[RFC PATCH v2 5/5] irqchip/realtek-rtl: add explicit output routing

[Sander Vanheule <sander@svanheule.net>]

Use the list of parent interrupts, and the optional output validity
mask, to build the list of routed output interrupts. This enables us to
remove the assumption that interrupt outputs (1..6) are always connected
to MIPS CPU interrupts (2..7).

Since the use of interrupt-map is non-standard, extra logic is required
to resolve the specified interrupts to one of the parent interrupts.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
---
 drivers/irqchip/irq-realtek-rtl.c | 137 +++++++++++++++++++++++++-----
 1 file changed, 117 insertions(+), 20 deletions(-)

diff --git a/drivers/irqchip/irq-realtek-rtl.c b/drivers/irqchip/irq-realtek-rtl.c
index 1f8f21a0bd1a..1b9c1108e945 100644
--- a/drivers/irqchip/irq-realtek-rtl.c
+++ b/drivers/irqchip/irq-realtek-rtl.c
@@ -22,6 +22,8 @@
 #define RTL_ICTL_IRR2		0x10
 #define RTL_ICTL_IRR3		0x14
 
+/* Support up to 6 active outputs for now */
+#define RTL_ICTL_OUTPUT_MASK	GENMASK(14, 0)
 #define RTL_ICTL_NUM_OUTPUTS	6
 
 #define REG(x)		(realtek_ictl_base + x)
@@ -31,6 +33,7 @@ static void __iomem *realtek_ictl_base;
 static struct irq_domain *realtek_ictl_domain;
 
 struct realtek_ictl_output {
+	int parent;
 	unsigned int routing_value;
 	u32 child_mask;
 };
@@ -142,10 +145,58 @@ static void __init set_routing(struct realtek_ictl_output *output, unsigned int
 	write_irr(REG(RTL_ICTL_IRR0), soc_int, output->routing_value);
 }
 
+static int __init resolve_parent(struct device_node *node, const __be32 *table,
+	unsigned int table_len, int *parent)
+{
+	struct of_phandle_args parent_irq;
+	struct device_node *parent_ictl;
+	unsigned int parent_cell_count;
+	unsigned int table_len_left;
+	int cell;
+	int ret;
+
+	if (!table_len)
+		return -EINVAL;
+
+	parent_ictl = of_find_node_by_phandle(be32_to_cpup(table++));
+	table_len_left = table_len - 1;
+
+	if (!parent_ictl)
+		return -EINVAL;
+
+	parent_irq.np = parent_ictl;
+
+	parent_cell_count = 0;
+	ret = of_property_read_u32(parent_ictl, "#interrupt-cells", &parent_cell_count);
+	if (ret)
+		goto out;
+
+	if (table_len_left < parent_cell_count) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	parent_irq.args_count = parent_cell_count;
+
+	for (cell = 0; cell < parent_cell_count; cell++)
+		parent_irq.args[cell] = be32_to_cpup(table++);
+
+	table_len_left -= parent_cell_count;
+
+	ret = of_irq_parse_raw(of_get_property(node, "reg", NULL), &parent_irq);
+	if (ret < 0)
+		goto out;
+
+	*parent = irq_create_of_mapping(&parent_irq);
+	ret = table_len - table_len_left;
+out:
+	of_node_put(parent_ictl);
+	return ret;
+}
+
 static int __init map_interrupts(struct device_node *node)
 {
 	struct realtek_ictl_output *output;
-	struct device_node *cpu_ictl;
 	const __be32 *imap;
 	u32 imaplen, soc_int, cpu_int, tmp;
 	int ret, i;
@@ -158,34 +209,76 @@ static int __init map_interrupts(struct device_node *node)
 	if (!imap || imaplen % 3)
 		return -EINVAL;
 
-	for (i = 0; i < imaplen; i += 3 * sizeof(u32)) {
-		soc_int = be32_to_cpup(imap);
-		if (soc_int > 31)
-			return -EINVAL;
+	imaplen /= sizeof(*imap);
+	while (imaplen > 1) {
+		soc_int = be32_to_cpup(imap++);
+		imaplen--;
 
-		cpu_ictl = of_find_node_by_phandle(be32_to_cpup(imap + 1));
-		if (!cpu_ictl)
-			return -EINVAL;
-		ret = of_property_read_u32(cpu_ictl, "#interrupt-cells", &tmp);
-		if (ret || tmp != 1)
+		if (soc_int > 31)
 			return -EINVAL;
-		of_node_put(cpu_ictl);
 
-		cpu_int = be32_to_cpup(imap + 2);
-		if (cpu_int > 7 || cpu_int < 2)
-			return -EINVAL;
+		cpu_int = 0;
+		ret = resolve_parent(node, imap, imaplen, &cpu_int);
+		if (ret < 0)
+			return ret;
+		imaplen -= ret;
+		imap += ret;
 
-		output = &realtek_ictl_outputs[cpu_int - 2];
+		i = 0;
+		output = &realtek_ictl_outputs[0];
 
-		if (!output->routing_value) {
-			irq_set_chained_handler_and_data(cpu_int, realtek_irq_dispatch, output);
-			/* Use routing values (1..6) for CPU interrupts (2..7) */
-			output->routing_value = cpu_int - 1;
+		while (i < RTL_ICTL_NUM_OUTPUTS && output->parent != cpu_int) {
+			output++;
+			i++;
 		}
 
+		if (i == RTL_ICTL_NUM_OUTPUTS)
+			return -EINVAL;
+
 		set_routing(output, soc_int);
+	}
+
+	return 0;
+}
 
-		imap += 3;
+static int __init route_parent_interrupts(struct device_node *node)
+{
+	struct realtek_ictl_output *output;
+	unsigned int current_output;
+	unsigned int num_parents;
+	unsigned int parent;
+	u32 output_mask;
+	int parent_irq;
+
+	output_mask = RTL_ICTL_OUTPUT_MASK;
+	of_property_read_u32(node, "realtek,output-valid-mask", &output_mask);
+	if (output_mask & ~RTL_ICTL_OUTPUT_MASK) {
+		pr_warn("realtek,output-valid-mask contains unsupported outputs\n");
+		output_mask &= RTL_ICTL_OUTPUT_MASK;
+	}
+
+	num_parents = of_irq_count(node);
+	if (num_parents > RTL_ICTL_NUM_OUTPUTS) {
+		pr_err("too many parent interrupts\n");
+		return -EINVAL;
+	}
+
+	for (parent = 0; output_mask && parent < num_parents; parent++) {
+		current_output = __ffs(output_mask);
+
+		parent_irq = of_irq_get(node, parent);
+		if (parent_irq < 0)
+			return parent_irq;
+		else if (!parent_irq)
+			return -ENODEV;
+
+		output = &realtek_ictl_outputs[parent];
+		output->parent = parent_irq;
+		output->routing_value = current_output + 1;
+
+		irq_set_chained_handler_and_data(parent_irq, realtek_irq_dispatch, output);
+
+		output_mask &= ~BIT(current_output);
 	}
 
 	return 0;
@@ -209,6 +302,10 @@ static int __init realtek_rtl_of_init(struct device_node *node, struct device_no
 
 	realtek_ictl_domain = irq_domain_add_simple(node, 32, 0, &irq_domain_ops, NULL);
 
+	ret = route_parent_interrupts(node);
+	if (ret)
+		return ret;
+
 	ret = map_interrupts(node);
 	if (ret) {
 		pr_err("invalid interrupt map\n");
-- 
2.33.1