[PATCH] PCI: aardvark: Fix masking and unmasking legacy INTx interrupts

[Pali Rohár]

irq_mask and irq_unmask callbacks need to be properly guarded by raw spin
locks as masking/unmasking procedure needs atomic read-modify-write
operation on hardware register.

Signed-off-by: Pali Rohár <pali at kernel.org>
Reported-by: Marc Zyngier <maz at kernel.org>
Cc: stable at vger.kernel.org
---
 drivers/pci/controller/pci-aardvark.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index fb8060160251..a49e8bad9f4f 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -234,6 +234,7 @@ struct advk_pcie {
 	u8 wins_count;
 	struct irq_domain *irq_domain;
 	struct irq_chip irq_chip;
+	raw_spinlock_t irq_lock;
 	struct irq_domain *msi_domain;
 	struct irq_domain *msi_inner_domain;
 	struct irq_chip msi_bottom_irq_chip;
@@ -1087,22 +1088,28 @@ static void advk_pcie_irq_mask(struct irq_data *d)
 {
 	struct advk_pcie *pcie = d->domain->host_data;
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
 	u32 mask;
 
+	raw_spin_lock_irqsave(&pcie->irq_lock, flags);
 	mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
 	mask |= PCIE_ISR1_INTX_ASSERT(hwirq);
 	advk_writel(pcie, mask, PCIE_ISR1_MASK_REG);
+	raw_spin_unlock_irqrestore(&pcie->irq_lock, flags);
 }
 
 static void advk_pcie_irq_unmask(struct irq_data *d)
 {
 	struct advk_pcie *pcie = d->domain->host_data;
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	unsigned long flags;
 	u32 mask;
 
+	raw_spin_lock_irqsave(&pcie->irq_lock, flags);
 	mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
 	mask &= ~PCIE_ISR1_INTX_ASSERT(hwirq);
 	advk_writel(pcie, mask, PCIE_ISR1_MASK_REG);
+	raw_spin_unlock_irqrestore(&pcie->irq_lock, flags);
 }
 
 static int advk_pcie_irq_map(struct irq_domain *h,
@@ -1186,6 +1193,8 @@ static int advk_pcie_init_irq_domain(struct advk_pcie *pcie)
 	struct irq_chip *irq_chip;
 	int ret = 0;
 
+	raw_spin_lock_init(&pcie->irq_lock);
+
 	pcie_intc_node =  of_get_next_child(node, NULL);
 	if (!pcie_intc_node) {
 		dev_err(dev, "No PCIe Intc node found\n");
-- 
2.20.1