On Thu, Aug 02, 2018 at 05:54:30PM +0100, Lorenzo Pieralisi wrote:
> On Wed, Aug 01, 2018 at 05:14:01PM +0200, Christoph Hellwig wrote:
> > There is currently no way for a PCIe bridge to impose constraints on
> > devices added to it. For example, the Xilinx PCIe host bridge only
> > supports 32-bit physical addresses (due to a limitation on the AXI
> > port's address width). Thus, even devices that claim to support 64-bit
> > DMA addresses must be restricted to 32-bit addresses when attached to
> > this host controller.
> >
> > This patch adds a "add_dev" method to struct pci_host_bridge that
> > allows the host driver to act upon acting adding devices.
> >
> > Based on an earlier patch from Wesley W. Terpstra <wesley@xxxxxxxxxx>.
> >
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > ---
> > drivers/pci/probe.c | 4 ++++
> > include/linux/pci.h | 1 +
> > 2 files changed, 5 insertions(+)
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index ac876e32de4b..8736d78ffc66 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -2290,6 +2290,7 @@ static void pci_set_msi_domain(struct pci_dev *dev)
> >
> > void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
> > {
> > + struct pci_host_bridge *host = pci_find_host_bridge(bus);
> > int ret;
> >
> > pci_configure_device(dev);
> > @@ -2331,6 +2332,9 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
> > /* Set up MSI IRQ domain */
> > pci_set_msi_domain(dev);
> >
> > + if (host->add_dev)
> > + host->add_dev(dev);
>
> Hi Christoph,
>
> while at it, IMHO it would be good to match the current
> pcibios_add_device() prototype (ie returning an int error value)
> so that this change can pave the way to removing yet another
> pcibios call.
>
> Actually we could make pcibios_add_device() removal as part of this
> series but you would have to patch all related host bridge drivers
> initializations so I am happy for this patch to go standalone (I can
> patch the rest of the code) - I leave it to Bjorn's decision.
This patch seems OK to me.
I don't really care about the prototype. There's only one
pcibios_add_device() implementation (x86) that returns anything other
than 0, and that's a pretty obscure error case related to f9a37be0f02a
("x86: Use PCI setup data"), which lets us use ROM data from boot
services. Even then the only thing that happens is a WARN_ON(). A
more descriptive printk would be a lot more useful.
I assume you'll probably merge this along with the rest of the series,
Lorenzo, so:
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > +
> > /* Notifier could use PCI capabilities */
> > dev->match_driver = false;
> > ret = device_add(&dev->dev);
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index abd5d5e17aee..5eedae8e8f2b 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -485,6 +485,7 @@ struct pci_host_bridge {
> > resource_size_t start,
> > resource_size_t size,
> > resource_size_t align);
> > + void (*add_dev)(struct pci_dev *dev);
> > unsigned long private[0] ____cacheline_aligned;
> > };
> >
> > --
> > 2.18.0
> >
