Writing Device Drivers

Check Changed Arguments of DDI Functions

Some of the DDI functions argument data types have been changed. These routines are listed below.


struct buf *getrbuf(int sleepflag);
In previous releases, sleepflag was defined as a type long.


 int drv_getparm(unsigned int parm, void *value_p);
In previous releases, value_p was defined to be type unsigned long *.

In the 64-bit kernel, drv_getparm(9F) can be used to fetch quantities that are both 32-bit and 64-bit, yet the interface does not define the data types of these quantities which encourages simple programming errors.

The following new routines offer a safer alternative:

clock_t  ddi_get_lbolt(void);
time_t   ddi_get_time(void);
cred_t   *ddi_get_cred(void);
pid_t    ddi_get_pid(void);
Driver writers are strongly urged to use these routines instead of drv_getparm(9F).

delay(9F) and timeout(9F)

void delay(clock_t ticks);
timeout_id_t timeout(void (*func)(caddr_t), caddr_t arg, clock_t ticks);
The ticks argument to both of these routines has been changed from long to clock_t.

rmallocmap(9F) and rmallocmap_wait(9F)

struct map *rmallocmap(size_t mapsize);
struct map *rmallocmap_wait(size_t mapsize);
The mapsize argument to both of these routines has been changed from ulong_t to size_t.


struct buf *scsi_alloc_consistent_buf(struct scsi_address *ap,
   struct buf *bp, size_t datalen, uint_t bflags,
   int (*callback )(caddr_t), caddr_t arg);
In previous releases, datalen was defined as an int and bflags was defined as a ulong.


int uiomove(caddr_t address, size_t nbytes,
   enum uio_rw rwflag, uio_t *uio_p);
The nbytes argument was defined as a type long, but since it represents a size in bytes, size_t is more appropriate.

cv_timedwait(9F) and cv_timedwait_sig(9F)

 int cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t timeout); 
int cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t timeout);
In previous releases, the timeout argument to both of these routines was defined to be of type long. Since they represent time in ticks, clock_t is more appropriate.


 int ddi_device_copy(ddi_acc_handle_t src_handle,
   caddr_t src_addr, ssize_t src_advcnt,
   ddi_acc_handle_t dest_handle, caddr_t dest_addr,
   ssize_t dest_advcnt, size_t bytecount, uint_t dev_datasz);
The src_advcnt, dest_advcnt, dev_datasz arguments have changed type. These were previously defined as long, long and ulong_t respectively.


int ddi_device_zero(ddi_acc_handle_t handle,
   caddr_t dev_addr, size_t bytecount, ssize_t dev_advcnt,
   uint_t dev_datasz):
In previous releases, dev_advcnt was defined as a type long and dev_datasz as a ulong_t.


int ddi_dma_mem_alloc(ddi_dma_handle_t handle,
   size_t length, ddi_device_acc_attr_t *accattrp,
   uint_t flags, int (*waitfp)(caddr_t), caddr_t arg,
   caddr_t *kaddrp, size_t *real_length,
   ddi_acc_handle_t *handlep);
In previous releases, length, flags and real_length were defined with types, uint_t, ulong_t and uint_t *.