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