On Mon, May 30, 2016 at 9:08 PM, Arnd Bergmann arnd@arndb.de wrote:
On Monday, May 30, 2016 5:14:22 PM CEST Tomasz Nowicki wrote:
bsz = 1 << pci_generic_ecam_ops.bus_shift;cfgres.start = root->mcfg_addr + bus_res->start * bsz;cfgres.end = cfgres.start + resource_size(bus_res) * bsz - 1;cfgres.flags = IORESOURCE_MEM;cfg = pci_ecam_create(&root->device->dev, &cfgres, bus_res,&pci_generic_ecam_ops);if (IS_ERR(cfg)) {pr_err("%04x:%pR error %ld mapping CAM\n", seg, bus_res,PTR_ERR(cfg));return PTR_ERR(cfg);}ri->cfg = cfg;return 0;+}
I wonder if we could do this a little simpler and just put a pointer to the mmconfig space into struct pci_host_bridge, and then have a trivial map_bus function alongside pci_generic_config_read/pci_generic_config_write.
As this code is specific to arch/arm64, we don't need any of the complexity of drivers/pci/ecam.c, which basically only exists to work around the limited virtual address space of 32-bit machines.
The map_bus provided by pci-ecam.h is already trivial in 64bit case, it was written so that it could be optimized at compile time. The pci_ecam_create is a useful to have here instead of redoing the request_resource/ioremap sequence.
The struct pci_config_window can be moved into struct pci_host_bridge (or a wrapper of pci_host_bridge) when we have the setup to point bus->sysdata to something like that. The ECAM API can be fixed up to handle that case as well. I did not make any changes since the pci_host_bridge discussion is still going on.
JC.