From 8c938ddc6df3bbe72809db1be6c9f3af83f5d7a9 Mon Sep 17 00:00:00 2001 From: Kuppuswamy Sathyanarayanan Date: Tue, 19 Feb 2019 11:06:09 -0800 Subject: [PATCH] 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 Cc: Jacob Pan Cc: Keith Busch Suggested-by: Ashok Raj Signed-off-by: Kuppuswamy Sathyanarayanan Acked-by: Bjorn Helgaas Signed-off-by: Joerg Roedel --- drivers/pci/ats.c | 27 +++++++++++++++++++++++++++ include/linux/pci.h | 2 ++ include/uapi/linux/pci_regs.h | 1 + 3 files changed, 30 insertions(+) diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index 420cd0a578d0..97c08146534a 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -142,6 +142,33 @@ int pci_ats_queue_depth(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_ats_queue_depth); +/** + * pci_ats_page_aligned - Return Page Aligned Request bit status. + * @pdev: the PCI device + * + * Returns 1, if the Untranslated Addresses generated by the device + * are always aligned or 0 otherwise. + * + * 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. + */ +int pci_ats_page_aligned(struct pci_dev *pdev) +{ + u16 cap; + + if (!pdev->ats_cap) + return 0; + + pci_read_config_word(pdev, pdev->ats_cap + PCI_ATS_CAP, &cap); + + if (cap & PCI_ATS_CAP_PAGE_ALIGNED) + return 1; + + return 0; +} +EXPORT_SYMBOL_GPL(pci_ats_page_aligned); + #ifdef CONFIG_PCI_PRI /** * pci_enable_pri - Enable PRI capability diff --git a/include/linux/pci.h b/include/linux/pci.h index 65f1d8c2f082..9724a8c0496b 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -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 diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 898be572b010..5c98133f2c94 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -866,6 +866,7 @@ #define PCI_ATS_CAP 0x04 /* ATS Capability Register */ #define PCI_ATS_CAP_QDEP(x) ((x) & 0x1f) /* Invalidate Queue Depth */ #define PCI_ATS_MAX_QDEP 32 /* Max Invalidate Queue Depth */ +#define PCI_ATS_CAP_PAGE_ALIGNED 0x0020 /* Page Aligned Request */ #define PCI_ATS_CTRL 0x06 /* ATS Control Register */ #define PCI_ATS_CTRL_ENABLE 0x8000 /* ATS Enable */ #define PCI_ATS_CTRL_STU(x) ((x) & 0x1f) /* Smallest Translation Unit */