[PATCH] pci: ensure valid link status bits for downstream ports

[Sebastian Ott]

PCI hotplug for downstream endpoints on arm fails because Linux'
PCIe hotplug driver doesn't like the QEMU provided LNKSTA:

  pcieport 0000:08:01.0: pciehp: Slot(2): Card present
  pcieport 0000:08:01.0: pciehp: Slot(2): Link Up
  pcieport 0000:08:01.0: pciehp: Slot(2): Cannot train link: status 0x2000

There's 2 cases where LNKSTA isn't setup properly:
* the downstream device has no express capability
* max link width of the bridge is 0

Fix these by making the LNKSTA modifications independent of each other.

Signed-off-by: Sebastian Ott <seb...@redhat.com>
---
 hw/pci/pcie.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 0b455c8654..f714f4fb7c 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -1109,20 +1109,20 @@ void pcie_sync_bridge_lnk(PCIDevice *bridge_dev)
         lnksta = target->config_read(target,
                                      target->exp.exp_cap + PCI_EXP_LNKSTA,
                                      sizeof(lnksta));
-
-        if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
-            lnksta &= ~PCI_EXP_LNKSTA_NLW;
-            lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
-        } else if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
-            lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
-        }
-
-        if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
-            lnksta &= ~PCI_EXP_LNKSTA_CLS;
-            lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
-        } else if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
-            lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
-        }
+    }
+    if ((lnksta & PCI_EXP_LNKSTA_NLW) > (lnkcap & PCI_EXP_LNKCAP_MLW)) {
+        lnksta &= ~PCI_EXP_LNKSTA_NLW;
+        lnksta |= lnkcap & PCI_EXP_LNKCAP_MLW;
+    }
+    if (!(lnksta & PCI_EXP_LNKSTA_NLW)) {
+        lnksta |= QEMU_PCI_EXP_LNKSTA_NLW(QEMU_PCI_EXP_LNK_X1);
+    }
+    if ((lnksta & PCI_EXP_LNKSTA_CLS) > (lnkcap & PCI_EXP_LNKCAP_SLS)) {
+        lnksta &= ~PCI_EXP_LNKSTA_CLS;
+        lnksta |= lnkcap & PCI_EXP_LNKCAP_SLS;
+    }
+    if (!(lnksta & PCI_EXP_LNKSTA_CLS)) {
+        lnksta |= QEMU_PCI_EXP_LNKSTA_CLS(QEMU_PCI_EXP_LNK_2_5GT);
     }
 
     pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
-- 
2.42.0