From patchwork Wed Oct 20 10:05:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 1543786 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=ek5PVsQp; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-gpio-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4HZ5rF4xzYz9sRR for ; Wed, 20 Oct 2021 21:07:09 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229900AbhJTKJV (ORCPT ); Wed, 20 Oct 2021 06:09:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbhJTKJV (ORCPT ); Wed, 20 Oct 2021 06:09:21 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A28FC061746 for ; Wed, 20 Oct 2021 03:07:07 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id b14so5990627plg.2 for ; Wed, 20 Oct 2021 03:07:07 -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:mime-version :content-transfer-encoding; bh=qJTZVvtzAveh2/17wfWFP1VGPuwFuEInL0+6uPcrxao=; b=ek5PVsQpZxv9uKoA1+RBbTzBQn5MOswMkGSzTyvKYw5qzujmG/G3tF4y0hrKFrsk70 95lC53XmU8M7s2f5S85WNPBlXSCR0Q4zyezDMvj7ysjgEqqlC6rNNb/0SpfieGZnl4RR CNC2ktSwd8dKwAQKwzdsmme4muwyEpUOp8cTZ2zO33DzLp4izdIJgHs3ZqDHvjd0kFi+ XGQP+JvluTi2LV3S+qyQmbBtzPCJzGzNMr4dJesp1HgNrKsiBL91Eelzmc2dZOGGKNs0 M3nox/vsj+NyVfysCrnFktGLW6jx1jZo3+OW6f7eFoZSgl7OPj5vPPvGfsiNoKnEGLDP MKnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=qJTZVvtzAveh2/17wfWFP1VGPuwFuEInL0+6uPcrxao=; b=KcB5TWFHT3iR03paA7iBAmP7JfWxoa+9XmLme4GzBJE3DfCfEGN2tSTC312EF8c+kv r/X8LZAgjatQccuEqrlI1wFKjxBQyyAnyhF0yvjm9M8xapTIiwudhObcxNeMGmpAdKa9 y8I5Gg033+AHJhBxgJCfIEJmSzrdTce1YLnZjjgLcK57NobsdGfIa92CDbfLfUuZgaci fw0L5FZInFoywDxCUZRsyb5yQdPYNhUCe62uptQGoPf3mLHJwjDmfj5XIbd9ayKGkv/J e1eVvVoygBqDxmRw9gORqQqb88WJ3u7Ejs5sBSqDGvsDiu9Nce/CX3p1IM/BaVNq9ML1 rKgw== X-Gm-Message-State: AOAM531iNtW4qRFjGVG0kQ/9fxG86lMd2wf4Z91omRm4Qi8NoWeuYZqh sgHE3UEYWjG6s4cWedwuyW1jtw== X-Google-Smtp-Source: ABdhPJyfr6JCzZc65P7PMVGRHJUxRrglESOvRZ1p0kR9TZtDnle5UERh2fU+D/T2Z/28Ejt+eih5Gg== X-Received: by 2002:a17:90a:f488:: with SMTP id bx8mr6313520pjb.86.1634724426556; Wed, 20 Oct 2021 03:07:06 -0700 (PDT) Received: from localhost ([106.201.113.61]) by smtp.gmail.com with ESMTPSA id i15sm1976880pfq.21.2021.10.20.03.07.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Oct 2021 03:07:06 -0700 (PDT) From: Viresh Kumar To: Arnd Bergmann , Linus Walleij , Bartosz Golaszewski , 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, Marc Zyngier , linux-gpio@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH V6] gpio: virtio: Add IRQ support Date: Wed, 20 Oct 2021 15:35:58 +0530 Message-Id: <8ca87330fd348fc5199ad08904ec90cc6a91a1bf.1634723848.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 2.31.1.272.g89b43f80a514 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org This patch adds IRQ support for the virtio GPIO driver. Note that this uses the irq_bus_lock/unlock() callbacks, since those operations over virtio may sleep. Reviewed-by: Linus Walleij Signed-off-by: Viresh Kumar --- Bartosz, The spec changes are close to merging now, I will let you know once the ballot is closed and the spec changes are merged. You can then pick this patch for 5.16. V5->V6: - Sent it separately as the other patches are already merged. - Queue the buffers only after enabling the irq (as per latest spec). - Migrate to raw_spinlock_t. drivers/gpio/Kconfig | 1 + drivers/gpio/gpio-virtio.c | 310 ++++++++++++++++++++++++++++++- include/uapi/linux/virtio_gpio.h | 25 +++ 3 files changed, 332 insertions(+), 4 deletions(-) diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index fae5141251e5..bfa723ff8e7c 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1674,6 +1674,7 @@ config GPIO_MOCKUP config GPIO_VIRTIO tristate "VirtIO GPIO support" depends on VIRTIO + select GPIOLIB_IRQCHIP help Say Y here to enable guest support for virtio-based GPIO controllers. diff --git a/drivers/gpio/gpio-virtio.c b/drivers/gpio/gpio-virtio.c index d24f1c9264bc..73fbe2eda4b9 100644 --- a/drivers/gpio/gpio-virtio.c +++ b/drivers/gpio/gpio-virtio.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -28,12 +29,30 @@ struct virtio_gpio_line { unsigned int rxlen; }; +struct vgpio_irq_line { + u8 type; + bool disabled; + bool masked; + bool queued; + bool update_pending; + bool queue_pending; + + struct virtio_gpio_irq_request ireq ____cacheline_aligned; + struct virtio_gpio_irq_response ires ____cacheline_aligned; +}; + struct virtio_gpio { struct virtio_device *vdev; struct mutex lock; /* Protects virtqueue operation */ struct gpio_chip gc; struct virtio_gpio_line *lines; struct virtqueue *request_vq; + + /* irq support */ + struct virtqueue *event_vq; + struct mutex irq_lock; /* Protects irq operation */ + raw_spinlock_t eventq_lock; /* Protects queuing of the buffer */ + struct vgpio_irq_line *irq_lines; }; static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio, @@ -186,6 +205,244 @@ static void virtio_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value) virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_SET_VALUE, gpio, value, NULL); } +/* Interrupt handling */ +static void virtio_gpio_irq_prepare(struct virtio_gpio *vgpio, u16 gpio) +{ + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[gpio]; + struct virtio_gpio_irq_request *ireq = &irq_line->ireq; + struct virtio_gpio_irq_response *ires = &irq_line->ires; + struct scatterlist *sgs[2], req_sg, res_sg; + int ret; + + if (WARN_ON(irq_line->queued || irq_line->masked || irq_line->disabled)) + return; + + ireq->gpio = cpu_to_le16(gpio); + sg_init_one(&req_sg, ireq, sizeof(*ireq)); + sg_init_one(&res_sg, ires, sizeof(*ires)); + sgs[0] = &req_sg; + sgs[1] = &res_sg; + + ret = virtqueue_add_sgs(vgpio->event_vq, sgs, 1, 1, irq_line, GFP_ATOMIC); + if (ret) { + dev_err(&vgpio->vdev->dev, "failed to add request to eventq\n"); + return; + } + + irq_line->queued = true; + virtqueue_kick(vgpio->event_vq); +} + +static void virtio_gpio_irq_enable(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + + raw_spin_lock(&vgpio->eventq_lock); + irq_line->disabled = false; + irq_line->masked = false; + irq_line->queue_pending = true; + raw_spin_unlock(&vgpio->eventq_lock); + + irq_line->update_pending = true; +} + +static void virtio_gpio_irq_disable(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + + raw_spin_lock(&vgpio->eventq_lock); + irq_line->disabled = true; + irq_line->masked = true; + irq_line->queue_pending = false; + raw_spin_unlock(&vgpio->eventq_lock); + + irq_line->update_pending = true; +} + +static void virtio_gpio_irq_mask(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + + raw_spin_lock(&vgpio->eventq_lock); + irq_line->masked = true; + raw_spin_unlock(&vgpio->eventq_lock); +} + +static void virtio_gpio_irq_unmask(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + + raw_spin_lock(&vgpio->eventq_lock); + irq_line->masked = false; + + /* Queue the buffer unconditionally on unmask */ + virtio_gpio_irq_prepare(vgpio, d->hwirq); + raw_spin_unlock(&vgpio->eventq_lock); +} + +static int virtio_gpio_irq_set_type(struct irq_data *d, unsigned int type) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + + switch (type) { + case IRQ_TYPE_NONE: + type = VIRTIO_GPIO_IRQ_TYPE_NONE; + break; + case IRQ_TYPE_EDGE_RISING: + type = VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING; + break; + case IRQ_TYPE_EDGE_FALLING: + type = VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING; + break; + case IRQ_TYPE_EDGE_BOTH: + type = VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH; + break; + case IRQ_TYPE_LEVEL_LOW: + type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW; + break; + case IRQ_TYPE_LEVEL_HIGH: + type = VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH; + break; + default: + dev_err(&vgpio->vdev->dev, "unsupported irq type: %u\n", type); + return -EINVAL; + } + + irq_line->type = type; + irq_line->update_pending = true; + + return 0; +} + +static void virtio_gpio_irq_bus_lock(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + + mutex_lock(&vgpio->irq_lock); +} + +static void virtio_gpio_irq_bus_sync_unlock(struct irq_data *d) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(d); + struct virtio_gpio *vgpio = gpiochip_get_data(gc); + struct vgpio_irq_line *irq_line = &vgpio->irq_lines[d->hwirq]; + u8 type = irq_line->disabled ? VIRTIO_GPIO_IRQ_TYPE_NONE : irq_line->type; + unsigned long flags; + + if (irq_line->update_pending) { + irq_line->update_pending = false; + virtio_gpio_req(vgpio, VIRTIO_GPIO_MSG_IRQ_TYPE, d->hwirq, type, + NULL); + + /* Queue the buffer only after interrupt is enabled */ + raw_spin_lock_irqsave(&vgpio->eventq_lock, flags); + if (irq_line->queue_pending) { + irq_line->queue_pending = false; + virtio_gpio_irq_prepare(vgpio, d->hwirq); + } + raw_spin_unlock_irqrestore(&vgpio->eventq_lock, flags); + } + + mutex_unlock(&vgpio->irq_lock); +} + +static struct irq_chip vgpio_irq_chip = { + .name = "virtio-gpio", + .irq_enable = virtio_gpio_irq_enable, + .irq_disable = virtio_gpio_irq_disable, + .irq_mask = virtio_gpio_irq_mask, + .irq_unmask = virtio_gpio_irq_unmask, + .irq_set_type = virtio_gpio_irq_set_type, + + /* These are required to implement irqchip for slow busses */ + .irq_bus_lock = virtio_gpio_irq_bus_lock, + .irq_bus_sync_unlock = virtio_gpio_irq_bus_sync_unlock, +}; + +static bool ignore_irq(struct virtio_gpio *vgpio, int gpio, + struct vgpio_irq_line *irq_line) +{ + bool ignore = false; + + raw_spin_lock(&vgpio->eventq_lock); + irq_line->queued = false; + + /* Interrupt is disabled currently */ + if (irq_line->masked || irq_line->disabled) { + ignore = true; + goto unlock; + } + + /* + * Buffer is returned as the interrupt was disabled earlier, but is + * enabled again now. Requeue the buffers. + */ + if (irq_line->ires.status == VIRTIO_GPIO_IRQ_STATUS_INVALID) { + virtio_gpio_irq_prepare(vgpio, gpio); + ignore = true; + goto unlock; + } + + if (WARN_ON(irq_line->ires.status != VIRTIO_GPIO_IRQ_STATUS_VALID)) + ignore = true; + +unlock: + raw_spin_unlock(&vgpio->eventq_lock); + + return ignore; +} + +static void virtio_gpio_event_vq(struct virtqueue *vq) +{ + struct virtio_gpio *vgpio = vq->vdev->priv; + struct device *dev = &vgpio->vdev->dev; + struct vgpio_irq_line *irq_line; + int irq, gpio, ret; + unsigned int len; + + while (true) { + irq_line = virtqueue_get_buf(vgpio->event_vq, &len); + if (!irq_line) + break; + + if (len != sizeof(irq_line->ires)) { + dev_err(dev, "irq with incorrect length (%u : %u)\n", + len, (unsigned int)sizeof(irq_line->ires)); + continue; + } + + /* + * Find GPIO line number from the offset of irq_line within the + * irq_lines block. We can also get GPIO number from + * irq-request, but better not to rely on a buffer returned by + * remote. + */ + gpio = irq_line - vgpio->irq_lines; + WARN_ON(gpio >= vgpio->gc.ngpio); + + if (unlikely(ignore_irq(vgpio, gpio, irq_line))) + continue; + + irq = irq_find_mapping(vgpio->gc.irq.domain, gpio); + WARN_ON(!irq); + + ret = generic_handle_irq(irq); + if (ret) + dev_err(dev, "failed to handle interrupt: %d\n", ret); + }; +} + static void virtio_gpio_request_vq(struct virtqueue *vq) { struct virtio_gpio_line *line; @@ -210,14 +467,15 @@ static void virtio_gpio_free_vqs(struct virtio_device *vdev) static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio, struct virtio_device *vdev) { - const char * const names[] = { "requestq" }; + const char * const names[] = { "requestq", "eventq" }; vq_callback_t *cbs[] = { virtio_gpio_request_vq, + virtio_gpio_event_vq, }; - struct virtqueue *vqs[1] = { NULL }; + struct virtqueue *vqs[2] = { NULL, NULL }; int ret; - ret = virtio_find_vqs(vdev, 1, vqs, cbs, names, NULL); + ret = virtio_find_vqs(vdev, vgpio->irq_lines ? 2 : 1, vqs, cbs, names, NULL); if (ret) { dev_err(&vdev->dev, "failed to find vqs: %d\n", ret); return ret; @@ -225,11 +483,23 @@ static int virtio_gpio_alloc_vqs(struct virtio_gpio *vgpio, if (!vqs[0]) { dev_err(&vdev->dev, "failed to find requestq vq\n"); - return -ENODEV; + goto out; } vgpio->request_vq = vqs[0]; + if (vgpio->irq_lines && !vqs[1]) { + dev_err(&vdev->dev, "failed to find eventq vq\n"); + goto out; + } + vgpio->event_vq = vqs[1]; + return 0; + +out: + if (vqs[0] || vqs[1]) + virtio_gpio_free_vqs(vdev); + + return -ENODEV; } static const char **virtio_gpio_get_names(struct virtio_gpio *vgpio, @@ -325,6 +595,32 @@ static int virtio_gpio_probe(struct virtio_device *vdev) vgpio->gc.owner = THIS_MODULE; vgpio->gc.can_sleep = true; + /* Interrupt support */ + if (virtio_has_feature(vdev, VIRTIO_GPIO_F_IRQ)) { + vgpio->irq_lines = devm_kcalloc(dev, ngpio, + sizeof(*vgpio->irq_lines), + GFP_KERNEL); + if (!vgpio->irq_lines) + return -ENOMEM; + + /* The event comes from the outside so no parent handler */ + vgpio->gc.irq.parent_handler = NULL; + vgpio->gc.irq.num_parents = 0; + vgpio->gc.irq.parents = NULL; + vgpio->gc.irq.default_type = IRQ_TYPE_NONE; + vgpio->gc.irq.handler = handle_level_irq; + vgpio->gc.irq.chip = &vgpio_irq_chip; + + for (i = 0; i < ngpio; i++) { + vgpio->irq_lines[i].type = VIRTIO_GPIO_IRQ_TYPE_NONE; + vgpio->irq_lines[i].disabled = true; + vgpio->irq_lines[i].masked = true; + } + + mutex_init(&vgpio->irq_lock); + raw_spin_lock_init(&vgpio->eventq_lock); + } + ret = virtio_gpio_alloc_vqs(vgpio, vdev); if (ret) return ret; @@ -357,7 +653,13 @@ static const struct virtio_device_id id_table[] = { }; MODULE_DEVICE_TABLE(virtio, id_table); +static const unsigned int features[] = { + VIRTIO_GPIO_F_IRQ, +}; + static struct virtio_driver virtio_gpio_driver = { + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), .id_table = id_table, .probe = virtio_gpio_probe, .remove = virtio_gpio_remove, diff --git a/include/uapi/linux/virtio_gpio.h b/include/uapi/linux/virtio_gpio.h index 0445f905d8cc..d04af9c5f0de 100644 --- a/include/uapi/linux/virtio_gpio.h +++ b/include/uapi/linux/virtio_gpio.h @@ -5,12 +5,16 @@ #include +/* Virtio GPIO Feature bits */ +#define VIRTIO_GPIO_F_IRQ 0 + /* Virtio GPIO request types */ #define VIRTIO_GPIO_MSG_GET_NAMES 0x0001 #define VIRTIO_GPIO_MSG_GET_DIRECTION 0x0002 #define VIRTIO_GPIO_MSG_SET_DIRECTION 0x0003 #define VIRTIO_GPIO_MSG_GET_VALUE 0x0004 #define VIRTIO_GPIO_MSG_SET_VALUE 0x0005 +#define VIRTIO_GPIO_MSG_IRQ_TYPE 0x0006 /* Possible values of the status field */ #define VIRTIO_GPIO_STATUS_OK 0x0 @@ -21,6 +25,14 @@ #define VIRTIO_GPIO_DIRECTION_OUT 0x01 #define VIRTIO_GPIO_DIRECTION_IN 0x02 +/* Virtio GPIO IRQ types */ +#define VIRTIO_GPIO_IRQ_TYPE_NONE 0x00 +#define VIRTIO_GPIO_IRQ_TYPE_EDGE_RISING 0x01 +#define VIRTIO_GPIO_IRQ_TYPE_EDGE_FALLING 0x02 +#define VIRTIO_GPIO_IRQ_TYPE_EDGE_BOTH 0x03 +#define VIRTIO_GPIO_IRQ_TYPE_LEVEL_HIGH 0x04 +#define VIRTIO_GPIO_IRQ_TYPE_LEVEL_LOW 0x08 + struct virtio_gpio_config { __le16 ngpio; __u8 padding[2]; @@ -44,4 +56,17 @@ struct virtio_gpio_response_get_names { __u8 value[]; }; +/* Virtio GPIO IRQ Request / Response */ +struct virtio_gpio_irq_request { + __le16 gpio; +}; + +struct virtio_gpio_irq_response { + __u8 status; +}; + +/* Possible values of the interrupt status field */ +#define VIRTIO_GPIO_IRQ_STATUS_INVALID 0x0 +#define VIRTIO_GPIO_IRQ_STATUS_VALID 0x1 + #endif /* _LINUX_VIRTIO_GPIO_H */