[Skiboot] [PATCH v2 2/5] fast-reboot: creset PHBs on fast reboot

[Gavin Shan]

On Fri, Jan 13, 2017 at 04:09:38PM +1100, Andrew Donnellan wrote:
>On fast reboot, perform a creset of all PHBs. This ensures that any PHBs
>that are fenced will be working after the reboot.
>
>A later patch will disable CAPI mode during cresets - as such, PHBs in CAPI
>mode will return to regular PCIe mode during a fast reboot.
>
>Signed-off-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>
>---
>
>This slows down fast reboot a bit. Could we do this in parallel? Should we
>limit it only to fenced/CAPI mode PHBs? (Resetting all PHBs might make
>things slightly more reliable, but probably only slightly...)
>---
> core/pci.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
>diff --git a/core/pci.c b/core/pci.c
>index 05fd80f..bef42b4 100644
>--- a/core/pci.c
>+++ b/core/pci.c
>@@ -1497,6 +1497,7 @@ static void __pci_reset(struct list_head *list)
> void pci_reset(void)
> {
> 	unsigned int i;
>+	struct pci_slot *slot;
> 
> 	prlog(PR_NOTICE, "PCI: Clearing all devices...\n");
> 
>@@ -1508,6 +1509,25 @@ void pci_reset(void)
> 		if (!phb)
> 			continue;
> 		__pci_reset(&phb->devices);

PCINOTICE(phb, 0, ...) indicates the message applies to root port,
not PHB.

>+
>+		slot = phb->slot;
>+		if (!slot || !slot->ops.creset) {
>+			PCINOTICE(phb, 0, "Can't do complete reset\n");
>+		} else {
>+			int rc = slot->ops.creset(slot);

slot->ops.create() returns error or delay whose data type is int64_t.

>+			while (rc > 0) {
>+				time_wait(rc);
>+				rc = slot->ops.poll(slot);
>+			}
>+			if (rc < 0) {
>+				PCIERR(phb, 0, "Complete reset failed, aborting"
>+				       	       "fast reboot\n");

It might be worthy to print @rc.

>+				if (platform.cec_reboot)
>+					platform.cec_reboot();
>+				while (true) {}

Rebooting the system in failing case seems not good idea. To
remove the failing PHB to avoid probing on it afterwards would
be better.

>+			}
>+		}
>+
> 		if (phb->ops->ioda_reset)
> 			phb->ops->ioda_reset(phb, true);
> 	}

Thanks,
Gavin