[PATCH v4 2/2] irqchip/loongson-eiointc: Simplify irq routing on some platforms

[Bibo Mao]

Some LoongArch systems have only one eiointc node such as 3A5000/2K2000
and qemu virt-machine. If there is only one eiointc node, all cpus can
access eiointc registers directly; if there is multiple eiointc nodes, each
cpu can only access eiointc belonging to specified node group, so anysend
or ipi needs to be used to configure irq routing. IRQ routing is simple on
such systems with one node, hacking method like anysend is not necessary.

This patch provides simpile IRQ routing method for systems with one eiointc
node, and is tested on 3A5000 board and qemu virt-machine.

Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
 drivers/irqchip/irq-loongson-eiointc.c | 80 ++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
index 603d323b8f8b..e6be9d6a18c8 100644
--- a/drivers/irqchip/irq-loongson-eiointc.c
+++ b/drivers/irqchip/irq-loongson-eiointc.c
@@ -127,6 +127,48 @@ static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *af
 	return IRQ_SET_MASK_OK;
 }
 
+static int eiointc_single_set_irq_affinity(struct irq_data *d,
+				const struct cpumask *affinity, bool force)
+{
+	unsigned int cpu;
+	unsigned long flags;
+	uint32_t vector, regaddr, data, coremap;
+	struct cpumask mask;
+	struct eiointc_priv *priv = d->domain->host_data;
+
+	cpumask_and(&mask, affinity, cpu_online_mask);
+	cpumask_and(&mask, &mask, &priv->cpuspan_map);
+	if (cpumask_empty(&mask))
+		return -EINVAL;
+
+	cpu = cpumask_first(&mask);
+	vector = d->hwirq;
+	regaddr = EIOINTC_REG_ENABLE + ((vector >> 5) << 2);
+	data = ~BIT(vector & 0x1F);
+	coremap = BIT(cpu_logical_map(cpu) % CORES_PER_EIO_NODE);
+
+	/*
+	 * simplify for platform with only one eiointc node
+	 * access eiointc registers directly rather than
+	 * use any_send method here
+	 */
+	raw_spin_lock_irqsave(&affinity_lock, flags);
+	iocsr_write32(EIOINTC_ALL_ENABLE & data, regaddr);
+	/*
+	 * get irq route info for continuous 4 vectors
+	 * and set affinity for specified vector
+	 */
+	data = iocsr_read32(EIOINTC_REG_ROUTE + (vector & ~3));
+	data &=  ~(0xff << ((vector & 3) * 8));
+	data |= coremap << ((vector & 3) * 8);
+	iocsr_write32(data, EIOINTC_REG_ROUTE + (vector & ~3));
+	iocsr_write32(EIOINTC_ALL_ENABLE, regaddr);
+	raw_spin_unlock_irqrestore(&affinity_lock, flags);
+
+	irq_data_update_effective_affinity(d, cpumask_of(cpu));
+	return IRQ_SET_MASK_OK;
+}
+
 static int eiointc_index(int node)
 {
 	int i;
@@ -238,22 +280,39 @@ static struct irq_chip eiointc_irq_chip = {
 	.irq_set_affinity	= eiointc_set_irq_affinity,
 };
 
+static struct irq_chip eiointc_irq_chipi_single = {
+	.name			= "EIOINTC-S",
+	.irq_ack		= eiointc_ack_irq,
+	.irq_mask		= eiointc_mask_irq,
+	.irq_unmask		= eiointc_unmask_irq,
+#ifdef CONFIG_SMP
+	.irq_set_affinity       = eiointc_single_set_irq_affinity,
+#endif
+};
+
 static int eiointc_domain_alloc(struct irq_domain *domain, unsigned int virq,
 				unsigned int nr_irqs, void *arg)
 {
 	int ret;
 	unsigned int i, type;
 	unsigned long hwirq = 0;
-	struct eiointc *priv = domain->host_data;
+	struct eiointc_priv *priv = domain->host_data;
+	struct irq_chip *chip;
 
 	ret = irq_domain_translate_onecell(domain, arg, &hwirq, &type);
 	if (ret)
 		return ret;
 
-	for (i = 0; i < nr_irqs; i++) {
-		irq_domain_set_info(domain, virq + i, hwirq + i, &eiointc_irq_chip,
+	/*
+	 * use simple irq routing method on single eiointc node
+	 */
+	if ((nr_pics == 1) && (nodes_weight(priv->node_map) == 1))
+		chip = &eiointc_irq_chipi_single;
+	else
+		chip = &eiointc_irq_chip;
+	for (i = 0; i < nr_irqs; i++)
+		irq_domain_set_info(domain, virq + i, hwirq + i, chip,
 					priv, handle_edge_irq, NULL, NULL);
-	}
 
 	return 0;
 }
@@ -310,6 +369,7 @@ static void eiointc_resume(void)
 	int i, j;
 	struct irq_desc *desc;
 	struct irq_data *irq_data;
+	struct irq_chip *chip;
 
 	eiointc_router_init(0);
 
@@ -319,7 +379,8 @@ static void eiointc_resume(void)
 			if (desc && desc->handle_irq && desc->handle_irq != handle_bad_irq) {
 				raw_spin_lock(&desc->lock);
 				irq_data = irq_domain_get_irq_data(eiointc_priv[i]->eiointc_domain, irq_desc_get_irq(desc));
-				eiointc_set_irq_affinity(irq_data, irq_data->common->affinity, 0);
+				chip = irq_data_get_irq_chip(irq_data);
+				chip->irq_set_affinity(irq_data, irq_data->common->affinity, 0);
 				raw_spin_unlock(&desc->lock);
 			}
 		}
@@ -497,7 +558,14 @@ static int __init eiointc_of_init(struct device_node *of_node,
 	priv->node = 0;
 	priv->domain_handle = of_node_to_fwnode(of_node);
 
-	ret = eiointc_init(priv, parent_irq, 0);
+	/*
+	 * 2k0500 and 2k2000 has only one eiointc node
+	 * set nodemap as 1 for simple irq routing
+	 *
+	 * Fixme: what about future embedded boards with more than 4 cpus?
+	 * nodemap and node need be added in dts like acpi table
+	 */
+	ret = eiointc_init(priv, parent_irq, 1);
 	if (ret < 0)
 		goto out_free_priv;
 
-- 
2.27.0