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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Victor Gu <xigu@marvell.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Evan Wang <xswang@marvell.com>,
        Nadav Haklai <nadavh@marvell.com>
Subject: [PATCH 4.16 071/113] PCI: aardvark: Use ISR1 instead of ISR0 interrupt in legacy irq mode
Date:   Mon, 30 Apr 2018 12:24:42 -0700
Message-Id: <20180430184018.218799432@linuxfoundation.org>
In-Reply-To: <20180430184015.043892819@linuxfoundation.org>
References: <20180430184015.043892819@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Victor Gu <xigu@marvell.com>

commit 3430f924a62905891c8fa9a3b97ea52007795bc3 upstream.

The Aardvark has two interrupts sets:

 - first set is bit[23:16] of PCIe ISR 0 register(RD0074840h)

 - second set is bit[11:8] of PCIe ISR 1 register(RD0074848h)

Only one set should be used, while another set should be masked.

The second set, ISR1, is more advanced, the Legacy INT_X status bit is
asserted once Assert_INTX message is received, and de-asserted after
Deassert_INTX message is received which matches what the driver is
currently doing in the ->irq_mask() and ->irq_unmask() functions.

The ISR0 requires additional work to deassert the interrupt, which the
driver does not currently implement, therefore it needs fixing.

Update the driver to use ISR1 register set, fixing current
implementation.

Fixes: 8c39d710363c1 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196339
Signed-off-by: Victor Gu <xigu@marvell.com>
[Thomas: tweak commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[lorenzo.pieralisi@arm.com: updated the commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Evan Wang <xswang@marvell.com>
Reviewed-by: Nadav Haklai <nadavh@marvell.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/host/pci-aardvark.c |   43 +++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 18 deletions(-)

--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -100,7 +100,8 @@
 #define PCIE_ISR1_MASK_REG			(CONTROL_BASE_ADDR + 0x4C)
 #define     PCIE_ISR1_POWER_STATE_CHANGE	BIT(4)
 #define     PCIE_ISR1_FLUSH			BIT(5)
-#define     PCIE_ISR1_ALL_MASK			GENMASK(5, 4)
+#define     PCIE_ISR1_INTX_ASSERT(val)		BIT(8 + (val))
+#define     PCIE_ISR1_ALL_MASK			GENMASK(11, 4)
 #define PCIE_MSI_ADDR_LOW_REG			(CONTROL_BASE_ADDR + 0x50)
 #define PCIE_MSI_ADDR_HIGH_REG			(CONTROL_BASE_ADDR + 0x54)
 #define PCIE_MSI_STATUS_REG			(CONTROL_BASE_ADDR + 0x58)
@@ -607,9 +608,9 @@ static void advk_pcie_irq_mask(struct ir
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 	u32 mask;
 
-	mask = advk_readl(pcie, PCIE_ISR0_MASK_REG);
-	mask |= PCIE_ISR0_INTX_ASSERT(hwirq);
-	advk_writel(pcie, mask, PCIE_ISR0_MASK_REG);
+	mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
+	mask |= PCIE_ISR1_INTX_ASSERT(hwirq);
+	advk_writel(pcie, mask, PCIE_ISR1_MASK_REG);
 }
 
 static void advk_pcie_irq_unmask(struct irq_data *d)
@@ -618,9 +619,9 @@ static void advk_pcie_irq_unmask(struct
 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
 	u32 mask;
 
-	mask = advk_readl(pcie, PCIE_ISR0_MASK_REG);
-	mask &= ~PCIE_ISR0_INTX_ASSERT(hwirq);
-	advk_writel(pcie, mask, PCIE_ISR0_MASK_REG);
+	mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
+	mask &= ~PCIE_ISR1_INTX_ASSERT(hwirq);
+	advk_writel(pcie, mask, PCIE_ISR1_MASK_REG);
 }
 
 static int advk_pcie_irq_map(struct irq_domain *h,
@@ -763,29 +764,35 @@ static void advk_pcie_handle_msi(struct
 
 static void advk_pcie_handle_int(struct advk_pcie *pcie)
 {
-	u32 val, mask, status;
+	u32 isr0_val, isr0_mask, isr0_status;
+	u32 isr1_val, isr1_mask, isr1_status;
 	int i, virq;
 
-	val = advk_readl(pcie, PCIE_ISR0_REG);
-	mask = advk_readl(pcie, PCIE_ISR0_MASK_REG);
-	status = val & ((~mask) & PCIE_ISR0_ALL_MASK);
-
-	if (!status) {
-		advk_writel(pcie, val, PCIE_ISR0_REG);
+	isr0_val = advk_readl(pcie, PCIE_ISR0_REG);
+	isr0_mask = advk_readl(pcie, PCIE_ISR0_MASK_REG);
+	isr0_status = isr0_val & ((~isr0_mask) & PCIE_ISR0_ALL_MASK);
+
+	isr1_val = advk_readl(pcie, PCIE_ISR1_REG);
+	isr1_mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
+	isr1_status = isr1_val & ((~isr1_mask) & PCIE_ISR1_ALL_MASK);
+
+	if (!isr0_status && !isr1_status) {
+		advk_writel(pcie, isr0_val, PCIE_ISR0_REG);
+		advk_writel(pcie, isr1_val, PCIE_ISR1_REG);
 		return;
 	}
 
 	/* Process MSI interrupts */
-	if (status & PCIE_ISR0_MSI_INT_PENDING)
+	if (isr0_status & PCIE_ISR0_MSI_INT_PENDING)
 		advk_pcie_handle_msi(pcie);
 
 	/* Process legacy interrupts */
 	for (i = 0; i < PCI_NUM_INTX; i++) {
-		if (!(status & PCIE_ISR0_INTX_ASSERT(i)))
+		if (!(isr1_status & PCIE_ISR1_INTX_ASSERT(i)))
 			continue;
 
-		advk_writel(pcie, PCIE_ISR0_INTX_ASSERT(i),
-			    PCIE_ISR0_REG);
+		advk_writel(pcie, PCIE_ISR1_INTX_ASSERT(i),
+			    PCIE_ISR1_REG);
 
 		virq = irq_find_mapping(pcie->irq_domain, i);
 		generic_handle_irq(virq);