of: pci: add registry of MSI chips

This commit adds a very basic registry of msi_chip structures, so that
an IRQ controller driver can register an msi_chip, and a PCIe host
controller can find it, based on a 'struct device_node'.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/of/of_pci.c

@@ -89,3 +89,48 @@ int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
+
+#ifdef CONFIG_PCI_MSI
+
+static LIST_HEAD(of_pci_msi_chip_list);
+static DEFINE_MUTEX(of_pci_msi_chip_mutex);
+
+int of_pci_msi_chip_add(struct msi_chip *chip)
+{
+	if (!of_property_read_bool(chip->of_node, "msi-controller"))
+		return -EINVAL;
+
+	mutex_lock(&of_pci_msi_chip_mutex);
+	list_add(&chip->list, &of_pci_msi_chip_list);
+	mutex_unlock(&of_pci_msi_chip_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_pci_msi_chip_add);
+
+void of_pci_msi_chip_remove(struct msi_chip *chip)
+{
+	mutex_lock(&of_pci_msi_chip_mutex);
+	list_del(&chip->list);
+	mutex_unlock(&of_pci_msi_chip_mutex);
+}
+EXPORT_SYMBOL_GPL(of_pci_msi_chip_remove);
+
+struct msi_chip *of_pci_find_msi_chip_by_node(struct device_node *of_node)
+{
+	struct msi_chip *c;
+
+	mutex_lock(&of_pci_msi_chip_mutex);
+	list_for_each_entry(c, &of_pci_msi_chip_list, list) {
+		if (c->of_node == of_node) {
+			mutex_unlock(&of_pci_msi_chip_mutex);
+			return c;
+		}
+	}
+	mutex_unlock(&of_pci_msi_chip_mutex);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(of_pci_find_msi_chip_by_node);
+
+#endif /* CONFIG_PCI_MSI */

include/linux/msi.h

@@ -68,6 +68,8 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq);
 struct msi_chip {
 	struct module *owner;
 	struct device *dev;
+	struct device_node *of_node;
+	struct list_head list;
 
 	int (*setup_irq)(struct msi_chip *chip, struct pci_dev *dev,
 			 struct msi_desc *desc);

include/linux/of_pci.h

@@ -2,6 +2,7 @@
 #define __OF_PCI_H
 
 #include <linux/pci.h>
+#include <linux/msi.h>
 
 struct pci_dev;
 struct of_irq;
@@ -13,4 +14,15 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
 int of_pci_get_devfn(struct device_node *np);
 int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
 
+#if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
+int of_pci_msi_chip_add(struct msi_chip *chip);
+void of_pci_msi_chip_remove(struct msi_chip *chip);
+struct msi_chip *of_pci_find_msi_chip_by_node(struct device_node *of_node);
+#else
+static inline int of_pci_msi_chip_add(struct msi_chip *chip) { return -EINVAL; }
+static inline void of_pci_msi_chip_remove(struct msi_chip *chip) { }
+static inline struct msi_chip *
+of_pci_find_msi_chip_by_node(struct device_node *of_node) { return NULL; }
+#endif
+
 #endif