On Tue, Jul 01, 2014 at 09:36:10PM +0200, Arnd Bergmann wrote:

On Tuesday 01 July 2014 19:43:28 Liviu Dudau wrote:

quoted

+/*
+ * 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.

Hi Arnd,

While I agree with you that at some moment the allocators were inconsistent
wrt each other, for this version I would respectfully disagree on this.
The allocator in pci_register_io_range() only makes sure that the ranges
are not overlapping, it doesn't do any mapping whatsoever, while
pci_remap_iospace() does only an ioremap_page_range(). The idea is that
you get the offset out of pci_address_to_pio() and apply it to
pci_remap_iospace().

Why do you think there are conflicts?

Best regards,
Liviu

	Arnd
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