SVR5

cm_read_devconfig8(D3)

cm_read_devconfig8 -- read byte from board's NVRAM extension information

Synopsis

   #include <sys/confmgr.h>
   #include <sys/ddi.h>
   
   int cm_read_devconfig8(rm_key_t key, size_t offset, uchar_t *buf)

Description

cm_read_devconfig8 is used to read a single byte from 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 read is determined by the bus driver (for example, the MCA bus driver).

Drivers should not use this routine to read standard board parameters directly. Rather, such parameters should be acquired via cm_getval(D3) requests.

cm_read_devconfig8 can be used by MCA drivers to directly read 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 the read.
buf: Buffer to hold data to be read.

Return values

cm_read_devconfig8 returns 0 for success. The following errnos are returned for failure:

EINVAL: if rm_key is invalid, buf is NULL or the read fails.
ENOENT: if the board is installed in an ISA bus or the bus doesn't provide the specified level of granularity.

Usage

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

Note, even though the cm_read_devconfig( ) function supports all levels of granularity, this interface is limited to those "inherent" on the system (in other words, there are bios calls to support them directly).

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_devconfig_size(D3), cm_getbrdkey(D3), cm_getval(D3), cm_read_devconfig(D3), cm_read_devconfig16(D3), cm_read_devconfig32(D3), cm_write_devconfig(D3), cm_write_devconfig8(D3), cm_write_devconfig16(D3), cm_write_devconfig32(D3), eisa_parse_devconfig(D3), eisa(D4), eisa(D5), mca(D5), pci(D5)

``Autoconfiguration'' in HDK Technical Reference