[Skiboot] [PATCH 06/10] phb4: Read PERST signal rather than assuming it's asserted

[Michael Neuling]

Currently we assume on boot that PERST is asserted so that we can skip
having to assert it ourselves.

This instead reads the PERST status and determines if we need to
assert it based on that.

Signed-off-by: Michael Neuling <mikey at neuling.org>
---
 hw/phb4.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/phb4.c b/hw/phb4.c
index 6c3ca60ae2..da1eaa1150 100644
--- a/hw/phb4.c
+++ b/hw/phb4.c
@@ -2338,9 +2338,9 @@ static int64_t phb4_freset(struct pci_slot *slot)
 			slot->ops.prepare_link_change(slot, false);
 		/* fall through */
 	case PHB4_SLOT_FRESET_START:
-		if (!p->skip_perst) {
+		reg = in_be64(p->regs + PHB_PCIE_CRESET);
+		if ((reg & PHB_PCIE_CRESET_PERST_N) != 0) {
 			PHBDBG(p, "FRESET: Assert\n");
-			reg = in_be64(p->regs + PHB_PCIE_CRESET);
 			reg &= ~PHB_PCIE_CRESET_PERST_N;
 			out_be64(p->regs + PHB_PCIE_CRESET, reg);
 			pci_slot_set_state(slot,
@@ -2348,7 +2348,7 @@ static int64_t phb4_freset(struct pci_slot *slot)
 			return pci_slot_set_sm_timeout(slot, secs_to_tb(1));
 		}
 
-		/* To skip the assert during boot time */
+		/* To skip perst assert if already asserted (ie. boot time) */
 		PHBDBG(p, "FRESET: Assert skipped\n");
 		pci_slot_set_state(slot, PHB4_SLOT_FRESET_ASSERT_DELAY);
 		p->skip_perst = false;
-- 
2.11.0