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From: Song Gao <gaosong@loongson.cn>
To: linux-kernel@vger.kernel.org
Cc: chenhuacai@kernel.org,
	jiaxun.yang@flygoat.com,
	tglx@linutronix.de,
	maobibo@loongson.cn
Subject: [PATCH v2] irqchip/loongson-eiointc: Add extioi virt extension support
Date: Tue, 11 Jun 2024 20:33:48 +0800
Message-Id: <20240611123348.8374-1-gaosong@loongson.cn>
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Interrupts can be routed to maximal four virtual CPUs with one external
hardware interrupt. Add the extioi virt extension support so that
Interrupts can be routed to 256 vcpus on hypervior mode.

Signed-off-by: Song Gao <gaosong@loongson.cn>
---
v2:
- Simplify commit messages and code.
- Follow the documented tip tree coding style.
- Add the virtual extended interrupt model to the documentation.
- Link to v1: https://lore.kernel.org/all/20240605070229.2569875-1-gaosong@loongson.cn/

 .../arch/loongarch/irq-chip-model.rst         |  28 +++++
 arch/loongarch/include/asm/irq.h              |   1 +
 drivers/irqchip/irq-loongson-eiointc.c        | 104 ++++++++++++++----
 3 files changed, 113 insertions(+), 20 deletions(-)

diff --git a/Documentation/arch/loongarch/irq-chip-model.rst b/Documentation/arch/loongarch/irq-chip-model.rst
index 7988f4192363..7c10d070b318 100644
--- a/Documentation/arch/loongarch/irq-chip-model.rst
+++ b/Documentation/arch/loongarch/irq-chip-model.rst
@@ -85,6 +85,34 @@ to CPUINTC directly::
     | Devices |
     +---------+
 
+Virt extended IRQ model
+=======================
+
+This model only work on hypervior mode. In this model, IPI (Inter-Processor Interrupt)
+and CPU Local Timer interrupt go to CPUINTC directly, CPU UARTS interrupts go to
+PCH_PIC, while all other devices interrupts go to PCH-PIC/PCH-LPC/PCH-MSI and
+gathered by V-EIOINTC(Virt Extended I/O Interrupt Controller), and then go to
+CPUINTC directly::
+
+       +-----+    +-------------------+     +-------+
+       | IPI |--> | CPUINTC(0-255vcpu)| <-- | Timer |
+       +-----+    +-------------------+     +-------+
+                            ^
+                            |
+                      +-----------+
+                      | V-EIOINTC |
+                      +-----------+
+                       ^         ^
+                       |         |
+                +---------+ +---------+
+                | PCH-PIC | | PCH-MSI |
+                +---------+ +---------+
+                  ^      ^          ^
+                  |      |          |
+           +--------+ +---------+ +---------+
+           | UARTs  | | Devices | | Devices |
+           +--------+ +---------+ +---------+
+
 ACPI-related definitions
 ========================
 
diff --git a/arch/loongarch/include/asm/irq.h b/arch/loongarch/include/asm/irq.h
index 480418bc5071..c97a7ab0e56f 100644
--- a/arch/loongarch/include/asm/irq.h
+++ b/arch/loongarch/include/asm/irq.h
@@ -53,6 +53,7 @@ struct acpi_vector_group {
 extern struct acpi_vector_group pch_group[MAX_IO_PICS];
 extern struct acpi_vector_group msi_group[MAX_IO_PICS];
 
+#define MAX_CORES_PER_EIO_NODE	256
 #define CORES_PER_EIO_NODE	4
 
 #define LOONGSON_CPU_UART0_VEC		10 /* CPU UART0 */
diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
index c7ddebf312ad..430fda9e8ce5 100644
--- a/drivers/irqchip/irq-loongson-eiointc.c
+++ b/drivers/irqchip/irq-loongson-eiointc.c
@@ -23,15 +23,43 @@
 #define EIOINTC_REG_ISR		0x1800
 #define EIOINTC_REG_ROUTE	0x1c00
 
+#define EXTIOI_VIRT_FEATURES           0x40000000
+#define  EXTIOI_HAS_VIRT_EXTENSION     BIT(0)
+#define  EXTIOI_HAS_ENABLE_OPTION      BIT(1)
+#define  EXTIOI_HAS_INT_ENCODE         BIT(2)
+#define  EXTIOI_HAS_CPU_ENCODE         BIT(3)
+#define EXTIOI_VIRT_CONFIG             0x40000004
+#define  EXTIOI_ENABLE                 BIT(1)
+#define  EXTIOI_ENABLE_INT_ENCODE      BIT(2)
+#define  EXTIOI_ENABLE_CPU_ENCODE      BIT(3)
+
 #define VEC_REG_COUNT		4
 #define VEC_COUNT_PER_REG	64
 #define VEC_COUNT		(VEC_REG_COUNT * VEC_COUNT_PER_REG)
 #define VEC_REG_IDX(irq_id)	((irq_id) / VEC_COUNT_PER_REG)
 #define VEC_REG_BIT(irq_id)     ((irq_id) % VEC_COUNT_PER_REG)
 #define EIOINTC_ALL_ENABLE	0xffffffff
+#define EIOINTC_ALL_ENABLE_VEC_MASK(vector) 	\
+	(EIOINTC_ALL_ENABLE & ~BIT(vector & 0x1F))
+#define EIOINTC_REG_ENABLE_VEC(vector)		\
+	(EIOINTC_REG_ENABLE + ((vector >> 5) << 2))
 
 #define MAX_EIO_NODES		(NR_CPUS / CORES_PER_EIO_NODE)
 
+/*
+ * Routing registers contain four vectors and have an offset of four to
+ * the base. The routing information is 8 bit wide.
+ */
+
+#define EIOINTC_REG_ROUTE_VEC(vector)		\
+	(EIOINTC_REG_ROUTE + (vector & ~0x03))
+
+#define EIOINTC_REG_ROUTE_VEC_SHIFT(vector) 	\
+	((vector & 0x03) << 3)
+
+#define EIOINTC_REG_ROUTE_VEC_MASK(vector)	\
+	(0xff << EIOINTC_REG_ROUTE_VEC_SHIFT(vector))
+
 static int nr_pics;
 
 struct eiointc_priv {
@@ -41,6 +69,7 @@ struct eiointc_priv {
 	cpumask_t		cpuspan_map;
 	struct fwnode_handle	*domain_handle;
 	struct irq_domain	*eiointc_domain;
+	bool			cpu_encoded;
 };
 
 static struct eiointc_priv *eiointc_priv[MAX_IO_PICS];
@@ -56,7 +85,9 @@ static void eiointc_enable(void)
 
 static int cpu_to_eio_node(int cpu)
 {
-	return cpu_logical_map(cpu) / CORES_PER_EIO_NODE;
+	int cores = cpu_has_hypervisor ? MAX_CORES_PER_EIO_NODE : CORES_PER_EIO_NODE;
+
+	return cpu_logical_map(cpu) / cores;
 }
 
 #ifdef CONFIG_SMP
@@ -88,6 +119,16 @@ static void eiointc_set_irq_route(int pos, unsigned int cpu, unsigned int mnode,
 
 static DEFINE_RAW_SPINLOCK(affinity_lock);
 
+static void virt_extioi_set_irq_route(unsigned int vector, unsigned int cpu)
+{
+	unsigned long reg = EIOINTC_REG_ROUTE_VEC(vector);
+	u32 data = iocsr_read32(reg);
+
+	data &= ~EIOINTC_REG_ROUTE_VEC_MASK(vector);
+	data |= cpu_logical_map(cpu) << EIOINTC_REG_ROUTE_VEC_SHIFT(vector);
+	iocsr_write32(data, reg);
+}
+
 static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *affinity, bool force)
 {
 	unsigned int cpu;
@@ -104,18 +145,24 @@ static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *af
 	}
 
 	vector = d->hwirq;
-	regaddr = EIOINTC_REG_ENABLE + ((vector >> 5) << 2);
-
-	/* Mask target vector */
-	csr_any_send(regaddr, EIOINTC_ALL_ENABLE & (~BIT(vector & 0x1F)),
-			0x0, priv->node * CORES_PER_EIO_NODE);
-
-	/* Set route for target vector */
-	eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
-
-	/* Unmask target vector */
-	csr_any_send(regaddr, EIOINTC_ALL_ENABLE,
-			0x0, priv->node * CORES_PER_EIO_NODE);
+	regaddr = EIOINTC_REG_ENABLE_VEC(vector);
+
+	if (priv->cpu_encoded) {
+		iocsr_write32(EIOINTC_ALL_ENABLE_VEC_MASK(vector), regaddr);
+		virt_extioi_set_irq_route(vector, cpu);
+		iocsr_write32(EIOINTC_ALL_ENABLE, regaddr);
+	} else {
+		/* Mask target vector */
+		csr_any_send(regaddr, EIOINTC_ALL_ENABLE_VEC_MASK(vector),
+			     0x0, priv->node * CORES_PER_EIO_NODE);
+
+		/* Set route for target vector */
+		eiointc_set_irq_route(vector, cpu, priv->node, &priv->node_map);
+
+		/* Unmask target vector */
+		csr_any_send(regaddr, EIOINTC_ALL_ENABLE,
+			     0x0, priv->node * CORES_PER_EIO_NODE);
+	}
 
 	irq_data_update_effective_affinity(d, cpumask_of(cpu));
 
@@ -139,17 +186,20 @@ static int eiointc_index(int node)
 
 static int eiointc_router_init(unsigned int cpu)
 {
-	int i, bit;
-	uint32_t data;
-	uint32_t node = cpu_to_eio_node(cpu);
-	int index = eiointc_index(node);
+	uint32_t data, node;
+	int i, bit, cores, index;
+
+	node = cpu_to_eio_node(cpu);
+	index = eiointc_index(node);
 
 	if (index < 0) {
 		pr_err("Error: invalid nodemap!\n");
-		return -1;
+		return -EINVAL;
 	}
 
-	if ((cpu_logical_map(cpu) % CORES_PER_EIO_NODE) == 0) {
+	cores = (cpu_has_hypervisor ? MAX_CORES_PER_EIO_NODE : CORES_PER_EIO_NODE);
+
+	if ((cpu_logical_map(cpu) % cores) == 0) {
 		eiointc_enable();
 
 		for (i = 0; i < eiointc_priv[0]->vec_count / 32; i++) {
@@ -165,7 +215,9 @@ static int eiointc_router_init(unsigned int cpu)
 
 		for (i = 0; i < eiointc_priv[0]->vec_count / 4; i++) {
 			/* Route to Node-0 Core-0 */
-			if (index == 0)
+			if (eiointc_priv[index]->cpu_encoded)
+				bit = cpu_logical_map(0);
+			else if (index == 0)
 				bit = BIT(cpu_logical_map(0));
 			else
 				bit = (eiointc_priv[index]->node << 4) | 1;
@@ -369,6 +421,7 @@ static int __init acpi_cascade_irqdomain_init(void)
 static int __init eiointc_init(struct eiointc_priv *priv, int parent_irq,
 			       u64 node_map)
 {
+	u32 val;
 	int i;
 
 	node_map = node_map ? node_map : -1ULL;
@@ -389,6 +442,17 @@ static int __init eiointc_init(struct eiointc_priv *priv, int parent_irq,
 		return -ENOMEM;
 	}
 
+	if (cpu_has_hypervisor) {
+		val = iocsr_read32(EXTIOI_VIRT_FEATURES);
+		if (val & BIT(EXTIOI_HAS_CPU_ENCODE)) {
+			val = iocsr_read32(EXTIOI_VIRT_CONFIG);
+			val |= BIT(EXTIOI_ENABLE_CPU_ENCODE);
+			iocsr_write32(val, EXTIOI_VIRT_CONFIG);
+			priv->cpu_encoded = true;
+			pr_info("loongson-extioi: enable cpu encodig \n");
+		}
+	}
+
 	eiointc_priv[nr_pics++] = priv;
 	eiointc_router_init(0);
 	irq_set_chained_handler_and_data(parent_irq, eiointc_irq_dispatch, priv);
-- 
2.39.3