Provide a function to parse the PCI DT ranges that can be used to
create a pci_host_bridge structure together with its associated
bus.

Cc: Bjorn Helgaas <bhelg...@google.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Grant Likely <grant.lik...@linaro.org>
Cc: Rob Herring <robh...@kernel.org>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Signed-off-by: Liviu Dudau <liviu.du...@arm.com>
---
 drivers/of/of_pci.c    | 102 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of_pci.h |  11 ++++++
 2 files changed, 113 insertions(+)

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index a107edb..36701da 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -1,7 +1,9 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/slab.h>
 
 static inline int __of_pci_pci_compare(struct device_node *node,
                                       unsigned int data)
@@ -123,6 +125,106 @@ int of_pci_get_domain_nr(struct device_node *node, bool 
allocate_if_missing)
 }
 EXPORT_SYMBOL_GPL(of_pci_get_domain_nr);
 
+/**
+ * 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 busses 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.
+ *
+ * It is the callers 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.
+ *
+ */
+int of_pci_get_host_bridge_resources(struct device_node *dev,
+                       unsigned char busno, unsigned char bus_max,
+                       struct list_head *resources, resource_size_t *io_base)
+{
+       struct resource *res;
+       struct resource *bus_range;
+       struct of_pci_range range;
+       struct of_pci_range_parser parser;
+       char range_type[4];
+       int err;
+
+       bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
+       if (!bus_range)
+               return -ENOMEM;
+
+       pr_info("PCI host bridge %s ranges:\n", dev->full_name);
+
+       err = of_pci_parse_bus_range(dev, 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 %s, using %pR\n",
+                       dev->full_name, &bus_range);
+       } else {
+               if (bus_range->end > bus_range->start + bus_max)
+                       bus_range->end = bus_range->start + bus_max;
+       }
+       pci_add_resource(resources, bus_range);
+
+       /* Check for ranges property */
+       err = of_pci_range_parser_init(&parser, dev);
+       if (err)
+               goto parse_failed;
+
+       pr_debug("Parsing ranges property...\n");
+       for_each_of_pci_range(&parser, &range) {
+               /* Read next ranges element */
+               if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
+                       snprintf(range_type, 4, " IO");
+               else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
+                       snprintf(range_type, 4, "MEM");
+               else
+                       snprintf(range_type, 4, "err");
+               pr_info("  %s %#010llx..%#010llx -> %#010llx\n", range_type,
+                       range.cpu_addr, range.cpu_addr + range.size - 1,
+                       range.pci_addr);
+
+               /*
+                * If we failed translation or got a zero-sized region
+                * then skip this range
+                */
+               if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
+                       continue;
+
+               res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+               if (!res) {
+                       err = -ENOMEM;
+                       goto parse_failed;
+               }
+
+               err = of_pci_range_to_resource(&range, dev, res);
+               if (err) {
+                       kfree(res);
+                       goto parse_failed;
+               }
+
+               if (resource_type(res) == IORESOURCE_IO) {
+                       if (*io_base)
+                               pr_warn("More than one I/O resource converted. 
CPU offset for old range lost!\n");
+                       *io_base = range.cpu_addr;
+               }
+
+               pci_add_resource_offset(resources, res, res->start - 
range.pci_addr);
+       }
+
+       return 0;
+
+parse_failed:
+       pci_free_resource_list(resources);
+       return err;
+}
+EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
+
 #ifdef CONFIG_PCI_MSI
 
 static LIST_HEAD(of_pci_msi_chip_list);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 3a3824c..a4b8a85 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -16,6 +16,10 @@ int of_pci_get_devfn(struct device_node *np);
 int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
 int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
 int of_pci_get_domain_nr(struct device_node *node, bool allocate_if_missing);
+int of_pci_get_host_bridge_resources(struct device_node *dev,
+                       unsigned char busno, unsigned char bus_max,
+                       struct list_head *resources, resource_size_t *io_base);
+
 #else
 static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct 
of_phandle_args *out_irq)
 {
@@ -50,6 +54,13 @@ of_pci_get_domain_nr(struct device_node *node, bool 
allocate_if_missing)
 {
        return -1;
 }
+
+int of_pci_get_host_bridge_resources(struct device_node *dev,
+                       unsigned char busno, unsigned char bus_max,
+                       struct list_head *resources, resource_size_t *io_base);
+{
+       return -EINVAL;
+}
 #endif
 
 #if defined(CONFIG_OF) && defined(CONFIG_PCI_MSI)
-- 
2.0.4

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