1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@bgdev.pl>
  4 */
  5
  6#include <linux/slab.h>
  7#include <linux/irq_sim.h>
  8#include <linux/irq.h>
  9
 10struct irq_sim_devres {
 11	struct irq_sim		*sim;
 12};
 13
 14static void irq_sim_irqmask(struct irq_data *data)
 15{
 16	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
 17
 18	irq_ctx->enabled = false;
 19}
 20
 21static void irq_sim_irqunmask(struct irq_data *data)
 22{
 23	struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
 24
 25	irq_ctx->enabled = true;
 26}
 27
 28static int irq_sim_set_type(struct irq_data *data, unsigned int type)
 29{
 30	/* We only support rising and falling edge trigger types. */
 31	if (type & ~IRQ_TYPE_EDGE_BOTH)
 32		return -EINVAL;
 33
 34	irqd_set_trigger_type(data, type);
 35
 36	return 0;
 37}
 38
 39static struct irq_chip irq_sim_irqchip = {
 40	.name		= "irq_sim",
 41	.irq_mask	= irq_sim_irqmask,
 42	.irq_unmask	= irq_sim_irqunmask,
 43	.irq_set_type	= irq_sim_set_type,
 44};
 45
 46static void irq_sim_handle_irq(struct irq_work *work)
 47{
 48	struct irq_sim_work_ctx *work_ctx;
 49	unsigned int offset = 0;
 50	struct irq_sim *sim;
 51	int irqnum;
 52
 53	work_ctx = container_of(work, struct irq_sim_work_ctx, work);
 54	sim = container_of(work_ctx, struct irq_sim, work_ctx);
 55
 56	while (!bitmap_empty(work_ctx->pending, sim->irq_count)) {
 57		offset = find_next_bit(work_ctx->pending,
 58				       sim->irq_count, offset);
 59		clear_bit(offset, work_ctx->pending);
 60		irqnum = irq_sim_irqnum(sim, offset);
 61		handle_simple_irq(irq_to_desc(irqnum));
 62	}
 63}
 64
 65/**
 66 * irq_sim_init - Initialize the interrupt simulator: allocate a range of
 67 *                dummy interrupts.
 68 *
 69 * @sim:        The interrupt simulator object to initialize.
 70 * @num_irqs:   Number of interrupts to allocate
 71 *
 72 * On success: return the base of the allocated interrupt range.
 73 * On failure: a negative errno.
 74 */
 75int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
 76{
 77	int i;
 78
 79	sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
 80	if (!sim->irqs)
 81		return -ENOMEM;
 82
 83	sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
 84	if (sim->irq_base < 0) {
 85		kfree(sim->irqs);
 86		return sim->irq_base;
 87	}
 88
 89	sim->work_ctx.pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
 90	if (!sim->work_ctx.pending) {
 91		kfree(sim->irqs);
 92		irq_free_descs(sim->irq_base, num_irqs);
 93		return -ENOMEM;
 94	}
 95
 96	for (i = 0; i < num_irqs; i++) {
 97		sim->irqs[i].irqnum = sim->irq_base + i;
 98		sim->irqs[i].enabled = false;
 99		irq_set_chip(sim->irq_base + i, &irq_sim_irqchip);
100		irq_set_chip_data(sim->irq_base + i, &sim->irqs[i]);
101		irq_set_handler(sim->irq_base + i, &handle_simple_irq);
102		irq_modify_status(sim->irq_base + i,
103				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
104	}
105
106	init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
107	sim->irq_count = num_irqs;
108
109	return sim->irq_base;
110}
111EXPORT_SYMBOL_GPL(irq_sim_init);
112
113/**
114 * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
115 *                descriptors and allocated memory.
116 *
117 * @sim:        The interrupt simulator to tear down.
118 */
119void irq_sim_fini(struct irq_sim *sim)
120{
121	irq_work_sync(&sim->work_ctx.work);
122	bitmap_free(sim->work_ctx.pending);
123	irq_free_descs(sim->irq_base, sim->irq_count);
124	kfree(sim->irqs);
125}
126EXPORT_SYMBOL_GPL(irq_sim_fini);
127
128static void devm_irq_sim_release(struct device *dev, void *res)
129{
130	struct irq_sim_devres *this = res;
131
132	irq_sim_fini(this->sim);
133}
134
135/**
136 * irq_sim_init - Initialize the interrupt simulator for a managed device.
137 *
138 * @dev:        Device to initialize the simulator object for.
139 * @sim:        The interrupt simulator object to initialize.
140 * @num_irqs:   Number of interrupts to allocate
141 *
142 * On success: return the base of the allocated interrupt range.
143 * On failure: a negative errno.
144 */
145int devm_irq_sim_init(struct device *dev, struct irq_sim *sim,
146		      unsigned int num_irqs)
147{
148	struct irq_sim_devres *dr;
149	int rv;
150
151	dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL);
152	if (!dr)
153		return -ENOMEM;
154
155	rv = irq_sim_init(sim, num_irqs);
156	if (rv < 0) {
157		devres_free(dr);
158		return rv;
159	}
160
161	dr->sim = sim;
162	devres_add(dev, dr);
163
164	return rv;
165}
166EXPORT_SYMBOL_GPL(devm_irq_sim_init);
167
168/**
169 * irq_sim_fire - Enqueue an interrupt.
170 *
171 * @sim:        The interrupt simulator object.
172 * @offset:     Offset of the simulated interrupt which should be fired.
173 */
174void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
175{
176	if (sim->irqs[offset].enabled) {
177		set_bit(offset, sim->work_ctx.pending);
178		irq_work_queue(&sim->work_ctx.work);
179	}
180}
181EXPORT_SYMBOL_GPL(irq_sim_fire);
182
183/**
184 * irq_sim_irqnum - Get the allocated number of a dummy interrupt.
185 *
186 * @sim:        The interrupt simulator object.
187 * @offset:     Offset of the simulated interrupt for which to retrieve
188 *              the number.
189 */
190int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
191{
192	return sim->irqs[offset].irqnum;
193}
194EXPORT_SYMBOL_GPL(irq_sim_irqnum);