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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Kernel Functions for Drivers

ddi_mapdev_intercept(9F)

INTERFACE LEVEL
PARAMETERS
DESCRIPTION
RETURN VALUES
EXAMPLES
CONTEXT
SEE ALSO

NAME

ddi_mapdev_intercept, ddi_mapdev_nointercept - control driver notification of user accesses

SYNOPSIS

#include <sys/sunddi.h> int ddi_mapdev_intercept(ddi_mapdev_handle_t handle, off_t offset, off_t len);

int ddi_mapdev_nointercept(ddi_mapdev_handle_t handle, off_t offset, off_t len);

PARAMETERS

handle: An opaque pointer to a device mapping handle.
offset: An offset in bytes within device memory.
len: Length in bytes.

Future releases of Solaris will provide these functions for binary and source compatibility. However, for increased functionality, use devmap_load(9F) or devmap_unload(9F) instead. See devmap_load(9F) and devmap_unload(9F) for details.

The ddi_mapdev_intercept() and ddi_mapdev_nointercept() functions control whether or not user accesses to device mappings created by ddi_mapdev(9F) in the specified range will generate calls to the mapdev_access(9E) entry point. ddi_mapdev_intercept() tells the system to intercept the user access and notify the driver to invalidate the mapping translations. ddi_mapdev_nointercept() tells the system to not intercept the user access and allow it to proceed by validating the mapping translations.

For both routines, the range to be affected is defined by the offset and len arguments. Requests affect the entire page containing the offset and all pages up to and including the page containing the last byte as indicated by offset + len.

Supplying a value of 0 for the len argument affects all addresses from the offset to the end of the mapping. Supplying a value of 0 for the offset argument and a value of 0 for len argument affect all addresses in the mapping.

To manage a device context, a device driver would call ddi_mapdev_intercept() on the context about to be switched out, switch contexts, and then call ddi_mapdev_nointercept() on the context switched in.

RETURN VALUES

ddi_mapdev_intercept() and ddi_mapdev_nointercept() return the following values:

0: Successful completion.
Non-zero: An error occurred.

EXAMPLES

Example 1. managing a device context that is one page in length

The following shows an example of managing a device context that is one page in length.

ddi_mapdev_handle_t cur_hdl; static int xxmapdev_access(ddi_mapdev_handle_t handle, void *devprivate, off_t offset) { int err; /* enable access callbacks for the current mapping */ if (cur_hdl != NULL) { if ((err = ddi_mapdev_intercept(cur_hdl, offset, 0)) != 0) return (err); } /* Switch device context - device dependent*/ ... /* Make handle the new current mapping */ cur_hdl = handle; /* * Disable callbacks and complete the access for the * mapping that generated this callback. */ return (ddi_mapdev_nointercept(handle, offset, 0)); }

CONTEXT

These routines can be called from user or kernel context only.