s390_pci_mmio_write, s390_pci_mmio_read - transfer data to/from PCI MMIO memory
page
#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);
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.
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.
- 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.
These system calls are available since Linux 3.19.
This Linux-specific system call is available only on the s390 architecture. The
required PCI support is available beginning with System z EC12.
Glibc does not provide a wrapper for this system call, use
syscall(2) to
call it.
syscall(2)