genirq/irq_sim: Add a simple interrupt simulator framework
Implement a simple, irq_work-based framework for simulating
interrupts. Currently the API exposes routines for initializing and
deinitializing the simulator object, enqueueing the interrupts and
retrieving the allocated interrupt numbers based on the offset of the
dummy interrupt in the simulator struct.
Change-Id: I949f4adff07284a613c6b317cd0908002074c4c0
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Cc: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Link: http://lkml.kernel.org/r/20170814145318.6495-2-brgl@bgdev.pl
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Git-commit: b19af510e67e6ca696b8721f45c148119437307c
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Vijay Navnath Kamble <vkambl@codeaurora.org>
diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
new file mode 100644
index 0000000..39ce57b
--- /dev/null
+++ b/include/linux/irq_sim.h
@@ -0,0 +1,41 @@
+#ifndef _LINUX_IRQ_SIM_H
+#define _LINUX_IRQ_SIM_H
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/irq_work.h>
+
+/*
+ * Provides a framework for allocating simulated interrupts which can be
+ * requested like normal irqs and enqueued from process context.
+ */
+
+struct irq_sim_work_ctx {
+ struct irq_work work;
+ int irq;
+};
+
+struct irq_sim_irq_ctx {
+ int irqnum;
+ bool enabled;
+};
+
+struct irq_sim {
+ struct irq_sim_work_ctx work_ctx;
+ int irq_base;
+ unsigned int irq_count;
+ struct irq_sim_irq_ctx *irqs;
+};
+
+int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs);
+void irq_sim_fini(struct irq_sim *sim);
+void irq_sim_fire(struct irq_sim *sim, unsigned int offset);
+int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset);
+
+#endif /* _LINUX_IRQ_SIM_H */
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 3bbfd6a..9b2d34f 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -59,6 +59,11 @@
config IRQ_DOMAIN
bool
+# Support for simulated interrupts
+config IRQ_SIM
+ bool
+ select IRQ_WORK
+
# Support for hierarchical irq domains
config IRQ_DOMAIN_HIERARCHY
bool
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 1d3ee31..2c0ba4e 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -3,6 +3,7 @@
obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o
obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
+obj-$(CONFIG_IRQ_SIM) += irq_sim.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o
diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
new file mode 100644
index 0000000..31a2c12
--- /dev/null
+++ b/kernel/irq/irq_sim.c
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/irq_sim.h>
+#include <linux/irq.h>
+
+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 struct irq_chip irq_sim_irqchip = {
+ .name = "irq_sim",
+ .irq_mask = irq_sim_irqmask,
+ .irq_unmask = irq_sim_irqunmask,
+};
+
+static void irq_sim_handle_irq(struct irq_work *work)
+{
+ struct irq_sim_work_ctx *work_ctx;
+
+ work_ctx = container_of(work, struct irq_sim_work_ctx, work);
+ handle_simple_irq(irq_to_desc(work_ctx->irq));
+}
+
+/**
+ * irq_sim_init - Initialize the interrupt simulator: allocate a range of
+ * dummy interrupts.
+ *
+ * @sim: The interrupt simulator object to initialize.
+ * @num_irqs: Number of interrupts to allocate
+ *
+ * Returns 0 on success and a negative error number on failure.
+ */
+int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs)
+{
+ int i;
+
+ sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
+ if (!sim->irqs)
+ return -ENOMEM;
+
+ sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
+ if (sim->irq_base < 0) {
+ kfree(sim->irqs);
+ return sim->irq_base;
+ }
+
+ for (i = 0; i < num_irqs; i++) {
+ sim->irqs[i].irqnum = sim->irq_base + i;
+ sim->irqs[i].enabled = false;
+ irq_set_chip(sim->irq_base + i, &irq_sim_irqchip);
+ irq_set_chip_data(sim->irq_base + i, &sim->irqs[i]);
+ irq_set_handler(sim->irq_base + i, &handle_simple_irq);
+ irq_modify_status(sim->irq_base + i,
+ IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
+ }
+
+ init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
+ sim->irq_count = num_irqs;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_sim_init);
+
+/**
+ * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt
+ * descriptors and allocated memory.
+ *
+ * @sim: The interrupt simulator to tear down.
+ */
+void irq_sim_fini(struct irq_sim *sim)
+{
+ irq_work_sync(&sim->work_ctx.work);
+ irq_free_descs(sim->irq_base, sim->irq_count);
+ kfree(sim->irqs);
+}
+EXPORT_SYMBOL_GPL(irq_sim_fini);
+
+/**
+ * irq_sim_fire - Enqueue an interrupt.
+ *
+ * @sim: The interrupt simulator object.
+ * @offset: Offset of the simulated interrupt which should be fired.
+ */
+void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
+{
+ if (sim->irqs[offset].enabled) {
+ sim->work_ctx.irq = irq_sim_irqnum(sim, offset);
+ irq_work_queue(&sim->work_ctx.work);
+ }
+}
+EXPORT_SYMBOL_GPL(irq_sim_fire);
+
+/**
+ * irq_sim_irqnum - Get the allocated number of a dummy interrupt.
+ *
+ * @sim: The interrupt simulator object.
+ * @offset: Offset of the simulated interrupt for which to retrieve
+ * the number.
+ */
+int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
+{
+ return sim->irqs[offset].irqnum;
+}
+EXPORT_SYMBOL_GPL(irq_sim_irqnum);