[V3,1/3] gpio: Add virtio-gpio driver

Message ID	10442926ae8a65f716bfc23f32339a6b35e51d5a.1623326176.git.viresh.kumar@linaro.org
State	New
Headers	show Delivered-To: patch@linaro.org Received-SPF: pass (google.com: domain of linux-gpio-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; From: Viresh Kumar <viresh.kumar@linaro.org> To: Bartosz Golaszewski <bgolaszewski@baylibre.com>, Linus Walleij <linus.walleij@linaro.org>, "Enrico Weigelt, metux IT consult" <info@metux.net>, Viresh Kumar <vireshk@kernel.org>, "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com> Cc: Viresh Kumar <viresh.kumar@linaro.org>, Vincent Guittot <vincent.guittot@linaro.org>, Bill Mills <bill.mills@linaro.org>, =?utf-8?q?Alex_Benn=C3=A9e?= <alex.bennee@linaro.org>, stratos-dev@op-lists.linaro.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Hajnoczi <stefanha@redhat.com>, "Stefano Garzarella --cc virtualization @ lists . linux-foundation . org" <sgarzare@redhat.com>, virtualization@lists.linux-foundation.org Subject: [PATCH V3 1/3] gpio: Add virtio-gpio driver Date: Thu, 10 Jun 2021 17:46:32 +0530 Message-Id: <10442926ae8a65f716bfc23f32339a6b35e51d5a.1623326176.git.viresh.kumar@linaro.org> In-Reply-To: <cover.1623326176.git.viresh.kumar@linaro.org> References: <cover.1623326176.git.viresh.kumar@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	gpio: Add virtio based driver \| expand [V3,0/3] gpio: Add virtio based driver [V3,1/3] gpio: Add virtio-gpio driver [V3,2/3] gpio: virtio: Add IRQ support [V3,3/3] MAINTAINERS: Add entry for Virtio-gpio

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index e3607ec4c2e8..7f12fb65d130 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1633,6 +1633,15 @@ config GPIO_MOCKUP tools/testing/selftests/gpio/gpio-mockup.sh. Reference the usage in it. +config GPIO_VIRTIO + tristate "VirtIO GPIO support" + depends on VIRTIO + help + Say Y here to enable guest support for virtio-based GPIO controllers. + + These virtual GPIOs can be routed to real GPIOs or attached to + simulators on the host (like QEMU). + endmenu endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index c58a90a3c3b1..ace004c80871 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -162,6 +162,7 @@ obj-$(CONFIG_GPIO_UCB1400) += gpio-ucb1400.o obj-$(CONFIG_GPIO_UNIPHIER) += gpio-uniphier.o obj-$(CONFIG_GPIO_VF610) += gpio-vf610.o obj-$(CONFIG_GPIO_VIPERBOARD) += gpio-viperboard.o +obj-$(CONFIG_GPIO_VIRTIO) += gpio-virtio.o obj-$(CONFIG_GPIO_VISCONTI) += gpio-visconti.o obj-$(CONFIG_GPIO_VR41XX) += gpio-vr41xx.o obj-$(CONFIG_GPIO_VX855) += gpio-vx855.o diff --git a/drivers/gpio/gpio-virtio.c b/drivers/gpio/gpio-virtio.c new file mode 100644 index 000000000000..1ba8ddf4693a --- /dev/null +++ b/drivers/gpio/gpio-virtio.c @@ -0,0 +1,326 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * GPIO driver for virtio-based virtual GPIO controllers + * + * Copyright (C) 2021 metux IT consult + * Enrico Weigelt, metux IT consult <info@metux.net> + * + * Copyright (C) 2021 Linaro. + * Viresh Kumar <viresh.kumar@linaro.org> + */ + +#include <linux/completion.h> +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/virtio_config.h> +#include <uapi/linux/virtio_gpio.h> +#include <uapi/linux/virtio_ids.h> + +struct virtio_gpio { + struct virtio_device *vdev; + struct mutex lock; + struct gpio_chip gc; + + struct completion completion; + struct virtqueue *command_vq; + struct virtio_gpio_request creq; + struct virtio_gpio_response cres; + + /* This must be kept as the last entry here, hint: gpio_names[0] */ + struct virtio_gpio_config config; +}; + +#define gpio_chip_to_vgpio(chip) container_of(chip, struct virtio_gpio, gc) + +static int virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, + u8 txdata, u8 *rxdata) +{ + struct virtio_gpio_response *res = &vgpio->cres; + struct virtio_gpio_request *req = &vgpio->creq; + struct scatterlist *sgs[2], req_sg, res_sg; + struct device *dev = &vgpio->vdev->dev; + unsigned long time_left; + unsigned int len; + int ret; + + req->type = cpu_to_le16(type); + req->gpio = cpu_to_le16(gpio); + req->data = txdata; + + sg_init_one(&req_sg, req, sizeof(*req)); + sg_init_one(&res_sg, res, sizeof(*res)); + sgs[0] = &req_sg; + sgs[1] = &res_sg; + + mutex_lock(&vgpio->lock); + ret = virtqueue_add_sgs(vgpio->command_vq, sgs, 1, 1, res, GFP_KERNEL); + if (ret) { + dev_err(dev, "failed to add request to vq\n"); + goto out; + } + + reinit_completion(&vgpio->completion); + virtqueue_kick(vgpio->command_vq); + + time_left = wait_for_completion_timeout(&vgpio->completion, HZ / 10); + if (!time_left) { + dev_err(dev, "virtio GPIO backend timeout\n"); + return -ETIMEDOUT; + } + + WARN_ON(res != virtqueue_get_buf(vgpio->command_vq, &len)); + if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) { + dev_err(dev, "virtio GPIO request failed: %d\n", gpio); + return -EINVAL; + } + + if (rxdata) + *rxdata = res->data; + +out: + mutex_unlock(&vgpio->lock); + + return ret; +} + +static int virtio_gpio_request(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + + return virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_ACTIVATE, gpio, 0, NULL); +} + +static void virtio_gpio_free(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + + virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_DEACTIVATE, gpio, 0, NULL); +} + +static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + u8 direction; + int ret; + + ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_GET_DIRECTION, gpio, 0, + &direction); + if (ret) + return ret; + + return direction; +} + +static int virtio_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + + return virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_DIRECTION_IN, gpio, 0, + NULL); +} + +static int virtio_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio, + int value) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + + return virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_DIRECTION_OUT, gpio, (u8) + value, NULL); +} + +static int virtio_gpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + u8 value; + int ret; + + ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_GET_VALUE, gpio, 0, &value); + if (ret) + return ret; + + return value; +} + +static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value) +{ + struct virtio_gpio *vgpio = gpio_chip_to_vgpio(gc); + + virtio_gpio_req(vgpio, VIRTIO_GPIO_REQ_SET_VALUE, gpio, value, NULL); +} + +static void virtio_gpio_command(struct virtqueue *vq) +{ + struct virtio_gpio *vgpio = vq->vdev->priv; + + complete(&vgpio->completion); +} + +static int virtio_gpio_alloc_vqs(struct virtio_device *vdev) +{ + struct virtio_gpio *vgpio = vdev->priv; + const char * const names[] = { "command" }; + vq_callback_t *cbs[] = { + virtio_gpio_command, + }; + struct virtqueue *vqs[1] = {NULL}; + int ret; + + ret = virtio_find_vqs(vdev, 1, vqs, cbs, names, NULL); + if (ret) { + dev_err(&vdev->dev, "failed to allocate vqs: %d\n", ret); + return ret; + } + + vgpio->command_vq = vqs[0]; + + /* Mark the device ready to perform operations from within probe() */ + virtio_device_ready(vgpio->vdev); + return 0; +} + +static void virtio_gpio_free_vqs(struct virtio_device *vdev) +{ + vdev->config->reset(vdev); + vdev->config->del_vqs(vdev); +} + +static const char **parse_gpio_names(struct virtio_device *vdev, + struct virtio_gpio_config *config) +{ + struct device *dev = &vdev->dev; + char *str = config->gpio_names; + const char **names; + int i, len; + + if (!config->gpio_names_size) + return NULL; + + names = devm_kcalloc(dev, config->ngpio, sizeof(names), GFP_KERNEL); + if (!names) + return ERR_PTR(-ENOMEM); + + /* NULL terminate the string instead of checking it */ + config->gpio_names[config->gpio_names_size - 1] = '\0'; + + for (i = 0; i < config->ngpio; i++) { + /* + * We have already marked the last byte with '\0' + * earlier, this shall be enough here. + */ + if (str == config->gpio_names + config->gpio_names_size) { + dev_err(dev, "Invalid gpio_names\n"); + return ERR_PTR(-EINVAL); + } + + len = strlen(str); + if (!len) { + dev_err(dev, "Missing GPIO name: %d\n", i); + return ERR_PTR(-EINVAL); + } + + names[i] = str; + str += len + 1; + } + + 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 size; + int ret; + + virtio_cread(vdev, struct virtio_gpio_config, gpio_names_size, &size); + size = cpu_to_le32(size); + + vgpio = devm_kzalloc(dev, sizeof(*vgpio) + size, GFP_KERNEL); + if (!vgpio) + return -ENOMEM; + + config = &vgpio->config; + + /* Read configuration */ + virtio_cread_bytes(vdev, 0, config, sizeof(*config) + size); + + /* NULL terminate the string instead of checking it */ + config->name[sizeof(config->name) - 1] = '\0'; + config->ngpio = cpu_to_le16(config->ngpio); + config->gpio_names_size = cpu_to_le32(config->gpio_names_size); + + if (!config->ngpio) { + dev_err(dev, "Number of GPIOs can't be zero\n"); + return -EINVAL; + } + + vgpio->vdev = vdev; + vgpio->gc.request = virtio_gpio_request; + 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 = config->ngpio; + vgpio->gc.base = -1; /* Allocate base dynamically */ + vgpio->gc.label = config->name[0] ? + config->name : dev_name(dev); + vgpio->gc.parent = dev; + vgpio->gc.owner = THIS_MODULE; + vgpio->gc.can_sleep = true; + vgpio->gc.names = parse_gpio_names(vdev, config); + if (IS_ERR(vgpio->gc.names)) + return PTR_ERR(vgpio->gc.names); + + vdev->priv = vgpio; + mutex_init(&vgpio->lock); + init_completion(&vgpio->completion); + + ret = virtio_gpio_alloc_vqs(vdev); + if (ret) + return ret; + + ret = gpiochip_add(&vgpio->gc); + 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 struct virtio_driver virtio_gpio_driver = { + .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"); diff --git a/include/uapi/linux/virtio_gpio.h b/include/uapi/linux/virtio_gpio.h new file mode 100644 index 000000000000..e805e33a79cb --- /dev/null +++ b/include/uapi/linux/virtio_gpio.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef _LINUX_VIRTIO_GPIO_H +#define _LINUX_VIRTIO_GPIO_H + +#include <linux/types.h> + +/* Virtio GPIO request types */ +#define VIRTIO_GPIO_REQ_ACTIVATE 0x01 +#define VIRTIO_GPIO_REQ_DEACTIVATE 0x02 +#define VIRTIO_GPIO_REQ_GET_DIRECTION 0x03 +#define VIRTIO_GPIO_REQ_DIRECTION_IN 0x04 +#define VIRTIO_GPIO_REQ_DIRECTION_OUT 0x05 +#define VIRTIO_GPIO_REQ_GET_VALUE 0x06 +#define VIRTIO_GPIO_REQ_SET_VALUE 0x07 + +/* Possible values of the status field */ +#define VIRTIO_GPIO_STATUS_OK 0x0 +#define VIRTIO_GPIO_STATUS_ERR 0x1 + +struct virtio_gpio_config { + char name[32]; + __u16 ngpio; + __u16 padding; + __u32 gpio_names_size; + char gpio_names[0]; +} __packed; + +/* Virtio GPIO Request / Response */ +struct virtio_gpio_request { + __u16 type; + __u16 gpio; + __u8 data; +}; + +struct virtio_gpio_response { + __u8 status; + __u8 data; +}; + +#endif /* _LINUX_VIRTIO_GPIO_H */ diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h index b89391dff6c9..0c24e8ae2499 100644 --- a/include/uapi/linux/virtio_ids.h +++ b/include/uapi/linux/virtio_ids.h @@ -55,5 +55,6 @@ #define VIRTIO_ID_PMEM 27 /* virtio pmem */ #define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */ #define VIRTIO_ID_I2C_ADAPTER 34 /* virtio i2c adapter */ +#define VIRTIO_ID_GPIO 41 /* virtio GPIO */ #endif /* _LINUX_VIRTIO_IDS_H */

[V3,1/3] gpio: Add virtio-gpio driver

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