linux-kernel - [RFC PATCH 05/21] PCI: endpoint: Add API to get reference to EPC from device-tree

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Message-ID: <20190926112933.8922-6-kishon@ti.com>
Date:   Thu, 26 Sep 2019 16:59:17 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Rob Herring <robh+dt@...nel.org>, Jon Mason <jdmason@...zu.us>,
        Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>
CC:     Mark Rutland <mark.rutland@....com>, <kishon@...com>,
        <linux-pci@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-ntb@...glegroups.com>
Subject: [RFC PATCH 05/21] PCI: endpoint: Add API to get reference to EPC from device-tree

Add of_pci_epc_get() and of_pci_epc_get_by_name() to get reference
to EPC from device-tree. This is added in preparation to define
an endpoint function from device tree.

Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
---
 drivers/pci/endpoint/pci-epc-core.c | 61 +++++++++++++++++++++++++++++
 include/linux/pci-epc.h             |  4 +-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 5bc094093a47..0c2fdd39090c 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -83,6 +83,66 @@ struct pci_epc *pci_epc_get(const char *epc_name)
 }
 EXPORT_SYMBOL_GPL(pci_epc_get);
 
+/**
+ * of_pci_epc_get() - get PCI endpoint controller from device node and index
+ * @node: device node which contains the phandle to endpoint controller
+ * @index: index of the endpoint controller in "epcs" property
+ *
+ * Returns the EPC corresponding to the _index_ entry in "epcs" property
+ * present in device node, after getting a refcount  to it or -ENODEV if
+ * there is no such EPC or -EPROBE_DEFER if there is a phandle to the phy,
+ * but the device is not yet loaded.
+ */
+struct pci_epc *of_pci_epc_get(struct device_node *node, int index)
+{
+	struct device_node *epc_node;
+	struct class_dev_iter iter;
+	struct pci_epc *epc;
+	struct device *dev;
+
+	epc_node = of_parse_phandle(node, "epcs", index);
+	if (!epc_node)
+		return ERR_PTR(-ENODEV);
+
+	class_dev_iter_init(&iter, pci_epc_class, NULL, NULL);
+	while ((dev = class_dev_iter_next(&iter))) {
+		epc = to_pci_epc(dev);
+		if (epc_node != epc->dev.of_node)
+			continue;
+
+		of_node_put(epc_node);
+		class_dev_iter_exit(&iter);
+		get_device(&epc->dev);
+		return epc;
+	}
+
+	of_node_put(node);
+	class_dev_iter_exit(&iter);
+	return ERR_PTR(-EPROBE_DEFER);
+}
+EXPORT_SYMBOL_GPL(of_pci_epc_get);
+
+/**
+ * of_pci_epc_get_by_name() - get PCI endpoint controller from device node
+ *                            and string
+ * @node: device node which contains the phandle to endpoint controller
+ * @epc_name: name of endpoint controller as present in "epc-names" property
+ *
+ * Returns the EPC corresponding to the epc_name in "epc-names" property
+ * present in device node.
+ */
+struct pci_epc *of_pci_epc_get_by_name(struct device_node *node,
+				       const char *epc_name)
+{
+	int index = 0;
+
+	if (epc_name)
+		index = of_property_match_string(node, "epc-names", epc_name);
+
+	return of_pci_epc_get(node, index);
+}
+EXPORT_SYMBOL_GPL(of_pci_epc_get_by_name);
+
 /**
  * pci_epc_get_first_free_bar() - helper to get first unreserved BAR
  * @epc_features: pci_epc_features structure that holds the reserved bar bitmap
@@ -661,6 +721,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 	device_initialize(&epc->dev);
 	epc->dev.class = pci_epc_class;
 	epc->dev.parent = dev;
+	epc->dev.of_node = dev->of_node;
 	epc->ops = ops;
 
 	ret = dev_set_name(&epc->dev, "%s", dev_name(dev));
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 0fff52675a6b..ef6531af6ed2 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -202,7 +202,9 @@ unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
 					*epc_features);
 struct pci_epc *pci_epc_get(const char *epc_name);
 void pci_epc_put(struct pci_epc *epc);
-
+struct pci_epc *of_pci_epc_get(struct device_node *node, int index);
+struct pci_epc *of_pci_epc_get_by_name(struct device_node *node,
+				       const char *epc_name);
 int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_addr, size_t size,
 		       size_t page_size);
 void pci_epc_mem_exit(struct pci_epc *epc);
-- 
2.17.1