diff options
Diffstat (limited to 'drivers/pci/ats.c')
| -rw-r--r-- | drivers/pci/ats.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index c570892b2090..87fa03540b8a 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -48,6 +48,39 @@ bool pci_ats_supported(struct pci_dev *dev) EXPORT_SYMBOL_GPL(pci_ats_supported); /** + * pci_prepare_ats - Setup the PS for ATS + * @dev: the PCI device + * @ps: the IOMMU page shift + * + * This must be done by the IOMMU driver on the PF before any VFs are created to + * ensure that the VF can have ATS enabled. + * + * Returns 0 on success, or negative on failure. + */ +int pci_prepare_ats(struct pci_dev *dev, int ps) +{ + u16 ctrl; + + if (!pci_ats_supported(dev)) + return -EINVAL; + + if (WARN_ON(dev->ats_enabled)) + return -EBUSY; + + if (ps < PCI_ATS_MIN_STU) + return -EINVAL; + + if (dev->is_virtfn) + return 0; + + dev->ats_stu = ps; + ctrl = PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU); + pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl); + return 0; +} +EXPORT_SYMBOL_GPL(pci_prepare_ats); + +/** * pci_enable_ats - enable the ATS capability * @dev: the PCI device * @ps: the IOMMU page shift |