From mboxrd@z Thu Jan 1 00:00:00 1970 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=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 22F7EC00A89 for ; Fri, 30 Oct 2020 10:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91E1020704 for ; Fri, 30 Oct 2020 10:34:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ChTHxwza" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726479AbgJ3KeU (ORCPT ); Fri, 30 Oct 2020 06:34:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725790AbgJ3KeT (ORCPT ); Fri, 30 Oct 2020 06:34:19 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FC2EC0613D2 for ; Fri, 30 Oct 2020 03:34:19 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id b12so2754947plr.4 for ; Fri, 30 Oct 2020 03:34:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=LYPs9iY20GzCD7l0lV5GirjS5+gTTzf1hOzaaAshKWQ=; b=ChTHxwza2Dmhf3oLLVsP4nj3w7bp4Ej7w/I5s3a5v4KzBN2ofrMfYC+41Np/QeteCZ WMGQGgFKH93FhKxwIXo4LIEreIKyGwmJIOVKpzxyB0/7ihATb4DPYpPvX7zi7J6HOcNS RZe5erfny9QBxhpqnvBeM5TiUmxYO3aB+bTTNdsdlyYCAmqVN7aXZNBGgb9dbJe2zMkv AnbriJq5ezbPS9G4bJQN7raOv5bOXLihjaq51vJ7No4eDH2a19IdfDlpV3TcbBKp9cGb EIqrL6n5mlW0s0wlQQSiyuUXg0V9nlKSUAXt0JKU20ae4fMDUimHHwq07fPbDbkYZu4t d+wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=LYPs9iY20GzCD7l0lV5GirjS5+gTTzf1hOzaaAshKWQ=; b=M1homvSCqvYbGn1zJE8IMeDPAUc0Ld5n8RilFNWGRdeG4r8EgBnUwQpmvbBB6SolDi 7zmgAflwxed6ee3OcwBi36SqcT9l8GNrvObUqtsIo9bDy+qkWjLNOOj9DjHs+wYxukLJ IbArAuwq8EUe6WtdphMHcZjxzVqSRI8ELEYUU4HdDk8yaOCgaa64mLreYRdEl9+SYdlS Qn+UCKj8XEm3vzEX0Om4GNxappCbaFBprdz7Pp+G4DoDC9O1f/JuVMEEjUz5Fc6XP+GG sztS/Z4xBvK0VBSY4rTN17Rt6UEzZRIdC31+rxWIvlFBLUyGiQsJMtmrqqO2xWBuGtbg bblA== X-Gm-Message-State: AOAM53357RvKxV4f/hXCO+44uJNGch+OJUv2t5giR4vC41/uuBrssjFJ QebaAQbzG5co3DfxMkjHafDt X-Google-Smtp-Source: ABdhPJwbfnM534Z50otfnIxRP7CVPczGBM8QcFkFVLv2PYktngK1Jl0SX4x+b9e6VdpGxJoIMQMJiA== X-Received: by 2002:a17:902:c20a:b029:d6:722b:6631 with SMTP id 10-20020a170902c20ab02900d6722b6631mr8166157pll.61.1604054058364; Fri, 30 Oct 2020 03:34:18 -0700 (PDT) Received: from Mani-XPS-13-9360 ([2409:4072:918:28fe:10d5:aaf5:e319:ec72]) by smtp.gmail.com with ESMTPSA id t5sm2912269pjq.7.2020.10.30.03.34.12 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 30 Oct 2020 03:34:17 -0700 (PDT) Date: Fri, 30 Oct 2020 16:04:10 +0530 From: Manivannan Sadhasivam To: Hemant Kumar Cc: gregkh@linuxfoundation.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, loic.poulain@linaro.org, netdev@vger.kernel.org Subject: Re: [PATCH v11 4/4] bus: mhi: Add userspace client interface driver Message-ID: <20201030103410.GD3818@Mani-XPS-13-9360> References: <1604025946-28288-1-git-send-email-hemantk@codeaurora.org> <1604025946-28288-5-git-send-email-hemantk@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1604025946-28288-5-git-send-email-hemantk@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hemant, On Thu, Oct 29, 2020 at 07:45:46PM -0700, Hemant Kumar wrote: > This MHI client driver allows userspace clients to transfer > raw data between MHI device and host using standard file operations. > Driver instantiates UCI device object which is associated to device > file node. UCI device object instantiates UCI channel object when device > file node is opened. UCI channel object is used to manage MHI channels > by calling MHI core APIs for read and write operations. MHI channels > are started as part of device open(). MHI channels remain in start > state until last release() is called on UCI device file node. Device > file node is created with format > > /dev/mhi__ > > Currently it supports LOOPBACK channel. > > Signed-off-by: Hemant Kumar Thanks for continuously updating the series based on reviews, now the locking part looks a _lot_ cleaner than it used to be. I just have one query (inline) regarding the usage of refcount for uci_chan and uci_dev. Once you fix that, I think this is good to go in. Thanks, Mani > --- > drivers/bus/mhi/Kconfig | 13 + > drivers/bus/mhi/Makefile | 4 + > drivers/bus/mhi/uci.c | 662 +++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 679 insertions(+) > create mode 100644 drivers/bus/mhi/uci.c > > diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig > index e841c10..476cc55 100644 > --- a/drivers/bus/mhi/Kconfig > +++ b/drivers/bus/mhi/Kconfig > @@ -20,3 +20,16 @@ config MHI_BUS_DEBUG > Enable debugfs support for use with the MHI transport. Allows > reading and/or modifying some values within the MHI controller > for debug and test purposes. > + > +config MHI_UCI > + tristate "MHI UCI" > + depends on MHI_BUS > + help > + MHI based Userspace Client Interface (UCI) driver is used for > + transferring raw data between host and device using standard file > + operations from userspace. Open, read, write, and close operations > + are supported by this driver. Please check mhi_uci_match_table for > + all supported channels that are exposed to userspace. > + > + To compile this driver as a module, choose M here: the module will be > + called mhi_uci. > diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile > index 19e6443..80feefb 100644 > --- a/drivers/bus/mhi/Makefile > +++ b/drivers/bus/mhi/Makefile > @@ -1,2 +1,6 @@ > # core layer > obj-y += core/ > + > +# MHI client > +mhi_uci-y := uci.o > +obj-$(CONFIG_MHI_UCI) += mhi_uci.o > diff --git a/drivers/bus/mhi/uci.c b/drivers/bus/mhi/uci.c > new file mode 100644 > index 0000000..ea73c08 > --- /dev/null > +++ b/drivers/bus/mhi/uci.c > @@ -0,0 +1,662 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/ > + > +#include > +#include > +#include > +#include > +#include > + > +#define DEVICE_NAME "mhi" > +#define MHI_UCI_DRIVER_NAME "mhi_uci" > +#define MAX_UCI_MINORS 128 Prefix MHI for these. > + > +static DEFINE_IDR(uci_idr); > +static DEFINE_MUTEX(uci_drv_mutex); > +static struct class *uci_dev_class; > +static int uci_dev_major; > + > +/** > + * struct uci_chan - MHI channel for a UCI device > + * @udev: associated UCI device object > + * @ul_wq: wait queue for writer > + * @write_lock: mutex write lock for ul channel > + * @dl_wq: wait queue for reader > + * @read_lock: mutex read lock for dl channel > + * @dl_pending_lock: spin lock for dl_pending list > + * @dl_pending: list of dl buffers userspace is waiting to read > + * @cur_buf: current buffer userspace is reading > + * @dl_size: size of the current dl buffer userspace is reading > + * @ref_count: uci_chan reference count > + */ > +struct uci_chan { > + struct uci_dev *udev; > + wait_queue_head_t ul_wq; > + > + /* ul channel lock to synchronize multiple writes */ I asked you to move these comments to Kdoc in previous iteration. > + struct mutex write_lock; > + > + wait_queue_head_t dl_wq; > + > + /* dl channel lock to synchronize multiple reads */ > + struct mutex read_lock; > + > + /* > + * protects pending list in bh context, channel release, read and > + * poll > + */ > + spinlock_t dl_pending_lock; > + > + struct list_head dl_pending; > + struct uci_buf *cur_buf; > + size_t dl_size; > + struct kref ref_count; I'm now thinking that instead of having two reference counts for uci_chan and uci_dev, why can't you club them together and just use uci_dev's refcount to handle the channel management also. For instance in uci_open, you are incrementing the refcount for uci_dev before starting the channel and then doing the same for uci_chan in mhi_uci_dev_start_chan(). So why can't you just use a single refcount once the mhi_uci_dev_start_chan() succeeds? The UCI device is useless without a channel, isn't it? > +}; > + > +/** > + * struct uci_buf - UCI buffer > + * @data: data buffer > + * @len: length of data buffer > + * @node: list node of the UCI buffer > + */ > +struct uci_buf { > + void *data; > + size_t len; > + struct list_head node; > +}; > + > +/** > + * struct uci_dev - MHI UCI device > + * @minor: UCI device node minor number > + * @mhi_dev: associated mhi device object > + * @uchan: UCI uplink and downlink channel object > + * @mtu: max TRE buffer length > + * @enabled: Flag to track the state of the UCI device > + * @lock: mutex lock to manage uchan object > + * @ref_count: uci_dev reference count > + */ > +struct uci_dev { > + unsigned int minor; > + struct mhi_device *mhi_dev; > + struct uci_chan *uchan; > + size_t mtu; > + bool enabled; > + > + /* synchronize open, release and driver remove */ > + struct mutex lock; > + struct kref ref_count; > +}; > + > +static void mhi_uci_dev_chan_release(struct kref *ref) > +{ > + struct uci_buf *buf_itr, *tmp; > + struct uci_chan *uchan = > + container_of(ref, struct uci_chan, ref_count); > + > + if (uchan->udev->enabled) > + mhi_unprepare_from_transfer(uchan->udev->mhi_dev); > + > + spin_lock_bh(&uchan->dl_pending_lock); > + list_for_each_entry_safe(buf_itr, tmp, &uchan->dl_pending, node) { > + list_del(&buf_itr->node); > + kfree(buf_itr->data); > + } > + spin_unlock_bh(&uchan->dl_pending_lock); > + > + wake_up(&uchan->ul_wq); > + wake_up(&uchan->dl_wq); > + > + mutex_lock(&uchan->read_lock); > + if (uchan->cur_buf) > + kfree(uchan->cur_buf->data); > + > + uchan->cur_buf = NULL; > + mutex_unlock(&uchan->read_lock); > + > + mutex_destroy(&uchan->write_lock); > + mutex_destroy(&uchan->read_lock); > + > + uchan->udev->uchan = NULL; > + kfree(uchan); > +} > + > +static int mhi_queue_inbound(struct uci_dev *udev) > +{ > + struct mhi_device *mhi_dev = udev->mhi_dev; > + struct device *dev = &mhi_dev->dev; > + int nr_trbs, i, ret = -EIO; s/nr_trbs/nr_desc > + size_t dl_buf_size; > + void *buf; > + struct uci_buf *ubuf; > + > + /* dont queue if dl channel is not supported */ > + if (!udev->mhi_dev->dl_chan) > + return 0; Not returning an error? > + > + nr_trbs = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); > + > + for (i = 0; i < nr_trbs; i++) { > + buf = kmalloc(udev->mtu, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + dl_buf_size = udev->mtu - sizeof(*ubuf); > + > + /* save uci_buf info at the end of buf */ > + ubuf = buf + dl_buf_size; > + ubuf->data = buf; > + > + dev_dbg(dev, "Allocated buf %d of %d size %zu\n", i, nr_trbs, > + dl_buf_size); > + > + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, dl_buf_size, > + MHI_EOT); > + if (ret) { > + kfree(buf); > + dev_err(dev, "Failed to queue buffer %d\n", i); > + return ret; > + } > + } > + > + return ret; > +} > + > +static int mhi_uci_dev_start_chan(struct uci_dev *udev) > +{ > + int ret = 0; > + struct uci_chan *uchan; > + > + mutex_lock(&udev->lock); > + if (!udev->uchan || !kref_get_unless_zero(&udev->uchan->ref_count)) { > + uchan = kzalloc(sizeof(*uchan), GFP_KERNEL); > + if (!uchan) { > + ret = -ENOMEM; > + goto error_chan_start; > + } > + > + udev->uchan = uchan; > + uchan->udev = udev; > + init_waitqueue_head(&uchan->ul_wq); > + init_waitqueue_head(&uchan->dl_wq); > + mutex_init(&uchan->write_lock); > + mutex_init(&uchan->read_lock); > + spin_lock_init(&uchan->dl_pending_lock); > + INIT_LIST_HEAD(&uchan->dl_pending); > + > + ret = mhi_prepare_for_transfer(udev->mhi_dev); > + if (ret) { > + dev_err(&udev->mhi_dev->dev, "Error starting transfer channels\n"); > + goto error_chan_cleanup; > + } > + > + ret = mhi_queue_inbound(udev); > + if (ret) > + goto error_chan_cleanup; > + > + kref_init(&uchan->ref_count); > + } > + > + mutex_unlock(&udev->lock); > + > + return 0; > + > +error_chan_cleanup: > + mhi_uci_dev_chan_release(&uchan->ref_count); > +error_chan_start: > + mutex_unlock(&udev->lock); > + return ret; > +} > + > +static void mhi_uci_dev_release(struct kref *ref) > +{ > + struct uci_dev *udev = > + container_of(ref, struct uci_dev, ref_count); > + > + mutex_destroy(&udev->lock); > + > + kfree(udev); > +} > + > +static int mhi_uci_open(struct inode *inode, struct file *filp) > +{ > + unsigned int minor = iminor(inode); > + struct uci_dev *udev = NULL; > + int ret; > + > + mutex_lock(&uci_drv_mutex); > + udev = idr_find(&uci_idr, minor); > + if (!udev) { > + pr_debug("uci dev: minor %d not found\n", minor); > + mutex_unlock(&uci_drv_mutex); > + return -ENODEV; > + } > + > + kref_get(&udev->ref_count); > + mutex_unlock(&uci_drv_mutex); > + > + ret = mhi_uci_dev_start_chan(udev); > + if (ret) { > + kref_put(&udev->ref_count, mhi_uci_dev_release); > + return ret; > + } > + > + filp->private_data = udev; > + > + return 0; > +} > + > +static int mhi_uci_release(struct inode *inode, struct file *file) > +{ > + struct uci_dev *udev = file->private_data; > + > + mutex_lock(&udev->lock); > + kref_put(&udev->uchan->ref_count, mhi_uci_dev_chan_release); > + mutex_unlock(&udev->lock); > + > + kref_put(&udev->ref_count, mhi_uci_dev_release); > + > + return 0; > +} > + > +static __poll_t mhi_uci_poll(struct file *file, poll_table *wait) > +{ > + struct uci_dev *udev = file->private_data; > + struct mhi_device *mhi_dev = udev->mhi_dev; > + struct device *dev = &mhi_dev->dev; > + struct uci_chan *uchan = udev->uchan; > + __poll_t mask = 0; > + > + poll_wait(file, &udev->uchan->ul_wq, wait); > + poll_wait(file, &udev->uchan->dl_wq, wait); > + > + if (!udev->enabled) { > + mask = EPOLLERR; > + goto done; > + } > + > + spin_lock_bh(&uchan->dl_pending_lock); > + if (!list_empty(&uchan->dl_pending) || uchan->cur_buf) { > + dev_dbg(dev, "Client can read from node\n"); Since you're printing the mask, no need of the debug statement here. > + mask |= EPOLLIN | EPOLLRDNORM; > + } > + spin_unlock_bh(&uchan->dl_pending_lock); > + > + if (mhi_get_free_desc_count(mhi_dev, DMA_TO_DEVICE) > 0) { > + dev_dbg(dev, "Client can write to node\n"); Same as above. > + mask |= EPOLLOUT | EPOLLWRNORM; > + } > + > + dev_dbg(dev, "Client attempted to poll, returning mask 0x%x\n", mask); > + > +done: > + return mask; > +} > + > +static ssize_t mhi_uci_write(struct file *file, > + const char __user *buf, > + size_t count, > + loff_t *offp) > +{ > + struct uci_dev *udev = file->private_data; > + struct mhi_device *mhi_dev = udev->mhi_dev; > + struct device *dev = &mhi_dev->dev; > + struct uci_chan *uchan = udev->uchan; > + size_t bytes_xfered = 0; > + int ret, nr_avail = 0; s/nr_avail/nr_desc > + > + /* if ul channel is not supported return error */ > + if (!buf || !count || !mhi_dev->ul_chan) Shouldn't we return ENOTSUPP for !mhi_dev->dl_chan? > + return -EINVAL; > + > + dev_dbg(dev, "%s: to xfer: %zu bytes\n", __func__, count); > + > + if (mutex_lock_interruptible(&uchan->write_lock)) > + return -EINTR; > + > + while (count) { > + size_t xfer_size; > + void *kbuf; > + enum mhi_flags flags; > + > + /* wait for free descriptors */ > + ret = wait_event_interruptible(uchan->ul_wq, > + (!udev->enabled) || > + (nr_avail = mhi_get_free_desc_count(mhi_dev, > + DMA_TO_DEVICE)) > 0); > + > + if (ret == -ERESTARTSYS) { > + dev_dbg(dev, "Interrupted by a signal in %s, exiting\n", > + __func__); > + goto err_mtx_unlock; > + } > + > + if (!udev->enabled) { > + ret = -ENODEV; > + goto err_mtx_unlock; > + } > + > + xfer_size = min_t(size_t, count, udev->mtu); > + kbuf = kmalloc(xfer_size, GFP_KERNEL); > + if (!kbuf) { > + ret = -ENOMEM; > + goto err_mtx_unlock; > + } > + > + ret = copy_from_user(kbuf, buf, xfer_size); > + if (ret) { > + kfree(kbuf); > + ret = -EFAULT; > + goto err_mtx_unlock; > + } > + > + /* if ring is full after this force EOT */ > + if (nr_avail > 1 && (count - xfer_size)) > + flags = MHI_CHAIN; > + else > + flags = MHI_EOT; > + > + ret = mhi_queue_buf(mhi_dev, DMA_TO_DEVICE, kbuf, xfer_size, > + flags); > + if (ret) { > + kfree(kbuf); > + goto err_mtx_unlock; > + } > + > + bytes_xfered += xfer_size; > + count -= xfer_size; > + buf += xfer_size; > + } > + > + mutex_unlock(&uchan->write_lock); > + dev_dbg(dev, "%s: bytes xferred: %zu\n", __func__, bytes_xfered); > + > + return bytes_xfered; > + > +err_mtx_unlock: > + mutex_unlock(&uchan->write_lock); > + > + return ret; > +} > + > +static ssize_t mhi_uci_read(struct file *file, > + char __user *buf, > + size_t count, > + loff_t *ppos) > +{ > + struct uci_dev *udev = file->private_data; > + struct mhi_device *mhi_dev = udev->mhi_dev; > + struct uci_chan *uchan = udev->uchan; > + struct device *dev = &mhi_dev->dev; > + struct uci_buf *ubuf; > + size_t rx_buf_size; > + char *ptr; > + size_t to_copy; > + int ret = 0; > + > + /* if dl channel is not supported return error */ > + if (!buf || !mhi_dev->dl_chan) > + return -EINVAL; Shouldn't we return ENOTSUPP for !mhi_dev->dl_chan? > + > + if (mutex_lock_interruptible(&uchan->read_lock)) > + return -EINTR; > + > + spin_lock_bh(&uchan->dl_pending_lock); > + /* No data available to read, wait */ > + if (!uchan->cur_buf && list_empty(&uchan->dl_pending)) { > + dev_dbg(dev, "No data available to read, waiting\n"); > + > + spin_unlock_bh(&uchan->dl_pending_lock); > + ret = wait_event_interruptible(uchan->dl_wq, > + (!udev->enabled || > + !list_empty(&uchan->dl_pending))); > + > + if (ret == -ERESTARTSYS) { > + dev_dbg(dev, "Interrupted by a signal in %s, exiting\n", > + __func__); > + goto err_mtx_unlock; > + } > + > + if (!udev->enabled) { > + ret = -ENODEV; > + goto err_mtx_unlock; > + } > + spin_lock_bh(&uchan->dl_pending_lock); > + } > + > + /* new read, get the next descriptor from the list */ > + if (!uchan->cur_buf) { > + ubuf = list_first_entry_or_null(&uchan->dl_pending, > + struct uci_buf, node); > + if (!ubuf) { > + ret = -EIO; > + goto err_spin_unlock; > + } > + > + list_del(&ubuf->node); > + uchan->cur_buf = ubuf; > + uchan->dl_size = ubuf->len; > + dev_dbg(dev, "Got pkt of size: %zu\n", uchan->dl_size); > + } > + spin_unlock_bh(&uchan->dl_pending_lock); > + > + ubuf = uchan->cur_buf; > + > + /* Copy the buffer to user space */ > + to_copy = min_t(size_t, count, uchan->dl_size); > + ptr = ubuf->data + (ubuf->len - uchan->dl_size); > + > + ret = copy_to_user(buf, ptr, to_copy); > + if (ret) { > + ret = -EFAULT; > + goto err_mtx_unlock; > + } > + > + dev_dbg(dev, "Copied %zu of %zu bytes\n", to_copy, uchan->dl_size); > + uchan->dl_size -= to_copy; > + > + /* we finished with this buffer, queue it back to hardware */ > + if (!uchan->dl_size) { > + uchan->cur_buf = NULL; > + > + rx_buf_size = udev->mtu - sizeof(*ubuf); > + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, ubuf->data, > + rx_buf_size, MHI_EOT); > + if (ret) { > + dev_err(dev, "Failed to recycle element: %d\n", ret); > + kfree(ubuf->data); > + goto err_mtx_unlock; > + } > + } > + mutex_unlock(&uchan->read_lock); > + > + dev_dbg(dev, "%s: Returning %zu bytes\n", __func__, to_copy); > + > + return to_copy; > + > +err_spin_unlock: > + spin_unlock_bh(&uchan->dl_pending_lock); > +err_mtx_unlock: > + mutex_unlock(&uchan->read_lock); > + return ret; > +} > + > +static const struct file_operations mhidev_fops = { > + .owner = THIS_MODULE, > + .open = mhi_uci_open, > + .release = mhi_uci_release, > + .read = mhi_uci_read, > + .write = mhi_uci_write, > + .poll = mhi_uci_poll, > +}; > + > +static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev, > + struct mhi_result *mhi_result) > +{ > + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); > + struct uci_chan *uchan = udev->uchan; > + struct device *dev = &mhi_dev->dev; > + > + dev_dbg(dev, "status: %d xfer_len: %zu\n", > + mhi_result->transaction_status, mhi_result->bytes_xferd); How this print is going to be useful alone? Atleast you should print the function name. > + > + kfree(mhi_result->buf_addr); > + > + if (!mhi_result->transaction_status) > + wake_up(&uchan->ul_wq); > +} > + > +static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, > + struct mhi_result *mhi_result) > +{ > + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); > + struct uci_chan *uchan = udev->uchan; > + struct device *dev = &mhi_dev->dev; > + struct uci_buf *ubuf; > + size_t dl_buf_size = udev->mtu - sizeof(*ubuf); > + > + dev_dbg(dev, "status: %d receive_len: %zu\n", > + mhi_result->transaction_status, mhi_result->bytes_xferd); Same as above. > + > + if (mhi_result->transaction_status && > + mhi_result->transaction_status != -EOVERFLOW) { > + kfree(mhi_result->buf_addr); > + return; > + } > + > + ubuf = mhi_result->buf_addr + dl_buf_size; > + ubuf->data = mhi_result->buf_addr; > + ubuf->len = mhi_result->bytes_xferd; > + spin_lock_bh(&uchan->dl_pending_lock); > + list_add_tail(&ubuf->node, &uchan->dl_pending); > + spin_unlock_bh(&uchan->dl_pending_lock); > + > + wake_up(&uchan->dl_wq); > +} > + > +static int mhi_uci_probe(struct mhi_device *mhi_dev, > + const struct mhi_device_id *id) > +{ > + struct uci_dev *udev; > + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; > + struct device *dev; > + int index; > + > + udev = kzalloc(sizeof(*udev), GFP_KERNEL); > + if (!udev) > + return -ENOMEM; > + > + kref_init(&udev->ref_count); > + mutex_init(&udev->lock); > + udev->mhi_dev = mhi_dev; > + > + mutex_lock(&uci_drv_mutex); > + index = idr_alloc(&uci_idr, udev, 0, MAX_UCI_MINORS, GFP_KERNEL); > + mutex_unlock(&uci_drv_mutex); > + if (index < 0) { > + kfree(udev); > + return index; > + } > + > + udev->minor = index; > + > + udev->mtu = min_t(size_t, id->driver_data, MHI_MAX_MTU); > + dev_set_drvdata(&mhi_dev->dev, udev); > + udev->enabled = true; > + > + /* create device file node /dev/mhi__ */ > + dev = device_create(uci_dev_class, &mhi_dev->dev, > + MKDEV(uci_dev_major, index), udev, > + DEVICE_NAME "_%s_%s", > + dev_name(mhi_cntrl->cntrl_dev), mhi_dev->name); > + if (IS_ERR(dev)) { > + mutex_lock(&uci_drv_mutex); > + idr_remove(&uci_idr, udev->minor); > + mutex_unlock(&uci_drv_mutex); > + dev_set_drvdata(&mhi_dev->dev, NULL); > + kfree(udev); > + return PTR_ERR(dev); > + } > + > + dev_dbg(&mhi_dev->dev, "probed uci dev: %s\n", id->chan); > + > + return 0; > +}; > + > +static void mhi_uci_remove(struct mhi_device *mhi_dev) > +{ > + struct uci_dev *udev = dev_get_drvdata(&mhi_dev->dev); > + > + /* disable the node */ > + mutex_lock(&udev->lock); > + udev->enabled = false; > + > + /* delete the node to prevent new opens */ > + device_destroy(uci_dev_class, MKDEV(uci_dev_major, udev->minor)); > + > + /* return error for any blocked read or write */ > + if (udev->uchan) { > + wake_up(&udev->uchan->ul_wq); > + wake_up(&udev->uchan->dl_wq); > + } > + mutex_unlock(&udev->lock); > + > + mutex_lock(&uci_drv_mutex); > + idr_remove(&uci_idr, udev->minor); > + kref_put(&udev->ref_count, mhi_uci_dev_release); > + mutex_unlock(&uci_drv_mutex); > +} > + > +/* .driver_data stores max mtu */ > +static const struct mhi_device_id mhi_uci_match_table[] = { > + { .chan = "LOOPBACK", .driver_data = 0x1000}, > + {}, > +}; > +MODULE_DEVICE_TABLE(mhi, mhi_uci_match_table); > + > +static struct mhi_driver mhi_uci_driver = { > + .id_table = mhi_uci_match_table, > + .remove = mhi_uci_remove, > + .probe = mhi_uci_probe, > + .ul_xfer_cb = mhi_ul_xfer_cb, > + .dl_xfer_cb = mhi_dl_xfer_cb, > + .driver = { > + .name = MHI_UCI_DRIVER_NAME, > + }, > +}; > + > +static int __init mhi_uci_init(void) > +{ > + int ret; > + > + ret = register_chrdev(0, MHI_UCI_DRIVER_NAME, &mhidev_fops); > + if (ret < 0) > + return ret; > + > + uci_dev_major = ret; > + uci_dev_class = class_create(THIS_MODULE, MHI_UCI_DRIVER_NAME); > + if (IS_ERR(uci_dev_class)) { > + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); > + return PTR_ERR(uci_dev_class); > + } > + > + ret = mhi_driver_register(&mhi_uci_driver); > + if (ret) { > + class_destroy(uci_dev_class); > + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); > + } > + > + return ret; > +} > + > +static void __exit mhi_uci_exit(void) > +{ > + mhi_driver_unregister(&mhi_uci_driver); > + class_destroy(uci_dev_class); > + unregister_chrdev(uci_dev_major, MHI_UCI_DRIVER_NAME); > + idr_destroy(&uci_idr); > +} > + > +module_init(mhi_uci_init); > +module_exit(mhi_uci_exit); > +MODULE_LICENSE("GPL v2"); > +MODULE_DESCRIPTION("MHI UCI Driver"); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >