On Mon, Sep 29, 2014 at 03:36:30PM +0100, Arnd Bergmann wrote:

On Sunday 28 September 2014 15:53:28 suravee.suthikulpanit at amd.com wrote:

quoted

+
+#ifdef CONFIG_ARM64
+struct pci_bus *gen_scan_root_bus(struct device *parent, int bus,
+                                      struct pci_ops *ops, void *sysdata,
+                                      struct list_head *resources)
+{

I don't see anything ARM64 specific in this, the function only uses
the newly added generic helpers.

I do not see it either, it is just a copy'n'paste of common PCI code,
plus msi management.

quoted

 static int gen_pci_probe(struct platform_device *pdev)
 {

@@ -326,6 +385,7 @@ static int gen_pci_probe(struct platform_device *pdev)
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
+#ifndef CONFIG_ARM64
        struct hw_pci hw = {
                .nr_controllers = 1,
                .private_data   = (void **)&pci,

@@ -333,6 +393,7 @@ static int gen_pci_probe(struct platform_device *pdev)
                .map_irq        = of_irq_parse_and_map_pci,
                .ops            = &gen_pci_ops,
        };
+#endif
 

Same here, I'd suggest marking this "#ifdef CONFIG_ARM" instead, as hw_pci
is an arm32 specific data structure.

I do not think we need hw struct at all, see below, we can write code so
that we do not rely on ARM32 PCI bios, I will have a stab at that and
post the resulting code.

quoted

        if (!pci)
                return -ENOMEM;

@@ -368,8 +429,24 @@ static int gen_pci_probe(struct platform_device *pdev)
                gen_pci_release_of_pci_ranges(pci);
                return err;
        }
+#ifdef CONFIG_ARM64
 
+#ifdef CONFIG_PCI_MSI
+       pci->msi_parent = of_parse_phandle(np, "msi-parent", 0);
+       if (!pci->msi_parent) {
+               dev_err(&pdev->dev, "Failed to allocate msi-parent.\n");
+               return -EINVAL;
+       }
+#endif

We probably want to enable MSI unconditionally on ARM64, so the #ifdef is
not necessary here. However, I don't think that a missing msi-parent should
be a fatal error here: we can still continue without MSI support if this
case.

quoted

+       if (!gen_scan_root_bus(&pdev->dev, pci->cfg.bus_range.start,
+                              &gen_pci_ops, pci, &pci->resources)) {
+               dev_err(&pdev->dev, "failed to enable PCIe ports\n");
+               return -ENODEV;
+       }
+#else
        pci_common_init_dev(dev, &hw);
+#endif /* CONFIG_ARM64 */

Again, just make the pci_common_init_dev() call #ifdef CONFIG_ARM, and move
the generic case after it, outside of the #ifdef.

I went through the code quickly but I think we can (and should) remove
this quite ugly ifdeffery altogether. Most of the functionality in
pci_common_init_dev() can be implemented through the common PCI API (and this
would make this driver arch agnostic as it should be), I will go through ARM32
PCI bios code to check what is executed in detail in pci_common_init_dev() and
make sure that we follow those initialization steps in the resulting probe code
for this PCI generic host controller driver.

Lorenzo