[PATCH 5.17 0526/1126] PCI: aardvark: Fix reading PCI_EXP_RTSTA_PME bit on emulated bridge

[Greg Kroah-Hartman]

From: Pali Rohár <pali@xxxxxxxxxx>

[ Upstream commit 735f5ae49e1b44742cc63ca9b5c1ffde3e94ba91 ]

The emulated bridge returns incorrect value for PCI_EXP_RTSTA register
during readout in advk_pci_bridge_emul_pcie_conf_read() function: the
correct bit is BIT(16), but we are setting BIT(23), because the code
does
  *value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16
where
  PCIE_MSG_PM_PME_MASK
is
  BIT(7).

The code should probably have been something like
  *value = (!!(isr0 & PCIE_MSG_PM_PME_MASK)) << 16,
but we are better of using an if() and using the proper macro for this
bit.

Link: https://lore.kernel.org/r/20220110015018.26359-15-kabel@xxxxxxxxxx
Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space")
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pci/controller/pci-aardvark.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 10e936363461..82e2c618d532 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -846,7 +846,9 @@ advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
 	case PCI_EXP_RTSTA: {
 		u32 isr0 = advk_readl(pcie, PCIE_ISR0_REG);
 		u32 msglog = advk_readl(pcie, PCIE_MSG_LOG_REG);
-		*value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16 | (msglog >> 16);
+		*value = msglog >> 16;
+		if (isr0 & PCIE_MSG_PM_PME_MASK)
+			*value |= PCI_EXP_RTSTA_PME;
 		return PCI_BRIDGE_EMUL_HANDLED;
 	}
 
-- 
2.34.1