[PATCH v3] PCI: aardvark: Fix PCI_EXP_RTCTL register configuration

[Remi Pommarel]

PCI_EXP_RTCTL is used to activate PME interrupt only, so writing into it
should not modify other interrupts' mask. The ISR mask polarity was also
inverted, when PCI_EXP_RTCTL_PMEIE is set PCIE_MSG_PM_PME_MASK mask bit
should actually be cleared.

Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space")
Signed-off-by: Remi Pommarel <repk@xxxxxxxxxxxx>
---
Changes since v1:
 * Improve code readability
 * Fix mask polarity
 * PME_MASK shift was off by one
Changes since v2:
 * Modify patch title
 * Change Fixes tag to commit that actually introduces the bug
---
 drivers/pci/controller/pci-aardvark.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 134e0306ff00..f6e55c4597b1 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -415,7 +415,7 @@ advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
 
 	case PCI_EXP_RTCTL: {
 		u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
-		*value = (val & PCIE_MSG_PM_PME_MASK) ? PCI_EXP_RTCTL_PMEIE : 0;
+		*value = (val & PCIE_MSG_PM_PME_MASK) ? 0 : PCI_EXP_RTCTL_PMEIE;
 		return PCI_BRIDGE_EMUL_HANDLED;
 	}
 
@@ -451,10 +451,15 @@ advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
 		advk_writel(pcie, new, PCIE_CORE_PCIEXP_CAP + reg);
 		break;
 
-	case PCI_EXP_RTCTL:
-		new = (new & PCI_EXP_RTCTL_PMEIE) << 3;
-		advk_writel(pcie, new, PCIE_ISR0_MASK_REG);
+	case PCI_EXP_RTCTL: {
+		/* Only mask/unmask PME interrupt */
+		u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG) &
+			~PCIE_MSG_PM_PME_MASK;
+		if ((new & PCI_EXP_RTCTL_PMEIE) == 0)
+			val |= PCIE_MSG_PM_PME_MASK;
+		advk_writel(pcie, val, PCIE_ISR0_MASK_REG);
 		break;
+	}
 
 	case PCI_EXP_RTSTA:
 		new = (new & PCI_EXP_RTSTA_PME) >> 9;
-- 
2.20.1