irqchip/loongarch-avec: Add AVEC irqchip support

Introduce the advanced extended interrupt controllers (AVECINTC). This
feature will allow each core to have 256 independent interrupt vectors
and MSI interrupts can be independently routed to any vector on any CPU.

The whole topology of irqchips in LoongArch machines looks like this if
AVECINTC is supported:

  +-----+     +-----------------------+     +-------+
  | IPI | --> |        CPUINTC        | <-- | Timer |
  +-----+     +-----------------------+     +-------+
               ^          ^          ^
               |          |          |
        +---------+ +----------+ +---------+     +-------+
        | EIOINTC | | AVECINTC | | LIOINTC | <-- | UARTs |
        +---------+ +----------+ +---------+     +-------+
             ^            ^
             |            |
        +---------+  +---------+
        | PCH-PIC |  | PCH-MSI |
        +---------+  +---------+
          ^     ^           ^
          |     |           |
  +---------+ +---------+ +---------+
  | Devices | | PCH-LPC | | Devices |
  +---------+ +---------+ +---------+
                   ^
                   |
              +---------+
              | Devices |
              +---------+

Co-developed-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Co-developed-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Co-developed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823104337.25577-2-zhangtianyang@loongson.cn

6 files changed, 449 insertions, 2 deletions

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 15635812b2d6..e3679ec2b9f7 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -110,7 +110,7 @@ obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
 obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
 obj-$(CONFIG_TI_SCI_INTA_IRQCHIP)	+= irq-ti-sci-inta.o
 obj-$(CONFIG_TI_PRUSS_INTC)		+= irq-pruss-intc.o
-obj-$(CONFIG_IRQ_LOONGARCH_CPU)		+= irq-loongarch-cpu.o
+obj-$(CONFIG_IRQ_LOONGARCH_CPU)		+= irq-loongarch-cpu.o irq-loongarch-avec.o
 obj-$(CONFIG_LOONGSON_LIOINTC)		+= irq-loongson-liointc.o
 obj-$(CONFIG_LOONGSON_EIOINTC)		+= irq-loongson-eiointc.o
 obj-$(CONFIG_LOONGSON_HTPIC)		+= irq-loongson-htpic.o
diff --git a/drivers/irqchip/irq-loongarch-avec.c b/drivers/irqchip/irq-loongarch-avec.c
new file mode 100644
index 000000000000..0f6e465dd309
--- /dev/null
+++ b/drivers/irqchip/irq-loongarch-avec.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2024 Loongson Technologies, Inc.
+ */
+
+#include <linux/cpuhotplug.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/msi.h>
+#include <linux/radix-tree.h>
+#include <linux/spinlock.h>
+
+#include <asm/loongarch.h>
+#include <asm/setup.h>
+
+#include "irq-msi-lib.h"
+#include "irq-loongson.h"
+
+#define VECTORS_PER_REG		64
+#define IRR_VECTOR_MASK		0xffUL
+#define IRR_INVALID_MASK	0x80000000UL
+#define AVEC_MSG_OFFSET		0x100000
+
+#ifdef CONFIG_SMP
+struct pending_list {
+	struct list_head	head;
+};
+
+static struct cpumask intersect_mask;
+static DEFINE_PER_CPU(struct pending_list, pending_list);
+#endif
+
+static DEFINE_PER_CPU(struct irq_desc * [NR_VECTORS], irq_map);
+
+struct avecintc_chip {
+	raw_spinlock_t		lock;
+	struct fwnode_handle	*fwnode;
+	struct irq_domain	*domain;
+	struct irq_matrix	*vector_matrix;
+	phys_addr_t		msi_base_addr;
+};
+
+static struct avecintc_chip loongarch_avec;
+
+struct avecintc_data {
+	struct list_head	entry;
+	unsigned int		cpu;
+	unsigned int		vec;
+	unsigned int		prev_cpu;
+	unsigned int		prev_vec;
+	unsigned int		moving;
+};
+
+static inline void avecintc_ack_irq(struct irq_data *d)
+{
+}
+
+static inline void avecintc_mask_irq(struct irq_data *d)
+{
+}
+
+static inline void avecintc_unmask_irq(struct irq_data *d)
+{
+}
+
+#ifdef CONFIG_SMP
+static inline void pending_list_init(int cpu)
+{
+	struct pending_list *plist = per_cpu_ptr(&pending_list, cpu);
+
+	INIT_LIST_HEAD(&plist->head);
+}
+
+static void avecintc_sync(struct avecintc_data *adata)
+{
+	struct pending_list *plist;
+
+	if (cpu_online(adata->prev_cpu)) {
+		plist = per_cpu_ptr(&pending_list, adata->prev_cpu);
+		list_add_tail(&adata->entry, &plist->head);
+		adata->moving = 1;
+		mp_ops.send_ipi_single(adata->prev_cpu, ACTION_CLEAR_VECTOR);
+	}
+}
+
+static int avecintc_set_affinity(struct irq_data *data, const struct cpumask *dest, bool force)
+{
+	int cpu, ret, vector;
+	struct avecintc_data *adata;
+
+	scoped_guard(raw_spinlock, &loongarch_avec.lock) {
+		adata = irq_data_get_irq_chip_data(data);
+
+		if (adata->moving)
+			return -EBUSY;
+
+		if (cpu_online(adata->cpu) && cpumask_test_cpu(adata->cpu, dest))
+			return 0;
+
+		cpumask_and(&intersect_mask, dest, cpu_online_mask);
+
+		ret = irq_matrix_alloc(loongarch_avec.vector_matrix, &intersect_mask, false, &cpu);
+		if (ret < 0)
+			return ret;
+
+		vector = ret;
+		adata->cpu = cpu;
+		adata->vec = vector;
+		per_cpu_ptr(irq_map, adata->cpu)[adata->vec] = irq_data_to_desc(data);
+		avecintc_sync(adata);
+	}
+
+	irq_data_update_effective_affinity(data, cpumask_of(cpu));
+
+	return IRQ_SET_MASK_OK;
+}
+
+static int avecintc_cpu_online(unsigned int cpu)
+{
+	if (!loongarch_avec.vector_matrix)
+		return 0;
+
+	guard(raw_spinlock)(&loongarch_avec.lock);
+
+	irq_matrix_online(loongarch_avec.vector_matrix);
+
+	pending_list_init(cpu);
+
+	return 0;
+}
+
+static int avecintc_cpu_offline(unsigned int cpu)
+{
+	struct pending_list *plist = per_cpu_ptr(&pending_list, cpu);
+
+	if (!loongarch_avec.vector_matrix)
+		return 0;
+
+	guard(raw_spinlock)(&loongarch_avec.lock);
+
+	if (!list_empty(&plist->head))
+		pr_warn("CPU#%d vector is busy\n", cpu);
+
+	irq_matrix_offline(loongarch_avec.vector_matrix);
+
+	return 0;
+}
+
+void complete_irq_moving(void)
+{
+	struct pending_list *plist = this_cpu_ptr(&pending_list);
+	struct avecintc_data *adata, *tdata;
+	int cpu, vector, bias;
+	uint64_t isr;
+
+	guard(raw_spinlock)(&loongarch_avec.lock);
+
+	list_for_each_entry_safe(adata, tdata, &plist->head, entry) {
+		cpu = adata->prev_cpu;
+		vector = adata->prev_vec;
+		bias = vector / VECTORS_PER_REG;
+		switch (bias) {
+		case 0:
+			isr = csr_read64(LOONGARCH_CSR_ISR0);
+			break;
+		case 1:
+			isr = csr_read64(LOONGARCH_CSR_ISR1);
+			break;
+		case 2:
+			isr = csr_read64(LOONGARCH_CSR_ISR2);
+			break;
+		case 3:
+			isr = csr_read64(LOONGARCH_CSR_ISR3);
+			break;
+		}
+
+		if (isr & (1UL << (vector % VECTORS_PER_REG))) {
+			mp_ops.send_ipi_single(cpu, ACTION_CLEAR_VECTOR);
+			continue;
+		}
+		list_del(&adata->entry);
+		irq_matrix_free(loongarch_avec.vector_matrix, cpu, vector, false);
+		this_cpu_write(irq_map[vector], NULL);
+		adata->moving = 0;
+		adata->prev_cpu = adata->cpu;
+		adata->prev_vec = adata->vec;
+	}
+}
+#endif
+
+static void avecintc_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	struct avecintc_data *adata = irq_data_get_irq_chip_data(d);
+
+	msg->address_hi = 0x0;
+	msg->address_lo = (loongarch_avec.msi_base_addr | (adata->vec & 0xff) << 4)
+			  | ((cpu_logical_map(adata->cpu & 0xffff)) << 12);
+	msg->data = 0x0;
+}
+
+static struct irq_chip avec_irq_controller = {
+	.name			= "AVECINTC",
+	.irq_ack		= avecintc_ack_irq,
+	.irq_mask		= avecintc_mask_irq,
+	.irq_unmask		= avecintc_unmask_irq,
+#ifdef CONFIG_SMP
+	.irq_set_affinity	= avecintc_set_affinity,
+#endif
+	.irq_compose_msi_msg	= avecintc_compose_msi_msg,
+};
+
+static void avecintc_irq_dispatch(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irq_desc *d;
+
+	chained_irq_enter(chip, desc);
+
+	while (true) {
+		unsigned long vector = csr_read64(LOONGARCH_CSR_IRR);
+		if (vector & IRR_INVALID_MASK)
+			break;
+
+		vector &= IRR_VECTOR_MASK;
+
+		d = this_cpu_read(irq_map[vector]);
+		if (d) {
+			generic_handle_irq_desc(d);
+		} else {
+			spurious_interrupt();
+			pr_warn("Unexpected IRQ occurs on CPU#%d [vector %ld]\n", smp_processor_id(), vector);
+		}
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static int avecintc_alloc_vector(struct irq_data *irqd, struct avecintc_data *adata)
+{
+	int cpu, ret;
+
+	guard(raw_spinlock_irqsave)(&loongarch_avec.lock);
+
+	ret = irq_matrix_alloc(loongarch_avec.vector_matrix, cpu_online_mask, false, &cpu);
+	if (ret < 0)
+		return ret;
+
+	adata->prev_cpu = adata->cpu = cpu;
+	adata->prev_vec = adata->vec = ret;
+	per_cpu_ptr(irq_map, adata->cpu)[adata->vec] = irq_data_to_desc(irqd);
+
+	return 0;
+}
+
+static int avecintc_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs, void *arg)
+{
+	for (unsigned int i = 0; i < nr_irqs; i++) {
+		struct irq_data *irqd = irq_domain_get_irq_data(domain, virq + i);
+		struct avecintc_data *adata = kzalloc(sizeof(*adata), GFP_KERNEL);
+		int ret;
+
+		if (!adata)
+			return -ENOMEM;
+
+		ret = avecintc_alloc_vector(irqd, adata);
+		if (ret < 0) {
+			kfree(adata);
+			return ret;
+		}
+
+		irq_domain_set_info(domain, virq + i, virq + i, &avec_irq_controller,
+				    adata, handle_edge_irq, NULL, NULL);
+		irqd_set_single_target(irqd);
+		irqd_set_affinity_on_activate(irqd);
+	}
+
+	return 0;
+}
+
+static void avecintc_free_vector(struct irq_data *irqd, struct avecintc_data *adata)
+{
+	guard(raw_spinlock_irqsave)(&loongarch_avec.lock);
+
+	per_cpu(irq_map, adata->cpu)[adata->vec] = NULL;
+	irq_matrix_free(loongarch_avec.vector_matrix, adata->cpu, adata->vec, false);
+
+#ifdef CONFIG_SMP
+	if (!adata->moving)
+		return;
+
+	per_cpu(irq_map, adata->prev_cpu)[adata->prev_vec] = NULL;
+	irq_matrix_free(loongarch_avec.vector_matrix, adata->prev_cpu, adata->prev_vec, false);
+	list_del_init(&adata->entry);
+#endif
+}
+
+static void avecintc_domain_free(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs)
+{
+	for (unsigned int i = 0; i < nr_irqs; i++) {
+		struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
+
+		if (d) {
+			struct avecintc_data *adata = irq_data_get_irq_chip_data(d);
+
+			avecintc_free_vector(d, adata);
+			irq_domain_reset_irq_data(d);
+			kfree(adata);
+		}
+	}
+}
+
+static const struct irq_domain_ops avecintc_domain_ops = {
+	.alloc		= avecintc_domain_alloc,
+	.free		= avecintc_domain_free,
+	.select		= msi_lib_irq_domain_select,
+};
+
+static int __init irq_matrix_init(void)
+{
+	loongarch_avec.vector_matrix = irq_alloc_matrix(NR_VECTORS, 0, NR_VECTORS);
+	if (!loongarch_avec.vector_matrix)
+		return -ENOMEM;
+
+	for (int i = 0; i < NR_LEGACY_VECTORS; i++)
+		irq_matrix_assign_system(loongarch_avec.vector_matrix, i, false);
+
+	irq_matrix_online(loongarch_avec.vector_matrix);
+
+	return 0;
+}
+
+static int __init avecintc_init(struct irq_domain *parent)
+{
+	int ret, parent_irq;
+	unsigned long value;
+
+	raw_spin_lock_init(&loongarch_avec.lock);
+
+	loongarch_avec.fwnode = irq_domain_alloc_named_fwnode("AVECINTC");
+	if (!loongarch_avec.fwnode) {
+		pr_err("Unable to allocate domain handle\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	loongarch_avec.domain = irq_domain_create_tree(loongarch_avec.fwnode,
+						       &avecintc_domain_ops, NULL);
+	if (!loongarch_avec.domain) {
+		pr_err("Unable to create IRQ domain\n");
+		ret = -ENOMEM;
+		goto out_free_handle;
+	}
+
+	parent_irq = irq_create_mapping(parent, INT_AVEC);
+	if (!parent_irq) {
+		pr_err("Failed to mapping hwirq\n");
+		ret = -EINVAL;
+		goto out_remove_domain;
+	}
+
+	ret = irq_matrix_init();
+	if (ret < 0) {
+		pr_err("Failed to init irq matrix\n");
+		goto out_remove_domain;
+	}
+	irq_set_chained_handler_and_data(parent_irq, avecintc_irq_dispatch, NULL);
+
+#ifdef CONFIG_SMP
+	pending_list_init(0);
+	cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_AVECINTC_STARTING,
+				  "irqchip/loongarch/avecintc:starting",
+				  avecintc_cpu_online, avecintc_cpu_offline);
+#endif
+	value = iocsr_read64(LOONGARCH_IOCSR_MISC_FUNC);
+	value |= IOCSR_MISC_FUNC_AVEC_EN;
+	iocsr_write64(value, LOONGARCH_IOCSR_MISC_FUNC);
+
+	return ret;
+
+out_remove_domain:
+	irq_domain_remove(loongarch_avec.domain);
+out_free_handle:
+	irq_domain_free_fwnode(loongarch_avec.fwnode);
+out:
+	return ret;
+}
+
+static int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
+				     const unsigned long end)
+{
+	struct acpi_madt_msi_pic *pchmsi_entry = (struct acpi_madt_msi_pic *)header;
+
+	loongarch_avec.msi_base_addr = pchmsi_entry->msg_address - AVEC_MSG_OFFSET;
+
+	return pch_msi_acpi_init_avec(loongarch_avec.domain);
+}
+
+static inline int __init acpi_cascade_irqdomain_init(void)
+{
+	return acpi_table_parse_madt(ACPI_MADT_TYPE_MSI_PIC, pch_msi_parse_madt, 1);
+}
+
+int __init avecintc_acpi_init(struct irq_domain *parent)
+{
+	int ret = avecintc_init(parent);
+	if (ret < 0) {
+		pr_err("Failed to init IRQ domain\n");
+		return ret;
+	}
+
+	ret = acpi_cascade_irqdomain_init();
+	if (ret < 0) {
+		pr_err("Failed to init cascade IRQ domain\n");
+		return ret;
+	}
+
+	return ret;
+}
diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
index 83f7492290a8..bcbd7fd33178 100644
--- a/drivers/irqchip/irq-loongarch-cpu.c
+++ b/drivers/irqchip/irq-loongarch-cpu.c
@@ -140,7 +140,10 @@ static int __init acpi_cascade_irqdomain_init(void)
 	if (r < 0)
 		return r;
 
-	return 0;
+	if (cpu_has_avecint)
+		r = avecintc_acpi_init(irq_domain);
+
+	return r;
 }
 
 static int __init cpuintc_acpi_init(union acpi_subtable_headers *header,
diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
index c756b7aa8055..e24db71a8783 100644
--- a/drivers/irqchip/irq-loongson-eiointc.c
+++ b/drivers/irqchip/irq-loongson-eiointc.c
@@ -362,6 +362,9 @@ static int __init acpi_cascade_irqdomain_init(void)
 	if (r < 0)
 		return r;
 
+	if (cpu_has_avecint)
+		return 0;
+
 	r = acpi_table_parse_madt(ACPI_MADT_TYPE_MSI_PIC, pch_msi_parse_madt, 1);
 	if (r < 0)
 		return r;
diff --git a/drivers/irqchip/irq-loongson-pch-msi.c b/drivers/irqchip/irq-loongson-pch-msi.c
index 0dc14550791d..bd337ecddb40 100644
--- a/drivers/irqchip/irq-loongson-pch-msi.c
+++ b/drivers/irqchip/irq-loongson-pch-msi.c
@@ -278,4 +278,18 @@ int __init pch_msi_acpi_init(struct irq_domain *parent, struct acpi_madt_msi_pic
 
 	return ret;
 }
+
+int __init pch_msi_acpi_init_avec(struct irq_domain *parent)
+{
+	if (pch_msi_handle[0])
+		return 0;
+
+	pch_msi_handle[0] = parent->fwnode;
+	irq_domain_update_bus_token(parent, DOMAIN_BUS_NEXUS);
+
+	parent->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
+	parent->msi_parent_ops = &pch_msi_parent_ops;
+
+	return 0;
+}
 #endif
diff --git a/drivers/irqchip/irq-loongson.h b/drivers/irqchip/irq-loongson.h
index b155f1258ed5..11fa138d1f44 100644
--- a/drivers/irqchip/irq-loongson.h
+++ b/drivers/irqchip/irq-loongson.h
@@ -12,6 +12,7 @@ int liointc_acpi_init(struct irq_domain *parent,
 					struct acpi_madt_lio_pic *acpi_liointc);
 int eiointc_acpi_init(struct irq_domain *parent,
 					struct acpi_madt_eio_pic *acpi_eiointc);
+int avecintc_acpi_init(struct irq_domain *parent);
 
 int htvec_acpi_init(struct irq_domain *parent,
 					struct acpi_madt_ht_pic *acpi_htvec);
@@ -21,5 +22,6 @@ int pch_pic_acpi_init(struct irq_domain *parent,
 					struct acpi_madt_bio_pic *acpi_pchpic);
 int pch_msi_acpi_init(struct irq_domain *parent,
 					struct acpi_madt_msi_pic *acpi_pchmsi);
+int pch_msi_acpi_init_avec(struct irq_domain *parent);
 
 #endif /* _DRIVERS_IRQCHIP_IRQ_LOONGSON_H */