[PATCH v2 2/4] PCI: designware: Add ARM64 support

Hi Zhou Wang,

Thanks for unifying arm and arm64 code.

On Wed, Jun 3, 2015 at 2:05 PM, Zhou Wang [off-list ref] wrote:

This patch tries to unify ARM32 and ARM64 PCIe in designware driver. Delete
function dw_pcie_setup, dw_pcie_scan_bus, dw_pcie_map_irq and struct hw_pci,
move related operations to dw_pcie_host_init. Also set pp->root_bus_nr = 0 in
each PCIe host driver which is based on pcie-designware.

I am not very clear about I/O resource management:

Following discussion may help to understand it, specially in the
context of designware.

http://marc.info/?l=linux-pci&m=138621989417562&w=2

quoted

      if (global_io_offset < SZ_1M && pp->io_size > 0) {
              pci_ioremap_io(global_io_offset, pp->io_base);
              global_io_offset += SZ_64K;
              pci_add_resource_offset(&res, &pp->io,
                                      global_io_offset - pp->io_bus_addr);
      }

so just move steps in dw_pcie_setup to dw_pcie_host_init.

I have compiled the driver with multi_v7_defconfig. However, I don't have
ARM32 PCIe related board to do test. It will be appreciated if someone could
help to test it.

Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Tested-by: Fabrice Gasnier <redacted>
---
 drivers/pci/host/pci-dra7xx.c      |   1 +
 drivers/pci/host/pci-exynos.c      |   2 +-
 drivers/pci/host/pci-imx6.c        |   2 +-
 drivers/pci/host/pci-keystone.c    |   2 +-
 drivers/pci/host/pci-layerscape.c  |   2 +-
 drivers/pci/host/pcie-designware.c | 128 +++++++++++++++----------------------
 drivers/pci/host/pcie-spear13xx.c  |   2 +-
 7 files changed, 56 insertions(+), 83 deletions(-)

[...]

similar change for pcie-spear13xx.c should be needed as well.

[...]

-#ifdef CONFIG_PCI_MSI
-       dw_pcie_msi_chip.dev = pp->dev;
-       dw_pci.msi_ctrl = &dw_pcie_msi_chip;
+#ifdef CONFIG_ARM
+       /*
+        * FIXME: we should really be able to use
+        * of_pci_get_host_bridge_resources on arm32 as well,
+        * but the conversion needs some more testing
+        */
+       if (global_io_offset < SZ_1M && pp->io_size > 0) {
+               pci_ioremap_io(global_io_offset, pp->io_base);
+               global_io_offset += SZ_64K;
+               pci_add_resource_offset(&res, &pp->io,
+                                       global_io_offset - pp->io_bus_addr);
+       }
+       pci_add_resource_offset(&res, &pp->mem,
+                               pp->mem.start - pp->mem_bus_addr);
+       pci_add_resource(&res, &pp->busn);
+#else
+       ret = of_pci_get_host_bridge_resources(np, 0, 0xff, &res, &pp->io_base);
+       if (ret)
+               return ret;
+#endif
+
+       bus = pci_create_root_bus(pp->dev, pp->root_bus_nr, &dw_pcie_ops,
+                             pp, &res);
+       if (!bus)
+               return -ENOMEM;
+
+#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+       bus->msi = container_of(&pp->irq_domain, struct msi_controller, domain);
+#else
+       bus->msi = &dw_pcie_msi_chip;
 #endif

-       dw_pci.nr_controllers = 1;
-       dw_pci.private_data = (void **)&pp;
+       pci_scan_child_bus(bus);
+       if (pp->ops->scan_bus)
+               pp->ops->scan_bus(pp);

-       pci_common_init_dev(pp->dev, &dw_pci);
+#ifdef CONFIG_ARM
+       /* support old dtbs that incorrectly describe IRQs */
+       pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+#endif
+
+       pci_assign_unassigned_bus_resources(bus);
+       pci_bus_add_devices(bus);

As James and Lorenzo has suggested, of_pci_get_host_bridge_resources should
work for ARM as well. I would suggest to move that just after cfg
resource parsing and
then to remove following piece of code.
for_each_of_pci_range(&parser, &range) {
...
}
ret = of_pci_parse_bus_range(np, &pp->busn);

Then you can have a loop like

         list_for_each_entry(entry, &res, node) {
                 struct resource *res_temp = entry->res;
                 if (resource_type(res_temp) == IORESOURCE_IO) {
                 } else if (resource_type(res_temp) == IORESOURCE_MEM) {
                }
         }

where you can fill, xx_size, xx_bus_addr, xx_mod_base etc.
You can also remove global_io_offset variable.

~Pratyush