On Wed, Jul 02, 2014 at 06:23:55PM +0100, Liviu Dudau wrote:
On Wed, Jul 02, 2014 at 12:22:30PM +0100, Will Deacon wrote:
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.
[...]
- }
- /* 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.
I think it was Arnd's idea at the time:
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-February/232225.h...
and it's probably worth keeping if possible (just to avoid changes to the behaviour of the existing driver).
However, that means I already need a host-controller callback via pcibios_fixup_bridge_ranges...
- 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?
I guess /proc/iomem prints it out? I set it in my current driver, if you want to take a look.
- }
- 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.
Again, take a look at my driver (it's in mainline now) to see how I deal with this.
Will