[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 <r...@triplefau.lt>
---
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