NAME¶
ugen —
USB generic device
support
SYNOPSIS¶
To compile this driver into the kernel, place the following line in your kernel
configuration file:
device ugen
Alternatively, to load the driver as a module at boot time, place the following
line in
loader.conf(5):
DESCRIPTION¶
The
ugen driver provides support for all USB devices that do
not have a special driver. It supports access to all parts of the device, but
not in a way that is as convenient as a special purpose driver.
There can be up to 127 USB devices connected to a USB bus. Each USB device can
have up to 16 endpoints. Each of these endpoints will communicate in one of
four different modes: control, isochronous, bulk, or interrupt. Each of the
endpoints will have a different device node. The four least significant bits
in the minor device number determines which endpoint the device accesses and
the rest of the bits determines which USB device.
If an endpoint address is used both for input and output the device can be
opened for both read or write.
To find out what endpoints that exist there are a series of
ioctl(2) operation on the control endpoint that returns the
USB descriptors of the device, configurations, interfaces, and endpoints.
The control transfer mode can only happen on the control endpoint which is
always endpoint 0. The control endpoint accepts request and may respond with
an answer to such request. Control request are issued by
ioctl(2) calls.
The bulk transfer mode can be in or out depending on the endpoint. To perform
I/O on a bulk endpoint
read(2) and
write(2) should be used. All I/O operations on a bulk
endpoint are unbuffered.
The interrupt transfer mode can be in or out depending on the endpoint. To
perform I/O on an interrupt endpoint
read(2) and
write(2) should be used. A moderate amount of buffering is
done by the driver.
All endpoints handle the following
ioctl(2) calls:
USB_SET_SHORT_XFER
(int)- Allow short read transfer. Normally a transfer from the
device which is shorter than the request specified is reported as an
error.
USB_SET_TIMEOUT
(int)- Set the timeout on the device operations, the time is
specified in milliseconds. The value 0 is used to indicate that there is
no timeout.
The control endpoint (endpoint 0) handles the following
ioctl(2) calls:
USB_GET_CONFIG
(int)- Get the device configuration number.
USB_SET_CONFIG
(int)- Set the device into the given configuration number.
This operation can only be performed when the control endpoint is the sole
open endpoint.
USB_GET_ALTINTERFACE
(struct usb_alt_interface)- Get the alternative setting number for the interface with
the given index. The uai_config_index is ignored in
this call.
struct usb_alt_interface {
int uai_config_index;
int uai_interface_index;
int uai_alt_no;
};
USB_SET_ALTINTERFACE
(struct usb_alt_interface)- Set the alternative setting to the given number in the
interface with the given index. The uai_config_index
is ignored in this call.
This operation can only be performed when no endpoints for the interface are
open.
USB_GET_NO_ALT
(struct usb_alt_interface)- Return the number of different alternate settings in the
uai_alt_no field.
USB_GET_DEVICE_DESC
(usb_device_descriptor_t)- Return the device descriptor.
USB_GET_CONFIG_DESC
(struct usb_config_desc)- Return the descriptor for the configuration with the given
index. For convenience the current configuration can be specified by
USB_CURRENT_CONFIG_INDEX.
struct usb_config_desc {
int ucd_config_index;
usb_config_descriptor_t ucd_desc;
};
USB_GET_INTERFACE_DESC
(struct usb_interface_desc)- Return the interface descriptor for an interface specified
by its configuration index, interface index, and alternative index. For
convenience the current alternative can be specified by
USB_CURRENT_ALT_INDEX.
struct usb_interface_desc {
int uid_config_index;
int uid_interface_index;
int uid_alt_index;
usb_interface_descriptor_t uid_desc;
};
USB_GET_ENDPOINT_DESC
(struct usb_endpoint_desc)- Return the endpoint descriptor for the endpoint specified
by its configuration index, interface index, alternative index, and
endpoint index.
struct usb_endpoint_desc {
int ued_config_index;
int ued_interface_index;
int ued_alt_index;
int ued_endpoint_index;
usb_endpoint_descriptor_t ued_desc;
};
USB_GET_FULL_DESC
(struct usb_full_desc)- Return all the descriptors for the given configuration.
struct usb_full_desc {
int ufd_config_index;
u_int ufd_size;
u_char *ufd_data;
};
The ufd_data field should point to a memory area of
the size given in the ufd_size field. The proper
size can be determined by first issuing a
USB_GET_CONFIG_DESC and inspecting the
wTotalLength field.
USB_GET_STRING_DESC
(struct usb_string_desc)- Get a string descriptor for the given language ID and
string index.
struct usb_string_desc {
int usd_string_index;
int usd_language_id;
usb_string_descriptor_t usd_desc;
};
USB_DO_REQUEST
(struct usb_ctl_request)- Send a USB request to the device on the control endpoint.
Any data sent to/from the device is located at
ucr_data. The size of the transferred data is
determined from the ucr_request. The
ucr_addr field is ignored in this call. The
ucr_flags field can be used to flag that the request
is allowed to be shorter than the requested size, and the
ucr_actlen will contain the actual size on
completion.
struct usb_ctl_request {
int ucr_addr;
usb_device_request_t ucr_request;
void *ucr_data;
int ucr_flags;
#define USBD_SHORT_XFER_OK 0x04 /* allow short reads */
int ucr_actlen; /* actual length transferred */
};
This is a dangerous operation in that it can perform arbitrary operations on
the device. Some of the most dangerous (e.g., changing the device address)
are not allowed.
USB_GET_DEVICEINFO
(struct usb_device_info)- Get an information summary for the device. This call will
not issue any USB transactions.
Note that there are two different ways of addressing configurations, interfaces,
alternatives, and endpoints: by index or by number. The index is the ordinal
number (starting from 0) of the descriptor as presented by the device. The
number is the respective number of the entity as found in its descriptor.
Enumeration of descriptors use the index, getting and setting typically uses
numbers.
Example: all endpoints (except the control endpoint) for the current
configuration can be found by iterating the
interface_index from 0 to
config_desc->bNumInterface-1 and for each of these
iterating the
endpoint_index from 0 to
interface_desc->bNumEndpoints. The
config_index should set to
USB_CURRENT_CONFIG_INDEX and
alt_index should be set to
USB_CURRENT_ALT_INDEX.
FILES¶
- /dev/ugenN.EE
- Endpoint EE of device
N.
SEE ALSO¶
usb(4)
HISTORY¶
The
ugen driver appeared in
NetBSD
1.4.
