From 35fc29603cd1d8ceee3ae054528f748d96ace70b Mon Sep 17 00:00:00 2001
From: Kishon Vijay Abraham I <kishon@ti.com>
Date: Tue, 30 Mar 2021 17:24:47 +0530
Subject: [PATCH] PCI: keystone: Convert to using hierarchy domain for legacy
 interrupts

K2G provides separate IRQ lines for each of the four legacy interrupts.
Model this using hierarchy domain instead of linear domain with chained
IRQ handler.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
---
 drivers/pci/controller/dwc/pci-keystone.c | 214 ++++++++++++----------
 1 file changed, 120 insertions(+), 94 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index 90482d5246ff..0493e43ba416 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -69,6 +69,7 @@
 
 #define IRQ_STATUS(n)			(0x184 + ((n) << 4))
 #define IRQ_ENABLE_SET(n)		(0x188 + ((n) << 4))
+#define IRQ_ENABLE_CLR(n)		(0x18c + ((n) << 4))
 #define INTx_EN				BIT(0)
 
 #define ERR_IRQ_STATUS			0x1c4
@@ -116,7 +117,6 @@ struct keystone_pcie {
 	struct dw_pcie		*pci;
 	/* PCI Device ID */
 	u32			device_id;
-	int			legacy_host_irqs[PCI_NUM_INTX];
 	struct			device_node *legacy_intc_np;
 
 	int			msi_host_irq;
@@ -124,7 +124,6 @@ struct keystone_pcie {
 	struct phy		**phy;
 	struct device_link	**link;
 	struct			device_node *msi_intc_np;
-	struct irq_domain	*legacy_irq_domain;
 	struct device_node	*np;
 
 	/* Application register space */
@@ -252,26 +251,6 @@ static int ks_pcie_msi_host_init(struct pcie_port *pp)
 	return dw_pcie_allocate_domains(pp);
 }
 
-static void ks_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie,
-				      int offset)
-{
-	struct dw_pcie *pci = ks_pcie->pci;
-	struct device *dev = pci->dev;
-	u32 pending;
-	int virq;
-
-	pending = ks_pcie_app_readl(ks_pcie, IRQ_STATUS(offset));
-
-	if (BIT(0) & pending) {
-		virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, offset);
-		dev_dbg(dev, ": irq: irq_offset %d, virq %d\n", offset, virq);
-		generic_handle_irq(virq);
-	}
-
-	/* EOI the INTx interrupt */
-	ks_pcie_app_writel(ks_pcie, IRQ_EOI, offset);
-}
-
 /*
  * Dummy function so that DW core doesn't configure MSI
  */
@@ -317,39 +296,120 @@ static irqreturn_t ks_pcie_handle_error_irq(struct keystone_pcie *ks_pcie)
 	return IRQ_HANDLED;
 }
 
-static void ks_pcie_ack_legacy_irq(struct irq_data *d)
+void ks_pcie_irq_eoi(struct irq_data *data)
 {
+	struct keystone_pcie *ks_pcie = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = data->hwirq;
+
+	ks_pcie_app_writel(ks_pcie, IRQ_EOI, hwirq);
+	irq_chip_eoi_parent(data);
 }
 
-static void ks_pcie_mask_legacy_irq(struct irq_data *d)
+void ks_pcie_irq_enable(struct irq_data *data)
 {
+	struct keystone_pcie *ks_pcie = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = data->hwirq;
+
+	ks_pcie_app_writel(ks_pcie, IRQ_ENABLE_SET(hwirq), INTx_EN);
+	irq_chip_enable_parent(data);
 }
 
-static void ks_pcie_unmask_legacy_irq(struct irq_data *d)
+void ks_pcie_irq_disable(struct irq_data *data)
 {
+	struct keystone_pcie *ks_pcie = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = data->hwirq;
+
+	ks_pcie_app_writel(ks_pcie, IRQ_ENABLE_CLR(hwirq), INTx_EN);
+	irq_chip_disable_parent(data);
 }
 
 static struct irq_chip ks_pcie_legacy_irq_chip = {
-	.name = "Keystone-PCI-Legacy-IRQ",
-	.irq_ack = ks_pcie_ack_legacy_irq,
-	.irq_mask = ks_pcie_mask_legacy_irq,
-	.irq_unmask = ks_pcie_unmask_legacy_irq,
+	.name			= "Keystone-PCI-Legacy-IRQ",
+	.irq_enable		= ks_pcie_irq_enable,
+	.irq_disable		= ks_pcie_irq_disable,
+	.irq_eoi		= ks_pcie_irq_eoi,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
 };
 
-static int ks_pcie_init_legacy_irq_map(struct irq_domain *d,
-				       unsigned int irq,
-				       irq_hw_number_t hw_irq)
+static int ks_pcie_legacy_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+					   unsigned int nr_irqs, void *data)
 {
-	irq_set_chip_and_handler(irq, &ks_pcie_legacy_irq_chip,
-				 handle_level_irq);
-	irq_set_chip_data(irq, d->host_data);
+	struct keystone_pcie *ks_pcie = domain->host_data;
+	struct device_node *np = ks_pcie->legacy_intc_np;
+	struct irq_fwspec parent_fwspec, *fwspec = data;
+	struct of_phandle_args out_irq;
+	int ret;
+
+	if (nr_irqs != 1)
+		return -EINVAL;
+
+	/*
+	 * Get the correct interrupt from legacy-interrupt-controller node
+	 * corresponding to INTA/INTB/INTC/INTD (passed in fwspec->param[0])
+	 * after performing mapping specified in "interrupt-map".
+	 * interrupt-map = <0 0 0 1 &pcie_intc0 0>, INTA (4th cell in
+	 * interrupt-map) corresponds to 1st entry in "interrupts" (6th cell
+	 * in interrupt-map)
+	 */
+	ret = of_irq_parse_one(np, fwspec->param[0], &out_irq);
+	if (ret < 0) {
+		pr_err("Failed to parse interrupt node\n");
+		return ret;
+	}
+
+	of_phandle_args_to_fwspec(np, out_irq.args, out_irq.args_count, &parent_fwspec);
+
+	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &parent_fwspec);
+	if (ret < 0) {
+		pr_err("Failed to allocate parent IRQ %u: %d\n",
+		       parent_fwspec.param[0], ret);
+		return ret;
+	}
+
+	ret = irq_domain_set_hwirq_and_chip(domain, virq, fwspec->param[0],
+					    &ks_pcie_legacy_irq_chip, ks_pcie);
+	if (ret < 0) {
+		pr_err("Failed to set hwirq and chip\n");
+		goto err_set_hwirq_and_chip;
+	}
 
 	return 0;
+
+err_set_hwirq_and_chip:
+	irq_domain_free_irqs_parent(domain, virq, 1);
+
+	return ret;
+}
+
+static int ks_pcie_irq_domain_translate(struct irq_domain *domain,
+					struct irq_fwspec *fwspec,
+					unsigned long *hwirq,
+					unsigned int *type)
+{
+	if (is_of_node(fwspec->fwnode)) {
+		if (fwspec->param_count != 2)
+			return -EINVAL;
+
+		if (fwspec->param[0] >= PCI_NUM_INTX)
+			return -EINVAL;
+
+		*hwirq = fwspec->param[0];
+		*type = fwspec->param[1];
+
+		return 0;
+	}
+
+	return -EINVAL;
 }
 
 static const struct irq_domain_ops ks_pcie_legacy_irq_domain_ops = {
-	.map = ks_pcie_init_legacy_irq_map,
-	.xlate = irq_domain_xlate_onetwocell,
+	.alloc		= ks_pcie_legacy_irq_domain_alloc,
+	.free		= irq_domain_free_irqs_common,
+	.translate	= ks_pcie_irq_domain_translate,
 };
 
 /**
@@ -616,35 +676,6 @@ static void ks_pcie_msi_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-/**
- * ks_pcie_legacy_irq_handler() - Handle legacy interrupt
- * @irq: IRQ line for legacy interrupts
- * @desc: Pointer to irq descriptor
- *
- * Traverse through pending legacy interrupts and invoke handler for each. Also
- * takes care of interrupt controller level mask/ack operation.
- */
-static void ks_pcie_legacy_irq_handler(struct irq_desc *desc)
-{
-	unsigned int irq = irq_desc_get_irq(desc);
-	struct keystone_pcie *ks_pcie = irq_desc_get_handler_data(desc);
-	struct dw_pcie *pci = ks_pcie->pci;
-	struct device *dev = pci->dev;
-	u32 irq_offset = irq - ks_pcie->legacy_host_irqs[0];
-	struct irq_chip *chip = irq_desc_get_chip(desc);
-
-	dev_dbg(dev, ": Handling legacy irq %d\n", irq);
-
-	/*
-	 * The chained irq handler installation would have replaced normal
-	 * interrupt driver handler so we need to take care of mask/unmask and
-	 * ack operation.
-	 */
-	chained_irq_enter(chip, desc);
-	ks_pcie_handle_legacy_irq(ks_pcie, irq_offset);
-	chained_irq_exit(chip, desc);
-}
-
 static int ks_pcie_config_msi_irq(struct keystone_pcie *ks_pcie)
 {
 	struct device *dev = ks_pcie->pci->dev;
@@ -704,20 +735,33 @@ static int ks_pcie_config_legacy_irq(struct keystone_pcie *ks_pcie)
 	struct device *dev = ks_pcie->pci->dev;
 	struct irq_domain *legacy_irq_domain;
 	struct device_node *np = ks_pcie->np;
+	struct irq_domain *parent_domain;
+	struct device_node *parent_node;
 	struct device_node *intc_np;
-	int irq_count, irq, ret = 0, i;
+	int irq_count, ret = 0;
 
-	intc_np = of_get_child_by_name(np, "legacy-interrupt-controller");
+	intc_np = of_get_child_by_name(np, "interrupt-controller");
 	if (!intc_np) {
-		/*
-		 * Since legacy interrupts are modeled as edge-interrupts in
-		 * AM6, keep it disabled for now.
-		 */
-		if (ks_pcie->is_am6)
-			return 0;
 		dev_warn(dev, "legacy-interrupt-controller node is absent\n");
 		return -EINVAL;
 	}
+	ks_pcie->legacy_intc_np = intc_np;
+
+	parent_node = of_irq_find_parent(intc_np);
+	if (!parent_node) {
+		dev_err(dev, "Unable to obtain parent node\n");
+		ret = -ENXIO;
+		goto err;
+	}
+
+	parent_domain = irq_find_host(parent_node);
+	if (!parent_domain) {
+		dev_err(dev, "Unable to obtain parent domain\n");
+		ret = -ENXIO;
+		goto err;
+	}
+
+	of_node_put(parent_node);
 
 	irq_count = of_irq_count(intc_np);
 	if (!irq_count) {
@@ -726,31 +770,13 @@ static int ks_pcie_config_legacy_irq(struct keystone_pcie *ks_pcie)
 		goto err;
 	}
 
-	for (i = 0; i < irq_count; i++) {
-		irq = irq_of_parse_and_map(intc_np, i);
-		if (!irq) {
-			ret = -EINVAL;
-			goto err;
-		}
-		ks_pcie->legacy_host_irqs[i] = irq;
-
-		irq_set_chained_handler_and_data(irq,
-						 ks_pcie_legacy_irq_handler,
-						 ks_pcie);
-	}
-
-	legacy_irq_domain =
-		irq_domain_add_linear(intc_np, PCI_NUM_INTX,
-				      &ks_pcie_legacy_irq_domain_ops, NULL);
+	legacy_irq_domain = irq_domain_add_hierarchy(parent_domain, 0, PCI_NUM_INTX, intc_np,
+						     &ks_pcie_legacy_irq_domain_ops, ks_pcie);
 	if (!legacy_irq_domain) {
 		dev_err(dev, "Failed to add irq domain for legacy irqs\n");
 		ret = -EINVAL;
 		goto err;
 	}
-	ks_pcie->legacy_irq_domain = legacy_irq_domain;
-
-	for (i = 0; i < PCI_NUM_INTX; i++)
-		ks_pcie_app_writel(ks_pcie, IRQ_ENABLE_SET(i), INTx_EN);
 
 err:
 	of_node_put(intc_np);
