PCI: aardvark: Add support for PME interrupts

Currently enabling PCI_EXP_RTSTA_PME bit in PCI_EXP_RTCTL register does
nothing. This is because PCIe PME driver expects to receive PCIe interrupt
defined in PCI_EXP_FLAGS_IRQ register, but aardvark hardware does not
trigger PCIe INTx/MSI interrupt for PME event, rather it triggers custom
aardvark interrupt which this driver is not processing yet.

Fix this issue by handling PME interrupt in advk_pcie_handle_int() and
chaining it to PCIe interrupt 0 with generic_handle_domain_irq() (since
aardvark sets PCI_EXP_FLAGS_IRQ to zero). With this change PCIe PME driver
finally starts receiving PME interrupt.

Link: https://lore.kernel.org/r/20220110015018.26359-17-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 2ae4399..8020dfb 100644 (file)
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1478,6 +1478,18 @@ static void advk_pcie_handle_int(struct advk_pcie *pcie)
        isr1_mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
        isr1_status = isr1_val & ((~isr1_mask) & PCIE_ISR1_ALL_MASK);
 
+       /* Process PME interrupt */
+       if (isr0_status & PCIE_MSG_PM_PME_MASK) {
+               /*
+                * Do not clear PME interrupt bit in ISR0, it is cleared by IRQ
+                * receiver by writing to the PCI_EXP_RTSTA register of emulated
+                * root bridge. Aardvark HW returns zero for PCI_EXP_FLAGS_IRQ,
+                * so use PCIe interrupt 0.
+                */
+               if (generic_handle_domain_irq(pcie->irq_domain, 0) == -EINVAL)
+                       dev_err_ratelimited(&pcie->pdev->dev, "unhandled PME IRQ\n");
+       }
+
        /* Process ERR interrupt */
        if (isr0_status & PCIE_ISR0_ERR_MASK) {
                advk_writel(pcie, PCIE_ISR0_ERR_MASK, PCIE_ISR0_REG);