PCI: add ID-based ordering enable/disable support
Add support to allow drivers to enable/disable ID-based ordering. Where
supported, ID-based ordering can significantly improve the latency of
individual requests by preventing them from queueing up behind unrelated
traffic.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 96f70d7..551ddcb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -828,6 +828,11 @@
return __pci_enable_wake(dev, state, false, enable);
}
+#define PCI_EXP_IDO_REQUEST (1<<0)
+#define PCI_EXP_IDO_COMPLETION (1<<1)
+void pci_enable_ido(struct pci_dev *dev, unsigned long type);
+void pci_disable_ido(struct pci_dev *dev, unsigned long type);
+
/* For use by arch with custom probe code */
void set_pcie_port_type(struct pci_dev *pdev);
void set_pcie_hotplug_bridge(struct pci_dev *pdev);
@@ -1207,6 +1212,14 @@
return 0;
}
+static inline void pci_enable_ido(struct pci_dev *dev, unsigned long type)
+{
+}
+
+static inline void pci_disable_ido(struct pci_dev *dev, unsigned long type)
+{
+}
+
static inline int pci_request_regions(struct pci_dev *dev, const char *res_name)
{
return -EIO;
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index be01380..d9acf9b 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -510,6 +510,8 @@
#define PCI_EXP_DEVCAP2_ARI 0x20 /* Alternative Routing-ID */
#define PCI_EXP_DEVCTL2 40 /* Device Control 2 */
#define PCI_EXP_DEVCTL2_ARI 0x20 /* Alternative Routing-ID */
+#define PCI_EXP_IDO_REQ_EN 0x100 /* ID-based ordering request enable */
+#define PCI_EXP_IDO_CMP_EN 0x200 /* ID-based ordering completion enable */
#define PCI_EXP_LNKCTL2 48 /* Link Control 2 */
#define PCI_EXP_SLTCTL2 56 /* Slot Control 2 */