until the device configuration is changed using usbd_set_config_index ();
    or usbd_set_config_no (.);
    If the device is unconfigured then NULL is returned instead.

    The function usbd_interface_count ();
    returns the number of interfaces available in the current device configuration. The usbd_get_no_alts ();
    function determines the number of alternate interfaces in a full configuration descriptor by counting the interface descriptors with Fa bInterfaceNumber equal to Fa ifaceno (the count includes alternate index zero). The usbd_find_idesc ();
    function locates an interface descriptor within a full configuration descriptor. The Fa ifaceidx parameter specifies the interface index number, which should be less than the number of interfaces in the configuration descriptor (i.e. the value returned by usbd_interface_count ();
    or the Fa bNumInterface field from the configuration descriptor). An alternate interface can be specified using a non-zero Fa altidx , which should be less than the value returned by usbd_get_no_alts (.);
    The return value is a pointer to the requested interface descriptor within the full configuration descriptor, or NULL if the specified interface descriptor does not exist. Note that the Fa altidx parameter specifies the alternate setting by index number starting at zero; it is not the alternate setting number defined in the interface descriptor.

    The function usbd_find_edesc ();
    locates an endpoint descriptor within a full configuration descriptor. The Fa ifaceidx and Fa altidx parameters are the same as described for usbd_find_idesc (,);
    and the Fa endptidx parameter is an endpoint index number that should be less than the Fa bNumEndpoints field in the interface descriptor. The return value is a pointer to the requested endpoint descriptor within the full configuration descriptor, or NULL if the specified endpoint descriptor does not exist. Note that the Fa altidx and Fa endptidx parameters are index numbers starting at zero; they are not the alternate setting and endpoint address defined in the descriptors.

    The usbd_get_speed ();
    function returns the device speed. This can be USB_SPEED_LOW USB_SPEED_FULL or USB_SPEED_HIGH

    USB devices optionally support string descriptors, which can be retrieved using the usbd_get_string ();
    or usbd_get_string_desc ();
    functions. Device, configuration and interface descriptors reference strings by an index number that can be supplied to these functions. The usbd_get_string ();
    function should be used unless a non-default language is required. It requires that Fa buf points to a buffer of at least USB_MAX_STRING_LEN bytes in size. The Fa si parameter specified which string to retrieve.

    The usb_find_desc ();
    function searches through the in-memory full configuration descriptor for the active configuration and finds the first descriptor that has a Fa bDescriptorType equal to Fa type , and if Fa subtype is not equal to USBD_SUBTYPE_ANY the descriptor must also have a Fa bDescriptorSubtype equal to Fa subtype . If found, then a pointer to the descriptor is returned. Otherwise, usb_find_desc ();
    returns NULL The returned pointer is valid until the device configuration is changed using usbd_set_config_index ();
    or usbd_set_config_no (.);

    The USB driver interface uses opaque interface handles to refer to configuration interfaces. These handles remain valid until the device configuration is changed using usbd_set_config_index ();
    or usbd_set_config_no (.);
    The usbd_device2interface_handle ();
    function retrieves an interface handle. The Fa ifaceno parameter is an interface index number starting at zero. If the device is configured and the specified interface exists, then USBD_NORMAL_COMPLETION is returned and the interface handle is stored in Fa *iface . Otherwise an error code is returned and Fa *iface is not changed. The usbd_interface2device_handle ();
    function retrieves the device handle from an interface handle. This is just for convenience to save passing around the device handle as well as the interface handle. The usbd_set_interface ();
    function changes the alternate setting number for an interface to the alternate setting identified by the zero-based index number Fa altidx . This operation invalidates any existing endpoints on this interface and their descriptors. The usbd_get_interface_altindex ();
    function returns the current alternative setting index as was specified when calling usbd_set_interface (.);
    The usbd_endpoint_count ();
    function retrieves the number of endpoints associated with the specified interface. The usbd_interface2endpoint_descriptor ();
    function returns a pointer to an in-memory endpoint descriptor for the endpoint that has an index number of Fa index . This pointer remains valid until the configuration or alternate setting number are changed. The function usbd_get_endpoint_descriptor ();
    is like usbd_interface2endpoint_descriptor ();
    but it accepts a Fa bEndpointAddress address value instead of an index.

    The usbd_fill_deviceinfo ();
    function fills out a Vt usb_device_info structure with information about the device. The vendor and product names come from the device itself, falling back to a table lookup or just providing the IDs in hexadecimal. If Fa usedev is zero then usbd_fill_deviceinfo ();
    will not attempt to retrieve the vendor and product names from the device. The usb_device_info structure is defined in    #include <dev/usb/usb.h>
    as follows:

    struct usb_device_info {
            u_int8_t        udi_bus;
            u_int8_t        udi_addr;       /* device address */
            usb_event_cookie_t udi_cookie;
            char            udi_product[USB_MAX_STRING_LEN];
            char            udi_vendor[USB_MAX_STRING_LEN];
            char            udi_release[8];
            u_int16_t       udi_productNo;
            u_int16_t       udi_vendorNo;
            u_int16_t       udi_releaseNo;
            u_int8_t        udi_class;
            u_int8_t        udi_subclass;
            u_int8_t        udi_protocol;
            u_int8_t        udi_config;
            u_int8_t        udi_speed;
    #define USB_SPEED_LOW  1
    #define USB_SPEED_FULL 2
    #define USB_SPEED_HIGH 3
            int             udi_power;      /* power consumption in mA */
            int             udi_nports;
            char            udi_devnames[USB_MAX_DEVNAMES][USB_MAX_DEVNAMELEN];
            /* hub only: addresses of devices on ports */
            u_int8_t        udi_ports[16];
    #define USB_PORT_ENABLED 0xff
    #define USB_PORT_SUSPENDED 0xfe
    #define USB_PORT_POWERED 0xfd
    }
    

    The usbd_devinfo ();
    function generates a string description of the USB device. The Fa cp argument should point to a 1024-byte buffer (XXX the maximum length is approximately 320 chars, but there is no sanity checking and everything uses 1024-character buffers). Device class information is included if the Fa showclass parameter is non-zero.

    The usbd_get_quirks ();
    function returns information from a table of devices that require special workarounds in order to function correctly. The returned structure is defined in    #include <dev/usb/usb_quirks.h>
    as follows:

    struct usbd_quirks {
            u_int32_t uq_flags;     /* Device problems */
    };
    

    See    #include <dev/usb/usb_quirks.h>
    for a list of all currently defined quirks.

    USB control requests are performed via Vt usb_device_request_t structures, defined in    #include <dev/usb/usb.h>
    as follows:

    typedef struct {
            uByte           bmRequestType;
            uByte           bRequest;
            uWord           wValue;
            uWord           wIndex;
            uWord           wLength;
    } UPACKED usb_device_request_t;
    

    The usbd_do_request ();
    function performs a single request synchronously. The Fa req parameter should point to a properly initialized Vt usb_device_request_t , and when the Fa wLength field is non-zero, Fa data should point at a buffer that is at least Fa wLength bytes in length. The request timeout is set to 5 seconds, so the operation will fail with Er USBD_TIMEOUT if the device does not respond within that time. The usbd_do_request_async ();
    function is like usbd_do_request (,);
    but it does not wait for the request to complete before returning. This routine does not block so it can be used from contexts where sleeping is not allowed. Note that there is no notification mechanism to report when the operation completed nor is there a way to determine whether the request succeeded, so this function is of limited use. See usbd_setup_default_xfer ();
    and usbd_transfer ();
    for a way to invoke an asynchronous callback upon completion of a control request. The usbd_do_request_flags ();
    function is like usbd_do_request (,);
    but additional flags can be specified, the timeout is configurable, and the actual number of bytes transferred is made available to the caller. The usbd_do_request_flags_pipe ();
    function uses a specified pipe instead of the default pipe.

    The function usbd_open_pipe ();
    creates a pipe connected to a specified endpoint on a specified interface. The parameter Fa address should be the Fa bEndpointAddress value from one of this interface's endpoint descriptors. If Fa flags contains USBD_EXCLUSIVE_USE then the operation will only succeed if there are no open pipes already connected to the specified endpoint. The usbd_open_pipe_intr ();
    function creates an interrupt pipe connected to the specified endpoint. The parameter Fa address should be the Fa bEndpointAddress value from one of this interface's endpoint descriptors. The Fa flags parameter is passed to usbd_setup_xfer (.);
    The Fa buffer and Fa len parameters define a buffer that is to be used for the interrupt transfers. The callback to be invoked each time a transfer completes is specified by Fa cb , and Fa priv is an argument to be passed to the callback function. The Fa ival parameter specifies the maximum acceptable interval between transfers; in practice the transfers may occur more frequently. The function usbd_pipe2device_handle ();
    returns the device associated with the specified Fa pipe .

    The usbd_abort_pipe ();
    function aborts all active or waiting transfers on the specified pipe. Each transfer is aborted with a USBD_CANCELLED status; callback routines must detect this error code to ensure that they do not attempt to initiate a new transfer in response to one being aborted. This routine blocks while it is waiting for the hardware to complete processing of aborted transfers, so it is only safe to call it in contexts where sleeping is allowed. The function usbd_abort_default_pipe ();
    aborts all active or waiting transfers on the default pipe. Like usbd_abort_pipe (,);
    it blocks waiting for the hardware processing to complete.

    When a pipe has no active or waiting transfers, the pipe may be closed using the usbd_close_pipe ();
    function. Once a pipe is closed, its pipe handle becomes invalid and may no longer be used.

    USB transfer handles are allocated using the function usbd_alloc_xfer ();
    and may be freed using usbd_free_xfer (.);

    The function usbd_setup_xfer ();
    initializes a transfer handle with the details of a transfer to or from a USB device. The Fa xfer parameter specifies the transfer handle to initialize, Fa pipe specifies the pipe on which the transfer is to take place, and Fa priv is an argument that will be passed to callback function. The arguments Fa buffer and Fa length define the data buffer for the transfer. If Fa length is zero then the Fa buffer may be NULL The Fa flags parameter may contain the following flags:

    USBD_NO_COPY
    This is used in association with usbd_alloc_buffer ();
    and usbd_free_buffer ();
    to use a dedicated DMA-capable buffer for the transfer.
    USBD_SYNCHRONOUS
    Wait for the transfer to compete in usbd_transfer (.);
    USBD_SHORT_XFER_OK
    Permit transfers shorter than the requested data length.
    USBD_FORCE_SHORT_XFER
    Force a short transfer at the end of a write operation to let the device know that the transfer has ended.

    The Fa timeout parameter specifies a timeout for the transfer in milliseconds. A value of USBD_NO_TIMEOUT indicates that no timeout should be configured. The parameter Fa callback specifies the function to call when the transfer completes. Note that usbd_setup_xfer ();
    does not actually initiate the transfer. The usbd_setup_default_xfer ();
    initializes a control transfer for the default pipe. The Fa req parameter should point at a completed Vt usb_device_request_t structure. The function Fa usbd_setup_isoc_xfer initializes a transfer for an isochronous pipe.

    The function usbd_transfer ();
    initiates a transfer. Normally it returns USBD_IN_PROGRESS to indicate that the transfer has been queued. If the USB stack is operating in polling mode, or if the transfer is synchronous, then USBD_NORMAL_COMPLETION may be returned. Other return values indicate that the transfer could not be initiated due to an error. The usbd_sync_transfer ();
    function executes a transfer synchronously. It will sleep waiting for the transfer to complete and then return the transfer status. Note that if the transfer has a callback routine, this will be invoked before usbd_sync_transfer ();
    returns.

    The usbd_intr_transfer ();
    and usbd_bulk_transfer ();
    functions set up a transfer and wait synchronously for it to complete but they allows signals to interrupt the wait. They returns USBD_INTERRUPTED if the transfer was interrupted by a signal. XXX these two functions are identical apart from their names.

    The function usbd_get_xfer_status ();
    retrieves various information from a completed transfer. If the Fa priv parameter is not NULL then the callback private argument is stored in Fa *priv . If Fa buffer is not NULL then the transfer buffer pointer is stored in Fa *buffer . The actual number of bytes transferred is stored in Fa *count if Fa count is not NULL. Finally, the transfer status is stored in Fa *status if Fa status is not NULL.

    The usbd_clear_endpoint_stall ();
    function clears an endpoint stall condition synchronously, i.e. it sleeps waiting for the stall clear request to complete. The function usbd_clear_endpoint_stall_async ();
    performs the same function asynchronously, but it provides no way to determine when the request completed, or whether it was successful. The usbd_clear_endpoint_toggle ();
    function instructs the host controller driver to reset the toggle bit on a pipe. This is used when manually clearing an endpoint stall using a control pipe request, in order to ensure that the host controller driver and the USB device restart with the same toggle value.

    Normally the USB subsystem maps and copies data to and from DMA-capable memory each time a transfer is performed. The function usbd_alloc_buffer ();
    allocates a permanent DMA-capable buffer associated with the transfer to avoid this overhead. The return value is the virtual address of the buffer. Any time that usbd_setup_xfer ();
    is called on the transfer with the USBD_NO_COPY flag enabled, the allocated buffer will be used directly and the Fa buffer argument passed to usbd_setup_xfer ();
    will be ignored. The usbd_get_buffer ();
    function returns a pointer to the virtual address of a buffer previously allocated by usbd_alloc_buffer (.);
    Finally, usbd_free_buffer ();
    deallocates the buffer.

    The usbd_errstr ();
    function converts a status code into a string for display.

    The function usbd_set_polling ();
    enables or disables polling mode. In polling mode, all operations will busy-wait for the device to respond, so its use is effectively limited to boot time and kernel debuggers. It is important to match up calls that enable and disable polling mode, because the implementation just increments a polling reference count when Fa on is non-zero and decrements it when Fa on is zero. The usbd_dopoll ();
    causes the host controller driver to poll for any activity. This should only be used when polling mode is enabled.

    The usbd_ratecheck ();
    function is used to limit the rate at which error messages are printed to approximately once per second. The Fa last argument should point at a persistent Vt struct timeval . A value of 1 will be returned if a message should be printed, but if usbd_ratecheck ();
    has already been called with the same Vt struct timeval parameter in the last second then 0 is returned and the error message should be suppressed.

    The functions usb_detach_wait ();
    and usb_detach_wakeup ();
    are used to wait for references to drain before completing the detachment of a device. The usb_detach_wait ();
    function will wait up to 60 seconds to receive a signal from usb_detach_wait (.);
     

    USB Descriptors

    The USB specification defines a number of standard descriptors by which USB devices report their attributes. These descriptors are fixed-format structures that all USB devices make available through USB control pipe requests.

    Every USB device has exactly one USB device descriptor. The USB subsystem retrieves this automatically when a device is attached, and a copy of the descriptor is kept in memory. The usbd_get_device_descriptor ();
    function returns a pointer to the descriptor. The device descriptor structure is defined in    #include <dev/usb/usb.h>
    as follows:

    typedef struct {
            uByte           bLength;
            uByte           bDescriptorType;
            uWord           bcdUSB;
    #define UD_USB_2_0              0x0200
    #define UD_IS_USB2(d) (UGETW((d)->bcdUSB) >= UD_USB_2_0)
            uByte           bDeviceClass;
            uByte           bDeviceSubClass;
            uByte           bDeviceProtocol;
            uByte           bMaxPacketSize;
            /* The fields below are not part of the initial descriptor. */
            uWord           idVendor;
            uWord           idProduct;
            uWord           bcdDevice;
            uByte           iManufacturer;
            uByte           iProduct;
            uByte           iSerialNumber;
            uByte           bNumConfigurations;
    } UPACKED usb_device_descriptor_t;
    #define USB_DEVICE_DESCRIPTOR_SIZE 18
    

    USB devices have at least one configuration descriptor. The Fa bNumConfigurations field of the device descriptor specifies the number of configuration descriptors that a device supports. The usbd_get_config_desc ();
    function retrieves a particular configuration descriptor from the device and the usbd_get_config_desc_full ();
    function retrieves a full Fa wTotalLength length configuration descriptor, which includes all related interface and endpoint descriptors. Only one configuration may be active at a time. The usbd_set_config_index ();
    function activates a specified configuration. The configuration descriptor structure is defined in    #include <dev/usb/usb.h>
    as follows:

    typedef struct {
            uByte           bLength;
            uByte           bDescriptorType;
            uWord           wTotalLength;
            uByte           bNumInterface;
            uByte           bConfigurationValue;
            uByte           iConfiguration;
            uByte           bmAttributes;
    #define UC_BUS_POWERED          0x80
    #define UC_SELF_POWERED         0x40
    #define UC_REMOTE_WAKEUP        0x20
            uByte           bMaxPower; /* max current in 2 mA units */
    #define UC_POWER_FACTOR 2
    } UPACKED usb_config_descriptor_t;
    #define USB_CONFIG_DESCRIPTOR_SIZE 9
    

    Each device configuration provides one or more interfaces. The Fa bNumInterface field of the configuration descriptor specifies the number of interfaces associated with a device configuration. Interfaces are described by an interface descriptor, which is defined in    #include <dev/usb/usb.h>
    as follows:

    typedef struct {
            uByte           bLength;
            uByte           bDescriptorType;
            uByte           bInterfaceNumber;
            uByte           bAlternateSetting;
            uByte           bNumEndpoints;
            uByte           bInterfaceClass;
            uByte           bInterfaceSubClass;
            uByte           bInterfaceProtocol;
            uByte           iInterface;
    } UPACKED usb_interface_descriptor_t;
    #define USB_INTERFACE_DESCRIPTOR_SIZE 9
    

    Configurations may also have alternate interfaces with the same Fa bInterfaceNumber but different Fa bAlternateSetting values. These alternate interface settings may be selected by passing a non-zero Fa altidx parameter to usbd_set_interface (.);

    Interfaces have zero or more endpoints, and each endpoint has an endpoint descriptor. Note that endpoint zero, which is always present, does not have an endpoint descriptor, and it is never included in the Fa bNumEndpoints count of endpoints. The endpoint descriptor is defined in    #include <dev/usb/usb.h>
    as follows:

    typedef struct {
            uByte           bLength;
            uByte           bDescriptorType;
            uByte           bEndpointAddress;
    #define UE_GET_DIR(a)   ((a) & 0x80)
    #define UE_SET_DIR(a,d) ((a) | (((d)&1) << 7))
    #define UE_DIR_IN       0x80
    #define UE_DIR_OUT      0x00
    #define UE_ADDR         0x0f
    #define UE_GET_ADDR(a)  ((a) & UE_ADDR)
            uByte           bmAttributes;
    #define UE_XFERTYPE     0x03
    #define  UE_CONTROL     0x00
    #define  UE_ISOCHRONOUS 0x01
    #define  UE_BULK        0x02
    #define  UE_INTERRUPT   0x03
    #define UE_GET_XFERTYPE(a)      ((a) & UE_XFERTYPE)
    #define UE_ISO_TYPE     0x0c
    #define  UE_ISO_ASYNC   0x04
    #define  UE_ISO_ADAPT   0x08
    #define  UE_ISO_SYNC    0x0c
    #define UE_GET_ISO_TYPE(a)      ((a) & UE_ISO_TYPE)
            uWord           wMaxPacketSize;
            uByte           bInterval;
    } UPACKED usb_endpoint_descriptor_t;
    #define USB_ENDPOINT_DESCRIPTOR_SIZE 7
    
     

    RETURN VALUES

    Many functions return a Vt usbd_status type to indicate the outcome of the operation. If the operation completed successfully then USBD_NORMAL_COMPLETION is returned. Operations that have been started but not yet completed will return USBD_IN_PROGRESS Other errors usually indicate a problem. Error codes can be converted to strings using usbd_errstr (.);
     

    ERRORS

    Bq Er USBD_PENDING_REQUESTS
    A pipe could not be closed because there are active requests.
    Bq Er USBD_NOT_STARTED
    The transfer has not yet been started.
    Bq Er USBD_INVAL
    An invalid value was supplied.
    Bq Er USBD_NOMEM
    An attempt to allocate memory failed.
    Bq Er USBD_CANCELLED
    The transfer was aborted.
    Bq Er USBD_BAD_ADDRESS
    The specified endpoint address was not found.
    Bq Er USBD_IN_USE
    The endpoint is already in use, or the configuration cannot be changed because some of its endpoints are in use.
    Bq Er USBD_NO_ADDR
    No free USB devices addresses were found to assign to the device.
    Bq Er USBD_SET_ADDR_FAILED
    The device address could not be set.
    Bq Er USBD_NO_POWER
    Insufficient power was available for the device.
    Bq Er USBD_TOO_DEEP
    Too many levels of chained hubs were found.
    Bq Er USBD_IOERROR
    There was an error communicating with the device.
    Bq Er USBD_NOT_CONFIGURED
    An operation that requires an active configuration was attempted while the device was in an unconfigured state.
    Bq Er USBD_TIMEOUT
    A transfer timed out.
    Bq Er USBD_SHORT_XFER
    A transfer that disallowed short data lengths completed with less than the requested length transferred.
    Bq Er USBD_STALLED
    A transfer failed because the pipe is stalled.
    Bq Er USBD_INTERRUPTED
    An interruptible operation caught a signal.

     

    SEE ALSO

    usb(4)  

    HISTORY

    The USB driver interface first appeared in Fx 3.0 .  

    AUTHORS

    The USB driver was written by An Lennart Augustsson for the Nx project.

    An -nosplit This manual page was written by An Ian Dowse Aq [email protected] .


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    USB Descriptors
    RETURN VALUES
    ERRORS
    SEE ALSO
    HISTORY
    AUTHORS


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