Проект OpenNet: MAN devmap_default_access (9) Ядро (FreeBSD и Linux)

Интерактивная система просмотра системных руководств (man-ов)

devmap_default_access (9)

>> devmap_default_access (9) ( Solaris man: Ядро )

NAME

devmap_default_access - default driver memory access function

SYNOPSIS

#include <sys/ddi.h> 
#include <sys/sunddi.h>


int devmap_default_access(devmap_cookie_t dhp, void *pvtp, 
    offset_t off, size_t len, uint_t type, uint_t rw);

INTERFACE LEVEL

Solaris DDI specific (Solaris DDI).

PARAMETERS

dhp

: An opaque mapping handle that the system uses to describe the mapping.

pvtp

: Driver private mapping data.

off

: User offset within the logical device memory at which the access begins.

len

: Length (in bytes) of the memory being accessed.

type

: Type of access operation.

: Type of access.

DESCRIPTION

devmap_default_access() is a function providing the semantics of devmap_access(9E). The drivers call devmap_default_access() to handle the mappings that do not support context switching. The drivers should call devmap_do_ctxmgt(9F) for the mappings that support context management.

devmap_default_access() can either be called from devmap_access(9E) or be used as the devmap_access(9E) entry point. The arguments dhp, pvtp, off, len, type, and rw are provided by the devmap_access(9E) entry point and must not be modified.

RETURN VALUES

: Successful completion.

Non-zero

: An error occurred.

CONTEXT

devmap_default_access() must be called from the driver's devmap_access(9E) entry point.

EXAMPLES

Example 1 Using devmap_default_access in devmap_access.

The following shows an example of using devmap_default_access() in the devmap_access(9E) entry point.

...
#define OFF_DO_CTXMGT  0x40000000
#define OFF_NORMAL     0x40100000
#define CTXMGT_SIZE    0x100000
#define NORMAL_SIZE    0x100000

/*
* Driver devmap_contextmgt(9E) callback function.
*/
static int
xx_context_mgt(devmap_cookie_t dhp, void *pvtp, offset_t offset,
   size_t length, uint_t type, uint_t rw)
{
   ......
   /*
    * see devmap_contextmgt(9E) for an example
    */
}

/*
* Driver devmap_access(9E) entry point
*/
static int
xxdevmap_access(devmap_cookie_t dhp, void *pvtp, offset_t off,
   size_t len, uint_t type, uint_t rw)
{
   offset_t diff;
   int err;

   /*
    * check if off is within the range that supports
    * context management.
    */
   if ((diff = off - OFF_DO_CTXMG) >= 0 && diff < CTXMGT_SIZE) {
       /*
        * calculates the length for context switching
        */
       if ((len + off) > (OFF_DO_CTXMGT + CTXMGT_SIZE))
           return (-1);
       /*
        * perform context switching
        */
       err = devmap_do_ctxmgt(dhp, pvtp, off, len, type,
           rw,  xx_context_mgt);
   /*
    * check if off is within the range that does normal
    * memory mapping.
    */
   } else if ((diff = off - OFF_NORMAL) >= 0 && diff < NORMAL_SIZE) {
       if ((len + off) > (OFF_NORMAL + NORMAL_SIZE))
           return (-1);
       err = devmap_default_access(dhp, pvtp, off, len, type, rw);
   } else
       return (-1);

   return (err);
}