PCI/ATS: Add pci_ats_page_aligned() interface

Return the Page Aligned Request bit in the ATS Capability Register.

As per PCIe spec r4.0, sec 10.5.1.2, if the Page Aligned Request bit is
set, it indicates the Untranslated Addresses generated by the device are
always aligned to a 4096 byte boundary.

An IOMMU that can only translate page-aligned addresses can only be used
with devices that always produce aligned Untranslated Addresses. This
interface will be used by drivers for such IOMMUs to determine whether
devices can use the ATS service.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Kuppuswamy Sathyanarayanan 2019-02-19 11:06:09 -08:00 committed by Joerg Roedel
parent 1b84778a62
commit 8c938ddc6d
3 changed files with 30 additions and 0 deletions

View file

@ -1524,11 +1524,13 @@ void pci_ats_init(struct pci_dev *dev);
int pci_enable_ats(struct pci_dev *dev, int ps);
void pci_disable_ats(struct pci_dev *dev);
int pci_ats_queue_depth(struct pci_dev *dev);
int pci_ats_page_aligned(struct pci_dev *dev);
#else
static inline void pci_ats_init(struct pci_dev *d) { }
static inline int pci_enable_ats(struct pci_dev *d, int ps) { return -ENODEV; }
static inline void pci_disable_ats(struct pci_dev *d) { }
static inline int pci_ats_queue_depth(struct pci_dev *d) { return -ENODEV; }
static inline int pci_ats_page_aligned(struct pci_dev *dev) { return 0; }
#endif
#ifdef CONFIG_PCIE_PTM