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SubjectRe: [PATCH 2/2] irq/irq_sim: use irq domain
On Mon, 12 Aug 2019 14:52:56 +0200
Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> We currently have a dedicated function to map the interrupt simulator
> offsets to global interrupt numbers. This is something that irq_domain
> should handle.
>
> Create a linear irq_domain when initializing the interrupt simulator
> and modify the irq_sim_fire() function to only take as parameter the
> global interrupt number.
>
> Convert both users in the same patch to using the new interface.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Hmm. Again, in principle looks fine, but what advantages do we get from
using an irq domain? Pure code wise, it's longer and only a little bit
simpler.

Jonathan

> ---
> drivers/gpio/gpio-mockup.c | 11 ++-
> drivers/iio/dummy/iio_dummy_evgen.c | 22 ++++--
> include/linux/irq_sim.h | 5 +-
> kernel/irq/Kconfig | 1 +
> kernel/irq/irq_sim.c | 110 +++++++++++++++++-----------
> 5 files changed, 94 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
> index 9b28ffec5826..4cf594f0e7cd 100644
> --- a/drivers/gpio/gpio-mockup.c
> +++ b/drivers/gpio/gpio-mockup.c
> @@ -186,7 +186,7 @@ static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
> {
> struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
>
> - return irq_sim_irqnum(chip->irqsim, offset);
> + return irq_create_mapping(irq_sim_get_domain(chip->irqsim), offset);
> }
>
> static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
> @@ -228,6 +228,7 @@ static ssize_t gpio_mockup_debugfs_write(struct file *file,
> struct gpio_mockup_dbgfs_private *priv;
> int rv, val, curr, irq, irq_type;
> struct gpio_mockup_chip *chip;
> + struct irq_domain *domain;
> struct seq_file *sfile;
> struct gpio_desc *desc;
> struct gpio_chip *gc;
> @@ -248,6 +249,7 @@ static ssize_t gpio_mockup_debugfs_write(struct file *file,
> gc = &chip->gc;
> desc = &gc->gpiodev->descs[priv->offset];
> sim = chip->irqsim;
> + domain = irq_sim_get_domain(sim);
>
> mutex_lock(&chip->lock);
>
> @@ -257,12 +259,15 @@ static ssize_t gpio_mockup_debugfs_write(struct file *file,
> if (curr == val)
> goto out;
>
> - irq = irq_sim_irqnum(sim, priv->offset);
> + irq = irq_find_mapping(domain, priv->offset);
> + if (!irq)
> + return -ENOENT;
> +
> irq_type = irq_get_trigger_type(irq);
>
> if ((val == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
> (val == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING)))
> - irq_sim_fire(sim, priv->offset);
> + irq_sim_fire(irq);
> }
>
> /* Change the value unless we're actively driving the line. */
> diff --git a/drivers/iio/dummy/iio_dummy_evgen.c b/drivers/iio/dummy/iio_dummy_evgen.c
> index efbcd4a5609e..cc827f60a535 100644
> --- a/drivers/iio/dummy/iio_dummy_evgen.c
> +++ b/drivers/iio/dummy/iio_dummy_evgen.c
> @@ -31,14 +31,13 @@
> * @lock: protect the evgen state
> * @inuse: mask of which irqs are connected
> * @irq_sim: interrupt simulator
> - * @base: base of irq range
> */
> struct iio_dummy_eventgen {
> struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
> struct mutex lock;
> bool inuse[IIO_EVENTGEN_NO];
> struct irq_sim *irq_sim;
> - int base;
> + struct irq_domain *domain;
> };
>
> /* We can only ever have one instance of this 'device' */
> @@ -56,7 +55,7 @@ static int iio_dummy_evgen_create(void)
> return PTR_ERR(iio_evgen->irq_sim);
> }
>
> - iio_evgen->base = irq_sim_irqnum(iio_evgen->irq_sim, 0);
> + iio_evgen->domain = irq_sim_get_domain(iio_evgen->irq_sim);
> mutex_init(&iio_evgen->lock);
>
> return 0;
> @@ -78,7 +77,7 @@ int iio_dummy_evgen_get_irq(void)
> mutex_lock(&iio_evgen->lock);
> for (i = 0; i < IIO_EVENTGEN_NO; i++) {
> if (!iio_evgen->inuse[i]) {
> - ret = irq_sim_irqnum(iio_evgen->irq_sim, i);
> + ret = irq_create_mapping(iio_evgen->domain, i);
> iio_evgen->inuse[i] = true;
> break;
> }
> @@ -99,15 +98,21 @@ EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
> */
> void iio_dummy_evgen_release_irq(int irq)
> {
> + struct irq_data *irqd;
> +
> + irqd = irq_get_irq_data(irq);
> +
> mutex_lock(&iio_evgen->lock);
> - iio_evgen->inuse[irq - iio_evgen->base] = false;
> + iio_evgen->inuse[irqd_to_hwirq(irqd)] = false;
> mutex_unlock(&iio_evgen->lock);
> }
> EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
>
> struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
> {
> - return &iio_evgen->regs[irq - iio_evgen->base];
> + struct irq_data *irqd = irq_get_irq_data(irq);
> +
> + return &iio_evgen->regs[irqd_to_hwirq(irqd)];
> }
> EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
>
> @@ -129,7 +134,7 @@ static ssize_t iio_evgen_poke(struct device *dev,
> {
> struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> unsigned long event;
> - int ret;
> + int ret, irq;
>
> ret = kstrtoul(buf, 10, &event);
> if (ret)
> @@ -138,7 +143,8 @@ static ssize_t iio_evgen_poke(struct device *dev,
> iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
> iio_evgen->regs[this_attr->address].reg_data = event;
>
> - irq_sim_fire(iio_evgen->irq_sim, this_attr->address);
> + irq = irq_create_mapping(iio_evgen->domain, this_attr->address);
> + irq_sim_fire(irq);
>
> return len;
> }
> diff --git a/include/linux/irq_sim.h b/include/linux/irq_sim.h
> index 4bbf036145e2..4056d0e7f0b4 100644
> --- a/include/linux/irq_sim.h
> +++ b/include/linux/irq_sim.h
> @@ -7,6 +7,7 @@
> #define _LINUX_IRQ_SIM_H
>
> #include <linux/irq_work.h>
> +#include <linux/irqdomain.h>
> #include <linux/device.h>
>
> /*
> @@ -19,7 +20,7 @@ struct irq_sim;
> struct irq_sim *irq_sim_new(unsigned int num_irqs);
> struct irq_sim *devm_irq_sim_new(struct device *dev, unsigned int num_irqs);
> void irq_sim_free(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);
> +void irq_sim_fire(int virq);
> +struct irq_domain *irq_sim_get_domain(struct irq_sim *sim);
>
> #endif /* _LINUX_IRQ_SIM_H */
> diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
> index f92d9a687372..d0890f7729d4 100644
> --- a/kernel/irq/Kconfig
> +++ b/kernel/irq/Kconfig
> @@ -68,6 +68,7 @@ config IRQ_DOMAIN
> config IRQ_SIM
> bool
> select IRQ_WORK
> + select IRQ_DOMAIN
>
> # Support for hierarchical irq domains
> config IRQ_DOMAIN_HIERARCHY
> diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c
> index 79f0a6494b6c..a1c91aefb6cd 100644
> --- a/kernel/irq/irq_sim.c
> +++ b/kernel/irq/irq_sim.c
> @@ -15,13 +15,14 @@ struct irq_sim_work_ctx {
> struct irq_sim_irq_ctx {
> int irqnum;
> bool enabled;
> + struct irq_sim_work_ctx *work_ctx;
> };
>
> struct irq_sim {
> struct irq_sim_work_ctx work_ctx;
> int irq_base;
> unsigned int irq_count;
> - struct irq_sim_irq_ctx *irqs;
> + struct irq_domain *domain;
> };
>
> struct irq_sim_devres {
> @@ -74,11 +75,46 @@ static void irq_sim_handle_irq(struct irq_work *work)
> offset = find_next_bit(work_ctx->pending,
> sim->irq_count, offset);
> clear_bit(offset, work_ctx->pending);
> - irqnum = irq_sim_irqnum(sim, offset);
> + irqnum = irq_find_mapping(sim->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 *sim = domain->host_data;
> + struct irq_sim_irq_ctx *ctx;
> +
> + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> + if (!ctx)
> + return -ENOMEM;
> +
> + irq_set_chip(virq, &irq_sim_irqchip);
> + irq_set_chip_data(virq, ctx);
> + irq_set_handler(virq, handle_simple_irq);
> + irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
> + ctx->work_ctx = &sim->work_ctx;
> +
> + return 0;
> +}
> +
> +static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
> +{
> + struct irq_sim_irq_ctx *ctx;
> + struct irq_data *irqd;
> +
> + irqd = irq_domain_get_irq_data(domain, virq);
> + ctx = irq_data_get_irq_chip_data(irqd);
> +
> + kfree(ctx);
> +}
> +
> +static const struct irq_domain_ops irq_sim_domain_ops = {
> + .map = irq_sim_domain_map,
> + .unmap = irq_sim_domain_unmap,
> +};
> +
> /**
> * irq_sim_new - Create a new interrupt simulator: allocate a range of
> * dummy interrupts.
> @@ -91,42 +127,21 @@ static void irq_sim_handle_irq(struct irq_work *work)
> struct irq_sim *irq_sim_new(unsigned int num_irqs)
> {
> struct irq_sim *sim;
> - int i;
>
> sim = kmalloc(sizeof(*sim), GFP_KERNEL);
> if (!sim)
> return ERR_PTR(-ENOMEM);
>
> - sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL);
> - if (!sim->irqs) {
> - kfree(sim);
> - return ERR_PTR(-ENOMEM);
> - }
> -
> - sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0);
> - if (sim->irq_base < 0) {
> - kfree(sim->irqs);
> - kfree(sim);
> - return ERR_PTR(sim->irq_base);
> - }
> -
> sim->work_ctx.pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
> if (!sim->work_ctx.pending) {
> - kfree(sim->irqs);
> kfree(sim);
> - irq_free_descs(sim->irq_base, num_irqs);
> return ERR_PTR(-ENOMEM);
> }
>
> - 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);
> - }
> + sim->domain = irq_domain_create_linear(NULL, num_irqs,
> + &irq_sim_domain_ops, sim);
> + if (!sim->domain)
> + return ERR_PTR(-ENOMEM);
>
> init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq);
> sim->irq_count = num_irqs;
> @@ -143,10 +158,17 @@ EXPORT_SYMBOL_GPL(irq_sim_new);
> */
> void irq_sim_free(struct irq_sim *sim)
> {
> + int i, irq;
> +
> + for (i = 0; i < sim->irq_count; i++) {
> + irq = irq_find_mapping(sim->domain, i);
> + if (irq)
> + irq_dispose_mapping(irq);
> + }
> +
> + irq_domain_remove(sim->domain);
> irq_work_sync(&sim->work_ctx.work);
> bitmap_free(sim->work_ctx.pending);
> - irq_free_descs(sim->irq_base, sim->irq_count);
> - kfree(sim->irqs);
> kfree(sim);
> }
> EXPORT_SYMBOL_GPL(irq_sim_free);
> @@ -189,27 +211,31 @@ EXPORT_SYMBOL_GPL(devm_irq_sim_new);
> /**
> * irq_sim_fire - Enqueue an interrupt.
> *
> - * @sim: The interrupt simulator object.
> - * @offset: Offset of the simulated interrupt which should be fired.
> + * @virq: Virtual interrupt number to fire. It must be associated with
> + * an existing interrupt simulator.
> */
> -void irq_sim_fire(struct irq_sim *sim, unsigned int offset)
> +void irq_sim_fire(int virq)
> {
> - if (sim->irqs[offset].enabled) {
> - set_bit(offset, sim->work_ctx.pending);
> - irq_work_queue(&sim->work_ctx.work);
> + struct irq_sim_irq_ctx *ctx;
> + struct irq_data *irqd;
> +
> + irqd = irq_get_irq_data(virq);
> + ctx = irq_data_get_irq_chip_data(irqd);
> +
> + if (ctx->enabled) {
> + set_bit(irqd_to_hwirq(irqd), ctx->work_ctx->pending);
> + irq_work_queue(&ctx->work_ctx->work);
> }
> }
> EXPORT_SYMBOL_GPL(irq_sim_fire);
>
> /**
> - * irq_sim_irqnum - Get the allocated number of a dummy interrupt.
> + * irq_sim_get_domain - Retrieve the interrupt domain for this simulator.
> *
> - * @sim: The interrupt simulator object.
> - * @offset: Offset of the simulated interrupt for which to retrieve
> - * the number.
> + * @sim: The interrupt simulator the domain of which we retrieve.
> */
> -int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset)
> +struct irq_domain *irq_sim_get_domain(struct irq_sim *sim)
> {
> - return sim->irqs[offset].irqnum;
> + return sim->domain;
> }
> -EXPORT_SYMBOL_GPL(irq_sim_irqnum);
> +EXPORT_SYMBOL(irq_sim_get_domain);

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