mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Michael S. Tsirkin](/assets/img/avatar_default.png)
This will enable cleanups down the road. The idea is to disable cbs, then add "flush_queued_cbs" callback as a parameter, this way drivers can flush any work queued after callbacks have been disabled. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
664 lines
17 KiB
C
664 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* GPIO driver for virtio-based virtual GPIO controllers
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*
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* Copyright (C) 2021 metux IT consult
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* Enrico Weigelt, metux IT consult <info@metux.net>
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*
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* Copyright (C) 2021 Linaro.
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* Viresh Kumar <viresh.kumar@linaro.org>
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*/
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#include <linux/completion.h>
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#include <linux/err.h>
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#include <linux/gpio/driver.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/virtio_config.h>
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#include <uapi/linux/virtio_gpio.h>
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#include <uapi/linux/virtio_ids.h>
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struct virtio_gpio_line {
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struct mutex lock; /* Protects line operation */
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struct completion completion;
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struct virtio_gpio_request req ____cacheline_aligned;
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struct virtio_gpio_response res ____cacheline_aligned;
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unsigned int rxlen;
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};
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struct vgpio_irq_line {
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u8 type;
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bool disabled;
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bool masked;
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bool queued;
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bool update_pending;
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bool queue_pending;
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struct virtio_gpio_irq_request ireq ____cacheline_aligned;
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struct virtio_gpio_irq_response ires ____cacheline_aligned;
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};
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struct virtio_gpio {
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struct virtio_device *vdev;
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struct mutex lock; /* Protects virtqueue operation */
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struct gpio_chip gc;
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struct virtio_gpio_line *lines;
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struct virtqueue *request_vq;
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/* irq support */
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struct virtqueue *event_vq;
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struct mutex irq_lock; /* Protects irq operation */
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raw_spinlock_t eventq_lock; /* Protects queuing of the buffer */
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struct vgpio_irq_line *irq_lines;
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};
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static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
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u8 txvalue, u8 *rxvalue, void *response, u32 rxlen)
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{
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struct virtio_gpio_line *line = &vgpio->lines[gpio];
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struct virtio_gpio_request *req = &line->req;
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struct virtio_gpio_response *res = response;
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struct scatterlist *sgs[2], req_sg, res_sg;
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struct device *dev = &vgpio->vdev->dev;
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int ret;
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/*
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* Prevent concurrent requests for the same line since we have
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* pre-allocated request/response buffers for each GPIO line. Moreover
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* Linux always accesses a GPIO line sequentially, so this locking shall
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* always go through without any delays.
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*/
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mutex_lock(&line->lock);
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req->type = cpu_to_le16(type);
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req->gpio = cpu_to_le16(gpio);
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req->value = cpu_to_le32(txvalue);
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sg_init_one(&req_sg, req, sizeof(*req));
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sg_init_one(&res_sg, res, rxlen);
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sgs[0] = &req_sg;
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sgs[1] = &res_sg;
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line->rxlen = 0;
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reinit_completion(&line->completion);
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/*
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* Virtqueue callers need to ensure they don't call its APIs with other
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* virtqueue operations at the same time.
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*/
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mutex_lock(&vgpio->lock);
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ret = virtqueue_add_sgs(vgpio->request_vq, sgs, 1, 1, line, GFP_KERNEL);
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if (ret) {
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dev_err(dev, "failed to add request to vq\n");
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mutex_unlock(&vgpio->lock);
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goto out;
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}
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virtqueue_kick(vgpio->request_vq);
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mutex_unlock(&vgpio->lock);
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wait_for_completion(&line->completion);
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if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) {
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dev_err(dev, "GPIO request failed: %d\n", gpio);
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ret = -EINVAL;
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goto out;
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}
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if (unlikely(line->rxlen != rxlen)) {
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dev_err(dev, "GPIO operation returned incorrect len (%u : %u)\n",
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rxlen, line->rxlen);
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ret = -EINVAL;
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goto out;
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}
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if (rxvalue)
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*rxvalue = res->value;
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out:
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mutex_unlock(&line->lock);
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return ret;
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}
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static int virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
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u8 txvalue, u8 *rxvalue)
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{
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struct virtio_gpio_line *line = &vgpio->lines[gpio];
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struct virtio_gpio_response *res = &line->res;
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return _virtio_gpio_req(vgpio, type, gpio, txvalue, rxvalue, res,
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sizeof(*res));
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}
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static void virtio_gpio_free(struct gpio_chip *gc, unsigned int gpio)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
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VIRTIO_GPIO_DIRECTION_NONE, NULL);
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}
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static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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u8 direction;
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int ret;
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ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_DIRECTION, gpio, 0,
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&direction);
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if (ret)
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return ret;
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switch (direction) {
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case VIRTIO_GPIO_DIRECTION_IN:
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return GPIO_LINE_DIRECTION_IN;
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case VIRTIO_GPIO_DIRECTION_OUT:
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return GPIO_LINE_DIRECTION_OUT;
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default:
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return -EINVAL;
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}
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}
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static int virtio_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
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VIRTIO_GPIO_DIRECTION_IN, NULL);
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}
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static int virtio_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio,
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int value)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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int ret;
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ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL);
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if (ret)
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return ret;
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return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio,
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VIRTIO_GPIO_DIRECTION_OUT, NULL);
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}
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static int virtio_gpio_get(struct gpio_chip *gc, unsigned int gpio)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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u8 value;
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int ret;
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ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_VALUE, gpio, 0, &value);
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return ret ? ret : value;
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}
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static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
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{
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL);
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}
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/* Interrupt handling */
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static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio)
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{
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio];
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struct virtio_gpio_irq_request *ireq = &irq_line->ireq;
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struct virtio_gpio_irq_response *ires = &irq_line->ires;
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struct scatterlist *sgs[2], req_sg, res_sg;
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int ret;
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if (WARN_ON(irq_line->queued || irq_line->masked || irq_line->disabled))
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return;
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ireq->gpio = cpu_to_le16(gpio);
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sg_init_one(&req_sg, ireq, sizeof(*ireq));
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sg_init_one(&res_sg, ires, sizeof(*ires));
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sgs[0] = &req_sg;
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sgs[1] = &res_sg;
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ret = virtqueue_add_sgs(vgpio->event_vq, sgs, 1, 1, irq_line, GFP_ATOMIC);
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if (ret) {
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dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n");
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return;
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}
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irq_line->queued = true;
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virtqueue_kick(vgpio->event_vq);
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}
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static void virtio_gpio_irq_enable(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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raw_spin_lock(&vgpio->eventq_lock);
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irq_line->disabled = false;
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irq_line->masked = false;
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irq_line->queue_pending = true;
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raw_spin_unlock(&vgpio->eventq_lock);
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irq_line->update_pending = true;
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}
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static void virtio_gpio_irq_disable(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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raw_spin_lock(&vgpio->eventq_lock);
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irq_line->disabled = true;
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irq_line->masked = true;
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irq_line->queue_pending = false;
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raw_spin_unlock(&vgpio->eventq_lock);
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irq_line->update_pending = true;
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}
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static void virtio_gpio_irq_mask(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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raw_spin_lock(&vgpio->eventq_lock);
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irq_line->masked = true;
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raw_spin_unlock(&vgpio->eventq_lock);
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}
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static void virtio_gpio_irq_unmask(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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raw_spin_lock(&vgpio->eventq_lock);
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irq_line->masked = false;
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/* Queue the buffer unconditionally on unmask */
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virtio_gpio_irq_prepare(vgpio, d->hwirq);
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raw_spin_unlock(&vgpio->eventq_lock);
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}
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static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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switch (type) {
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case IRQ_TYPE_EDGE_RISING:
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type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING;
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break;
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case IRQ_TYPE_EDGE_FALLING:
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type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING;
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break;
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case IRQ_TYPE_EDGE_BOTH:
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type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH;
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break;
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case IRQ_TYPE_LEVEL_LOW:
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type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW;
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break;
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case IRQ_TYPE_LEVEL_HIGH:
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type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH;
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break;
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default:
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dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type);
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return -EINVAL;
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}
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irq_line->type = type;
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irq_line->update_pending = true;
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return 0;
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}
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static void virtio_gpio_irq_bus_lock(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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mutex_lock(&vgpio->irq_lock);
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}
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static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d)
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{
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struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
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struct virtio_gpio *vgpio = gpiochip_get_data(gc);
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struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq];
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u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type;
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unsigned long flags;
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if (irq_line->update_pending) {
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irq_line->update_pending = false;
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virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, d->hwirq, type,
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NULL);
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/* Queue the buffer only after interrupt is enabled */
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raw_spin_lock_irqsave(&vgpio->eventq_lock, flags);
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if (irq_line->queue_pending) {
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irq_line->queue_pending = false;
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virtio_gpio_irq_prepare(vgpio, d->hwirq);
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}
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raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags);
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}
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mutex_unlock(&vgpio->irq_lock);
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}
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static struct irq_chip vgpio_irq_chip = {
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.name = "virtio-gpio",
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.irq_enable = virtio_gpio_irq_enable,
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.irq_disable = virtio_gpio_irq_disable,
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.irq_mask = virtio_gpio_irq_mask,
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.irq_unmask = virtio_gpio_irq_unmask,
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.irq_set_type = virtio_gpio_irq_set_type,
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/* These are required to implement irqchip for slow busses */
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.irq_bus_lock = virtio_gpio_irq_bus_lock,
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.irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock,
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};
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static bool ignore_irq(struct virtio_gpio *vgpio, int gpio,
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struct vgpio_irq_line *irq_line)
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{
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bool ignore = false;
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raw_spin_lock(&vgpio->eventq_lock);
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irq_line->queued = false;
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/* Interrupt is disabled currently */
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if (irq_line->masked || irq_line->disabled) {
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ignore = true;
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goto unlock;
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}
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/*
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* Buffer is returned as the interrupt was disabled earlier, but is
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* enabled again now. Requeue the buffers.
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*/
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if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) {
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virtio_gpio_irq_prepare(vgpio, gpio);
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ignore = true;
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goto unlock;
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}
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if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID))
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ignore = true;
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unlock:
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raw_spin_unlock(&vgpio->eventq_lock);
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return ignore;
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}
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static void virtio_gpio_event_vq(struct virtqueue *vq)
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{
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struct virtio_gpio *vgpio = vq->vdev->priv;
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struct device *dev = &vgpio->vdev->dev;
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struct vgpio_irq_line *irq_line;
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int gpio, ret;
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unsigned int len;
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while (true) {
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irq_line = virtqueue_get_buf(vgpio->event_vq, &len);
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if (!irq_line)
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break;
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if (len != sizeof(irq_line->ires)) {
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dev_err(dev, "irq with incorrect length (%u : %u)\n",
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len, (unsigned int)sizeof(irq_line->ires));
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continue;
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}
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/*
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* Find GPIO line number from the offset of irq_line within the
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* irq_lines block. We can also get GPIO number from
|
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* irq-request, but better not to rely on a buffer returned by
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* remote.
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*/
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gpio = irq_line - vgpio->irq_lines;
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WARN_ON(gpio >= vgpio->gc.ngpio);
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if (unlikely(ignore_irq(vgpio, gpio, irq_line)))
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continue;
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ret = generic_handle_domain_irq(vgpio->gc.irq.domain, gpio);
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if (ret)
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dev_err(dev, "failed to handle interrupt: %d\n", ret);
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}
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}
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static void virtio_gpio_request_vq(struct virtqueue *vq)
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{
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struct virtio_gpio_line *line;
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unsigned int len;
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do {
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line = virtqueue_get_buf(vq, &len);
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if (!line)
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return;
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line->rxlen = len;
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complete(&line->completion);
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} while (1);
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}
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static void virtio_gpio_free_vqs(struct virtio_device *vdev)
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{
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virtio_reset_device(vdev);
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vdev->config->del_vqs(vdev);
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}
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static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio,
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struct virtio_device *vdev)
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{
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const char * const names[] = { "requestq", "eventq" };
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vq_callback_t *cbs[] = {
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virtio_gpio_request_vq,
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virtio_gpio_event_vq,
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};
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struct virtqueue *vqs[2] = { NULL, NULL };
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int ret;
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ret = virtio_find_vqs(vdev, vgpio->irq_lines ? 2 : 1, vqs, cbs, names, NULL);
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if (ret) {
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dev_err(&vdev->dev, "failed to find vqs: %d\n", ret);
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return ret;
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}
|
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|
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if (!vqs[0]) {
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dev_err(&vdev->dev, "failed to find requestq vq\n");
|
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goto out;
|
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}
|
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vgpio->request_vq = vqs[0];
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|
|
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,
|
|
u32 gpio_names_size, u16 ngpio)
|
|
{
|
|
struct virtio_gpio_response_get_names *res;
|
|
struct device *dev = &vgpio->vdev->dev;
|
|
u8 *gpio_names, *str;
|
|
const char **names;
|
|
int i, ret, len;
|
|
|
|
if (!gpio_names_size)
|
|
return NULL;
|
|
|
|
len = sizeof(*res) + gpio_names_size;
|
|
res = devm_kzalloc(dev, len, GFP_KERNEL);
|
|
if (!res)
|
|
return NULL;
|
|
gpio_names = res->value;
|
|
|
|
ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, 0, 0, NULL,
|
|
res, len);
|
|
if (ret) {
|
|
dev_err(dev, "Failed to get GPIO names: %d\n", ret);
|
|
return NULL;
|
|
}
|
|
|
|
names = devm_kcalloc(dev, ngpio, sizeof(*names), GFP_KERNEL);
|
|
if (!names)
|
|
return NULL;
|
|
|
|
/* NULL terminate the string instead of checking it */
|
|
gpio_names[gpio_names_size - 1] = '\0';
|
|
|
|
for (i = 0, str = gpio_names; i < ngpio; i++) {
|
|
names[i] = str;
|
|
str += strlen(str) + 1; /* zero-length strings are allowed */
|
|
|
|
if (str > gpio_names + gpio_names_size) {
|
|
dev_err(dev, "gpio_names block is too short (%d)\n", i);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
return names;
|
|
}
|
|
|
|
static int virtio_gpio_probe(struct virtio_device *vdev)
|
|
{
|
|
struct virtio_gpio_config config;
|
|
struct device *dev = &vdev->dev;
|
|
struct virtio_gpio *vgpio;
|
|
u32 gpio_names_size;
|
|
u16 ngpio;
|
|
int ret, i;
|
|
|
|
vgpio = devm_kzalloc(dev, sizeof(*vgpio), GFP_KERNEL);
|
|
if (!vgpio)
|
|
return -ENOMEM;
|
|
|
|
/* Read configuration */
|
|
virtio_cread_bytes(vdev, 0, &config, sizeof(config));
|
|
gpio_names_size = le32_to_cpu(config.gpio_names_size);
|
|
ngpio = le16_to_cpu(config.ngpio);
|
|
if (!ngpio) {
|
|
dev_err(dev, "Number of GPIOs can't be zero\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
vgpio->lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->lines), GFP_KERNEL);
|
|
if (!vgpio->lines)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < ngpio; i++) {
|
|
mutex_init(&vgpio->lines[i].lock);
|
|
init_completion(&vgpio->lines[i].completion);
|
|
}
|
|
|
|
mutex_init(&vgpio->lock);
|
|
vdev->priv = vgpio;
|
|
|
|
vgpio->vdev = vdev;
|
|
vgpio->gc.free = virtio_gpio_free;
|
|
vgpio->gc.get_direction = virtio_gpio_get_direction;
|
|
vgpio->gc.direction_input = virtio_gpio_direction_input;
|
|
vgpio->gc.direction_output = virtio_gpio_direction_output;
|
|
vgpio->gc.get = virtio_gpio_get;
|
|
vgpio->gc.set = virtio_gpio_set;
|
|
vgpio->gc.ngpio = ngpio;
|
|
vgpio->gc.base = -1; /* Allocate base dynamically */
|
|
vgpio->gc.label = dev_name(dev);
|
|
vgpio->gc.parent = dev;
|
|
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;
|
|
|
|
/* Mark the device ready to perform operations from within probe() */
|
|
virtio_device_ready(vdev);
|
|
|
|
vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio);
|
|
|
|
ret = gpiochip_add_data(&vgpio->gc, vgpio);
|
|
if (ret) {
|
|
virtio_gpio_free_vqs(vdev);
|
|
dev_err(dev, "Failed to add virtio-gpio controller\n");
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void virtio_gpio_remove(struct virtio_device *vdev)
|
|
{
|
|
struct virtio_gpio *vgpio = vdev->priv;
|
|
|
|
gpiochip_remove(&vgpio->gc);
|
|
virtio_gpio_free_vqs(vdev);
|
|
}
|
|
|
|
static const struct virtio_device_id id_table[] = {
|
|
{ VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID },
|
|
{},
|
|
};
|
|
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,
|
|
.driver = {
|
|
.name = KBUILD_MODNAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
};
|
|
module_virtio_driver(virtio_gpio_driver);
|
|
|
|
MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
|
|
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
|
|
MODULE_DESCRIPTION("VirtIO GPIO driver");
|
|
MODULE_LICENSE("GPL");
|