PCI: add latency tolerance reporting enable/disable support
Latency tolerance reporting allows devices to send messages to the root
complex indicating their latency tolerance for snooped & unsnooped
memory transactions. Add support for enabling & disabling this
feature, along with a routine to set the max latencies a device should
send upstream.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 45a035c..df4d69b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -840,6 +840,11 @@
int pci_enable_obff(struct pci_dev *dev, enum pci_obff_signal_type);
void pci_disable_obff(struct pci_dev *dev);
+bool pci_ltr_supported(struct pci_dev *dev);
+int pci_enable_ltr(struct pci_dev *dev);
+void pci_disable_ltr(struct pci_dev *dev);
+int pci_set_ltr(struct pci_dev *dev, int snoop_lat_ns, int nosnoop_lat_ns);
+
/* 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);
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index aa42026..e884096 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -508,6 +508,7 @@
#define PCI_EXP_RTSTA_PENDING 0x20000 /* PME pending */
#define PCI_EXP_DEVCAP2 36 /* Device Capabilities 2 */
#define PCI_EXP_DEVCAP2_ARI 0x20 /* Alternative Routing-ID */
+#define PCI_EXP_DEVCAP2_LTR 0x800 /* Latency tolerance reporting */
#define PCI_EXP_OBFF_MASK 0xc0000 /* OBFF support mechanism */
#define PCI_EXP_OBFF_MSG 0x40000 /* New message signaling */
#define PCI_EXP_OBFF_WAKE 0x80000 /* Re-use WAKE# for OBFF */
@@ -515,6 +516,7 @@
#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_LTR_EN 0x400 /* Latency tolerance reporting */
#define PCI_EXP_OBFF_MSGA_EN 0x2000 /* OBFF enable with Message type A */
#define PCI_EXP_OBFF_MSGB_EN 0x4000 /* OBFF enable with Message type B */
#define PCI_EXP_OBFF_WAKE_EN 0x6000 /* OBFF using WAKE# signaling */
@@ -535,6 +537,7 @@
#define PCI_EXT_CAP_ID_ARI 14
#define PCI_EXT_CAP_ID_ATS 15
#define PCI_EXT_CAP_ID_SRIOV 16
+#define PCI_EXT_CAP_ID_LTR 24
/* Advanced Error Reporting */
#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
@@ -691,6 +694,12 @@
#define PCI_SRIOV_VFM_MO 0x2 /* Active.MigrateOut */
#define PCI_SRIOV_VFM_AV 0x3 /* Active.Available */
+#define PCI_LTR_MAX_SNOOP_LAT 0x4
+#define PCI_LTR_MAX_NOSNOOP_LAT 0x6
+#define PCI_LTR_VALUE_MASK 0x000003ff
+#define PCI_LTR_SCALE_MASK 0x00001c00
+#define PCI_LTR_SCALE_SHIFT 10
+
/* Access Control Service */
#define PCI_ACS_CAP 0x04 /* ACS Capability Register */
#define PCI_ACS_SV 0x01 /* Source Validation */