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SubjectRe: [PATCH v9 2/9] PCI: Using PCI configuration space header type instead of class type to assign resource
On Tue, Oct 16, 2018 at 06:44:43PM +0800, honghui.zhang@mediatek.com wrote:
> From: Honghui Zhang <honghui.zhang@mediatek.com>
>
> The PCI configuration space header type defines the layout of the rest
> of the header (PCI r3.0 sec 6.1, PCIe r4.0 sec 7.5.1.1.9) while the
> resource assignment is based on the configuration space layout instead
> of its class type. Using configuration space header type instead of
> class type for the resource assignment.
>
> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
> ---
> drivers/pci/pci.c | 3 +--
> drivers/pci/probe.c | 3 ---
> drivers/pci/setup-bus.c | 20 ++++++++++----------
> 3 files changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 29ff961..7d379ca 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5908,8 +5908,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
> * to enable the kernel to reassign new resource
> * window later on.
> */
> - if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE &&
> - (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
> + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
> for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) {
> r = &dev->resource[i];
> if (!(r->flags & IORESOURCE_MEM))
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index ec78400..29a35c1 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1695,9 +1695,6 @@ int pci_setup_device(struct pci_dev *dev)
> break;
>
> case PCI_HEADER_TYPE_BRIDGE: /* bridge header */
> - if (class != PCI_CLASS_BRIDGE_PCI)
> - goto bad;
> -
> /*
> * The PCI-to-PCI bridge spec requires that subtractive
> * decoding (i.e. transparent) bridge must have programming
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 79b1824..69f90f4 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -182,7 +182,7 @@ static void __dev_sort_resources(struct pci_dev *dev,
> u16 class = dev->class >> 8;
>
> /* Don't touch classless devices or host bridges or ioapics. */
> - if (class == PCI_CLASS_NOT_DEFINED || class == PCI_CLASS_BRIDGE_HOST)
> + if (class == PCI_CLASS_NOT_DEFINED)

I think this check has been there since the first initial git commit,
whether that's _really_ needed or not in the current kernel it is very
hard to say.

I am not that sure it is safe to remove it, especially given that we are at
-rc8 and close to a release, it would be good if this patch could sit in
next to give it some exposure to testing before merging it upstream.

Lorenzo

> return;
>
> /* Don't touch ioapic devices already enabled by firmware */
> @@ -1221,12 +1221,12 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
> if (!b)
> continue;
>
> - switch (dev->class >> 8) {
> - case PCI_CLASS_BRIDGE_CARDBUS:
> + switch (dev->hdr_type) {
> + case PCI_HEADER_TYPE_CARDBUS:
> pci_bus_size_cardbus(b, realloc_head);
> break;
>
> - case PCI_CLASS_BRIDGE_PCI:
> + case PCI_HEADER_TYPE_BRIDGE:
> default:
> __pci_bus_size_bridges(b, realloc_head);
> break;
> @@ -1237,12 +1237,12 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
> if (pci_is_root_bus(bus))
> return;
>
> - switch (bus->self->class >> 8) {
> - case PCI_CLASS_BRIDGE_CARDBUS:
> + switch (bus->self->hdr_type) {
> + case PCI_HEADER_TYPE_CARDBUS:
> /* don't size cardbuses yet. */
> break;
>
> - case PCI_CLASS_BRIDGE_PCI:
> + case PCI_HEADER_TYPE_BRIDGE:
> pci_bridge_check_ranges(bus);
> if (bus->self->is_hotplug_bridge) {
> additional_io_size = pci_hotplug_io_size;
> @@ -1391,13 +1391,13 @@ void __pci_bus_assign_resources(const struct pci_bus *bus,
>
> __pci_bus_assign_resources(b, realloc_head, fail_head);
>
> - switch (dev->class >> 8) {
> - case PCI_CLASS_BRIDGE_PCI:
> + switch (dev->hdr_type) {
> + case PCI_HEADER_TYPE_BRIDGE:
> if (!pci_is_enabled(dev))
> pci_setup_bridge(b);
> break;
>
> - case PCI_CLASS_BRIDGE_CARDBUS:
> + case PCI_HEADER_TYPE_CARDBUS:
> pci_setup_cardbus(b);
> break;
>
> --
> 2.6.4
>

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