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    Subject[PATCH 5.15 722/917] PCI: uniphier: Serialize INTx masking/unmasking and fix the bit operation
    Date
    From: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>

    [ Upstream commit 4caab28a6215da5f3c1b505ff08810bc6acfe365 ]

    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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/pci/controller/dwc/pcie-uniphier.c | 26 +++++++++-------------
    1 file changed, 10 insertions(+), 16 deletions(-)

    diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c
    index d842fd0181299..d05be942956e2 100644
    --- 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,
    };
    --
    2.33.0


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