x11r4 man page for s390_pci_mmio_write

S390_PCI_MMIO_WRITE(2)						System Calls Manual					    S390_PCI_MMIO_WRITE(2)

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

SYNOPSIS
       #include <asm/unistd.h>

       int s390_pci_mmio_write(unsigned long mmio_addr,
			       void *user_buffer, size_t length);
       int s390_pci_mmio_read(unsigned long mmio_addr,
			       void *user_buffer, size_t length);

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  map-
       ping  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 error, -1 is returned and errno is set to one of the  error  codes
       listed below.

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.

VERSIONS
       These system calls are available since Linux 3.19.

CONFORMING TO
       This  Linux-specific system call is available only on the s390 architecture.  The required PCI support is available beginning with System z
       EC12.

NOTES
       Glibc does not provide a wrapper for this system call, use syscall(2) to call it.

SEE ALSO
       syscall(2)

COLOPHON
       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux Programmer's Manual					    2017-09-15						    S390_PCI_MMIO_WRITE(2)