Hi Simon,
On Thu, Aug 13, 2015 at 10:09 AM, Simon Glass <s...@chromium.org> wrote:
> At present, until a PCI bus is probed, it cannot be found by its sequence
> number unless it has an alias. This is the same with any device.
>
> However with PCI this is more annoying than usual, since bus 0 is always the
> same device.
>
> Add a function that tries a little harder to locate PCI bus 0. This means
> that PCI enumeration will happen automatically on the first access.
>
> Signed-off-by: Simon Glass <s...@chromium.org>
> ---
>
> drivers/pci/pci-uclass.c | 22 +++++++++++++++++++---
> 1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
> index 7d41d56..a72e297 100644
> --- a/drivers/pci/pci-uclass.c
> +++ b/drivers/pci/pci-uclass.c
> @@ -17,6 +17,22 @@
>
> DECLARE_GLOBAL_DATA_PTR;
>
> +static int pci_get_bus(int busnum, struct udevice **busp)
> +{
> + int ret;
> +
> + ret = uclass_get_device_by_seq(UCLASS_PCI, busnum, busp);
> +
> + /* Since buses may not be numbered yet, try a little harder with bus
> 0*/
> + if (ret == -ENODEV && !busnum) {
We should remove !busnum as it is possible to read configuration
registers that are not on bus 0.
> + ret = uclass_first_device(UCLASS_PCI, busp);
> + if (!ret && (*busp)->seq != busnum)
The test of (*busp)->seq has the assumption that busnum should be 0,
however it is not always the case.
> + return -ENODEV;
> + }
> +
> + return ret;
> +}
> +
> struct pci_controller *pci_bus_to_hose(int busnum)
> {
> struct udevice *bus;
> @@ -125,7 +141,7 @@ int pci_bus_find_bdf(pci_dev_t bdf, struct udevice **devp)
> struct udevice *bus;
> int ret;
>
> - ret = uclass_get_device_by_seq(UCLASS_PCI, PCI_BUS(bdf), &bus);
> + ret = pci_get_bus(PCI_BUS(bdf), &bus);
> if (ret)
> return ret;
> return pci_bus_find_devfn(bus, PCI_MASK_BUS(bdf), devp);
> @@ -203,7 +219,7 @@ int pci_write_config(pci_dev_t bdf, int offset, unsigned
> long value,
> struct udevice *bus;
> int ret;
>
> - ret = uclass_get_device_by_seq(UCLASS_PCI, PCI_BUS(bdf), &bus);
> + ret = pci_get_bus(PCI_BUS(bdf), &bus);
> if (ret)
> return ret;
>
> @@ -268,7 +284,7 @@ int pci_read_config(pci_dev_t bdf, int offset, unsigned
> long *valuep,
> struct udevice *bus;
> int ret;
>
> - ret = uclass_get_device_by_seq(UCLASS_PCI, PCI_BUS(bdf), &bus);
> + ret = pci_get_bus(PCI_BUS(bdf), &bus);
> if (ret)
> return ret;
>
> --
Regards,
Bin
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