s390_pci_mmio_write(2) Linux Man Page

Name

s390_pci_mmio_write, s390_pci_mmio_read - transfer data to/from PCI MMIO memory page

Library

Standard C library ( libc ", " -lc )

Synopsis

"#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"#include <unistd.h> 
int syscall(SYS_s390_pci_mmio_write, unsigned long  mmio_addr ,
                       const void " user_buffer [. length ], \
size_t " length );
int syscall(SYS_s390_pci_mmio_read, unsigned long  mmio_addr ,
                       void " user_buffer [. length "], size_t  length );

Note : glibc provides no wrappers for these system calls, necessitating the use of syscall(2).

Description

The s390_pci_mmio_write() system call writes length bytes of data from the user-space buffer user_buffer to the PCI MMIO memory location specified by mmio_addr. The s390_pci_mmio_read() system call reads length bytes of data from the PCI MMIO memory location specified by mmio_addr to the user-space buffer user_buffer.

These system calls must be used instead of the simple assignment or data-transfer operations that are used to access the PCI MMIO memory areas mapped to user space on the Linux System z platform. The address specified by mmio_addr must belong to a PCI MMIO memory page mapping in the caller's address space, and the data being written or read must not cross a page boundary. The length value cannot be greater than the system page size.

Return Value

On success, s390_pci_mmio_write() and s390_pci_mmio_read() return 0. On failure, -1 is returned and errno is set to indicate the error.

Errors

EFAULT The address in mmio_addr is invalid.

EFAULT user_buffer does not point to a valid location in the caller's address space.

EINVAL Invalid length argument.

ENODEV PCI support is not enabled.

ENOMEM Insufficient memory.

Standards

Linux on s390.

History

Linux 3.19. System z EC12.

System Grab Bag