s390_pci_mmio_read(2)

1S390_PCI_MMIO_WRITE(2)        System Calls Manual       S390_PCI_MMIO_WRITE(2)
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NAME

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

10       #include <asm/unistd.h>
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12       int s390_pci_mmio_write(unsigned long mmio_addr,
13                               void *user_buffer, size_t length);
14       int s390_pci_mmio_read(unsigned long mmio_addr,
15                               void *user_buffer, size_t length);
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DESCRIPTION

18       The s390_pci_mmio_write() system call writes length bytes of data  from
19       the user-space buffer user_buffer to the PCI MMIO memory location spec‐
20       ified by mmio_addr.  The s390_pci_mmio_read() system call reads  length
21       bytes  of data from the PCI MMIO memory location specified by mmio_addr
22       to the user-space buffer user_buffer.
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24       These system calls must be used instead of  the  simple  assignment  or
25       data-transfer  operations  that  are used to access the PCI MMIO memory
26       areas mapped to user space on the Linux System z platform.  The address
27       specified by mmio_addr must belong to a PCI MMIO memory page mapping in
28       the caller's address space, and the data being written or read must not
29       cross  a  page  boundary.   The length value cannot be greater than the
30       system page size.
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RETURN VALUE

33       On success, s390_pci_mmio_write() and  s390_pci_mmio_read()  return  0.
34       On  error,  -1  is  returned and errno is set to one of the error codes
35       listed below.
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ERRORS

38       EFAULT The address in mmio_addr is invalid.
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40       EFAULT user_buffer does not point to a valid location in  the  caller's
41              address space.
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43       EINVAL Invalid length argument.
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45       ENODEV PCI support is not enabled.
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47       ENOMEM Insufficient memory.
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VERSIONS

50       These system calls are available since Linux 3.19.
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CONFORMING TO

53       This Linux-specific system call is available only on the s390 architec‐
54       ture.  The required PCI support is available beginning  with  System  z
55       EC12.
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NOTES

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

65       This page is part of release 4.16 of the Linux  man-pages  project.   A
66       description  of  the project, information about reporting bugs, and the
67       latest    version    of    this    page,    can     be     found     at
68       https://www.kernel.org/doc/man-pages/.
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72Linux Programmer's Manual         2017-09-15            S390_PCI_MMIO_WRITE(2)