PCI: endpoint: Add support to associate secondary EPC with EPF

In the case of standard endpoint functions, only one endpoint controller
(EPC) will be associated with an endpoint function (EPF). However for
providing NTB (non transparent bridge) functionality, two EPCs should be
associated with a single EPF.  Add support to associate secondary EPC with
EPF. This is in preparation for adding NTB endpoint function driver.

Link: https://lore.kernel.org/r/20210201195809.7342-7-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

2 files changed, 38 insertions, 4 deletions

diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 88d311bad984..d9cb3944fb87 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -13,6 +13,12 @@
 
 struct pci_epc;
 
+enum pci_epc_interface_type {
+	UNKNOWN_INTERFACE = -1,
+	PRIMARY_INTERFACE,
+	SECONDARY_INTERFACE,
+};
+
 enum pci_epc_irq_type {
 	PCI_EPC_IRQ_UNKNOWN,
 	PCI_EPC_IRQ_LEGACY,
@@ -20,6 +26,19 @@ enum pci_epc_irq_type {
 	PCI_EPC_IRQ_MSIX,
 };
 
+static inline const char *
+pci_epc_interface_string(enum pci_epc_interface_type type)
+{
+	switch (type) {
+	case PRIMARY_INTERFACE:
+		return "primary";
+	case SECONDARY_INTERFACE:
+		return "secondary";
+	default:
+		return "UNKNOWN interface";
+	}
+}
+
 /**
  * struct pci_epc_ops - set of function pointers for performing EPC operations
  * @write_header: ops to populate configuration space header
@@ -175,10 +194,12 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 		 struct module *owner);
 void devm_pci_epc_destroy(struct device *dev, struct pci_epc *epc);
 void pci_epc_destroy(struct pci_epc *epc);
-int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf);
+int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
+		    enum pci_epc_interface_type type);
 void pci_epc_linkup(struct pci_epc *epc);
 void pci_epc_init_notify(struct pci_epc *epc);
-void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf);
+void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
+			enum pci_epc_interface_type type);
 int pci_epc_write_header(struct pci_epc *epc, u8 func_no,
 			 struct pci_epf_header *hdr);
 int pci_epc_set_bar(struct pci_epc *epc, u8 func_no,
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index f373a134ac04..1dc66824f5a8 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -14,6 +14,7 @@
 #include <linux/pci.h>
 
 struct pci_epf;
+enum pci_epc_interface_type;
 
 enum pci_notify_event {
 	CORE_INIT,
@@ -119,6 +120,11 @@ struct pci_epf_bar {
  * @list: to add pci_epf as a list of PCI endpoint functions to pci_epc
  * @nb: notifier block to notify EPF of any EPC events (like linkup)
  * @lock: mutex to protect pci_epf_ops
+ * @sec_epc: the secondary EPC device to which this EPF device is bound
+ * @sec_epc_list: to add pci_epf as list of PCI endpoint functions to secondary
+ *   EPC device
+ * @sec_epc_bar: represents the BAR of EPF device associated with secondary EPC
+ * @sec_epc_func_no: unique (physical) function number within the secondary EPC
  */
 struct pci_epf {
 	struct device		dev;
@@ -135,6 +141,12 @@ struct pci_epf {
 	struct notifier_block   nb;
 	/* mutex to protect against concurrent access of pci_epf_ops */
 	struct mutex		lock;
+
+	/* Below members are to attach secondary EPC to an endpoint function */
+	struct pci_epc		*sec_epc;
+	struct list_head	sec_epc_list;
+	struct pci_epf_bar	sec_epc_bar[6];
+	u8			sec_epc_func_no;
 };
 
 /**
@@ -171,8 +183,9 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
 			      struct module *owner);
 void pci_epf_unregister_driver(struct pci_epf_driver *driver);
 void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
-			  size_t align);
-void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar);
+			  size_t align, enum pci_epc_interface_type type);
+void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
+			enum pci_epc_interface_type type);
 int pci_epf_bind(struct pci_epf *epf);
 void pci_epf_unbind(struct pci_epf *epf);
 #endif /* __LINUX_PCI_EPF_H */