radio(9) [netbsd man page]

RADIO(9)						   BSD Kernel Developer's Manual						  RADIO(9)

NAME

     radio -- interface between low and high level radio drivers

DESCRIPTION

     The radio device driver is divided into a high level, hardware independent layer, and a low level hardware dependent layer.  The interface
     between these is the radio_hw_if structure.

     struct radio_hw_if {
	     int     (*open)(void *, int, int, struct lwp *);
	     int     (*close)(void *, int, int, struct lwp *);
	     int     (*get_info)(void *, struct radio_info *);
	     int     (*set_info)(void *, struct radio_info *);
	     int     (*search)(void *, int);
     };

     The high level radio driver attaches to the low level driver when the latter calls radio_attach_mi.  This call should be

	 void
	 radio_attach_mi(rhwp, hdlp, dev)
	     struct radio_hw_if *rhwp;
	     void *hdlp;
	     struct device *dev;

     The radio_hw_if struct is as shown above.	The hdlp argument is a handle to some low level data structure.  It is sent as the first argument
     to all the functions in radio_hw_if when the high level driver calls them.  dev is the device struct for the hardware device.

     The fields of radio_hw_if are described in some more detail below.

     int open (void *, int flags, int fmt, struct lwp *p);
       Optional.
       Is called when the radio device is opened.
       Returns 0 on success, otherwise an error code.

     int close (void *, int flags, int fmt, struct lwp *p);
       Optional.
       Is called when the radio device is closed.
       Returns 0 on success, otherwise an error code.

     int get_info (void *, struct radio_info *);
       Fill the radio_info struct.
       Returns 0 on success, otherwise an error code.

     int set_info (void *, struct radio_info *);
       Set values from the radio_info struct.
       Returns 0 on success, otherwise an error code.

     int search (void *, int);
       Returns 0 on success, otherwise an error code.

SEE ALSO

     radio(4)

BSD
								 December 20, 2005							       BSD

DOFILEREAD(9)						   BSD Kernel Developer's Manual					     DOFILEREAD(9)

NAME

     dofileread, dofilereadv, dofilewrite, dofilewritev -- high-level file operations

SYNOPSIS

     #include <sys/file.h>

     int
     dofileread(struct lwp *l, int fd, struct file *fp, void *buf, size_t nbyte, off_t *offset, int flags, register_t *retval);

     int
     dofilewrite(struct lwp *l, int fd, struct file *fp, const void *buf, size_t nbyte, off_t *offset, int flags, register_t *retval);

     int
     dofilereadv(struct lwp *l, int fd, struct file *fp, const struct iovec *iovp, int iovcnt, off_t *offset, int flags, register_t *retval);

     int
     dofilewritev(struct lwp *l, int fd, struct file *fp, const struct iovec *iovp, int iovcnt, off_t *offset, int flags, register_t *retval);

DESCRIPTION

     The functions implement the underlying functionality of the read(2), write(2), readv(2), and writev(2) system calls.  They are also used
     throughout the kernel as high-level access routines for file I/O.

     The dofileread() function attempts to read nbytes of data from the object referenced by file entry fp into the buffer pointed to by buf.  The
     dofilewrite() function attempts to write nbytes of data to the object referenced by file entry fp from the buffer pointed to by buf.

     The dofilereadv() and dofilewritev() functions perform the same operations, but scatter the data with the iovcnt buffers specified by the
     members of the iov array.

     The offset of the file operations is explicitly specified by *offset.  The new file offset after the file operation is returned in *offset.
     If the FOF_UPDATE_OFFSET flag is specified in the flags argument, the file offset in the file entry fp is updated to reflect the new file
     offset, otherwise it remains unchanged after the operation.

     The file descriptor fd is largely unused except for use by the ktrace framework for reporting to userlevel the process's file descriptor.

     Upon successful completion the number of bytes which were transferred is returned in *retval.

RETURN VALUES

     Upon successful completion zero is returned, otherwise an appropriate error is returned.

CODE REFERENCES

     The framework for these file operations is implemented within the file sys/kern/sys_generic.c.

SEE ALSO

     file(9)

BSD
								 December 20, 2005							       BSD