Re: [Patch v7 4/7] PCI/ACPI: Add interface acpi_pci_root_create()

Tomasz Nowicki
2015-11-05T14:21:50Z

On 14.10.2015 08:29, Jiang Liu wrote:
> Introduce common interface acpi_pci_root_create() and related data
> structures to create PCI root bus for ACPI PCI host bridges. It will
> be used to kill duplicated arch specific code for IA64 and x86. It may
> also help ARM64 in future.
>
> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Tested-by: Tony Luck <tony.luck@intel.com>
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Signed-off-by: Liu Jiang <jiang.liu@linux.intel.com>
> ---
> drivers/acpi/pci_root.c | 204 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pci-acpi.h | 24 ++++++
> 2 files changed, 228 insertions(+)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 393706a5261b..850d7bf0c873 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -652,6 +652,210 @@ static void acpi_pci_root_remove(struct acpi_device *device)
> kfree(root);
> }
>
> +/*
> + * Following code to support acpi_pci_root_create() is copied from
> + * arch/x86/pci/acpi.c and modified so it could be reused by x86, IA64
> + * and ARM64.
> + */
> +static void acpi_pci_root_validate_resources(struct device *dev,
> + struct list_head *resources,
> + unsigned long type)
> +{
> + LIST_HEAD(list);
> + struct resource *res1, *res2, *root = NULL;
> + struct resource_entry *tmp, *entry, *entry2;
> +
> + BUG_ON((type & (IORESOURCE_MEM | IORESOURCE_IO)) == 0);
> + root = (type & IORESOURCE_MEM) ? &iomem_resource : &ioport_resource;
> +
> + list_splice_init(resources, &list);
> + resource_list_for_each_entry_safe(entry, tmp, &list) {
> + bool free = false;
> + resource_size_t end;
> +
> + res1 = entry->res;
> + if (!(res1->flags & type))
> + goto next;
> +
> + /* Exclude non-addressable range or non-addressable portion */
> + end = min(res1->end, root->end);
> + if (end <= res1->start) {
> + dev_info(dev, "host bridge window %pR (ignored, not CPU addressable)\n",
> + res1);
> + free = true;
> + goto next;
> + } else if (res1->end != end) {
> + dev_info(dev, "host bridge window %pR ([%#llx-%#llx] ignored, not CPU addressable)\n",
> + res1, (unsigned long long)end + 1,
> + (unsigned long long)res1->end);
> + res1->end = end;
> + }
> +
> + resource_list_for_each_entry(entry2, resources) {
> + res2 = entry2->res;
> + if (!(res2->flags & type))
> + continue;
> +
> + /*
> + * I don't like throwing away windows because then
> + * our resources no longer match the ACPI _CRS, but
> + * the kernel resource tree doesn't allow overlaps.
> + */
> + if (resource_overlaps(res1, res2)) {
> + res2->start = min(res1->start, res2->start);
> + res2->end = max(res1->end, res2->end);
> + dev_info(dev, "host bridge window expanded to %pR; %pR ignored\n",
> + res2, res1);
> + free = true;
> + goto next;
> + }
> + }
> +
> +next:
> + resource_list_del(entry);
> + if (free)
> + resource_list_free_entry(entry);
> + else
> + resource_list_add_tail(entry, resources);
> + }
> +}
> +
> +int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
> +{
> + int ret;
> + struct list_head *list = &info->resources;
> + struct acpi_device *device = info->bridge;
> + struct resource_entry *entry, *tmp;
> + unsigned long flags;
> +
> + flags = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_MEM_8AND16BIT;
> + ret = acpi_dev_get_resources(device, list,
> + acpi_dev_filter_resource_type_cb,
> + (void *)flags);
> + if (ret < 0)
> + dev_warn(&device->dev,
> + "failed to parse _CRS method, error code %d\n", ret);
> + else if (ret == 0)
> + dev_dbg(&device->dev,
> + "no IO and memory resources present in _CRS\n");
> + else {
> + resource_list_for_each_entry_safe(entry, tmp, list) {
> + if (entry->res->flags & IORESOURCE_DISABLED)
> + resource_list_destroy_entry(entry);
> + else
> + entry->res->name = info->name;
> + }
> + acpi_pci_root_validate_resources(&device->dev, list,
> + IORESOURCE_MEM);
> + acpi_pci_root_validate_resources(&device->dev, list,
> + IORESOURCE_IO);

It is not clear to me why we need these two calls above ^^^. We are
using pci_acpi_root_add_resources(info) later. Is it not enough?

Also, I cannot use acpi_pci_probe_root_resources() in my ARM64 PCI
driver. It is because acpi_dev_get_resources is adding
translation_offset to IO ranges start address and then:
acpi_pci_root_validate_resources(&device->dev, list,
IORESOURCE_IO);
rejects that IO regions as it is out of my 0x0-SZ_16M window.

Does acpi_pci_probe_root_resources meant to be x86 specific and I should
avoid using it?

Thanks,
Tomasz