On Wed, Jul 02, 2014 at 12:22:30PM +0100, Will Deacon wrote:
Hi Liviu,
On Tue, Jul 01, 2014 at 07:43:33PM +0100, Liviu Dudau wrote:
Several platforms use a rather generic version of parsing the device tree to find the host bridge ranges. Move the common code into the generic PCI code and use it to create a pci_host_bridge structure that can be used by arch code.
Based on early attempts by Andrew Murray to unify the code. Used powerpc and microblaze PCI code as starting point.
I just had a quick look at this to see how it differs from the parsing in pci-host-generic.c and there a few small differences worth discussing.
+static int pci_host_bridge_of_get_ranges(struct device_node *dev,
struct list_head *resources, resource_size_t *io_base)+{
- struct resource *res;
- struct of_pci_range range;
- struct of_pci_range_parser parser;
- int err;
- pr_info("PCI host bridge %s ranges:\n", dev->full_name);
- /* Check for ranges property */
- err = of_pci_range_parser_init(&parser, dev);
- if (err)
return err;- pr_debug("Parsing ranges property...\n");
- for_each_of_pci_range(&parser, &range) {
/* Read next ranges element */pr_debug("pci_space: 0x%08x pci_addr:0x%016llx cpu_addr:0x%016llx size:0x%016llx\n",range.pci_space, range.pci_addr, range.cpu_addr, range.size);/** 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)return -ENOMEM;err = of_pci_range_to_resource(&range, dev, res);if (err)return err;if (resource_type(res) == IORESOURCE_IO)*io_base = range.cpu_addr;pci_add_resource_offset(resources, res,res->start - range.pci_addr);Where do you request_resource before adding it?
I don't, because I'm expecting that arch code might filter the list. When the host bridge code calls pci_scan_root_bus() the resources will be requested then.
- }
- /* Apply architecture specific fixups for the ranges */
- return pcibios_fixup_bridge_ranges(resources);
I currently mandate at least one non-prefetchable resource in the device-tree. Should I simply drop this restriction, or do I have to somehow hook this into the pcibios callback?
Don't think I understand why you need at least one non-prefetcheable resource but if you want to mandate that then the pcibios_fixup_bridge_ranges() would be the place to put that check.
+}
+static atomic_t domain_nr = ATOMIC_INIT(-1);
+/**
- of_create_pci_host_bridge - Create a PCI host bridge structure using
- information passed in the DT.
- @parent: device owning this host bridge
- @ops: pci_ops associated with the host controller
- @host_data: opaque data structure used by the host controller.
- returns a pointer to the newly created pci_host_bridge structure, or
- NULL if the call failed.
- This function will try to obtain the host bridge domain number by
- using of_alias_get_id() call with "pci-domain" as a stem. If that
- fails, a local allocator will be used that will put each host bridge
- in a new domain.
- */
+struct pci_host_bridge * +of_create_pci_host_bridge(struct device *parent, struct pci_ops *ops, void *host_data) +{
- int err, domain, busno;
- struct resource *bus_range;
- struct pci_bus *root_bus;
- struct pci_host_bridge *bridge;
- resource_size_t io_base;
- LIST_HEAD(res);
- bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
- if (!bus_range)
return ERR_PTR(-ENOMEM);- domain = of_alias_get_id(parent->of_node, "pci-domain");
- if (domain == -ENODEV)
domain = atomic_inc_return(&domain_nr);- err = of_pci_parse_bus_range(parent->of_node, bus_range);
- if (err) {
dev_info(parent, "No bus range for %s, using default [0-255]\n",parent->of_node->full_name);bus_range->start = 0;bus_range->end = 255;bus_range->flags = IORESOURCE_BUS;What about bus_range->name?
Don't know! Is anyone using it?
- }
- busno = bus_range->start;
- pci_add_resource(&res, bus_range);
I currently truncate the bus range to fit inside the Configuration Space window I have (in the reg property). How can I continue to do that with this patch?
Not easily. Unless I add an argument to this function that will allow you to pass in the max number for the bus range, then the code becomes:
+ err = of_pci_parse_bus_range(parent->of_node, bus_range); + if (err) { + dev_info(parent, "No bus range for %s, using default [0-%d]\n", + parent->of_node->full_name, max_range); + bus_range->start = 0; + bus_range->end = max_range; + bus_range->flags = IORESOURCE_BUS; + } else { + if (bus_range->end > bus_range->start + max_range) { + bus_range->end = bus_range->start + max_range; + } + }
Or something like that.
Best regards, Liviu
Will
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