CXL_MMIO_READ64(3)

NAME
cxl_mmio_read64 - read a 64-bit word from the mapped AFU Problem State Area

SYNOPSIS
#include <libcxl.h>

int cxl_mmio_read64(struct cxl_afu_h *afu, uint64_t offset, uint64_t *data);

DESCRIPTION
cxl_mmio_read64() reads the 64-bit word at offset from the address of the mapped Problem State Area of afu, and copies its value to the word pointed to by data.

offset must be a multiple of 64, lower than the MMIO size returned by cxl_get_mmio_size(). The address of the mapped MMIO space is returned by cxl_mmio_ptr().

If the MMIO access fails due to an IO error, a SIGBUS may be sent to the application, which would ordinarily result in the process being terminated. libcxl provides an optional SIGBUS handler, which can be installed with cxl_mmio_install_sigbus_handler(). Installing this signal handler prior to using the MMIO accessor functions will cause them to return -1 and set errno to EIO in the event of an IO error. Additionally, if this handler has NOT been installed, the cxl_mmio_read* functions will raise a SIGBUS in the event that they detect an IO error due to a read of all F's for consistency.

RETURN VALUE
On success, 0 is returned. On error, -1 is returned and errno is set appropriately.

ERRORS

EINVAL
    Invalid argument value, or unmapped MMIO space.

EIO An unrecoverable error ( cxl_mmio_install_sigbus_handler() must have been previously called)

SEE ALSO
cxl(3), cxl_get_mmio_size(3), cxl_mmio_install_sigbus_handler(3), cxl_mmio_map(3), cxl_mmio_ptr(3), cxl_mmio_read32(3), cxl_mmio_unmap(3), cxl_mmio_write32(3), cxl_mmio_write64(3)