[Skiboot] [PATCH v3 2/5] fast-reboot: creset PHBs on fast reboot

[Andrew Donnellan]

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...)

V2->V3 - suggestions from Gavin:
* fix creset return code type
* print rc when creset fails
---
 core/pci.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/core/pci.c b/core/pci.c
index 05fd80f..25a7d02 100644
--- a/core/pci.c
+++ b/core/pci.c
@@ -1497,6 +1497,8 @@ static void __pci_reset(struct list_head *list)
 void pci_reset(void)
 {
 	unsigned int i;
+	struct pci_slot *slot;
+	int64_t rc;
 
 	prlog(PR_NOTICE, "PCI: Clearing all devices...\n");
 
@@ -1508,6 +1510,25 @@ void pci_reset(void)
 		if (!phb)
 			continue;
 		__pci_reset(&phb->devices);
+
+		slot = phb->slot;
+		if (!slot || !slot->ops.creset) {
+			PCINOTICE(phb, 0, "Can't do complete reset\n");
+		} else {
+			rc = slot->ops.creset(slot);
+			while (rc > 0) {
+				time_wait(rc);
+				rc = slot->ops.poll(slot);
+			}
+			if (rc < 0) {
+				PCIERR(phb, 0, "Complete reset failed, aborting"
+				               "fast reboot (rc=%lld)\n", rc);
+				if (platform.cec_reboot)
+					platform.cec_reboot();
+				while (true) {}
+			}
+		}
+
 		if (phb->ops->ioda_reset)
 			phb->ops->ioda_reset(phb, true);
 	}
-- 
git-series 0.9.1