From patchwork Tue Nov 17 16:23:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Ardelean X-Patchwork-Id: 11912705 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B71FDC71155 for ; Tue, 17 Nov 2020 16:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 967CF208CA for ; Tue, 17 Nov 2020 16:19:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727920AbgKQQTD (ORCPT ); Tue, 17 Nov 2020 11:19:03 -0500 Received: from mx0a-00128a01.pphosted.com ([148.163.135.77]:36964 "EHLO mx0a-00128a01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727877AbgKQQTC (ORCPT ); Tue, 17 Nov 2020 11:19:02 -0500 Received: from pps.filterd (m0167089.ppops.net [127.0.0.1]) by mx0a-00128a01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AHGImGs028498; Tue, 17 Nov 2020 11:18:49 -0500 Received: from nwd2mta4.analog.com ([137.71.173.58]) by mx0a-00128a01.pphosted.com with ESMTP id 34td199y85-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 17 Nov 2020 11:18:48 -0500 Received: from ASHBMBX8.ad.analog.com (ASHBMBX8.ad.analog.com [10.64.17.5]) by nwd2mta4.analog.com (8.14.7/8.14.7) with ESMTP id 0AHGIjcx044690 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=FAIL); Tue, 17 Nov 2020 11:18:45 -0500 Received: from ASHBCASHYB5.ad.analog.com (10.64.17.133) by ASHBMBX8.ad.analog.com (10.64.17.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Tue, 17 Nov 2020 11:18:44 -0500 Received: from ASHBMBX9.ad.analog.com (10.64.17.10) by ASHBCASHYB5.ad.analog.com (10.64.17.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Tue, 17 Nov 2020 11:18:44 -0500 Received: from zeus.spd.analog.com (10.66.68.11) by ASHBMBX9.ad.analog.com (10.64.17.10) with Microsoft SMTP Server id 15.1.1779.2 via Frontend Transport; Tue, 17 Nov 2020 11:18:44 -0500 Received: from localhost.localdomain ([10.48.65.12]) by zeus.spd.analog.com (8.15.1/8.15.1) with ESMTP id 0AHGIRTY032565; Tue, 17 Nov 2020 11:18:42 -0500 From: Alexandru Ardelean To: , CC: , , Alexandru Ardelean Subject: [RFC PATCH 12/12] iio: buffer: add ioctl() to support opening extra buffers for IIO device Date: Tue, 17 Nov 2020 18:23:40 +0200 Message-ID: <20201117162340.43924-13-alexandru.ardelean@analog.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201117162340.43924-1-alexandru.ardelean@analog.com> References: <20201117162340.43924-1-alexandru.ardelean@analog.com> MIME-Version: 1.0 X-ADIRuleOP-NewSCL: Rule Triggered X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-17_06:2020-11-17,2020-11-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 suspectscore=2 impostorscore=0 mlxscore=0 malwarescore=0 adultscore=0 clxscore=1015 phishscore=0 priorityscore=1501 lowpriorityscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011170117 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org With this change, an ioctl() call is added to open a character device for a buffer. The ioctl() will not work for the first buffer, as that buffer is already opened/reserved for the IIO device's character device. This is also to preserve backwards compatibility. For any other extra buffer (after the first buffer) this ioctl() will be required. Signed-off-by: Alexandru Ardelean --- drivers/iio/industrialio-buffer.c | 111 ++++++++++++++++++++++++++++++ drivers/iio/industrialio-core.c | 8 +++ include/linux/iio/buffer_impl.h | 5 ++ include/linux/iio/iio-opaque.h | 2 + include/uapi/linux/iio/buffer.h | 16 +++++ 5 files changed, 142 insertions(+) create mode 100644 include/uapi/linux/iio/buffer.h diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index daa68822cea7..77f02870cd18 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -9,6 +9,7 @@ * - Better memory allocation techniques? * - Alternative access techniques? */ +#include #include #include #include @@ -1399,6 +1400,99 @@ static void iio_sysfs_del_attrs(struct kobject *kobj, struct attribute **ptr) sysfs_remove_file(kobj, ptr[i]); } +static int iio_buffer_chrdev_release(struct inode *inode, struct file *filep) +{ + struct iio_dev_buffer_pair *ib = filep->private_data; + struct iio_dev *indio_dev = ib->indio_dev; + struct iio_buffer *buffer = ib->buffer; + + clear_bit(IIO_BUSY_BIT_POS, &buffer->flags); + iio_device_put(indio_dev); + kfree(ib); + + return 0; +} + +static const struct file_operations iio_buffer_chrdev_fileops = { + .owner = THIS_MODULE, + .llseek = noop_llseek, + .read = iio_buffer_read_outer_addr, + .poll = iio_buffer_poll_addr, + .compat_ioctl = compat_ptr_ioctl, + .release = iio_buffer_chrdev_release, +}; + +static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg) +{ + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); + int __user *ival = (int __user *)arg; + char buf_name[sizeof("iio:buffer:xxx")]; + struct iio_dev_buffer_pair *ib; + struct iio_buffer *buffer; + int fd, idx; + + if (copy_from_user(&idx, ival, sizeof(idx))) + return -EFAULT; + + if (idx >= iio_dev_opaque->attached_buffers_cnt) + return -ENOENT; + + fd = mutex_lock_interruptible(&indio_dev->mlock); + if (fd) + return fd; + + buffer = iio_dev_opaque->attached_buffers[idx]; + + if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) { + fd = -EBUSY; + goto error_unlock; + } + + iio_device_get(indio_dev); + + ib = kzalloc(sizeof(*ib), GFP_KERNEL); + if (!ib) { + fd = -ENOMEM; + goto error_iio_dev_put; + } + + ib->indio_dev = indio_dev; + ib->buffer = buffer; + + fd = anon_inode_getfd(buf_name, &iio_buffer_chrdev_fileops, + ib, O_RDWR | O_CLOEXEC); + if (fd < 0) + goto error_free_ib; + + if (copy_to_user(ival, &fd, sizeof(fd))) { + fd = -EFAULT; + goto error_free_ib; + } + + mutex_unlock(&indio_dev->mlock); + return fd; + +error_free_ib: + kfree(ib); +error_iio_dev_put: + iio_device_put(indio_dev); + clear_bit(IIO_BUSY_BIT_POS, &buffer->flags); +error_unlock: + mutex_unlock(&indio_dev->mlock); + return fd; +} + +static long iio_device_buffer_ioctl(struct iio_dev *indio_dev, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case IIO_BUFFER_GET_FD_IOCTL: + return iio_device_buffer_getfd(indio_dev, arg); + default: + return IIO_IOCTL_UNHANDLED; + } +} + static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer, struct iio_dev *indio_dev, unsigned int idx) @@ -1549,8 +1643,21 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) if (ret) goto error_remove_buffer_dir_link; + i = sizeof(*(iio_dev_opaque->buffer_ioctl_handler)); + iio_dev_opaque->buffer_ioctl_handler = kzalloc(i, GFP_KERNEL); + if (!iio_dev_opaque->buffer_ioctl_handler) { + ret = -ENOMEM; + goto error_remove_scan_el_dir; + } + + iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl; + iio_device_ioctl_handler_register(indio_dev, + iio_dev_opaque->buffer_ioctl_handler); + return 0; +error_remove_scan_el_dir: + sysfs_remove_link(&indio_dev->dev.kobj, "scan_elements"); error_remove_buffer_dir_link: sysfs_remove_link(&indio_dev->dev.kobj, "buffer"); i = iio_dev_opaque->attached_buffers_cnt - 1; @@ -1585,6 +1692,10 @@ void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) if (!buffer) return; + iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler); + kfree(iio_dev_opaque->buffer_ioctl_handler); + iio_dev_opaque->buffer_ioctl_handler = NULL; + sysfs_remove_link(&indio_dev->dev.kobj, "scan_elements"); sysfs_remove_link(&indio_dev->dev.kobj, "buffer"); diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 9e7a76723f00..b4f7dd75bef5 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -1685,6 +1685,9 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp) ib->indio_dev = indio_dev; ib->buffer = indio_dev->buffer; + if (indio_dev->buffer) + test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->buffer->flags); + filp->private_data = ib; return 0; @@ -1702,6 +1705,11 @@ static int iio_chrdev_release(struct inode *inode, struct file *filp) struct iio_dev_buffer_pair *ib = filp->private_data; struct iio_dev *indio_dev = container_of(inode->i_cdev, struct iio_dev, chrdev); + struct iio_buffer *buffer = ib->buffer; + + if (buffer) + clear_bit(IIO_BUSY_BIT_POS, &buffer->flags); + clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags); iio_device_put(indio_dev); kfree(ib); diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h index e25d26a7f601..78da590b5607 100644 --- a/include/linux/iio/buffer_impl.h +++ b/include/linux/iio/buffer_impl.h @@ -6,6 +6,8 @@ #ifdef CONFIG_IIO_BUFFER +#include + struct iio_dev; struct iio_buffer; @@ -75,6 +77,9 @@ struct iio_buffer { /** @length: Number of datums in buffer. */ unsigned int length; + /** @flags: File ops flags including busy flag. */ + unsigned long flags; + /** @bytes_per_datum: Size of individual datum including timestamp. */ size_t bytes_per_datum; diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h index 1db0ea09520e..d0429b13afa8 100644 --- a/include/linux/iio/iio-opaque.h +++ b/include/linux/iio/iio-opaque.h @@ -9,6 +9,7 @@ * @event_interface: event chrdevs associated with interrupt lines * @attached_buffers: array of buffers statically attached by the driver * @attached_buffers_cnt: number of buffers in the array of statically attached buffers + * @buffer_ioctl_handler: ioctl() handler for this IIO device's buffer interface * @buffer_list: list of all buffers currently attached * @channel_attr_list: keep track of automatically created channel * attributes @@ -24,6 +25,7 @@ struct iio_dev_opaque { struct iio_event_interface *event_interface; struct iio_buffer **attached_buffers; unsigned int attached_buffers_cnt; + struct iio_ioctl_handler *buffer_ioctl_handler; struct list_head buffer_list; struct list_head channel_attr_list; struct attribute_group chan_attr_group; diff --git a/include/uapi/linux/iio/buffer.h b/include/uapi/linux/iio/buffer.h new file mode 100644 index 000000000000..3794eca78dad --- /dev/null +++ b/include/uapi/linux/iio/buffer.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* industrial I/O buffer definitions needed both in and out of kernel + * + * Copyright (c) 2020 Alexandru Ardelean + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ + +#ifndef _UAPI_IIO_BUFFER_H_ +#define _UAPI_IIO_BUFFER_H_ + +#define IIO_BUFFER_GET_FD_IOCTL _IOWR('i', 0xa0, int) + +#endif /* _UAPI_IIO_BUFFER_H_ */