[PATCH v3 5/7] PCI: dwc: support AC5 Legacy PCIe interrupts

[Elad Nachman]

From: Elad Nachman <enachman@xxxxxxxxxxx>

Support message emulation of Legacy PCIe interrupts for Marvell AC5/X.
These message emulations require writing an additional status register
with acknowledge bits.

Signed-off-by: Elad Nachman <enachman@xxxxxxxxxxx>
---
 drivers/pci/controller/dwc/pcie-armada8k.c | 41 +++++++++++++++-------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c
index 02481ecadd25..145434c7a9fb 100644
--- a/drivers/pci/controller/dwc/pcie-armada8k.c
+++ b/drivers/pci/controller/dwc/pcie-armada8k.c
@@ -46,7 +46,7 @@ struct armada8k_pcie_of_data {
 	const struct dw_pcie_ops *pcie_ops;
 };
 
-#define PCIE_VENDOR_REGS_OFFSET		0x8000	/* in ac5 is 0x10000 */
+#define PCIE_VENDOR_REGS_OFFSET		0x8000	/* in ac5 is in another region */
 
 #define PCIE_GLOBAL_CONTROL_REG		(PCIE_VENDOR_REGS_OFFSET + 0x0)
 #define PCIE_APP_LTSSM_EN		BIT(2)
@@ -61,6 +61,7 @@ struct armada8k_pcie_of_data {
 
 #define PCIE_GLOBAL_INT_CAUSE1_REG	(PCIE_VENDOR_REGS_OFFSET + 0x1C)
 #define PCIE_GLOBAL_INT_MASK1_REG	(PCIE_VENDOR_REGS_OFFSET + 0x20)
+#define PCIE_GLOBAL_INT_CAUSE2_REG	(PCIE_VENDOR_REGS_OFFSET + 0x24)
 #define PCIE_GLOBAL_INT_MASK2_REG	(PCIE_VENDOR_REGS_OFFSET + 0x28)
 #define PCIE_INT_A_ASSERT_MASK		BIT(9)
 #define PCIE_INT_B_ASSERT_MASK		BIT(10)
@@ -267,8 +268,14 @@ static irqreturn_t armada8k_pcie_irq_handler(int irq, void *arg)
 	 */
 	val = dw_pcie_readl_dbi(pci, PCIE_GLOBAL_INT_CAUSE1_REG);
 	dw_pcie_writel_dbi(pci, PCIE_GLOBAL_INT_CAUSE1_REG, val);
-	if ((PCIE_MSI_MASK_AC5 & val) && (pcie->pcie_type == ARMADA8K_PCIE_TYPE_AC5))
-		dw_handle_msi_irq(&pci->pp);
+	if (pcie->pcie_type == ARMADA8K_PCIE_TYPE_AC5) {
+		if (PCIE_MSI_MASK_AC5 & val)
+			dw_handle_msi_irq(&pci->pp);
+
+		val = dw_pcie_readl_dbi(pci, PCIE_GLOBAL_INT_CAUSE2_REG);
+		/* Now clear the second interrupt cause. */
+		dw_pcie_writel_dbi(pci, PCIE_GLOBAL_INT_CAUSE2_REG, val);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -307,24 +314,29 @@ static int armada8k_add_pcie_port(struct armada8k_pcie *pcie,
 	return 0;
 }
 
-static u32 ac5_xlate_dbi_reg(u32 reg)
+static void __iomem *ac5_xlate_dbi_reg(struct dw_pcie *pci,
+				       void __iomem *base,
+				       u32 reg)
 {
 	/* Handle AC5 ATU access */
 	if ((reg & ~0xfffff) == PCIE_ATU_ACCESS_MASK_AC5) {
 		reg &= 0xfffff;
-		/* ATU registers offset is 0xC00 + 0x200 * n,
+		/* ATU registers offset is 0xC000 + 0x200 * n,
 		 * from RFU registers.
 		 */
-		reg = 0xc000 | (0x200 * (reg >> 9)) | (reg & 0xff);
+		reg = (0x200 * (reg >> 9)) | (reg & 0xff);
+		return pci->atu_base + reg;
 	} else if ((reg & 0xfffff000) == PCIE_VENDOR_REGS_OFFSET) {
 		/* PCIe RFU registers in A8K are at offset 0x8000 from base
 		 * (0xf2600000) while in AC5 offset is 0x10000 from base
-		 * (0x800a0000) therefore need the addition of 0x8000.
+		 * (0x800a0000) therefore need to be reduced by 0x8000
+		 * and rebased from dbi2 base, which is set to the PCIe rfu
+		 * base in the AC5 dts:
 		 */
-		reg += PCIE_VENDOR_REGS_OFFSET;
+		reg -= PCIE_VENDOR_REGS_OFFSET;
+		return pci->dbi_base2 + reg;
 	}
-
-	return reg;
+	return base + reg;
 }
 
 static u32 ac5_pcie_read_dbi(struct dw_pcie *pci, void __iomem *base,
@@ -332,14 +344,14 @@ static u32 ac5_pcie_read_dbi(struct dw_pcie *pci, void __iomem *base,
 {
 	u32 val;
 
-	dw_pcie_read(base + ac5_xlate_dbi_reg(reg), size, &val);
+	dw_pcie_read(ac5_xlate_dbi_reg(pci, base, reg), size, &val);
 	return val;
 }
 
 static void ac5_pcie_write_dbi(struct dw_pcie *pci, void __iomem *base,
 			       u32 reg, size_t size, u32 val)
 {
-	dw_pcie_write(base + ac5_xlate_dbi_reg(reg), size, val);
+	dw_pcie_write(ac5_xlate_dbi_reg(pci, base, reg), size, val);
 }
 
 static const struct dw_pcie_ops armada8k_dw_pcie_ops = {
@@ -418,7 +430,6 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
 		ret = PTR_ERR(pci->dbi_base);
 		goto fail_clkreg;
 	}
-
 	ret = armada8k_pcie_setup_phys(pcie);
 	if (ret)
 		goto fail_clkreg;
@@ -429,6 +440,10 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		goto disable_phy;
 
+	/* backwards compatibility with older dts files: */
+	if (!pci->dbi_base2)
+		pci->dbi_base2 = pci->dbi_base;
+
 	return 0;
 
 disable_phy:
-- 
2.17.1