[PATCH v1] PCI: imx6: Set MSI enable bit of RC in resume

[Richard Zhu]

The MSI Enable bit controls delivery of MSI interrupts from components
below the Root Port. This bit might lost during the suspend, should be
re-configured during resume.

Encapsulate the MSI enable set into a standalone function, and invoke it
in both probe and resume.

Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
---
 drivers/pci/controller/dwc/pci-imx6.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 2616585ca5f8..dba15546075f 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1041,6 +1041,21 @@ static void imx6_pcie_pm_turnoff(struct imx6_pcie *imx6_pcie)
 	usleep_range(1000, 10000);
 }
 
+static void pci_imx_set_msi_en(struct dw_pcie *pci)
+{
+	u8 offset;
+	u16 val;
+
+	if (pci_msi_enabled()) {
+		offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
+		dw_pcie_dbi_ro_wr_en(pci);
+		val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS);
+		val |= PCI_MSI_FLAGS_ENABLE;
+		dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val);
+		dw_pcie_dbi_ro_wr_dis(pci);
+	}
+}
+
 static int imx6_pcie_suspend_noirq(struct device *dev)
 {
 	struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
@@ -1073,6 +1088,7 @@ static int imx6_pcie_resume_noirq(struct device *dev)
 	if (imx6_pcie->link_is_up)
 		imx6_pcie_start_link(imx6_pcie->pci);
 
+	pci_imx_set_msi_en(imx6_pcie->pci);
 	return 0;
 }
 
@@ -1090,7 +1106,6 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	struct resource *dbi_base;
 	struct device_node *node = dev->of_node;
 	int ret;
-	u16 val;
 
 	imx6_pcie = devm_kzalloc(dev, sizeof(*imx6_pcie), GFP_KERNEL);
 	if (!imx6_pcie)
@@ -1282,12 +1297,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	if (pci_msi_enabled()) {
-		u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
-		val = dw_pcie_readw_dbi(pci, offset + PCI_MSI_FLAGS);
-		val |= PCI_MSI_FLAGS_ENABLE;
-		dw_pcie_writew_dbi(pci, offset + PCI_MSI_FLAGS, val);
-	}
+	pci_imx_set_msi_en(pci);
 
 	return 0;
 }
-- 
2.25.1