diff options
Diffstat (limited to 'Documentation/PCI/pci.rst')
| -rw-r--r-- | Documentation/PCI/pci.rst | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/Documentation/PCI/pci.rst b/Documentation/PCI/pci.rst index 87c6f4a6ca32..cced568d78e9 100644 --- a/Documentation/PCI/pci.rst +++ b/Documentation/PCI/pci.rst @@ -273,25 +273,25 @@ Set the DMA mask size While all drivers should explicitly indicate the DMA capability (e.g. 32 or 64 bit) of the PCI bus master, devices with more than 32-bit bus master capability for streaming data need the driver -to "register" this capability by calling pci_set_dma_mask() with +to "register" this capability by calling dma_set_mask() with appropriate parameters. In general this allows more efficient DMA on systems where System RAM exists above 4G _physical_ address. Drivers for all PCI-X and PCIe compliant devices must call -pci_set_dma_mask() as they are 64-bit DMA devices. +dma_set_mask() as they are 64-bit DMA devices. Similarly, drivers must also "register" this capability if the device -can directly address "consistent memory" in System RAM above 4G physical -address by calling pci_set_consistent_dma_mask(). +can directly address "coherent memory" in System RAM above 4G physical +address by calling dma_set_coherent_mask(). Again, this includes drivers for all PCI-X and PCIe compliant devices. Many 64-bit "PCI" devices (before PCI-X) and some PCI-X devices are 64-bit DMA capable for payload ("streaming") data but not control -("consistent") data. +("coherent") data. Setup shared control data ------------------------- -Once the DMA masks are set, the driver can allocate "consistent" (a.k.a. shared) +Once the DMA masks are set, the driver can allocate "coherent" (a.k.a. shared) memory. See Documentation/core-api/dma-api.rst for a full description of the DMA APIs. This section is just a reminder that it needs to be done before enabling DMA on the device. @@ -367,7 +367,7 @@ steps need to be performed: - Disable the device from generating IRQs - Release the IRQ (free_irq()) - Stop all DMA activity - - Release DMA buffers (both streaming and consistent) + - Release DMA buffers (both streaming and coherent) - Unregister from other subsystems (e.g. scsi or netdev) - Disable device from responding to MMIO/IO Port addresses - Release MMIO/IO Port resource(s) @@ -420,7 +420,7 @@ Once DMA is stopped, clean up streaming DMA first. I.e. unmap data buffers and return buffers to "upstream" owners if there is one. -Then clean up "consistent" buffers which contain the control data. +Then clean up "coherent" buffers which contain the control data. See Documentation/core-api/dma-api.rst for details on unmapping interfaces. |