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Subject[PATCH v3 1/6] PCI: support the ATS capability
Date
The ATS spec can be found at http://www.pcisig.com/specifications/iov/ats/
(it requires membership).

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
---
drivers/pci/pci.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 16 ++++++++++
include/linux/pci_regs.h | 10 ++++++
3 files changed, 98 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e3efe6b..87018ab 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1462,6 +1462,78 @@ void pci_enable_ari(struct pci_dev *dev)
}

/**
+ * pci_enable_ats - enable the ATS capability
+ * @dev: the PCI device
+ * @ps: the IOMMU page shift
+ *
+ * Returns 0 on success, or a negative value on error.
+ */
+int pci_enable_ats(struct pci_dev *dev, int ps)
+{
+ int pos;
+ u16 ctrl;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
+ if (!pos)
+ return -ENODEV;
+
+ if (ps < PCI_ATS_MIN_STU)
+ return -EINVAL;
+
+ ctrl = PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU) | PCI_ATS_CTRL_ENABLE;
+ pci_write_config_word(dev, pos + PCI_ATS_CTRL, ctrl);
+
+ dev->ats_enabled = 1;
+
+ return 0;
+}
+
+/**
+ * pci_disable_ats - disable the ATS capability
+ * @dev: the PCI device
+ */
+void pci_disable_ats(struct pci_dev *dev)
+{
+ int pos;
+ u16 ctrl;
+
+ if (!dev->ats_enabled)
+ return;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
+ if (!pos)
+ return;
+
+ pci_read_config_word(dev, pos + PCI_ATS_CTRL, &ctrl);
+ ctrl &= ~PCI_ATS_CTRL_ENABLE;
+ pci_write_config_word(dev, pos + PCI_ATS_CTRL, ctrl);
+}
+
+/**
+ * pci_ats_queue_depth - query ATS Invalidate Queue Depth
+ * @dev: the PCI device
+ *
+ * Returns the queue depth on success, or 0 on error.
+ */
+int pci_ats_queue_depth(struct pci_dev *dev)
+{
+ int pos;
+ u16 cap;
+
+ if (dev->ats_qdep)
+ return dev->ats_qdep;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
+ if (!pos)
+ return 0;
+
+ pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
+ dev->ats_qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
+ PCI_ATS_MAX_QDEP;
+ return dev->ats_qdep;
+}
+
+/**
* pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge
* @dev: the PCI device
* @pin: the INTx pin (1=INTA, 2=INTB, 3=INTD, 4=INTD)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7bd624b..cab680b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -254,6 +254,7 @@ struct pci_dev {
unsigned int msi_enabled:1;
unsigned int msix_enabled:1;
unsigned int ari_enabled:1; /* ARI forwarding */
+ unsigned int ats_enabled:1; /* Address Translation Service */
unsigned int is_managed:1;
unsigned int is_pcie:1;
unsigned int state_saved:1;
@@ -270,6 +271,7 @@ struct pci_dev {
struct list_head msi_list;
#endif
struct pci_vpd *vpd;
+ int ats_qdep; /* ATS Invalidate Queue Depth */
};

extern struct pci_dev *alloc_pci_dev(void);
@@ -1194,5 +1196,19 @@ int pci_ext_cfg_avail(struct pci_dev *dev);

void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar);

+extern int pci_enable_ats(struct pci_dev *dev, int ps);
+extern void pci_disable_ats(struct pci_dev *dev);
+extern int pci_ats_queue_depth(struct pci_dev *dev);
+/**
+ * pci_ats_enabled - query the ATS status
+ * @dev: the PCI device
+ *
+ * Returns 1 if ATS capability is enabled, or 0 if not.
+ */
+static inline int pci_ats_enabled(struct pci_dev *dev)
+{
+ return dev->ats_enabled;
+}
+
#endif /* __KERNEL__ */
#endif /* LINUX_PCI_H */
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index 027815b..3858b4f 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -498,6 +498,7 @@
#define PCI_EXT_CAP_ID_DSN 3
#define PCI_EXT_CAP_ID_PWR 4
#define PCI_EXT_CAP_ID_ARI 14
+#define PCI_EXT_CAP_ID_ATS 15

/* Advanced Error Reporting */
#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
@@ -615,4 +616,13 @@
#define PCI_ARI_CTRL_ACS 0x0002 /* ACS Function Groups Enable */
#define PCI_ARI_CTRL_FG(x) (((x) >> 4) & 7) /* Function Group */

+/* Address Translation Service */
+#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_CTRL 0x06 /* ATS Control Register */
+#define PCI_ATS_CTRL_ENABLE 0x8000 /* ATS Enable */
+#define PCI_ATS_CTRL_STU(x) ((x) & 0x1f) /* Smallest Translation Unit */
+#define PCI_ATS_MIN_STU 12 /* shift of minimum STU block */
+
#endif /* LINUX_PCI_REGS_H */
--
1.6.1


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