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gpio: virtio: Add IRQ support 

This patch adds IRQ support for the virtio GPIO driver. Note that this
uses the irq_bus_lock/unlock() callbacks, since those operations over
virtio may sleep.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
This commit is contained in:
Viresh Kumar 2021-10-21 16:34:19 +05:30 committed by Bartosz Golaszewski
parent 585a070799
commit eff5cdd745
3 changed files with 324 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/gpio/Kconfig
View File

@ -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.

302
drivers/gpio/gpio-virtio.c
View File

@ -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,

25
include/uapi/linux/virtio_gpio.h
View File

@ -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 */