On Thursday 27 February 2014 13:09:59 Liviu Dudau wrote:
+/*
- PCI address space differs from physical memory address space
- */
+#define PCI_DMA_BUS_IS_PHYS (0)
+extern int isa_dma_bridge_buggy;
I got curious about isa_dma_bridge_buggy: apparently this is a quirk for some old x86 bridges. We don't have those on arm64, and we also don't have ISA_DMA_API, so just define this to (0).
+static inline int pci_domain_nr(struct pci_bus *bus) +{
- struct pci_host_bridge *bridge = to_pci_host_bridge(bus->bridge);
- if (bridge)
return bridge->domain_nr;- return 0;
+}
+static inline int pci_proc_domain(struct pci_bus *bus) +{
- return pci_domain_nr(bus);
+}
And this one I would change to always return '1': we can deal with domain numbers showing up in /procfs for all buses, since there is no legacy software to worry about.
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c new file mode 100644 index 0000000..496df41 --- /dev/null +++ b/arch/arm64/kernel/pci.c @@ -0,1 +1,126 @@
Ok, this is nice and short. Let's see if we can reduce it to nothing ;-)
+/*
- Called after each bus is probed, but before its children are examined
- */
+void pcibios_fixup_bus(struct pci_bus *bus) +{
- struct pci_dev *dev;
- struct resource *res;
- int i;
- if (!pci_is_root_bus(bus)) {
pci_read_bridge_bases(bus);pci_bus_for_each_resource(bus, res, i) {if (!res || !res->flags || res->parent)continue;/** If we are going to reassign everything, we can* shrink the P2P resource to have zero size to* save space*/if (pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {res->flags |= IORESOURCE_UNSET;res->start = 0;res->end = -1;continue;}}- }
- list_for_each_entry(dev, &bus->devices, bus_list) {
/* Ignore fully discovered devices */if (dev->is_added)continue;set_dev_node(&dev->dev, pcibus_to_node(dev->bus));/* Read default IRQs and fixup if necessary */dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);- }
+} +EXPORT_SYMBOL(pcibios_fixup_bus);
Shrinking the P2P resources I suppose is optional, but everything else is in fact needed for any DT based architecture. Could this be turned into a generic helper function in the PCI core that we can call from architecture code?
If you name it pci_generic_fixup_bus(), we can add a weak helper like:
void __weak pcibios_fixup_bus(struct pci_bus *bus) { pci_generic_fixup_bus(bus); }
for architectures like arm64 that don't actually need to do anything else.
+/*
- We don't have to worry about legacy ISA devices, so nothing to do here
- */
+resource_size_t pcibios_align_resource(void *data, const struct resource *res,
resource_size_t size, resource_size_t align)+{
- return ALIGN(res->start, align);
+} +EXPORT_SYMBOL(pcibios_align_resource);
Where did this come from? The most common implementation seems to be
resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { return start; } EXPORT_SYMBOL(pcibios_align_resource);
if you don't have to worry about ISA devices. The ALIGN() part seems to be handled by __find_resource() already.
I'd say that should be made the default implementation in the PCI core.
I'm also pretty sure you don't need the EXPORT_SYMBOL, since the PCI core cannot be a loadable module (yet).
+int pcibios_enable_device(struct pci_dev *dev, int mask) +{
- return pci_enable_resources(dev, mask);
+}
+void pcibios_fixup_bridge_ranges(struct list_head *resources) +{ +}
These are clearly the right implementations, but they should be weak functions, too.
+#define IO_SPACE_PAGES ((IO_SPACE_LIMIT + 1) / PAGE_SIZE) +static DECLARE_BITMAP(pci_iospace, IO_SPACE_PAGES);
+unsigned long pci_ioremap_io(const struct resource *res, phys_addr_t phys_addr) +{
- unsigned long start, len, virt_start;
- int err;
- if (res->end > IO_SPACE_LIMIT)
return -EINVAL;- /*
* try finding free space for the whole size first,* fall back to 64K if not available*/- len = resource_size(res);
- start = bitmap_find_next_zero_area(pci_iospace, IO_SPACE_PAGES,
res->start / PAGE_SIZE, len / PAGE_SIZE, 0);- if (start == IO_SPACE_PAGES && len > SZ_64K) {
len = SZ_64K;start = 0;start = bitmap_find_next_zero_area(pci_iospace, IO_SPACE_PAGES,start, len / PAGE_SIZE, 0);- }
- /* no 64K area found */
- if (start == IO_SPACE_PAGES)
return -ENOMEM;- /* ioremap physical aperture to virtual aperture */
- virt_start = start * PAGE_SIZE + (unsigned long)PCI_IOBASE;
- err = ioremap_page_range(virt_start, virt_start + len,
phys_addr, __pgprot(PROT_DEVICE_nGnRE));- if (err)
return err;- bitmap_set(pci_iospace, start, len / PAGE_SIZE);
- /* return io_offset */
- return start * PAGE_SIZE - res->start;
+}
Maybe this can become an optional helper function with a separate Kconfig symbol to enable it.
Arnd