Register PCH_PIC_INT_ID constains version and supported irq number
information, and it is read only register. The detailed value can
be set at initial stage, rather than read callback.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 arch/loongarch/include/asm/kvm_pch_pic.h | 15 +++++++++++-
 arch/loongarch/kvm/intc/pch_pic.c        | 30 +++++++++++++++++-------
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/arch/loongarch/include/asm/kvm_pch_pic.h b/arch/loongarch/include/asm/kvm_pch_pic.h
index e6df6a4c1c70..3228db8f84a3 100644
--- a/arch/loongarch/include/asm/kvm_pch_pic.h
+++ b/arch/loongarch/include/asm/kvm_pch_pic.h
@@ -34,13 +34,26 @@
 #define PCH_PIC_INT_ISR_END		0x3af
 #define PCH_PIC_POLARITY_START		0x3e0
 #define PCH_PIC_POLARITY_END		0x3e7
-#define PCH_PIC_INT_ID_VAL		0x7000000UL
+#define PCH_PIC_INT_ID_VAL		0x7UL
 #define PCH_PIC_INT_ID_VER		0x1UL
 
+union LoongArchPIC_ID {
+	struct {
+		uint8_t _reserved_0[3];
+		uint8_t id;
+		uint8_t version;
+		uint8_t _reserved_1;
+		uint8_t irq_num;
+		uint8_t _reserved_2;
+	} desc;
+	uint64_t data;
+};
+
 struct loongarch_pch_pic {
 	spinlock_t lock;
 	struct kvm *kvm;
 	struct kvm_io_device device;
+	union LoongArchPIC_ID id;
 	uint64_t mask; /* 1:disable irq, 0:enable irq */
 	uint64_t htmsi_en; /* 1:msi */
 	uint64_t edge; /* 1:edge triggered, 0:level triggered */
diff --git a/arch/loongarch/kvm/intc/pch_pic.c b/arch/loongarch/kvm/intc/pch_pic.c
index 6f00ffe05c54..2c26c0836a05 100644
--- a/arch/loongarch/kvm/intc/pch_pic.c
+++ b/arch/loongarch/kvm/intc/pch_pic.c
@@ -120,20 +120,13 @@ static int loongarch_pch_pic_read(struct loongarch_pch_pic *s, gpa_t addr, int l
 {
 	int offset, index, ret = 0;
 	u32 data = 0;
-	u64 int_id = 0;
 
 	offset = addr - s->pch_pic_base;
 
 	spin_lock(&s->lock);
 	switch (offset) {
 	case PCH_PIC_INT_ID_START ... PCH_PIC_INT_ID_END:
-		/* int id version */
-		int_id |= (u64)PCH_PIC_INT_ID_VER << 32;
-		/* irq number */
-		int_id |= (u64)31 << (32 + 16);
-		/* int id value */
-		int_id |= PCH_PIC_INT_ID_VAL;
-		*(u64 *)val = int_id;
+		*(u64 *)val = s->id.data;
 		break;
 	case PCH_PIC_MASK_START ... PCH_PIC_MASK_END:
 		offset -= PCH_PIC_MASK_START;
@@ -467,7 +460,7 @@ static int kvm_setup_default_irq_routing(struct kvm *kvm)
 
 static int kvm_pch_pic_create(struct kvm_device *dev, u32 type)
 {
-	int ret;
+	int ret, i, irq_num;
 	struct kvm *kvm = dev->kvm;
 	struct loongarch_pch_pic *s;
 
@@ -483,6 +476,25 @@ static int kvm_pch_pic_create(struct kvm_device *dev, u32 type)
 	if (!s)
 		return -ENOMEM;
 
+	/*
+	 * With Loongson 7A1000 user manual
+	 * Chapter 5.2 "Description of Interrupt-related Registers"
+	 *
+	 * Interrupt controller identification register 1
+	 *   Bit 24-31 Interrupt Controller ID
+	 * Interrupt controller identification register 2
+	 *   Bit  0-7  Interrupt Controller version number
+	 *   Bit 16-23 The number of interrupt sources supported
+	 */
+	irq_num = 32;
+	s->id.desc.id = PCH_PIC_INT_ID_VAL;
+	s->id.desc.version = PCH_PIC_INT_ID_VER;
+	s->id.desc.irq_num = irq_num - 1;
+	s->mask = -1UL;
+	for (i = 0; i < irq_num; i++) {
+		s->route_entry[i] = 1;
+		s->htmsi_vector[i] = i;
+	}
 	spin_lock_init(&s->lock);
 	s->kvm = kvm;
 	kvm->arch.pch_pic = s;
-- 
2.39.3