Manual Pages for UNIX Operating System command usage for man ddi_btop

Kernel Functions for Drivers                         ddi_btop(9F)



NAME
     ddi_btop, ddi_btopr, ddi_ptob - page size conversions

SYNOPSIS
     #include 
     #include 



     unsigned long ddi_btop(dev_info_t *dip, unsigned long bytes);


     unsigned long ddi_btopr(dev_info_t *dip, unsigned long bytes);


     unsigned long ddi_ptob(dev_info_t *dip, unsigned long pages);


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI).

DESCRIPTION
     This set of routines use the parent nexus driver to  perform
     conversions in page size units.


     The ddi_btop() function converts the given number  of  bytes
     to the number of memory pages that it corresponds to, round-
     ing down in the case that the byte count is not a page  mul-
     tiple.


     The ddi_btopr() function converts the given number of  bytes
     to the number of memory pages that it corresponds to, round-
     ing up in the case that the byte count is not a page  multi-
     ple.


     The ddi_ptob() function converts the given number  of  pages
     to the number of bytes that it corresponds to.


     Because bus nexus may possess  their  own  hardware  address
     translation  facilities,  these  routines  should be used in
     preference to the corresponding DDI/DKI  routines  btop(9F),
     btopr(9F),  and  ptob(9F),  which  only deal in terms of the
     pagesize of the main system MMU.

RETURN VALUES
     The ddi_btop() and ddi_btopr() functions return  the  number
     of corresponding pages. ddi_ptob() returns the corresponding
     number of bytes. There are no error return values.



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                         ddi_btop(9F)



CONTEXT
     This function can be called from user, interrupt, or  kernel
     context.

EXAMPLES
     Example 1 Find the size (in bytes) of one page

       pagesize = ddi_ptob(dip, 1L);


SEE ALSO
     btop(9F), btopr(9F), ptob(9F)


     Writing Device Drivers








































SunOS 5.11          Last change: 16 Jan 2006                    2