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![Viresh Kumar](/assets/img/avatar_default.png)
Fix warnings reported by sparse, related to type mismatch between u16
and __le16.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 3a29355a22
("gpio: Add virtio-gpio driver")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
374 lines
9.2 KiB
C
374 lines
9.2 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/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 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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};
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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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if (!wait_for_completion_timeout(&line->completion, HZ)) {
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dev_err(dev, "GPIO operation timed out\n");
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ret = -ETIMEDOUT;
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goto out;
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}
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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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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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vdev->config->reset(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" };
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vq_callback_t *cbs[] = {
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virtio_gpio_request_vq,
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};
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struct virtqueue *vqs[1] = { NULL };
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int ret;
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ret = virtio_find_vqs(vdev, 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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if (!vqs[0]) {
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dev_err(&vdev->dev, "failed to find requestq vq\n");
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return -ENODEV;
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}
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vgpio->request_vq = vqs[0];
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return 0;
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}
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static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio,
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u32 gpio_names_size, u16 ngpio)
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{
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struct virtio_gpio_response_get_names *res;
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struct device *dev = &vgpio->vdev->dev;
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u8 *gpio_names, *str;
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const char **names;
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int i, ret, len;
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if (!gpio_names_size)
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return NULL;
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len = sizeof(*res) + gpio_names_size;
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res = devm_kzalloc(dev, len, GFP_KERNEL);
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if (!res)
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return NULL;
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gpio_names = res->value;
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ret = _virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_NAMES, 0, 0, NULL,
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res, len);
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if (ret) {
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dev_err(dev, "Failed to get GPIO names: %d\n", ret);
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return NULL;
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}
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names = devm_kcalloc(dev, ngpio, sizeof(*names), GFP_KERNEL);
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if (!names)
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return NULL;
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/* NULL terminate the string instead of checking it */
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gpio_names[gpio_names_size - 1] = '\0';
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for (i = 0, str = gpio_names; i < ngpio; i++) {
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names[i] = str;
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str += strlen(str) + 1; /* zero-length strings are allowed */
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if (str > gpio_names + gpio_names_size) {
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dev_err(dev, "gpio_names block is too short (%d)\n", i);
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return NULL;
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}
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}
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return names;
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}
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static int virtio_gpio_probe(struct virtio_device *vdev)
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{
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struct virtio_gpio_config config;
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struct device *dev = &vdev->dev;
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struct virtio_gpio *vgpio;
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u32 gpio_names_size;
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u16 ngpio;
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int ret, i;
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vgpio = devm_kzalloc(dev, sizeof(*vgpio), GFP_KERNEL);
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if (!vgpio)
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return -ENOMEM;
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/* Read configuration */
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virtio_cread_bytes(vdev, 0, &config, sizeof(config));
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gpio_names_size = le32_to_cpu(config.gpio_names_size);
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ngpio = le16_to_cpu(config.ngpio);
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if (!ngpio) {
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dev_err(dev, "Number of GPIOs can't be zero\n");
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return -EINVAL;
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}
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vgpio->lines = devm_kcalloc(dev, ngpio, sizeof(*vgpio->lines), GFP_KERNEL);
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if (!vgpio->lines)
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return -ENOMEM;
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for (i = 0; i < ngpio; i++) {
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mutex_init(&vgpio->lines[i].lock);
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init_completion(&vgpio->lines[i].completion);
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}
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mutex_init(&vgpio->lock);
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vdev->priv = vgpio;
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vgpio->vdev = vdev;
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vgpio->gc.free = virtio_gpio_free;
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vgpio->gc.get_direction = virtio_gpio_get_direction;
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vgpio->gc.direction_input = virtio_gpio_direction_input;
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vgpio->gc.direction_output = virtio_gpio_direction_output;
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vgpio->gc.get = virtio_gpio_get;
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vgpio->gc.set = virtio_gpio_set;
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vgpio->gc.ngpio = ngpio;
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vgpio->gc.base = -1; /* Allocate base dynamically */
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vgpio->gc.label = dev_name(dev);
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vgpio->gc.parent = dev;
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vgpio->gc.owner = THIS_MODULE;
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vgpio->gc.can_sleep = true;
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ret = virtio_gpio_alloc_vqs(vgpio, vdev);
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if (ret)
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return ret;
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/* Mark the device ready to perform operations from within probe() */
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virtio_device_ready(vdev);
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vgpio->gc.names = virtio_gpio_get_names(vgpio, gpio_names_size, ngpio);
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ret = gpiochip_add_data(&vgpio->gc, vgpio);
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if (ret) {
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virtio_gpio_free_vqs(vdev);
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dev_err(dev, "Failed to add virtio-gpio controller\n");
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}
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return ret;
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}
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static void virtio_gpio_remove(struct virtio_device *vdev)
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{
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struct virtio_gpio *vgpio = vdev->priv;
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gpiochip_remove(&vgpio->gc);
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virtio_gpio_free_vqs(vdev);
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}
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static const struct virtio_device_id id_table[] = {
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{ VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID },
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{},
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};
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MODULE_DEVICE_TABLE(virtio, id_table);
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static struct virtio_driver virtio_gpio_driver = {
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.id_table = id_table,
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.probe = virtio_gpio_probe,
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.remove = virtio_gpio_remove,
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.driver = {
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.name = KBUILD_MODNAME,
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.owner = THIS_MODULE,
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},
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};
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module_virtio_driver(virtio_gpio_driver);
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MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>");
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MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
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MODULE_DESCRIPTION("VirtIO GPIO driver");
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MODULE_LICENSE("GPL");
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