1 files changed, 250 insertions, 0 deletions
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
new file mode 100644
index 000000000..dd76323ea
--- /dev/null
+++ b/kernel/irq/irq_sim.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@bgdev.pl>
+ * Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#include <linux/irq.h>
+#include <linux/irq_sim.h>
+#include <linux/irq_work.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+
+struct irq_sim_work_ctx {
+	struct irq_work		work;
+	int			irq_base;
+	unsigned int		irq_count;
+	unsigned long		*pending;
+	struct irq_domain	*domain;
+};
+
+struct irq_sim_irq_ctx {
+	int			irqnum;
+	bool			enabled;
+	struct irq_sim_work_ctx	*work_ctx;
+};
+
+static void irq_sim_irqmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = false;
+}
+
+static void irq_sim_irqunmask(struct irq_data *data)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+
+	irq_ctx->enabled = true;
+}
+
+static int irq_sim_set_type(struct irq_data *data, unsigned int type)
+{
+	/* We only support rising and falling edge trigger types. */
+	if (type & ~IRQ_TYPE_EDGE_BOTH)
+		return -EINVAL;
+
+	irqd_set_trigger_type(data, type);
+
+	return 0;
+}
+
+static int irq_sim_get_irqchip_state(struct irq_data *data,
+				     enum irqchip_irq_state which, bool *state)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	switch (which) {
+	case IRQCHIP_STATE_PENDING:
+		if (irq_ctx->enabled)
+			*state = test_bit(hwirq, irq_ctx->work_ctx->pending);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int irq_sim_set_irqchip_state(struct irq_data *data,
+				     enum irqchip_irq_state which, bool state)
+{
+	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	switch (which) {
+	case IRQCHIP_STATE_PENDING:
+		if (irq_ctx->enabled) {
+			assign_bit(hwirq, irq_ctx->work_ctx->pending, state);
+			if (state)
+				irq_work_queue(&irq_ctx->work_ctx->work);
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static struct irq_chip irq_sim_irqchip = {
+	.name			= "irq_sim",
+	.irq_mask		= irq_sim_irqmask,
+	.irq_unmask		= irq_sim_irqunmask,
+	.irq_set_type		= irq_sim_set_type,
+	.irq_get_irqchip_state	= irq_sim_get_irqchip_state,
+	.irq_set_irqchip_state	= irq_sim_set_irqchip_state,
+};
+
+static void irq_sim_handle_irq(struct irq_work *work)
+{
+	struct irq_sim_work_ctx *work_ctx;
+	unsigned int offset = 0;
+	int irqnum;
+
+	work_ctx = container_of(work, struct irq_sim_work_ctx, work);
+
+	while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
+		offset = find_next_bit(work_ctx->pending,
+				       work_ctx->irq_count, offset);
+		clear_bit(offset, work_ctx->pending);
+		irqnum = irq_find_mapping(work_ctx->domain, offset);
+		handle_simple_irq(irq_to_desc(irqnum));
+	}
+}
+
+static int irq_sim_domain_map(struct irq_domain *domain,
+			      unsigned int virq, irq_hw_number_t hw)
+{
+	struct irq_sim_work_ctx *work_ctx = domain->host_data;
+	struct irq_sim_irq_ctx *irq_ctx;
+
+	irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
+	if (!irq_ctx)
+		return -ENOMEM;
+
+	irq_set_chip(virq, &irq_sim_irqchip);
+	irq_set_chip_data(virq, irq_ctx);
+	irq_set_handler(virq, handle_simple_irq);
+	irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+	irq_ctx->work_ctx = work_ctx;
+
+	return 0;
+}
+
+static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
+{
+	struct irq_sim_irq_ctx *irq_ctx;
+	struct irq_data *irqd;
+
+	irqd = irq_domain_get_irq_data(domain, virq);
+	irq_ctx = irq_data_get_irq_chip_data(irqd);
+
+	irq_set_handler(virq, NULL);
+	irq_domain_reset_irq_data(irqd);
+	kfree(irq_ctx);
+}
+
+static const struct irq_domain_ops irq_sim_domain_ops = {
+	.map		= irq_sim_domain_map,
+	.unmap		= irq_sim_domain_unmap,
+};
+
+/**
+ * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
+ *                         allocate a range of dummy interrupts.
+ *
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
+ * @num_irqs:   Number of interrupts to allocate.
+ *
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
+ */
+struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
+					 unsigned int num_irqs)
+{
+	struct irq_sim_work_ctx *work_ctx;
+
+	work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
+	if (!work_ctx)
+		goto err_out;
+
+	work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
+	if (!work_ctx->pending)
+		goto err_free_work_ctx;
+
+	work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
+						    &irq_sim_domain_ops,
+						    work_ctx);
+	if (!work_ctx->domain)
+		goto err_free_bitmap;
+
+	work_ctx->irq_count = num_irqs;
+	work_ctx->work = IRQ_WORK_INIT_HARD(irq_sim_handle_irq);
+
+	return work_ctx->domain;
+
+err_free_bitmap:
+	bitmap_free(work_ctx->pending);
+err_free_work_ctx:
+	kfree(work_ctx);
+err_out:
+	return ERR_PTR(-ENOMEM);
+}
+EXPORT_SYMBOL_GPL(irq_domain_create_sim);
+
+/**
+ * irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
+ *                         the interrupt descriptors and allocated memory.
+ *
+ * @domain:     The interrupt simulator domain to tear down.
+ */
+void irq_domain_remove_sim(struct irq_domain *domain)
+{
+	struct irq_sim_work_ctx *work_ctx = domain->host_data;
+
+	irq_work_sync(&work_ctx->work);
+	bitmap_free(work_ctx->pending);
+	kfree(work_ctx);
+
+	irq_domain_remove(domain);
+}
+EXPORT_SYMBOL_GPL(irq_domain_remove_sim);
+
+static void devm_irq_domain_remove_sim(void *data)
+{
+	struct irq_domain *domain = data;
+
+	irq_domain_remove_sim(domain);
+}
+
+/**
+ * devm_irq_domain_create_sim - Create a new interrupt simulator for
+ *                              a managed device.
+ *
+ * @dev:        Device to initialize the simulator object for.
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
+ * @num_irqs:   Number of interrupts to allocate
+ *
+ * On success: return a new irq_domain object.
+ * On failure: a negative errno wrapped with ERR_PTR().
+ */
+struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
+					      struct fwnode_handle *fwnode,
+					      unsigned int num_irqs)
+{
+	struct irq_domain *domain;
+	int ret;
+
+	domain = irq_domain_create_sim(fwnode, num_irqs);
+	if (IS_ERR(domain))
+		return domain;
+
+	ret = devm_add_action_or_reset(dev, devm_irq_domain_remove_sim, domain);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return domain;
+}
+EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);