s390_pci_mmio_write.2: srcfix

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.\" Copyright (c) IBM Corp. 2015
.\" Author: Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
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.TH S390_PCI_MMIO_WRITE 2 2015-01-15 "Linux Programmer's Manual"
.SH NAME
s390_pci_mmio_write, s390_pci_mmio_read \- transfer data to/from PCI
MMIO memory page
.SH SYNOPSIS
.nf
.B #include <asm/unistd.h>

.BI "int s390_pci_mmio_write(unsigned long " mmio_addr ",
.BI "                     void *" user_buffer ",
.BI "                     size_t " length ");
.br
.BI "int s390_pci_mmio_read(unsigned long " mmio_addr ",
.BI "                    void *" user_buffer ",
.BI "                    size_t " length ");
.fi
.SH DESCRIPTION
The
.BR s390_pci_mmio_write ()
system call writes data of length
.IR length
from the user space buffer
.IR user_buffer
to a PCI MMIO memory location.
The
.BR s390_pci_mmio_read ()
system call reads data from a PCI MMIO memory location
to the user space buffer
.IR user_buffer
of
.IR length
bytes size.

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 the user space on the Linux on System z platform.
The address specified by the
.IR mmio_addr
parameter must belong to a PCI MMIO memory page mapping in the user
address space, and the data being written or read must not cross a
page boundary.
The
.IR length
parameter value cannot be greater than the page size.
.SH RETURN VALUE
On success,
.BR s390_pci_mmio_write ()
and
.BR s390_pci_mmio_read ()
return 0.
On error, \-1 is returned and 
.IR errno
is set to one of the error codes listed below.
.SH ERRORS
.TP
.B ENODEV
PCI support is not enabled.
.TP
.B ENOMEM
Insufficient memory.
.TP
.B EFAULT
Invalid address was specified.
.TP
.B EINVAL
Invalid parameter value.
.SH VERSIONS
These system calls are available since Linux 3.19.
.SH 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.
.SH NOTES
Glibc does not provide a wrapper for this system call, use
.BR syscall (2)
to call it.
.SH SEE ALSO
.BR syscall (2)