On Sunday, January 13, 2013 11:40:12 PM Jiang Liu wrote:
> On 01/13/2013 07:49 AM, Rafael J. Wysocki wrote:
> > On Friday, January 11, 2013 02:40:48 PM Yinghai Lu wrote:
> >> with that we could move out attaching driver for pci device,
> >> out of device_add for pci hot add path.
> >>
> >> pci_bus_attach_device() will attach driver to pci device.
> >
> > Clever, but I wonder why exactly we need to do that?
> Hi Rafael,
> To make following sequence possible,
> 1) Create PCI device objects for hot-added PCI host bridge
> 2) Create IOMMU devices for DMAR units belong to the hot-added PCI host bridge
> 3) Bind and start all PCI devices connected to the PCI host bridge.
OK, but why exactly isn't it possible without that change?
Rafael
> >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> >> ---
> >> drivers/pci/bus.c | 10 ++++++++++
> >> drivers/pci/pci-driver.c | 6 +++++-
> >> include/linux/pci.h | 1 +
> >> 3 files changed, 16 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> >> index 5f9c728..1f5916a 100644
> >> --- a/drivers/pci/bus.c
> >> +++ b/drivers/pci/bus.c
> >> @@ -160,6 +160,15 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
> >>
> >> void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
> >>
> >> +static void pci_bus_attach_device(struct pci_dev *dev)
> >> +{
> >> + int ret;
> >> +
> >> + dev->match_driver = true;
> >> + ret = device_attach(&dev->dev);
> >> + WARN_ON(ret < 0);
> >> +}
> >> +
> >> /**
> >> * pci_bus_add_device - add a single device
> >> * @dev: device to add
> >> @@ -181,6 +190,7 @@ int pci_bus_add_device(struct pci_dev *dev)
> >> if (retval)
> >> return retval;
> >>
> >> + pci_bus_attach_device(dev);
> >> dev->is_added = 1;
> >> pci_proc_attach_device(dev);
> >> pci_create_sysfs_dev_files(dev);
> >> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> >> index f79cbcd..acdcc3c 100644
> >> --- a/drivers/pci/pci-driver.c
> >> +++ b/drivers/pci/pci-driver.c
> >> @@ -1186,9 +1186,13 @@ pci_dev_driver(const struct pci_dev *dev)
> >> static int pci_bus_match(struct device *dev, struct device_driver *drv)
> >> {
> >> struct pci_dev *pci_dev = to_pci_dev(dev);
> >> - struct pci_driver *pci_drv = to_pci_driver(drv);
> >> + struct pci_driver *pci_drv;
> >> const struct pci_device_id *found_id;
> >>
> >> + if (!pci_dev->match_driver)
> >> + return 0;
> >> +
> >> + pci_drv = to_pci_driver(drv);
> >> found_id = pci_match_device(pci_drv, pci_dev);
> >> if (found_id)
> >> return 1;
> >> diff --git a/include/linux/pci.h b/include/linux/pci.h
> >> index 907b455..d73af08 100644
> >> --- a/include/linux/pci.h
> >> +++ b/include/linux/pci.h
> >> @@ -286,6 +286,7 @@ struct pci_dev {
> >> unsigned int irq;
> >> struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */
> >>
> >> + bool match_driver;
> >> /* These fields are used by common fixups */
> >> unsigned int transparent:1; /* Transparent PCI bridge */
> >> unsigned int multifunction:1;/* Part of multi-function device */
> >>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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