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devmap_default_access - default driver memory access function

#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);

illumos DDI specific (illumos DDI). dhp pvtp off len type rw 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.

0 Non-zero devmap_default_access() must be called from the driver's devmap_access(9E) entry point. 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);
}

devmap_access(9E), devmap_do_ctxmgt(9F), devmap_callback_ctl(9S)

Writing Device Drivers