[PATCH V3 1/2] PCI: retrieve host bridge by PCI bus
shangw at linux.vnet.ibm.com
Tue Jun 26 10:30:21 EST 2012
>> With current implementation, there is one function to retrieve
>> the corresponding host bridge (struct pci_host_bridge) according
>> to the given PCI device (struct pci_dev) and that function has
>> been declared as "static". Further, we don't have the public
>> function to retrieve host bridge from PCI bus yet. The function
>> is useful somewhere.
>> The additional information like minimal resource alignment for I/O
>> and MMIO bars of p2p bridges will be put into the PCI host bridge.
>> The patch introduces the public function pci_bus_host_bridge() to
>> retrieve the corresponding PCI host bridge according to the specified
>> PCI bus, then accessing the information regarding the minimal resource
>> alignment for I/O and MMIO bars of p2p bridges.
>> Signed-off-by: Gavin Shan <shangw at linux.vnet.ibm.com>
>> Reviewed-by: Ram Pai <linuxram at us.ibm.com>
>> Reviewed-by: Richard Yang <weiyang at linux.vnet.ibm.com>
>> Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
>> drivers/pci/host-bridge.c | 13 +++++++++++++
>> include/linux/pci.h | 2 +-
>> 2 files changed, 14 insertions(+), 1 deletion(-)
>> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
>> index a68dc61..b95f0ce 100644
>> --- a/drivers/pci/host-bridge.c
>> +++ b/drivers/pci/host-bridge.c
>> @@ -27,6 +27,19 @@ static struct pci_host_bridge *find_pci_host_bridge(struct pci_dev *dev)
>> return to_pci_host_bridge(bus->bridge);
>> +struct pci_host_bridge *pci_bus_host_bridge(struct pci_bus *bus)
>> + struct pci_bus *b = bus;
>> + /* Find the PCI root bus */
>> + while (b->parent)
>> + b = b->parent;
>> + return to_pci_host_bridge(b->bridge);
Yinghai, thanks for your time on this :-)
>why do you need to export it?
The reason is that we have introduced extra fields to "struct pci_host_bridge"
in [PATCH 2/2] and platform want to access those extra fields.
int io_align_shift; /* P2P I/O bar minimal alignment shift */
int mem_align_shift; /* P2P MMIO bar minimal alignment shift */
int pmem_align_shift; /* P2P prefetchable MMIO bar minimal alignment shift */
>> void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
>> void (*release_fn)(struct pci_host_bridge *),
>> void *release_data)
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index fefb4e1..6d5bb1c 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -656,7 +656,7 @@ void pcibios_update_irq(struct pci_dev *, int irq);
>> void pci_fixup_cardbus(struct pci_bus *);
>> /* Generic PCI functions used internally */
>> +struct pci_host_bridge *pci_bus_host_bridge(struct pci_bus *bus);
>> void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
>> struct resource *res);
>> void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
>have one patch will change parameter all to bus instead of bridge.
>in that case, we can just make find_pci_host_bridge() global.
Yeah, I think your patch meets the requirement: access "struct pci_host_bridge",
and when will you merge your patch into mainline?
By the way, could you please take your a litle bit time to review [PATCH 2/2]?
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