From patchwork Mon Jun 3 15:53:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Gunthorpe X-Patchwork-Id: 13683967 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (mail-bn7nam10on2046.outbound.protection.outlook.com [40.107.92.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C71311369B9; Mon, 3 Jun 2024 15:53:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.92.46 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717430021; cv=fail; b=p66+ky5Zz89DBZO3Hk5dOsXA26hZqWolOOJYdXjW6TUnpShLOoa9ZauDu7/87LxytwCWFbyhTh4VX2JC4d4vrr730bNOYoQkBCcClTWzlk9p55cVN+oouM7+NK9SxHfpvS991pyrpiLM9mMTK4DvcdYTuxNfxK8AivCzeqH+6yw= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717430021; c=relaxed/simple; bh=B/w8Xxl6ahlkPyMmOt3teiLon1egwfwQDSUl7nT3IhM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=JQAh42wCCmaQAySAnurzpcdgKCxxKO3jkzhqFLiAlN/8jSr9aaT3CeURqjDx+61CtcDpbzfAhlaF5F5t32eB07DuG/9YPRswNVFt1pOOhKl8OtA/n9i355ZfQiwSKTapNN77YUY7qC/aueDxPeDaoXNTX8zCOeOYB64GPI8YwH8= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=Ez8a4Gm0; arc=fail smtp.client-ip=40.107.92.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="Ez8a4Gm0" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=K8YjDSsmzUcLX6dz4thHvaXm+ERC1xcRZnSCLHBYbjEL/onGycf08j4jAr/VGM9BJ8Ff8LTVCHhCXAIW45FRf5AeDjU090kqCfagC2//b7i3SMDi6W0BPGhLPKWw+A9TE+vR6gcjuDFjQuYp2wQkkeh5NwFdCuilj8fr2bi7tuYL152Jm+udH+0J4Y38QnnDEAVeRBaNOXAPQmrd0blvMU4f4jzjei4EkI9a2yoBowlcxVuHvPJg+JRAcUcf6czqLLaKkJBXlD0aBfOCZOwd9VseFOqrML3Zl2sIZE4dAu/+4wnUYTbs/NlrrpZOSz0vqLIfFx4Td3GysuDvyT2Y7A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=OXbAZ+GPpPi0It5Sp5wSafN7Ssgy5hSKQTFJVJhh69o=; b=gJWQVlieq+Cp2GNrgoIaGFQSGZubZbbhUKHVoWe8ULBmhnGxcR7vUN1MZ6EazvChyaXFtUPwhUQsUYb0fOpNSu6Nz3OGtT2ss0zjHntZaekbQaKt95xOnEQO71Ccm+ZMHufj+mw9hTS2U9wasBe+8AEnhygvR16mYdo0qt6H6zgnKgW0S71RgvnmJp9OpKhiog5NbhQ/xTBEfYj26dd8lcdyIfWZlbtepHXrdWPO1IRnp3HYuXRuOxYffQNJRowDUfKLHcSqyuif/hYpFtVXbKj5tC1RrRA2JtZgN5xfI3OJcKZ02HK6IqLoB3wcKoHUcQvyzYTuwtpj1cy+pPjsCw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=OXbAZ+GPpPi0It5Sp5wSafN7Ssgy5hSKQTFJVJhh69o=; b=Ez8a4Gm0iTtizx8AtvRkmSUvImq903IpGqmjh9YVVh0OI/4FpJmmww8S4YvcQyHeahm+ebaANPZKkDbiFmc4uhh9EDIzLN2/9Enl/0kLqvAwqTcsSP0gw2U0H42vsX38l0YzXPRS3HDktQKPrESUSgesxK/J3DMKtmXKUwLqQD23N7/CxbX2Lqu2OwxDPgbtND1GWWL2VmVzgM24okJ6NEcgTaA9MY8Y5XIXTJqx20Sv8ThfWxClPmUW81+04d+eU1XdDfpjH6biI/ugVWzHgZ4EB0qdD9Faar69AznKIwHj3yNYAqnfRNT+aTNeWSYjTirbsxdx9qEK//vRzCArsA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM6PR12MB3849.namprd12.prod.outlook.com (2603:10b6:5:1c7::26) by MN0PR12MB6197.namprd12.prod.outlook.com (2603:10b6:208:3c6::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7633.21; Mon, 3 Jun 2024 15:53:32 +0000 Received: from DM6PR12MB3849.namprd12.prod.outlook.com ([fe80::c296:774b:a5fc:965e]) by DM6PR12MB3849.namprd12.prod.outlook.com ([fe80::c296:774b:a5fc:965e%4]) with mapi id 15.20.7633.021; Mon, 3 Jun 2024 15:53:32 +0000 From: Jason Gunthorpe To: Jonathan Corbet , Itay Avraham , Jakub Kicinski , Leon Romanovsky , linux-doc@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Paolo Abeni , Saeed Mahameed , Tariq Toukan Cc: Andy Gospodarek , Aron Silverton , Dan Williams , David Ahern , Christoph Hellwig , Jiri Pirko , Leonid Bloch , Leon Romanovsky , linux-cxl@vger.kernel.org, patches@lists.linux.dev Subject: [PATCH 1/8] fwctl: Add basic structure for a class subsystem with a cdev Date: Mon, 3 Jun 2024 12:53:17 -0300 Message-ID: <1-v1-9912f1a11620+2a-fwctl_jgg@nvidia.com> In-Reply-To: <0-v1-9912f1a11620+2a-fwctl_jgg@nvidia.com> References: X-ClientProxiedBy: YT4PR01CA0121.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:d5::9) To DM6PR12MB3849.namprd12.prod.outlook.com (2603:10b6:5:1c7::26) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6PR12MB3849:EE_|MN0PR12MB6197:EE_ X-MS-Office365-Filtering-Correlation-Id: 859840b4-0825-460b-e86d-08dc83e54fca X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230031|1800799015|7416005|366007|376005|921011; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM6PR12MB3849.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(1800799015)(7416005)(366007)(376005)(921011);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: SHzBHd+hpb6Ku52iVsTWOxLK1rfL4pYwmBce7kESFKxuzBjcLB7JXxThKdqnoVqueCwweILFLVHE3JET6ZuujatIpO/fSVLh1pHb/bcORffz3E5UymSmQt8TwQD0vBhOXoYr0XLQoNIPQWIBT2FGkWUmEieC+nxmMjiUC6dPlU1Q+lFK6Oq9wQGHOYKo43z7iW4ydR2m/CU5U+0qGH62YrX4+1yqZNbJluENI0pa1G6/XQctKkCBK4EYCZS0uYPWqoy9bqfa+GMEIMXepbXMN5+qtfANfAxCo1TMuXbcDsn9H3E59wOumdxlTJKZbnPv3DWFxykLGGl6dwYczNyDIdTGmMr0vDW7Lx/bBsTmB4J10EARjdwMEd41Q4kfFUfAsP5nJO89cv4JsUXcHqkHwbpa5sEZclCqOCDpitF+4OmAxUz+BaxksyP27R7jhUBVXNEsrfLd7ZJQ2S/TQd/1IpWkqKi7gXKuoQOZbJhsTN+n00mm1rEBreO10jMjDyOUj5DRD1dh+9RvRyc0unLRBkPca7E2rv1Uo31ex7EnDQki3vLnJHmmjTU7yOcclH9XIdMULNtD+GFhgAx9YvP2BRnQmGhczvOD8W3M+svjeJMh8jpwOA0oO8/hRDkprFtQ31eR2O3sciF0jECTnnTsOVAUI6hSkcDtOR0+SPamFLI5Cdt7b/zUSz79HqU3ujwX+Tx4C0nB82IHb78piKb74X3KQ2pmTNZPOVNdSUkCYpTvt0PJ3wPEQSAxfBTkw5KjuHS060W57jwWZtETYAPR0qpZn13Ct+dAQ7YXt2C2zdj6x6VN/fefVPDMTUVdKLPvagF/eVp9Y7rfGKa0H0YpGWjk/JbMMLm1xa05QUV7byU0W53MKiMunVZjq6XxVzO90LhQ+uFINHLXcXNg9fP7yVdFzj3kw9KbtY9jq0N4mgbmjRg2A2VIaV6FBsQE531DrSWcVS/dQoXfptn4pZ5giXWntHzD099cnuGh+UkkmjMHRHpbwrLpOYVqal/iHaeaUITABSzpKzsI9sNo8zUuNAKHda5cxR6O66cl0p+AI96+w6yV5Y+HbWB02scHMkavvJCR6j4eG++BJMuxvhAbkAjPuvmOGOtyHbL5ra9w0Kbm9Oew2DgL8mSst+WNfhN7oybG4rDxVYT/1YGk5X7YZg28Edg9Y9CcBezEIq/Z56LdmsKwazBoYR5x8QgAyYFg2dzS/so34i9e4IvUOl0EdFCf+d3/aOECY/vGEGdEc/ahcXSufYjEUf5Ay/VfbE62SrnosJZQgv5W8WVwSavV0I1xGa2mGDiQE3x3T8OUKY+f14dfjnDHt2D3Pk80juc5wo3rbPkIdPsDEfw3hKEACznkj8UI3SSn3+jq4hah34fKZONgKV7jQNE738nEdRYmKhLBJUhaTzRiBNOaPYxfXGZcvlm9LUUlGTGb+xbX8oT7KRfJlY86lOJady2QbKcDm4rqWQ+Rm6u+czcyRFQGkss0CPTmhQb0zuzajwJ5KNXOymjG30sesqNEmD+eu4a60h+5jRMLvFVfOkxf4UTQiTDDBzmgv15JyK5bIDXTtpb0/icbBlEJFfU1lRi9GlYJ X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 859840b4-0825-460b-e86d-08dc83e54fca X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3849.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Jun 2024 15:53:29.4671 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: o3aSmVgjEj5MpSVSCpLqrFHBgJc1HZIQQ0dZg4xF5hqjP5oF5A9g7cIeKCA2Tdpo X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB6197 Create the class, character device and functions for a fwctl driver to un/register to the subsystem. A typical fwctl driver has a sysfs presence like: $ ls -l /dev/fwctl/fwctl0 crw------- 1 root root 250, 0 Apr 25 19:16 /dev/fwctl/fwctl0 $ ls /sys/class/fwctl/fwctl0 dev device power subsystem uevent $ ls /sys/class/fwctl/fwctl0/device/infiniband/ ibp0s10f0 $ ls /sys/class/infiniband/ibp0s10f0/device/fwctl/ fwctl0/ $ ls /sys/devices/pci0000:00/0000:00:0a.0/fwctl/fwctl0 dev device power subsystem uevent Which allows userspace to link all the multi-subsystem driver components together and learn the subsystem specific names for the device's components. Signed-off-by: Jason Gunthorpe --- MAINTAINERS | 8 ++ drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/fwctl/Kconfig | 9 +++ drivers/fwctl/Makefile | 4 + drivers/fwctl/main.c | 174 +++++++++++++++++++++++++++++++++++++++++ include/linux/fwctl.h | 68 ++++++++++++++++ 7 files changed, 266 insertions(+) create mode 100644 drivers/fwctl/Kconfig create mode 100644 drivers/fwctl/Makefile create mode 100644 drivers/fwctl/main.c create mode 100644 include/linux/fwctl.h diff --git a/MAINTAINERS b/MAINTAINERS index 8754ac2c259dc9..833b853808421e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9077,6 +9077,14 @@ F: kernel/futex/* F: tools/perf/bench/futex* F: tools/testing/selftests/futex/ +FWCTL SUBSYSTEM +M: Jason Gunthorpe +M: Saeed Mahameed +S: Maintained +F: Documentation/userspace-api/fwctl.rst +F: drivers/fwctl/ +F: include/linux/fwctl.h + GALAXYCORE GC0308 CAMERA SENSOR DRIVER M: Sebastian Reichel L: linux-media@vger.kernel.org diff --git a/drivers/Kconfig b/drivers/Kconfig index 7bdad836fc6207..7c556c5ac4fddc 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -21,6 +21,8 @@ source "drivers/connector/Kconfig" source "drivers/firmware/Kconfig" +source "drivers/fwctl/Kconfig" + source "drivers/gnss/Kconfig" source "drivers/mtd/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index fe9ceb0d2288ad..f6a241b747b29c 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -133,6 +133,7 @@ obj-$(CONFIG_MEMSTICK) += memstick/ obj-y += leds/ obj-$(CONFIG_INFINIBAND) += infiniband/ obj-y += firmware/ +obj-$(CONFIG_FWCTL) += fwctl/ obj-$(CONFIG_CRYPTO) += crypto/ obj-$(CONFIG_SUPERH) += sh/ obj-y += clocksource/ diff --git a/drivers/fwctl/Kconfig b/drivers/fwctl/Kconfig new file mode 100644 index 00000000000000..6ceee3347ae642 --- /dev/null +++ b/drivers/fwctl/Kconfig @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig FWCTL + tristate "fwctl device firmware access framework" + help + fwctl provides a userspace API for restricted access to communicate + with on-device firmware. The communication channel is intended to + support a wide range of lockdown compatible device behaviors including + manipulating device FLASH, debugging, and other activities that don't + fit neatly into an existing subsystem. diff --git a/drivers/fwctl/Makefile b/drivers/fwctl/Makefile new file mode 100644 index 00000000000000..1cad210f6ba580 --- /dev/null +++ b/drivers/fwctl/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_FWCTL) += fwctl.o + +fwctl-y += main.o diff --git a/drivers/fwctl/main.c b/drivers/fwctl/main.c new file mode 100644 index 00000000000000..ff9b7bad5a2b0d --- /dev/null +++ b/drivers/fwctl/main.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES + */ +#define pr_fmt(fmt) "fwctl: " fmt +#include +#include +#include +#include +#include + +enum { + FWCTL_MAX_DEVICES = 256, +}; +static dev_t fwctl_dev; +static DEFINE_IDA(fwctl_ida); + +static int fwctl_fops_open(struct inode *inode, struct file *filp) +{ + struct fwctl_device *fwctl = + container_of(inode->i_cdev, struct fwctl_device, cdev); + + get_device(&fwctl->dev); + filp->private_data = fwctl; + return 0; +} + +static int fwctl_fops_release(struct inode *inode, struct file *filp) +{ + struct fwctl_device *fwctl = filp->private_data; + + fwctl_put(fwctl); + return 0; +} + +static const struct file_operations fwctl_fops = { + .owner = THIS_MODULE, + .open = fwctl_fops_open, + .release = fwctl_fops_release, +}; + +static void fwctl_device_release(struct device *device) +{ + struct fwctl_device *fwctl = + container_of(device, struct fwctl_device, dev); + + if (fwctl->dev.devt) + ida_free(&fwctl_ida, fwctl->dev.devt - fwctl_dev); + kfree(fwctl); +} + +static char *fwctl_devnode(const struct device *dev, umode_t *mode) +{ + return kasprintf(GFP_KERNEL, "fwctl/%s", dev_name(dev)); +} + +static struct class fwctl_class = { + .name = "fwctl", + .dev_release = fwctl_device_release, + .devnode = fwctl_devnode, +}; + +static struct fwctl_device * +_alloc_device(struct device *parent, const struct fwctl_ops *ops, size_t size) +{ + struct fwctl_device *fwctl __free(kfree) = kzalloc(size, GFP_KERNEL); + + if (!fwctl) + return NULL; + fwctl->dev.class = &fwctl_class; + fwctl->dev.parent = parent; + device_initialize(&fwctl->dev); + return_ptr(fwctl); +} + +/* Drivers use the fwctl_alloc_device() wrapper */ +struct fwctl_device *_fwctl_alloc_device(struct device *parent, + const struct fwctl_ops *ops, + size_t size) +{ + struct fwctl_device *fwctl __free(fwctl) = + _alloc_device(parent, ops, size); + int devnum; + + devnum = ida_alloc_max(&fwctl_ida, FWCTL_MAX_DEVICES - 1, GFP_KERNEL); + if (devnum < 0) + return NULL; + fwctl->dev.devt = fwctl_dev + devnum; + + cdev_init(&fwctl->cdev, &fwctl_fops); + fwctl->cdev.owner = THIS_MODULE; + + if (dev_set_name(&fwctl->dev, "fwctl%d", fwctl->dev.devt - fwctl_dev)) + return NULL; + + fwctl->ops = ops; + return_ptr(fwctl); +} +EXPORT_SYMBOL_NS_GPL(_fwctl_alloc_device, FWCTL); + +/** + * fwctl_register - Register a new device to the subsystem + * @fwctl: Previously allocated fwctl_device + * + * On return the device is visible through sysfs and /dev, driver ops may be + * called. + */ +int fwctl_register(struct fwctl_device *fwctl) +{ + int ret; + + ret = cdev_device_add(&fwctl->cdev, &fwctl->dev); + if (ret) + return ret; + return 0; +} +EXPORT_SYMBOL_NS_GPL(fwctl_register, FWCTL); + +/** + * fwctl_unregister - Unregister a device from the subsystem + * @fwctl: Previously allocated and registered fwctl_device + * + * Undoes fwctl_register(). On return no driver ops will be called. The + * caller must still call fwctl_put() to free the fwctl. + * + * Unregister will return even if userspace still has file descriptors open. + * This will call ops->close_uctx() on any open FDs and after return no driver + * op will be called. The FDs remain open but all fops will return -ENODEV. + * + * The design of fwctl allows this sort of disassociation of the driver from the + * subsystem primarily by keeping memory allocations owned by the core subsytem. + * The fwctl_device and fwctl_uctx can both be freed without requiring a driver + * callback. This allows the module to remain unlocked while FDs are open. + */ +void fwctl_unregister(struct fwctl_device *fwctl) +{ + cdev_device_del(&fwctl->cdev, &fwctl->dev); + + /* + * The driver module may unload after this returns, the op pointer will + * not be valid. + */ + fwctl->ops = NULL; +} +EXPORT_SYMBOL_NS_GPL(fwctl_unregister, FWCTL); + +static int __init fwctl_init(void) +{ + int ret; + + ret = alloc_chrdev_region(&fwctl_dev, 0, FWCTL_MAX_DEVICES, "fwctl"); + if (ret) + return ret; + + ret = class_register(&fwctl_class); + if (ret) + goto err_chrdev; + return 0; + +err_chrdev: + unregister_chrdev_region(fwctl_dev, FWCTL_MAX_DEVICES); + return ret; +} + +static void __exit fwctl_exit(void) +{ + class_unregister(&fwctl_class); + unregister_chrdev_region(fwctl_dev, FWCTL_MAX_DEVICES); +} + +module_init(fwctl_init); +module_exit(fwctl_exit); +MODULE_DESCRIPTION("fwctl device firmware access framework"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/fwctl.h b/include/linux/fwctl.h new file mode 100644 index 00000000000000..ef4eaa87c945e4 --- /dev/null +++ b/include/linux/fwctl.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES + */ +#ifndef __LINUX_FWCTL_H +#define __LINUX_FWCTL_H +#include +#include +#include + +struct fwctl_device; +struct fwctl_uctx; + +struct fwctl_ops { +}; + +/** + * struct fwctl_device - Per-driver registration struct + * @dev: The sysfs (class/fwctl/fwctlXX) device + * + * Each driver instance will have one of these structs with the driver + * private data following immeidately after. This struct is refcounted, + * it is freed by calling fwctl_put(). + */ +struct fwctl_device { + struct device dev; + /* private: */ + struct cdev cdev; + const struct fwctl_ops *ops; +}; + +struct fwctl_device *_fwctl_alloc_device(struct device *parent, + const struct fwctl_ops *ops, + size_t size); +/** + * fwctl_alloc_device - Allocate a fwctl + * @parent: Physical device that provides the FW interface + * @ops: Driver ops to register + * @drv_struct: 'struct driver_fwctl' that holds the struct fwctl_device + * @member: Name of the struct fwctl_device in @drv_struct + * + * This allocates and initializes the fwctl_device embedded in the drv_struct. + * Upon success the pointer must be freed via fwctl_put(). Returns NULL on + * failure. Returns a 'drv_struct *' on success, NULL on error. + */ +#define fwctl_alloc_device(parent, ops, drv_struct, member) \ + container_of(_fwctl_alloc_device( \ + parent, ops, \ + sizeof(drv_struct) + \ + BUILD_BUG_ON_ZERO( \ + offsetof(drv_struct, member))), \ + drv_struct, member) + +static inline struct fwctl_device *fwctl_get(struct fwctl_device *fwctl) +{ + get_device(&fwctl->dev); + return fwctl; +} +static inline void fwctl_put(struct fwctl_device *fwctl) +{ + put_device(&fwctl->dev); +} +DEFINE_FREE(fwctl, struct fwctl_device *, if (_T) fwctl_put(_T)); + +int fwctl_register(struct fwctl_device *fwctl); +void fwctl_unregister(struct fwctl_device *fwctl); + +#endif