[PATCH v8 3/9] pci: Introduce pci_register_io_range() helper function.
From: arnd@arndb.de (Arnd Bergmann)
Date: 2014-07-01 19:36:24
Also in:
linux-devicetree, linux-pci, lkml
On Tuesday 01 July 2014 19:43:28 Liviu Dudau wrote:
+/*
+ * Record the PCI IO range (expressed as CPU physical address + size).
+ * Return a negative value if an error has occured, zero otherwise
+ */
+int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size)
+{
+#ifdef PCI_IOBASE
+ struct io_range *res;
+ resource_size_t allocated_size = 0;
+
+ /* check if the range hasn't been previously recorded */
+ list_for_each_entry(res, &io_range_list, list) {
+ if (addr >= res->start && addr + size <= res->start + size)
+ return 0;
+ allocated_size += res->size;
+ }
+
+ /* range not registed yet, check for available space */
+ if (allocated_size + size - 1 > IO_SPACE_LIMIT)
+ return -E2BIG;
+
+ /* add the range to the list */
+ res = kzalloc(sizeof(*res), GFP_KERNEL);
+ if (!res)
+ return -ENOMEM;
+
+ res->start = addr;
+ res->size = size;
+
+ list_add_tail(&res->list, &io_range_list);
+
+ return 0;
+#else
+ return -EINVAL;
+#endif
+}
+
unsigned long __weak pci_address_to_pio(phys_addr_t address)
{
+#ifdef PCI_IOBASE
+ struct io_range *res;
+ resource_size_t offset = 0;
+
+ list_for_each_entry(res, &io_range_list, list) {
+ if (address >= res->start &&
+ address < res->start + res->size) {
+ return res->start - address + offset;
+ }
+ offset += res->size;
+ }
+
+ return (unsigned long)-1;
+#else
if (address > IO_SPACE_LIMIT)
return (unsigned long)-1;
return (unsigned long) address;
+#endif
}This still conflicts with the other allocator you have in patch 9 for pci_remap_iospace: nothing guarantees that the mapping is the same for both. Also, this is a completely pointless exercise at this moment, because nobody cares about the result of pci_address_to_pio on architectures that don't already provide this function. If we ever get a proper Open Firmware implementation that wants to put hardcoded PCI devices into DT, we can add an implementation, but for now this seems overkill. The allocator in pci_register_io_range seems reasonable, why not merge this function with pci_remap_iospace() as I have asked you multiple times before? Just make it return the io_offset so the caller can put that into the PCI host resources. Arnd