PCI: uniphier: Serialize INTx masking/unmasking and fix the bit operation

The condition register PCI_RCV_INTX is used in irq_mask() and irq_unmask()
callbacks. Accesses to register can occur at the same time without a lock.
Add a lock into each callback to prevent the issue.

And INTX mask and unmask fields in PCL_RCV_INTX register should only be
set/reset for each bit. Clearing by PCL_RCV_INTX_ALL_MASK should be
removed.

INTX status fields in PCL_RCV_INTX register only indicates each INTX
interrupt status, so the handler can't clear by writing 1 to the field.
The status is expected to be cleared by the interrupt origin.
The ack function has no meaning, so should remove it.

Suggested-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/1631924579-24567-1-git-send-email-hayashi.kunihiko@socionext.com
Fixes: 7e6d5cd88a6f ("PCI: uniphier: Add UniPhier PCIe host controller support")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>

diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c
index d842fd0..d05be94 100644 (file)
--- a/drivers/pci/controller/dwc/pcie-uniphier.c
+++ b/drivers/pci/controller/dwc/pcie-uniphier.c
@@ -168,30 +168,21 @@ static void uniphier_pcie_irq_enable(struct uniphier_pcie_priv *priv)
        writel(PCL_RCV_INTX_ALL_ENABLE, priv->base + PCL_RCV_INTX);
 }
 
-static void uniphier_pcie_irq_ack(struct irq_data *d)
-{
-       struct pcie_port *pp = irq_data_get_irq_chip_data(d);
-       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-       struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
-       u32 val;
-
-       val = readl(priv->base + PCL_RCV_INTX);
-       val &= ~PCL_RCV_INTX_ALL_STATUS;
-       val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_STATUS_SHIFT);
-       writel(val, priv->base + PCL_RCV_INTX);
-}
-
 static void uniphier_pcie_irq_mask(struct irq_data *d)
 {
        struct pcie_port *pp = irq_data_get_irq_chip_data(d);
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
+       unsigned long flags;
        u32 val;
 
+       raw_spin_lock_irqsave(&pp->lock, flags);
+
        val = readl(priv->base + PCL_RCV_INTX);
-       val &= ~PCL_RCV_INTX_ALL_MASK;
        val |= BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
        writel(val, priv->base + PCL_RCV_INTX);
+
+       raw_spin_unlock_irqrestore(&pp->lock, flags);
 }
 
 static void uniphier_pcie_irq_unmask(struct irq_data *d)
@@ -199,17 +190,20 @@ static void uniphier_pcie_irq_unmask(struct irq_data *d)
        struct pcie_port *pp = irq_data_get_irq_chip_data(d);
        struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
        struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
+       unsigned long flags;
        u32 val;
 
+       raw_spin_lock_irqsave(&pp->lock, flags);
+
        val = readl(priv->base + PCL_RCV_INTX);
-       val &= ~PCL_RCV_INTX_ALL_MASK;
        val &= ~BIT(irqd_to_hwirq(d) + PCL_RCV_INTX_MASK_SHIFT);
        writel(val, priv->base + PCL_RCV_INTX);
+
+       raw_spin_unlock_irqrestore(&pp->lock, flags);
 }
 
 static struct irq_chip uniphier_pcie_irq_chip = {
        .name = "PCI",
-       .irq_ack = uniphier_pcie_irq_ack,
        .irq_mask = uniphier_pcie_irq_mask,
        .irq_unmask = uniphier_pcie_irq_unmask,
 };