Re: [coreboot] [PATCH] Don't loop endlessly in get_pbus

[Marc Jones]

On Tue, Mar 3, 2009 at 4:48 PM, Carl-Daniel Hailfinger
 wrote:
> If get_pbus() is called for a device which has no parent/ancestor bus
> with nonzero PCI bus operations, get_pbus() will get stuck in a silent
> endless loop.
> Detect the endless loop and break out with an error message.
>
> Such a situation can happen if the device tree is not yet
> initialized/walked completely.
>
> This fixes the unexplainable hang if pci_{read,write}_config{8,16,32}was
> used in early mainboard code for the AMD DBM690T. Instead, the code will
> now die() with a meaningful error message.
>
> Thanks to Ward Vandewege for testing my patches to track down that bug.
>
> Signed-off-by: Carl-Daniel Hailfinger
> Index: LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c
>
> --- LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c       (Revision 3967)
> +++ LinuxBIOSv2-asus_m2a-vm/src/devices/pci_ops.c       (Arbeitskopie)
> @@ -28,6 +28,12 @@
>  {
>        struct bus *pbus = dev->bus;
>        while(pbus && pbus->dev && !ops_pci_bus(pbus)) {
> if (pbus == pbus->dev->bus) {
> printk_alert("%s in endless loop looking for a parent "
> "bus with ops_pci_bus for %s, breaking out\n",
> __func__, dev_path(dev));
> break;
> }
>
> pbus = pbus->dev->bus;
>        }
>        if (!pbus || !pbus->dev || !pbus->dev->ops || !pbus->dev->ops->ops_pci_bus) {

Acked-by: Marc Jones