linux-kernel - [PATCH 5.17 134/140] PCI: aardvark: Add support for PME interrupts

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Date:   Tue, 10 May 2022 15:08:44 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, pali@...nel.org,
        Marek Behún <kabel@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Subject: [PATCH 5.17 134/140] PCI: aardvark: Add support for PME interrupts

From: Pali Rohár <pali@...nel.org>

commit 0fc75d87454195885bd1a81fc7e6ce92572b6109 upstream.

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@...nel.org>
Signed-off-by: Marek Behún <kabel@...nel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Signed-off-by: Marek Behún <kabel@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/pci/controller/pci-aardvark.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- 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
 	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);