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authorDavid Woodhouse <dwmw@amazon.co.uk>2017-04-12 15:25:59 +0300
committerBjorn Helgaas <bhelgaas@google.com>2017-04-20 16:47:47 +0300
commitf719582435afe9c7985206e42d804ea6aa315d33 (patch)
tree0f0ea2ee1adc77e1e81c1410e5569e5d6136ffb6 /Documentation/filesystems
parentf66e225828c1b046c7db1db65b0dd2d135f6a2da (diff)
downloadlinux-f719582435afe9c7985206e42d804ea6aa315d33.tar.xz
PCI: Add pci_mmap_resource_range() and use it for ARM64
Starting to leave behind the legacy of the pci_mmap_page_range() interface which takes "user-visible" BAR addresses. This takes just the resource and offset. For now, both APIs coexist and depending on the platform, one is implemented as a wrapper around the other. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/sysfs-pci.txt10
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 46b95d82c4fd..06f1d64c6f70 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -113,9 +113,13 @@ 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