gpio: virtio: Add IRQ support (eff5cdd7) · Commits · EulixOS / Software / Kernel

drivers/gpio/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -1686,6 +1686,7 @@ config GPIO_MOCKUP
		config GPIO_VIRTIO
		tristate "VirtIO GPIO support"
		depends on VIRTIO
		select GPIOLIB_IRQCHIP
		help
		Say Y here to enable guest support for virtio-based GPIO controllers.

drivers/gpio/gpio-virtio.c

+298 −4

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/mutex.h>
		#include <linux/spinlock.h>
		#include <linux/virtio_config.h>
		#include <uapi/linux/virtio_gpio.h>
		#include <uapi/linux/virtio_ids.h>
		@@ -28,12 +29,30 @@ struct virtio_gpio_line {
		unsigned int rxlen;
		};

		struct vgpio_irq_line {
		u8 type;
		bool disabled;
		bool masked;
		bool queued;
		bool update_pending;
		bool queue_pending;

		struct virtio_gpio_irq_request ireq ____cacheline_aligned;
		struct virtio_gpio_irq_response ires ____cacheline_aligned;
		};

		struct virtio_gpio {
		struct virtio_device *vdev;
		struct mutex lock; /* Protects virtqueue operation */
		struct gpio_chip gc;
		struct virtio_gpio_line *lines;
		struct virtqueue *request_vq;

		/* irq support */
		struct virtqueue *event_vq;
		struct mutex irq_lock; /* Protects irq operation */
		raw_spinlock_t eventq_lock; /* Protects queuing of the buffer */
		struct vgpio_irq_line *irq_lines;
		};

		static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
		@@ -186,6 +205,238 @@ static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
		virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL);
		}

		/* Interrupt handling */
		static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio)
		{
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio];
		struct virtio_gpio_irq_request *ireq = &irq_line->ireq;
		struct virtio_gpio_irq_response *ires = &irq_line->ires;
		struct scatterlist *sgs[2], req_sg, res_sg;
		int ret;

		if (WARN_ON(irq_line->queued \|\| irq_line->masked \|\| irq_line->disabled))
		return;

		ireq->gpio = cpu_to_le16(gpio);
		sg_init_one(&req_sg, ireq, sizeof(*ireq));
		sg_init_one(&res_sg, ires, sizeof(*ires));
		sgs[0] = &req_sg;
		sgs[1] = &res_sg;

		ret = virtqueue_add_sgs(vgpio->event_vq, sgs, 1, 1, irq_line, GFP_ATOMIC);
		if (ret) {
		dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n");
		return;
		}

		irq_line->queued = true;
		virtqueue_kick(vgpio->event_vq);
		}

		static void virtio_gpio_irq_enable(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];

		raw_spin_lock(&vgpio->eventq_lock);
		irq_line->disabled = false;
		irq_line->masked = false;
		irq_line->queue_pending = true;
		raw_spin_unlock(&vgpio->eventq_lock);

		irq_line->update_pending = true;
		}

		static void virtio_gpio_irq_disable(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];

		raw_spin_lock(&vgpio->eventq_lock);
		irq_line->disabled = true;
		irq_line->masked = true;
		irq_line->queue_pending = false;
		raw_spin_unlock(&vgpio->eventq_lock);

		irq_line->update_pending = true;
		}

		static void virtio_gpio_irq_mask(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];

		raw_spin_lock(&vgpio->eventq_lock);
		irq_line->masked = true;
		raw_spin_unlock(&vgpio->eventq_lock);
		}

		static void virtio_gpio_irq_unmask(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];

		raw_spin_lock(&vgpio->eventq_lock);
		irq_line->masked = false;

		/* Queue the buffer unconditionally on unmask */
		virtio_gpio_irq_prepare(vgpio, d->hwirq);
		raw_spin_unlock(&vgpio->eventq_lock);
		}

		static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];

		switch (type) {
		case IRQ_TYPE_EDGE_RISING:
		type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING;
		break;
		case IRQ_TYPE_EDGE_FALLING:
		type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING;
		break;
		case IRQ_TYPE_EDGE_BOTH:
		type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH;
		break;
		case IRQ_TYPE_LEVEL_LOW:
		type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW;
		break;
		case IRQ_TYPE_LEVEL_HIGH:
		type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH;
		break;
		default:
		dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type);
		return -EINVAL;
		}

		irq_line->type = type;
		irq_line->update_pending = true;

		return 0;
		}

		static void virtio_gpio_irq_bus_lock(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);

		mutex_lock(&vgpio->irq_lock);
		}

		static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d)
		{
		struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
		struct virtio_gpio *vgpio = gpiochip_get_data(gc);
		struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
		u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type;
		unsigned long flags;

		if (irq_line->update_pending) {
		irq_line->update_pending = false;
		virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, d->hwirq, type,
		NULL);

		/* Queue the buffer only after interrupt is enabled */
		raw_spin_lock_irqsave(&vgpio->eventq_lock, flags);
		if (irq_line->queue_pending) {
		irq_line->queue_pending = false;
		virtio_gpio_irq_prepare(vgpio, d->hwirq);
		}
		raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags);
		}

		mutex_unlock(&vgpio->irq_lock);
		}

		static struct irq_chip vgpio_irq_chip = {
		.name = "virtio-gpio",
		.irq_enable = virtio_gpio_irq_enable,
		.irq_disable = virtio_gpio_irq_disable,
		.irq_mask = virtio_gpio_irq_mask,
		.irq_unmask = virtio_gpio_irq_unmask,
		.irq_set_type = virtio_gpio_irq_set_type,

		/* These are required to implement irqchip for slow busses */
		.irq_bus_lock = virtio_gpio_irq_bus_lock,
		.irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock,
		};

		static bool ignore_irq(struct virtio_gpio *vgpio, int gpio,
		struct vgpio_irq_line *irq_line)
		{
		bool ignore = false;

		raw_spin_lock(&vgpio->eventq_lock);
		irq_line->queued = false;

		/* Interrupt is disabled currently */
		if (irq_line->masked \|\| irq_line->disabled) {
		ignore = true;
		goto unlock;
		}

		/*
		* Buffer is returned as the interrupt was disabled earlier, but is
		* enabled again now. Requeue the buffers.
		*/
		if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) {
		virtio_gpio_irq_prepare(vgpio, gpio);
		ignore = true;
		goto unlock;
		}

		if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID))
		ignore = true;

		unlock:
		raw_spin_unlock(&vgpio->eventq_lock);

		return ignore;
		}

		static void virtio_gpio_event_vq(struct virtqueue *vq)
		{
		struct virtio_gpio *vgpio = vq->vdev->priv;
		struct device *dev = &vgpio->vdev->dev;
		struct vgpio_irq_line *irq_line;
		int gpio, ret;
		unsigned int len;

		while (true) {
		irq_line = virtqueue_get_buf(vgpio->event_vq, &len);
		if (!irq_line)
		break;

		if (len != sizeof(irq_line->ires)) {
		dev_err(dev, "irq with incorrect length (%u : %u)\n",
		len, (unsigned int)sizeof(irq_line->ires));
		continue;
		}

		/*
		* Find GPIO line number from the offset of irq_line within the
		* irq_lines block. We can also get GPIO number from
		* irq-request, but better not to rely on a buffer returned by
		* remote.
		*/
		gpio = irq_line - vgpio->irq_lines;
		WARN_ON(gpio >= vgpio->gc.ngpio);

		if (unlikely(ignore_irq(vgpio, gpio, irq_line)))
		continue;

		ret = generic_handle_domain_irq(vgpio->gc.irq.domain, gpio);
		if (ret)
		dev_err(dev, "failed to handle interrupt: %d\n", ret);
		};
		}

		static void virtio_gpio_request_vq(struct virtqueue *vq)
		{
		struct virtio_gpio_line *line;
		@@ -210,14 +461,15 @@ static void virtio_gpio_free_vqs(struct virtio_device *vdev)
		static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,
		struct virtio_device *vdev)
		{
		const char * const names[] = { "requestq" };
		const char * const names[] = { "requestq", "eventq" };
		vq_callback_t *cbs[] = {
		virtio_gpio_request_vq,
		virtio_gpio_event_vq,
		};
		struct virtqueue *vqs[1] = { NULL };
		struct virtqueue *vqs[2] = { NULL, NULL };
		int ret;

		ret = virtio_find_vqs(vdev, 1, vqs, cbs, names, NULL);
		ret = virtio_find_vqs(vdev, vgpio->irq_lines ? 2 : 1, vqs, cbs, names, NULL);
		if (ret) {
		dev_err(&vdev->dev, "failed to find vqs: %d\n", ret);
		return ret;
		@@ -225,11 +477,23 @@ static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,

		if (!vqs[0]) {
		dev_err(&vdev->dev, "failed to find requestq vq\n");
		return -ENODEV;
		goto out;
		}
		vgpio->request_vq = vqs[0];

		if (vgpio->irq_lines && !vqs[1]) {
		dev_err(&vdev->dev, "failed to find eventq vq\n");
		goto out;
		}
		vgpio->event_vq = vqs[1];

		return 0;

		out:
		if (vqs[0] \|\| vqs[1])
		virtio_gpio_free_vqs(vdev);

		return -ENODEV;
		}

		static const char *virtio_gpio_get_names(struct virtio_gpio vgpio,
		@@ -325,6 +589,30 @@ static int virtio_gpio_probe(struct virtio_device *vdev)
		vgpio->gc.owner = THIS_MODULE;
		vgpio->gc.can_sleep = true;

		/* Interrupt support */
		if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) {
		vgpio->irq_lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->irq_lines), GFP_KERNEL);
		if (!vgpio->irq_lines)
		return -ENOMEM;

		/* The event comes from the outside so no parent handler */
		vgpio->gc.irq.parent_handler = NULL;
		vgpio->gc.irq.num_parents = 0;
		vgpio->gc.irq.parents = NULL;
		vgpio->gc.irq.default_type = IRQ_TYPE_NONE;
		vgpio->gc.irq.handler = handle_level_irq;
		vgpio->gc.irq.chip = &vgpio_irq_chip;

		for (i = 0; i < ngpio; i++) {
		vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE;
		vgpio->irq_lines[i].disabled = true;
		vgpio->irq_lines[i].masked = true;
		}

		mutex_init(&vgpio->irq_lock);
		raw_spin_lock_init(&vgpio->eventq_lock);
		}

		ret = virtio_gpio_alloc_vqs(vgpio, vdev);
		if (ret)
		return ret;
		@@ -357,7 +645,13 @@ static const struct virtio_device_id id_table[] = {
		};
		MODULE_DEVICE_TABLE(virtio, id_table);

		static const unsigned int features[] = {
		VIRTIO_GPIO_F_IRQ,
		};

		static struct virtio_driver virtio_gpio_driver = {
		.feature_table = features,
		.feature_table_size = ARRAY_SIZE(features),
		.id_table = id_table,
		.probe = virtio_gpio_probe,
		.remove = virtio_gpio_remove,

include/uapi/linux/virtio_gpio.h

+25 −0

Original line number	Diff line number	Diff line
		@@ -5,12 +5,16 @@

		#include <linux/types.h>

		/* Virtio GPIO Feature bits */
		#define VIRTIO_GPIO_F_IRQ 0

		/* Virtio GPIO request types */
		#define VIRTIO_GPIO_MSG_GET_NAMES 0x0001
		#define VIRTIO_GPIO_MSG_GET_DIRECTION 0x0002
		#define VIRTIO_GPIO_MSG_SET_DIRECTION 0x0003
		#define VIRTIO_GPIO_MSG_GET_VALUE 0x0004
		#define VIRTIO_GPIO_MSG_SET_VALUE 0x0005
		#define VIRTIO_GPIO_MSG_IRQ_TYPE 0x0006

		/* Possible values of the status field */
		#define VIRTIO_GPIO_STATUS_OK 0x0
		@@ -21,6 +25,14 @@
		#define VIRTIO_GPIO_DIRECTION_OUT 0x01
		#define VIRTIO_GPIO_DIRECTION_IN 0x02

		/* Virtio GPIO IRQ types */
		#define VIRTIO_GPIO_IRQ_TYPE_NONE 0x00
		#define VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING 0x01
		#define VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING 0x02
		#define VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH 0x03
		#define VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH 0x04
		#define VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW 0x08

		struct virtio_gpio_config {
		__le16 ngpio;
		__u8 padding[2];
		@@ -44,4 +56,17 @@ struct virtio_gpio_response_get_names {
		__u8 value[];
		};

		/* Virtio GPIO IRQ Request / Response */
		struct virtio_gpio_irq_request {
		__le16 gpio;
		};

		struct virtio_gpio_irq_response {
		__u8 status;
		};

		/* Possible values of the interrupt status field */
		#define VIRTIO_GPIO_IRQ_STATUS_INVALID 0x0
		#define VIRTIO_GPIO_IRQ_STATUS_VALID 0x1

		#endif /* _LINUX_VIRTIO_GPIO_H */