[PATCH v2 1/2] PCI: dwc: Fix resume failure if no EP is connected on some platforms

[Richard Zhu]

The dw_pcie_suspend_noirq() function currently returns success directly
if no endpoint (EP) device is connected. However, on some platforms,
power loss occurs during suspend, causing dw_resume() to do nothing in
this case. This results in a system halt because the DWC controller is
not initialized after power-on during resume.

Call deinit() in suspend and init() at resume regardless of whether
there are EP device connections or not. It is not harmful to perform
deinit() and init() again for the no power-off case, and it keeps the
code simple and consistent in logic.

Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality")
Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
---
 .../pci/controller/dwc/pcie-designware-host.c | 30 +++++++++----------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index a0822d5371bc..a52101bbecf4 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -933,23 +933,23 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
 		return 0;
 
-	if (dw_pcie_get_ltssm(pci) <= DW_PCIE_LTSSM_DETECT_ACT)
-		return 0;
-
-	if (pci->pp.ops->pme_turn_off)
-		pci->pp.ops->pme_turn_off(&pci->pp);
-	else
-		ret = dw_pcie_pme_turn_off(pci);
+	/* Only send out PME_TURN_OFF when PCIE link is up */
+	if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_ACT) {
+		if (pci->pp.ops->pme_turn_off)
+			pci->pp.ops->pme_turn_off(&pci->pp);
+		else
+			ret = dw_pcie_pme_turn_off(pci);
 
-	if (ret)
-		return ret;
+		if (ret)
+			return ret;
 
-	ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE,
-				PCIE_PME_TO_L2_TIMEOUT_US/10,
-				PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
-	if (ret) {
-		dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
-		return ret;
+		ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE,
+					PCIE_PME_TO_L2_TIMEOUT_US/10,
+					PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
+		if (ret) {
+			dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
+			return ret;
+		}
 	}
 
 	if (pci->pp.ops->deinit)
-- 
2.37.1