[PATCH 3/6] PCI: Introduce devm_of_pci_get_host_bridge_resources

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

of_pci_get_host_bridge_resources allocates the resource structures it
fills dynamically, but none of its callers care to release them so far.
Rather than requiring everyone to do this explicitly, introduce a
managed version of that service. This differs API-wise only in taking a
reference to the associated device, rather than to the device tree node.

As of_pci_get_host_bridge_resources is an exported interface, we cannot
simply drop it at this point. After converting all in-tree users to the
new API, we could phase out the unmanaged one over some grace period.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 drivers/pci/of.c       | 89 ++++++++++++++++++++++++++++++++------------------
 include/linux/of_pci.h | 14 ++++++--
 2 files changed, 70 insertions(+), 33 deletions(-)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index a28355c273ae..6eab0bde2ab3 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -243,26 +243,8 @@ void of_pci_check_probe_only(void)
 EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
 
 #if defined(CONFIG_OF_ADDRESS)
-/**
- * of_pci_get_host_bridge_resources - Parse PCI host bridge resources from DT
- * @dev: device node of the host bridge having the range property
- * @busno: bus number associated with the bridge root bus
- * @bus_max: maximum number of buses for this bridge
- * @resources: list where the range of resources will be added after DT parsing
- * @io_base: pointer to a variable that will contain on return the physical
- * address for the start of the I/O range. Can be NULL if the caller doesn't
- * expect I/O ranges to be present in the device tree.
- *
- * It is the caller's job to free the @resources list.
- *
- * This function will parse the "ranges" property of a PCI host bridge device
- * node and setup the resource mapping based on its content. It is expected
- * that the property conforms with the Power ePAPR document.
- *
- * It returns zero if the range parsing has been successful or a standard error
- * value if it failed.
- */
-int of_pci_get_host_bridge_resources(struct device_node *dev,
+static int __of_pci_get_host_bridge_resources(struct device *dev,
+			struct device_node *dev_node,
 			unsigned char busno, unsigned char bus_max,
 			struct list_head *resources, resource_size_t *io_base)
 {
@@ -277,19 +259,22 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 	if (io_base)
 		*io_base = (resource_size_t)OF_BAD_ADDR;
 
-	bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
+	if (dev)
+		bus_range = devm_kzalloc(dev,sizeof(*bus_range), GFP_KERNEL);
+	else
+		bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
 	if (!bus_range)
 		return -ENOMEM;
 
-	pr_info("host bridge %pOF ranges:\n", dev);
+	pr_info("host bridge %pOF ranges:\n", dev_node);
 
-	err = of_pci_parse_bus_range(dev, bus_range);
+	err = of_pci_parse_bus_range(dev_node, bus_range);
 	if (err) {
 		bus_range->start = busno;
 		bus_range->end = bus_max;
 		bus_range->flags = IORESOURCE_BUS;
 		pr_info("  No bus range found for %pOF, using %pR\n",
-			dev, bus_range);
+			dev_node, bus_range);
 	} else {
 		if (bus_range->end > bus_range->start + bus_max)
 			bus_range->end = bus_range->start + bus_max;
@@ -297,7 +282,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 	pci_add_resource(resources, bus_range);
 
 	/* Check for ranges property */
-	err = of_pci_range_parser_init(&parser, dev);
+	err = of_pci_range_parser_init(&parser, dev_node);
 	if (err)
 		goto parse_failed;
 
@@ -321,13 +306,17 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 			continue;
 
-		res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+		if (dev)
+			res = devm_kzalloc(dev, sizeof(struct resource),
+					   GFP_KERNEL);
+		else
+			res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 		if (!res) {
 			err = -ENOMEM;
 			goto parse_failed;
 		}
 
-		err = of_pci_range_to_resource(&range, dev, res);
+		err = of_pci_range_to_resource(&range, dev_node, res);
 		if (err) {
 			kfree(res);
 			continue;
@@ -336,13 +325,13 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 		if (resource_type(res) == IORESOURCE_IO) {
 			if (!io_base) {
 				pr_err("I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
-					dev);
+					dev_node);
 				err = -EINVAL;
 				goto conversion_failed;
 			}
 			if (*io_base != (resource_size_t)OF_BAD_ADDR)
 				pr_warn("More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
-					dev);
+					dev_node);
 			*io_base = range.cpu_addr;
 		}
 
@@ -354,12 +343,50 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
 conversion_failed:
 	kfree(res);
 parse_failed:
-	resource_list_for_each_entry(window, resources)
-		kfree(window->res);
+	if (!dev);
+		resource_list_for_each_entry(window, resources)
+			kfree(window->res);
 	pci_free_resource_list(resources);
 	return err;
 }
+
+/**
+ * of_pci_get_host_bridge_resources - Parse PCI host bridge resources from DT
+ * @dev: device node of the host bridge having the range property
+ * @busno: bus number associated with the bridge root bus
+ * @bus_max: maximum number of buses for this bridge
+ * @resources: list where the range of resources will be added after DT parsing
+ * @io_base: pointer to a variable that will contain on return the physical
+ * address for the start of the I/O range. Can be NULL if the caller doesn't
+ * expect I/O ranges to be present in the device tree.
+ *
+ * It is the caller's job to free the @resources list.
+ *
+ * This function will parse the "ranges" property of a PCI host bridge device
+ * node and setup the resource mapping based on its content. It is expected
+ * that the property conforms with the Power ePAPR document.
+ *
+ * It returns zero if the range parsing has been successful or a standard error
+ * value if it failed.
+ */
+int of_pci_get_host_bridge_resources(struct device_node *dev_node,
+			unsigned char busno, unsigned char bus_max,
+			struct list_head *resources, resource_size_t *io_base)
+{
+	return __of_pci_get_host_bridge_resources(NULL, dev_node, busno,
+						  bus_max, resources, io_base);
+}
 EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
+
+int devm_of_pci_get_host_bridge_resources(struct device *dev,
+			unsigned char busno, unsigned char bus_max,
+			struct list_head *resources, resource_size_t *io_base)
+{
+	return __of_pci_get_host_bridge_resources(dev, dev->of_node, busno,
+						  bus_max, resources, io_base);
+}
+EXPORT_SYMBOL_GPL(devm_of_pci_get_host_bridge_resources);
+
 #endif /* CONFIG_OF_ADDRESS */
 
 /**
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 091033a6b836..08b8f02426a5 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -71,11 +71,21 @@ of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
 #endif
 
 #if defined(CONFIG_OF_ADDRESS)
-int of_pci_get_host_bridge_resources(struct device_node *dev,
+int of_pci_get_host_bridge_resources(struct device_node *dev_node,
+			unsigned char busno, unsigned char bus_max,
+			struct list_head *resources, resource_size_t *io_base);
+int devm_of_pci_get_host_bridge_resources(struct device *dev,
 			unsigned char busno, unsigned char bus_max,
 			struct list_head *resources, resource_size_t *io_base);
 #else
-static inline int of_pci_get_host_bridge_resources(struct device_node *dev,
+static inline int of_pci_get_host_bridge_resources(struct device_node *dev_node,
+			unsigned char busno, unsigned char bus_max,
+			struct list_head *resources, resource_size_t *io_base)
+{
+	return -EINVAL;
+}
+
+static inline int devm_of_pci_get_host_bridge_resources(struct device *dev,
 			unsigned char busno, unsigned char bus_max,
 			struct list_head *resources, resource_size_t *io_base)
 {
-- 
2.13.6