[PATCH 5.14 689/849] PCI: uniphier: Serialize INTx masking/unmasking and fix the bit operation

Greg Kroah-Hartman
2021-11-16T01:17:26Z

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 7e8bad3267701..5cf699dbee7ca 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