From patchwork Thu Dec 3 22:45:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 337000 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, 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 39906C193FE for ; Thu, 3 Dec 2020 22:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAAF9223E8 for ; Thu, 3 Dec 2020 22:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389292AbgLCWqd (ORCPT ); Thu, 3 Dec 2020 17:46:33 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:60370 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388768AbgLCWqd (ORCPT ); Thu, 3 Dec 2020 17:46:33 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1607035569; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=vTSJJj/mqYlqSjy1P4jPSBlecvXpEXbz9kGAuxBK598=; b=fNas1aXzb/lwaO0fH37JYZcZpDK9XsBjpImD2W2926LMY9ZOxgRRNQrPcjtEzuQVjC41B4AS 1vSTo/6JpnDKu2Lo/svMXm2Ty7v694YXUhV0FWDLjGCMsPxpU68IZcVdsujxaWp8CSHV/lgM Tx6syuSYsBULWM7ba1pytaTr9ng= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 5fc96a86b50fb3818a7daa65 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 03 Dec 2020 22:45:26 GMT Sender: hemantk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 8F014C433C6; Thu, 3 Dec 2020 22:45:25 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id 61747C433C6; Thu, 3 Dec 2020 22:45:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 61747C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org, gregkh@linuxfoundation.org Cc: 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, Hemant Kumar Subject: [PATCH v15 2/4] bus: mhi: core: Move MHI_MAX_MTU to external header file Date: Thu, 3 Dec 2020 14:45:14 -0800 Message-Id: <1607035516-3093-3-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> References: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Currently this macro is defined in internal MHI header as a TRE length mask. Moving it to external header allows MHI client drivers to set this upper bound for the transmit buffer size. Signed-off-by: Hemant Kumar Reviewed-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam --- drivers/bus/mhi/core/internal.h | 1 - include/linux/mhi.h | 3 +++ 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h index 6f80ec3..2b9c063 100644 --- a/drivers/bus/mhi/core/internal.h +++ b/drivers/bus/mhi/core/internal.h @@ -453,7 +453,6 @@ enum mhi_pm_state { #define CMD_EL_PER_RING 128 #define PRIMARY_CMD_RING 0 #define MHI_DEV_WAKE_DB 127 -#define MHI_MAX_MTU 0xffff #define MHI_RANDOM_U32_NONZERO(bmsk) (prandom_u32_max(bmsk) + 1) enum mhi_er_type { diff --git a/include/linux/mhi.h b/include/linux/mhi.h index e36d575..f072605 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -15,6 +15,9 @@ #include #include +/* MHI client drivers to set this upper bound for tx buffer */ +#define MHI_MAX_MTU 0xffff + #define MHI_MAX_OEM_PK_HASH_SEGMENTS 16 struct mhi_chan; From patchwork Thu Dec 3 22:45:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 336999 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, 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 1B431C4167B for ; Thu, 3 Dec 2020 22:46:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6248223E4 for ; Thu, 3 Dec 2020 22:46:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388741AbgLCWqZ (ORCPT ); Thu, 3 Dec 2020 17:46:25 -0500 Received: from m43-15.mailgun.net ([69.72.43.15]:62387 "EHLO m43-15.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729644AbgLCWqZ (ORCPT ); Thu, 3 Dec 2020 17:46:25 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1607035558; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=wywm4i+WEBOzifFxi65jP0ysRzXvf/6QXNek0ey6mUg=; b=kXYIEx5FfRlfTUU7xm6Mr7baGO8jy55+6eN+QS6bCSOJ+KVtV0zw5zPegfS7AigTm9qmoIi4 gP6uhpMDUkSXGxSYD1LPGHEBRjn5jVvwCb8oW3wsgGEqpVVjoo3dT7u6eVrAO9nxIa1iFVTz pIXaswFSxRhjfOgvWgdaDs0maZY= X-Mailgun-Sending-Ip: 69.72.43.15 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n02.prod.us-west-2.postgun.com with SMTP id 5fc96a8708086a3dc7d1da6a (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 03 Dec 2020 22:45:27 GMT Sender: hemantk=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 68EFDC433CA; Thu, 3 Dec 2020 22:45:27 +0000 (UTC) Received: from codeaurora.org (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: hemantk) by smtp.codeaurora.org (Postfix) with ESMTPSA id B1922C43462; Thu, 3 Dec 2020 22:45:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org B1922C43462 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org, gregkh@linuxfoundation.org Cc: 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, Hemant Kumar Subject: [PATCH v15 4/4] bus: mhi: Add userspace client interface driver Date: Thu, 3 Dec 2020 14:45:16 -0800 Message-Id: <1607035516-3093-5-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> References: <1607035516-3093-1-git-send-email-hemantk@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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/ Currently it supports QMI channel. Signed-off-by: Hemant Kumar Reviewed-by: Manivannan Sadhasivam Reviewed-by: Jeffrey Hugo --- drivers/bus/mhi/Kconfig | 13 + drivers/bus/mhi/Makefile | 3 + drivers/bus/mhi/uci.c | 664 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 680 insertions(+) create mode 100644 drivers/bus/mhi/uci.c diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig index da5cd0c..5194e8e 100644 --- a/drivers/bus/mhi/Kconfig +++ b/drivers/bus/mhi/Kconfig @@ -29,3 +29,16 @@ config MHI_BUS_PCI_GENERIC This driver provides MHI PCI controller driver for devices such as Qualcomm SDX55 based PCIe modems. +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, poll 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 0a2d778..69f2111 100644 --- a/drivers/bus/mhi/Makefile +++ b/drivers/bus/mhi/Makefile @@ -4,3 +4,6 @@ obj-y += core/ obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o mhi_pci_generic-y += pci_generic.o +# MHI client +mhi_uci-y := uci.o +obj-$(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..1df2377 --- /dev/null +++ b/drivers/bus/mhi/uci.c @@ -0,0 +1,664 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.*/ + +#include +#include +#include +#include +#include + +#define MHI_UCI_DRIVER_NAME "mhi_uci" +#define MHI_MAX_UCI_MINORS 128 + +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 */ + 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; +}; + +/** + * 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_desc, i, ret = -EIO; + size_t dl_buf_size; + void *buf; + struct uci_buf *ubuf; + + /* + * skip queuing without error if dl channel is not supported. This + * allows open to succeed for udev, supporting ul only channel. + */ + if (!udev->mhi_dev->dl_chan) + return 0; + + nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + for (i = 0; i < nr_desc; 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_desc, + 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) + mask |= EPOLLIN | EPOLLRDNORM; + spin_unlock_bh(&uchan->dl_pending_lock); + + if (mhi_get_free_desc_count(mhi_dev, DMA_TO_DEVICE) > 0) + 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_desc = 0; + + /* if ul channel is not supported return error */ + if (!mhi_dev->ul_chan) + return -EOPNOTSUPP; + + if (!buf || !count) + 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_desc = 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_desc > 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 (!mhi_dev->dl_chan) + return -EOPNOTSUPP; + + if (!buf) + return -EINVAL; + + 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, "%s: status: %d xfer_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + 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, "%s: status: %d receive_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + 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 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, MHI_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/ */ + dev = device_create(uci_dev_class, &mhi_dev->dev, + MKDEV(uci_dev_major, index), udev, "%s", + dev_name(&mhi_dev->dev)); + 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 = "QMI", .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");