linux-kernel - [PATCH 27/42] PCI: aardvark: Disable bus mastering and mask all interrupts when unbinding driver

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Date:   Thu,  6 May 2021 17:31:38 +0200
From:   Pali Rohár <pali@...nel.org>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     Russell King <rmk+kernel@...linux.org.uk>,
        Marek Behún <kabel@...nel.org>,
        Remi Pommarel <repk@...plefau.lt>, Xogium <contact@...ium.me>,
        Tomasz Maciej Nowak <tmn505@...il.com>,
        Marc Zyngier <maz@...nel.org>, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 27/42] PCI: aardvark: Disable bus mastering and mask all interrupts when unbinding driver

Ensure that after unbinding aardvark driver, PCIe cards are not be able to
forward memory and I/O requests in the upstream direction and also that no
interrupt can be triggered.

Signed-off-by: Pali Rohár <pali@...nel.org>
Reviewed-by: Marek Behún <kabel@...nel.org>
Fixes: 526a76991b7b ("PCI: aardvark: Implement driver 'remove' function and allow to build it as module")
---
 drivers/pci/controller/pci-aardvark.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 92f93ec48d6b..28ddffce1bec 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1453,12 +1453,41 @@ static int advk_pcie_remove(struct platform_device *pdev)
 {
 	struct advk_pcie *pcie = platform_get_drvdata(pdev);
 	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
+	u32 val;
 
+	/* Remove PCI bus with all devices */
 	pci_lock_rescan_remove();
 	pci_stop_root_bus(bridge->bus);
 	pci_remove_root_bus(bridge->bus);
 	pci_unlock_rescan_remove();
 
+	/* Disable Root Bridge I/O space, memory space and bus mastering */
+	val = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
+	val &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
+	advk_writel(pcie, val, PCIE_CORE_CMD_STATUS_REG);
+
+	/* Disable MSI */
+	val = advk_readl(pcie, PCIE_CORE_CTRL2_REG);
+	val &= ~PCIE_CORE_CTRL2_MSI_ENABLE;
+	advk_writel(pcie, val, PCIE_CORE_CTRL2_REG);
+
+	/* Clear MSI address */
+	advk_writel(pcie, 0, PCIE_MSI_ADDR_LOW_REG);
+	advk_writel(pcie, 0, PCIE_MSI_ADDR_HIGH_REG);
+
+	/* Mask all interrupts */
+	advk_writel(pcie, PCIE_MSI_ALL_MASK, PCIE_MSI_MASK_REG);
+	advk_writel(pcie, PCIE_ISR0_ALL_MASK, PCIE_ISR0_MASK_REG);
+	advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_MASK_REG);
+	advk_writel(pcie, PCIE_IRQ_ALL_MASK, HOST_CTRL_INT_MASK_REG);
+
+	/* Clear all interrupts */
+	advk_writel(pcie, PCIE_MSI_ALL_MASK, PCIE_MSI_STATUS_REG);
+	advk_writel(pcie, PCIE_ISR0_ALL_MASK, PCIE_ISR0_REG);
+	advk_writel(pcie, PCIE_ISR1_ALL_MASK, PCIE_ISR1_REG);
+	advk_writel(pcie, PCIE_IRQ_ALL_MASK, HOST_CTRL_INT_STATUS_REG);
+
+	/* Remove IRQ domains */
 	advk_pcie_remove_msi_irq_domain(pcie);
 	advk_pcie_remove_irq_domain(pcie);
 
-- 
2.20.1