On Wed, Jul 02, 2014 at 12:22:22PM +0100, Will Deacon wrote: > On Tue, Jul 01, 2014 at 07:43:28PM +0100, Liviu Dudau wrote: > > Some architectures do not have a simple view of the PCI I/O space > > and instead use a range of CPU addresses that map to bus addresses. For > > some architectures these ranges will be expressed by OF bindings > > in a device tree file. > > > > Introduce a pci_register_io_range() helper function with a generic > > implementation that can be used by such architectures to keep track > > of the I/O ranges described by the PCI bindings. If the PCI_IOBASE > > macro is not defined that signals lack of support for PCI and we > > return an error. > > [...] > > > +/* > > + * 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; > > Hopefully a stupid question, but how is this serialised? I'm just surprised > that adding to and searching a list are sufficient, unless there's a big > lock somewhere. Sorry, tripped into my own filters! You are right, there is no serialisation here, will add one. Best regards, Liviu > > Will > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html