pci_read_config8()

Read a byte from the configuration space of a device

Synopsis:

#include <hw/pci.h>

int pci_read_config8( unsigned bus,
                      unsigned dev_func,
                      unsigned offset,
                      unsigned count,
                      char* buff );

Arguments:

bus: The bus number.
dev_func: The name of the device or function.
offset: The register offset into the configuration space, in the range [0...255].
count: The number of bytes to read.
buff: A pointer to a buffer where the requested bytes are placed.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The pci_read_config8() function reads the specified number of bytes from the configuration space of the given device or function. For the details of the configuration space, see the _pci_config_regs structure in <hw/pci.h>.

Note:

You must successfully call pci_attach() before calling any of the other PCI functions.
The pci_read_config*() functions can return inconsistent data if another process is extensively using the PCI bus.

Returns:

PCI_BAD_REGISTER_NUMBER: An invalid register offset was given.
PCI_BUFFER_TOO_SMALL: The PCI BIOS server reads only 100 bytes at a time; count is too large.
PCI_SUCCESS: The device or function was found.
-1: You haven't called pci_attach(), or the call to it failed.

Examples:

See pci_attach_device() and pci_read_config16().

Classification:

QNX Neutrino

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	Yes
Thread	Yes