SVR5

cm_write_devconfig16(D3)

cm_write_devconfig16 -- write byte to board's NVRAM extension information

Synopsis

   #include <sys/confmgr.h>
   #include <sys/ddi.h>
   
   int cm_write_devconfig16(rm_key_t key, size_t offset, const uchar_t *buf)

Description

cm_write_devconfig16 is used to write a single word (two-bytes) to the NVRAM extension information associated with a selected board instance. The extension information is specific to the bus type of the board and exactly what information is written is determined by the bus driver (for example, the MCA bus driver).

Drivers should not use this routine to write standard board parameters directly. Rather, such parameters should be stored with cm_addval(D3) requests.

cm_write_devconfig16 can be used by MCA drivers to write directly to the POS registers.

Arguments

key: Resource manager key selecting a particular board instance.
offset: Offset from the beginning of the board's device configuration space to start writing data.
buf: Buffer containing data to be written.

Return values

cm_write_devconfig16 returns 0 for success. The following errnos are returned for failure:

EINVAL: if rm_key is invalid, buf is NULL, or the write fails.
ENOENT: if the board is installed in an ISA bus or the bus does not provide the specified level of granularity.

Note, even though the cm_write_devconfig(D3) function supports all levels of granularity, this interface is limited to those "inherent" on the system (i.e. there are BIOS calls to support them directly).

Usage

The caller must not have a resource manager transaction pending (see cm_begin_trans(D3)) when this function is called.

Examples

See cm_read_devconfig16(D3) for a code example that illustrates the use of cm_write_devconfig16( ).

Context and synchronization

All contexts.

Hardware applicability

All

Version applicability

ddi: 7.1, 7.1mp, 8, 8mp

Differences between versions

In DDI versions 7.1 and 7.1mp, the offset argument is cast as size_t rather than an off_t. When porting drivers from earlier DDI versions, it is not necessary to modify the type of the offset argument.

References

cm_addval(D3), cm_devconfig_size(D3), cm_getbrdkey(D3), cm_read_devconfig(D3), cm_read_devconfig8(D3), cm_read_devconfig32(D3), cm_write_devconfig(D3), cm_write_devconfig16(D3), cm_write_devconfig32(D3), eisa(D4), eisa(D5), mca(D5), pci(D5)

``Autoconfiguration'' in HDK Technical Reference