diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/sysfs-pci.txt | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 6ea1ceda6f52..06f1d64c6f70 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -113,9 +113,18 @@ Supporting PCI access on new platforms -------------------------------------- In order to support PCI resource mapping as described above, Linux platform -code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function. -Platforms are free to only support subsets of the mmap functionality, but -useful return codes should be provided. +code should ideally define ARCH_GENERIC_PCI_MMAP_RESOURCE and use the generic +implementation of that functionality. To support the historical interface of +mmap() through files in /proc/bus/pci, platforms may also set HAVE_PCI_MMAP. + +Alternatively, platforms which set HAVE_PCI_MMAP may provide their own +implementation of pci_mmap_page_range() instead of defining +ARCH_GENERIC_PCI_MMAP_RESOURCE. + +Platforms which support write-combining maps of PCI resources must define +arch_can_pci_mmap_wc() which shall evaluate to non-zero at runtime when +write-combining is permitted. Platforms which support maps of I/O resources +define arch_can_pci_mmap_io() similarly. Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms wishing to support legacy functionality should define it and provide |