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[23.128.96.18]) by mx.google.com with ESMTP id y14si2275972ilb.66.2021.08.10.03.25.32; Tue, 10 Aug 2021 03:25:32 -0700 (PDT) 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; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=E7tQ4RfS; spf=pass (google.com: domain of linux-gpio-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-gpio-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231650AbhHJKZx (ORCPT + 3 others); Tue, 10 Aug 2021 06:25:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231247AbhHJKZw (ORCPT ); Tue, 10 Aug 2021 06:25:52 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07CC9C0613D3 for ; Tue, 10 Aug 2021 03:25:31 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id b7so557062plh.7 for ; Tue, 10 Aug 2021 03:25:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=SJNs1y0sMMvih2QgKCIls+eEidULg1+VeluUs6F/Dy0=; b=E7tQ4RfSXuwRKRy9mgGufaBEvtvlp6gFQ8WPhkrmoVkRHLMO8j4256bbGpmG5UCAk4 Hn8nBg7qD/cSMul+xED3lvdkX+Jl4ZcvLGO/qK8tTdsYct7Tp1Dv0J0ZfcoS44LO4I// DU0cFRIQneVwMiu+vbsrlxB3gXwMxctXfcsJBFXaq/LJhOe9TQnm7W1lHCXy3evX8rRS 519MvyFTffhM6vp9Td+FS1k9hEGT5mTVmpLDZg7e14epLWEKhIKLKEL/l943nyQxvL06 5dum27mourdJrS9TEjUXKOtuCkb5AN7fnWSVv2Pcq1YZ+mNVvsqT3IIDEm+CEaCFU2Cn pPwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=SJNs1y0sMMvih2QgKCIls+eEidULg1+VeluUs6F/Dy0=; b=PLcJDsY2G3AqxQJ8vP92JzpPCFOYWdg5YVe6cE+KSxqaxE9mMNpYYPlQ0C8ecxZqr7 ZdXeywFB5DWF8jgYmgX7gGMPAtJgjzEnoVgzMpUzzNojallunrNNqs6CmWMM8PAKQ4B6 hLEOLxOYbevvDI7rEHOgH8AKi8K/z9ZL+Vv8e0uPLyk33Xqh6I2j4pJyodBw9HuqG3a0 r7Sn/L2KJr68lVICKSvx9HlvjYDijmLsTZBTgeJEHUFmN4ejvNK56vsc22frsIhkX70V TCQ8eqU67h3mffUyz1gns4ah06GOGSq/9MXDSzD/q91fHvMWlt1I19yCdUWp0DRuMsYm fhWg== X-Gm-Message-State: AOAM5303YjQ1Ho1BmeigVwai54fNROlb3R03O6Koytitsx/GZh7HHebP HIUcZ6xzncQwff3ncJmMZiUo/w== X-Received: by 2002:a65:63c2:: with SMTP id n2mr91182pgv.292.1628591130506; Tue, 10 Aug 2021 03:25:30 -0700 (PDT) Received: from localhost ([122.172.201.85]) by smtp.gmail.com with ESMTPSA id k197sm2143426pfd.190.2021.08.10.03.25.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Aug 2021 03:25:29 -0700 (PDT) From: Viresh Kumar To: Arnd Bergmann , Linus Walleij , Bartosz Golaszewski , "Enrico Weigelt, metux IT consult" , Viresh Kumar , "Michael S. Tsirkin" , Jason Wang Cc: Viresh Kumar , Vincent Guittot , Jean-Philippe Brucker , Bill Mills , =?utf-8?q?Alex_Benn=C3=A9e?= , Cornelia Huck , Geert Uytterhoeven , stratos-dev@op-lists.linaro.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Marc Zyngier , linux-gpio@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH V5 1/2] gpio: Add virtio-gpio driver Date: Tue, 10 Aug 2021 15:55:15 +0530 Message-Id: X-Mailer: git-send-email 2.31.1.272.g89b43f80a514 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org This patch adds a new driver for Virtio based GPIO devices. This allows a guest VM running Linux to access GPIO lines provided by the host. It supports all basic operations, except interrupts for the GPIO lines. Based on the initial work posted by: "Enrico Weigelt, metux IT consult" . Signed-off-by: Viresh Kumar --- Enrico, lemme know if you want me to add your co-developed by and signed-off-by. Didn't want to add without checking with you first. --- MAINTAINERS | 7 + drivers/gpio/Kconfig | 9 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-virtio.c | 375 +++++++++++++++++++++++++++++++ include/uapi/linux/virtio_gpio.h | 47 ++++ 5 files changed, 439 insertions(+) create mode 100644 drivers/gpio/gpio-virtio.c create mode 100644 include/uapi/linux/virtio_gpio.h -- 2.31.1.272.g89b43f80a514 Reviewed-by: Linus Walleij diff --git a/MAINTAINERS b/MAINTAINERS index a61f4f3b78a9..f632acd7d98c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19647,6 +19647,13 @@ F: Documentation/filesystems/virtiofs.rst F: fs/fuse/virtio_fs.c F: include/uapi/linux/virtio_fs.h +VIRTIO GPIO DRIVER +M: Enrico Weigelt, metux IT consult +M: Viresh Kumar +S: Maintained +F: drivers/gpio/gpio-virtio.c +F: include/uapi/linux/virtio_gpio.h + VIRTIO GPU DRIVER M: David Airlie M: Gerd Hoffmann diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index fab571016adf..e5993d6864fb 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1669,6 +1669,15 @@ 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 32a32659866a..e0301cfedd8d 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -165,6 +165,7 @@ 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..4dc2d383508f --- /dev/null +++ b/drivers/gpio/gpio-virtio.c @@ -0,0 +1,375 @@ +// 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 + * + * Copyright (C) 2021 Linaro. + * Viresh Kumar + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct virtio_gpio_line { + struct mutex lock; /* Protects line operation */ + struct completion completion; + struct virtio_gpio_request req ____cacheline_aligned; + struct virtio_gpio_response res ____cacheline_aligned; + unsigned int rxlen; +}; + +struct virtio_gpio { + struct virtio_device *vdev; + struct mutex lock; /* Protects virtqueue operation */ + struct gpio_chip gc; + struct virtio_gpio_config config; + struct virtio_gpio_line *lines; + struct virtqueue *request_vq; +}; + +static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, + u8 txvalue, u8 *rxvalue, void *response, u32 rxlen) +{ + struct virtio_gpio_line *line = &vgpio->lines[gpio]; + struct virtio_gpio_request *req = &line->req; + struct virtio_gpio_response *res = response; + struct scatterlist *sgs[2], req_sg, res_sg; + struct device *dev = &vgpio->vdev->dev; + int ret; + + /* + * Prevent concurrent requests for the same line since we have + * pre-allocated request/response buffers for each GPIO line. Moreover + * Linux always accesses a GPIO line sequentially, so this locking shall + * always go through without any delays. + */ + mutex_lock(&line->lock); + + req->type = cpu_to_le16(type); + req->gpio = cpu_to_le16(gpio); + req->value = txvalue; + + sg_init_one(&req_sg, req, sizeof(*req)); + sg_init_one(&res_sg, res, rxlen); + sgs[0] = &req_sg; + sgs[1] = &res_sg; + + line->rxlen = 0; + reinit_completion(&line->completion); + + /* + * Virtqueue callers need to ensure they don't call its APIs with other + * virtqueue operations at the same time. + */ + mutex_lock(&vgpio->lock); + ret = virtqueue_add_sgs(vgpio->request_vq, sgs, 1, 1, line, GFP_KERNEL); + if (ret) { + dev_err(dev, "failed to add request to vq\n"); + mutex_unlock(&vgpio->lock); + goto out; + } + + virtqueue_kick(vgpio->request_vq); + mutex_unlock(&vgpio->lock); + + if (!wait_for_completion_timeout(&line->completion, HZ)) { + dev_err(dev, "GPIO operation timed out\n"); + ret = -ETIMEDOUT; + goto out; + } + + if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) { + dev_err(dev, "GPIO request failed: %d\n", gpio); + ret = -EINVAL; + goto out; + } + + if (unlikely(line->rxlen != rxlen)) { + dev_err(dev, "GPIO operation returned incorrect len (%u : %u)\n", + rxlen, line->rxlen); + ret = -EINVAL; + goto out; + } + + if (rxvalue) + *rxvalue = res->value; + +out: + mutex_unlock(&line->lock); + return ret; +} + +static int virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, + u8 txvalue, u8 *rxvalue) +{ + struct virtio_gpio_line *line = &vgpio->lines[gpio]; + struct virtio_gpio_response *res = &line->res; + + return _virtio_gpio_req(vgpio, type, gpio, txvalue, rxvalue, res, + sizeof(*res)); +} + +static void virtio_gpio_free(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + + virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, + VIRTIO_GPIO_DIRECTION_NONE, NULL); +} + +static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + u8 direction; + int ret; + + ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_DIRECTION, gpio, 0, + &direction); + if (ret) + return ret; + + switch (direction) { + case VIRTIO_GPIO_DIRECTION_IN: + return GPIO_LINE_DIRECTION_IN; + case VIRTIO_GPIO_DIRECTION_OUT: + return GPIO_LINE_DIRECTION_OUT; + default: + return -EINVAL; + } +} + +static int virtio_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + + return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, + VIRTIO_GPIO_DIRECTION_IN, NULL); +} + +static int virtio_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio, + int value) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + int ret; + + ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL); + if (ret) + return ret; + + return virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_DIRECTION, gpio, + VIRTIO_GPIO_DIRECTION_OUT, NULL); +} + +static int virtio_gpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + u8 value; + int ret; + + ret = virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_GET_VALUE, gpio, 0, &value); + return ret ? ret : value; +} + +static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value) +{ + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + + virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL); +} + +static void virtio_gpio_request_vq(struct virtqueue *vq) +{ + struct virtio_gpio_line *line; + unsigned int len; + + do { + line = virtqueue_get_buf(vq, &len); + if (!line) + return; + + line->rxlen = len; + complete(&line->completion); + } while (1); +} + +static void virtio_gpio_free_vqs(struct virtio_device *vdev) +{ + vdev->config->reset(vdev); + vdev->config->del_vqs(vdev); +} + +static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio, + struct virtio_device *vdev) +{ + const char * const names[] = { "requestq" }; + vq_callback_t *cbs[] = { + virtio_gpio_request_vq, + }; + 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 find vqs: %d\n", ret); + return ret; + } + + if (!vqs[0]) { + dev_err(&vdev->dev, "failed to find requestq vq\n"); + return -ENODEV; + } + vgpio->request_vq = vqs[0]; + + return 0; +} + +static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio) +{ + struct virtio_gpio_config *config = &vgpio->config; + 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 (!config->gpio_names_size) + return NULL; + + len = sizeof(*res) + config->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, config->ngpio, sizeof(names), GFP_KERNEL); + if (!names) + return NULL; + + /* NULL terminate the string instead of checking it */ + gpio_names[config->gpio_names_size - 1] = '\0'; + + for (i = 0, str = gpio_names; i < config->ngpio; i++) { + names[i] = str; + str += strlen(str) + 1; /* zero-length strings are allowed */ + + if (str > gpio_names + config->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; + int ret, i; + + vgpio = devm_kzalloc(dev, sizeof(*vgpio), GFP_KERNEL); + if (!vgpio) + return -ENOMEM; + + config = &vgpio->config; + + /* Read configuration */ + virtio_cread_bytes(vdev, 0, config, sizeof(*config)); + config->gpio_names_size = le32_to_cpu(config->gpio_names_size); + config->ngpio = le16_to_cpu(config->ngpio); + if (!config->ngpio) { + dev_err(dev, "Number of GPIOs can't be zero\n"); + return -EINVAL; + } + + vgpio->lines = devm_kcalloc(dev, config->ngpio, sizeof(*vgpio->lines), GFP_KERNEL); + if (!vgpio->lines) + return -ENOMEM; + + for (i = 0; i < config->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 = config->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; + + 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); + + 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 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 "); +MODULE_AUTHOR("Viresh Kumar "); +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..844574acf095 --- /dev/null +++ b/include/uapi/linux/virtio_gpio.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef _LINUX_VIRTIO_GPIO_H +#define _LINUX_VIRTIO_GPIO_H + +#include + +/* 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 + +/* Possible values of the status field */ +#define VIRTIO_GPIO_STATUS_OK 0x0 +#define VIRTIO_GPIO_STATUS_ERR 0x1 + +/* Direction types */ +#define VIRTIO_GPIO_DIRECTION_NONE 0x00 +#define VIRTIO_GPIO_DIRECTION_OUT 0x01 +#define VIRTIO_GPIO_DIRECTION_IN 0x02 + +struct virtio_gpio_config { + __u16 ngpio; + __u8 padding[2]; + __u32 gpio_names_size; +} __packed; + +/* Virtio GPIO Request / Response */ +struct virtio_gpio_request { + __u16 type; + __u16 gpio; + __u32 value; +}; + +struct virtio_gpio_response { + __u8 status; + __u8 value; +}; + +struct virtio_gpio_response_get_names { + __u8 status; + __u8 value[]; +}; + +#endif /* _LINUX_VIRTIO_GPIO_H */