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>

4 files changed, 87 insertions, 34 deletions

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 7a1f3abfde48..c0ac4e9cbe72 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -619,7 +619,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
 
 		if (epf_test->reg[bar]) {
 			pci_epc_clear_bar(epc, epf->func_no, epf_bar);
-			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			pci_epf_free_space(epf, epf_test->reg[bar], bar,
+					   PRIMARY_INTERFACE);
 		}
 	}
 }
@@ -651,7 +652,8 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
 
 		ret = pci_epc_set_bar(epc, epf->func_no, epf_bar);
 		if (ret) {
-			pci_epf_free_space(epf, epf_test->reg[bar], bar);
+			pci_epf_free_space(epf, epf_test->reg[bar], bar,
+					   PRIMARY_INTERFACE);
 			dev_err(dev, "Failed to set BAR%d\n", bar);
 			if (bar == test_reg_bar)
 				return ret;
@@ -771,7 +773,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 	}
 
 	base = pci_epf_alloc_space(epf, test_reg_size, test_reg_bar,
-				   epc_features->align);
+				   epc_features->align, PRIMARY_INTERFACE);
 	if (!base) {
 		dev_err(dev, "Failed to allocated register space\n");
 		return -ENOMEM;
@@ -789,7 +791,8 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 			continue;
 
 		base = pci_epf_alloc_space(epf, bar_size[bar], bar,
-					   epc_features->align);
+					   epc_features->align,
+					   PRIMARY_INTERFACE);
 		if (!base)
 			dev_err(dev, "Failed to allocate space for BAR%d\n",
 				bar);
diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
index 3710adf51912..6ca9e2f92460 100644
--- a/drivers/pci/endpoint/pci-ep-cfs.c
+++ b/drivers/pci/endpoint/pci-ep-cfs.c
@@ -94,13 +94,13 @@ static int pci_epc_epf_link(struct config_item *epc_item,
 	struct pci_epc *epc = epc_group->epc;
 	struct pci_epf *epf = epf_group->epf;
 
-	ret = pci_epc_add_epf(epc, epf);
+	ret = pci_epc_add_epf(epc, epf, PRIMARY_INTERFACE);
 	if (ret)
 		return ret;
 
 	ret = pci_epf_bind(epf);
 	if (ret) {
-		pci_epc_remove_epf(epc, epf);
+		pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
 		return ret;
 	}
 
@@ -120,7 +120,7 @@ static void pci_epc_epf_unlink(struct config_item *epc_item,
 	epc = epc_group->epc;
 	epf = epf_group->epf;
 	pci_epf_unbind(epf);
-	pci_epc_remove_epf(epc, epf);
+	pci_epc_remove_epf(epc, epf, PRIMARY_INTERFACE);
 }
 
 static struct configfs_item_operations pci_epc_item_ops = {
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index ea7e7465ce7a..3693eca5b030 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -493,21 +493,28 @@ EXPORT_SYMBOL_GPL(pci_epc_write_header);
  * pci_epc_add_epf() - bind PCI endpoint function to an endpoint controller
  * @epc: the EPC device to which the endpoint function should be added
  * @epf: the endpoint function to be added
+ * @type: Identifies if the EPC is connected to the primary or secondary
+ *        interface of EPF
  *
  * A PCI endpoint device can have one or more functions. In the case of PCIe,
  * the specification allows up to 8 PCIe endpoint functions. Invoke
  * pci_epc_add_epf() to add a PCI endpoint function to an endpoint controller.
  */
-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)
 {
+	struct list_head *list;
 	u32 func_no;
 	int ret = 0;
 
-	if (epf->epc)
+	if (IS_ERR_OR_NULL(epc))
+		return -EINVAL;
+
+	if (type == PRIMARY_INTERFACE && epf->epc)
 		return -EBUSY;
 
-	if (IS_ERR(epc))
-		return -EINVAL;
+	if (type == SECONDARY_INTERFACE && epf->sec_epc)
+		return -EBUSY;
 
 	mutex_lock(&epc->lock);
 	func_no = find_first_zero_bit(&epc->function_num_map,
@@ -524,11 +531,17 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf)
 	}
 
 	set_bit(func_no, &epc->function_num_map);
-	epf->func_no = func_no;
-	epf->epc = epc;
-
-	list_add_tail(&epf->list, &epc->pci_epf);
+	if (type == PRIMARY_INTERFACE) {
+		epf->func_no = func_no;
+		epf->epc = epc;
+		list = &epf->list;
+	} else {
+		epf->sec_epc_func_no = func_no;
+		epf->sec_epc = epc;
+		list = &epf->sec_epc_list;
+	}
 
+	list_add_tail(list, &epc->pci_epf);
 ret:
 	mutex_unlock(&epc->lock);
 
@@ -543,14 +556,26 @@ EXPORT_SYMBOL_GPL(pci_epc_add_epf);
  *
  * Invoke to remove PCI endpoint function from the endpoint controller.
  */
-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)
 {
+	struct list_head *list;
+	u32 func_no = 0;
+
 	if (!epc || IS_ERR(epc) || !epf)
 		return;
 
+	if (type == PRIMARY_INTERFACE) {
+		func_no = epf->func_no;
+		list = &epf->list;
+	} else {
+		func_no = epf->sec_epc_func_no;
+		list = &epf->sec_epc_list;
+	}
+
 	mutex_lock(&epc->lock);
-	clear_bit(epf->func_no, &epc->function_num_map);
-	list_del(&epf->list);
+	clear_bit(func_no, &epc->function_num_map);
+	list_del(list);
 	epf->epc = NULL;
 	mutex_unlock(&epc->lock);
 }
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index e44a317a2a2a..79329ec6373c 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -74,24 +74,37 @@ EXPORT_SYMBOL_GPL(pci_epf_bind);
  * @epf: the EPF device from whom to free the memory
  * @addr: the virtual address of the PCI EPF register space
  * @bar: the BAR number corresponding to the register space
+ * @type: Identifies if the allocated space is for primary EPC or secondary EPC
  *
  * Invoke to free the allocated PCI EPF register space.
  */
-void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar)
+void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
+			enum pci_epc_interface_type type)
 {
 	struct device *dev = epf->epc->dev.parent;
+	struct pci_epf_bar *epf_bar;
+	struct pci_epc *epc;
 
 	if (!addr)
 		return;
 
-	dma_free_coherent(dev, epf->bar[bar].size, addr,
-			  epf->bar[bar].phys_addr);
+	if (type == PRIMARY_INTERFACE) {
+		epc = epf->epc;
+		epf_bar = epf->bar;
+	} else {
+		epc = epf->sec_epc;
+		epf_bar = epf->sec_epc_bar;
+	}
+
+	dev = epc->dev.parent;
+	dma_free_coherent(dev, epf_bar[bar].size, addr,
+			  epf_bar[bar].phys_addr);
 
-	epf->bar[bar].phys_addr = 0;
-	epf->bar[bar].addr = NULL;
-	epf->bar[bar].size = 0;
-	epf->bar[bar].barno = 0;
-	epf->bar[bar].flags = 0;
+	epf_bar[bar].phys_addr = 0;
+	epf_bar[bar].addr = NULL;
+	epf_bar[bar].size = 0;
+	epf_bar[bar].barno = 0;
+	epf_bar[bar].flags = 0;
 }
 EXPORT_SYMBOL_GPL(pci_epf_free_space);
 
@@ -101,15 +114,18 @@ EXPORT_SYMBOL_GPL(pci_epf_free_space);
  * @size: the size of the memory that has to be allocated
  * @bar: the BAR number corresponding to the allocated register space
  * @align: alignment size for the allocation region
+ * @type: Identifies if the allocation is for primary EPC or secondary EPC
  *
  * Invoke to allocate memory for the PCI EPF register space.
  */
 void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
-			  size_t align)
+			  size_t align, enum pci_epc_interface_type type)
 {
-	void *space;
-	struct device *dev = epf->epc->dev.parent;
+	struct pci_epf_bar *epf_bar;
 	dma_addr_t phys_addr;
+	struct pci_epc *epc;
+	struct device *dev;
+	void *space;
 
 	if (size < 128)
 		size = 128;
@@ -119,17 +135,26 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 	else
 		size = roundup_pow_of_two(size);
 
+	if (type == PRIMARY_INTERFACE) {
+		epc = epf->epc;
+		epf_bar = epf->bar;
+	} else {
+		epc = epf->sec_epc;
+		epf_bar = epf->sec_epc_bar;
+	}
+
+	dev = epc->dev.parent;
 	space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL);
 	if (!space) {
 		dev_err(dev, "failed to allocate mem space\n");
 		return NULL;
 	}
 
-	epf->bar[bar].phys_addr = phys_addr;
-	epf->bar[bar].addr = space;
-	epf->bar[bar].size = size;
-	epf->bar[bar].barno = bar;
-	epf->bar[bar].flags |= upper_32_bits(size) ?
+	epf_bar[bar].phys_addr = phys_addr;
+	epf_bar[bar].addr = space;
+	epf_bar[bar].size = size;
+	epf_bar[bar].barno = bar;
+	epf_bar[bar].flags |= upper_32_bits(size) ?
 				PCI_BASE_ADDRESS_MEM_TYPE_64 :
 				PCI_BASE_ADDRESS_MEM_TYPE_32;