From patchwork Thu Jun 11 18:13:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 188541 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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 86EAEC433E1 for ; Thu, 11 Jun 2020 18:14:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FE7620792 for ; Thu, 11 Jun 2020 18:14:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="UX7jHR7K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727010AbgFKSOL (ORCPT ); Thu, 11 Jun 2020 14:14:11 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:28339 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726972AbgFKSOI (ORCPT ); Thu, 11 Jun 2020 14:14:08 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1591899248; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=bXMXa2q0kBPywAqymgm7CebcLLhjCuyUceLkBJWseiA=; b=UX7jHR7KsHb/pTylmkqBrMw/HQD55yFlvLBo500S3g9VBt/NPyeiihwT0u3dWm2C5iHtHXRl zEw0zpaTwVmx5bQaHTyJ/kWETtn8s9B9o8IyqPgRQzrCaWopDnYS9X6Q8+qTLxdMp0yWRJlf VePwI18Bveo8pHzBTr2xJxhX0jQ= X-Mailgun-Sending-Ip: 104.130.122.27 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-n01.prod.us-west-2.postgun.com with SMTP id 5ee2745f6bebe35debd5479e (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 11 Jun 2020 18:13:51 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 4FDCEC433CB; Thu, 11 Jun 2020 18:13:51 +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 8D8D8C43387; Thu, 11 Jun 2020 18:13:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 8D8D8C43387 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=none smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, Hemant Kumar Subject: [PATCH v3 3/4] docs: Add documentation for user space client interface Date: Thu, 11 Jun 2020 11:13:43 -0700 Message-Id: <1591899224-3403-4-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1591899224-3403-1-git-send-email-hemantk@codeaurora.org> References: <1591899224-3403-1-git-send-email-hemantk@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org MHI user space client driver is creating device file node for user application to perform file operations. File operations are handled by MHI core driver. Currently Loopback MHI channel is supported by this driver. Signed-off-by: Hemant Kumar --- Documentation/mhi/index.rst | 1 + Documentation/mhi/uci.rst | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) create mode 100644 Documentation/mhi/uci.rst diff --git a/Documentation/mhi/index.rst b/Documentation/mhi/index.rst index 1d8dec3..c75a371 100644 --- a/Documentation/mhi/index.rst +++ b/Documentation/mhi/index.rst @@ -9,6 +9,7 @@ MHI mhi topology + uci .. only:: subproject and html diff --git a/Documentation/mhi/uci.rst b/Documentation/mhi/uci.rst new file mode 100644 index 0000000..a5c5c4f --- /dev/null +++ b/Documentation/mhi/uci.rst @@ -0,0 +1,19 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================= +User space Client Interface (UCI) +================================= + +UCI driver enables user space clients to communicate to external MHI devices +like modem and WLAN. It creates standard character device file nodes for user +space clients to perform open, read, write, pool and close file operations. + +Device file node is created with format:- + +/dev/mhi__ + +controller_name is the name of underlying bus used to transfer data. +mhi_device_name is the name of the MHI channel being used by MHI client +to send or receive data using MHI protocol. MHI channels are statically +defined by MHI specification. Driver currently supports LOOPBACK channel +index 0 (Host to device) and 1 (Device to Host). From patchwork Thu Jun 11 18:13:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hemant Kumar X-Patchwork-Id: 188542 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=-9.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 761D5C433E0 for ; Thu, 11 Jun 2020 18:13:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BE1F20792 for ; Thu, 11 Jun 2020 18:13:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="Gzx1dpXf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725869AbgFKSNz (ORCPT ); Thu, 11 Jun 2020 14:13:55 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:26063 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726651AbgFKSNy (ORCPT ); Thu, 11 Jun 2020 14:13:54 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1591899233; h=References: In-Reply-To: Message-Id: Date: Subject: Cc: To: From: Sender; bh=47ndPSojhmIubKCWo5i5IwQSHgsAeT8S7hMsFV72gaM=; b=Gzx1dpXf+ATeVnN8KDFk887hm+B36KfCJkn9bLgmtV5YIyL/7Fj8lmbOO76j1Vq+z87teMAA IOPD1w03HS0UG1PWAPg+9YWkwlN6qOT0yAKe5FbcsRt7t1UBtWdq+XtvMlM3/Xhh60gXxSis kVyUE9W+ZL1QVKQjDNi+Nr3MQgk= X-Mailgun-Sending-Ip: 69.72.43.7 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-n13.prod.us-west-2.postgun.com with SMTP id 5ee27460117610c7ff93f27c (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 11 Jun 2020 18:13:52 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 4781EC433CA; Thu, 11 Jun 2020 18:13:52 +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 05985C43395; Thu, 11 Jun 2020 18:13:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 05985C43395 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=none smtp.mailfrom=hemantk@codeaurora.org From: Hemant Kumar To: manivannan.sadhasivam@linaro.org Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, jhugo@codeaurora.org, bbhatt@codeaurora.org, Hemant Kumar Subject: [PATCH v3 4/4] bus: mhi: clients: Add user space client interface driver Date: Thu, 11 Jun 2020 11:13:44 -0700 Message-Id: <1591899224-3403-5-git-send-email-hemantk@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1591899224-3403-1-git-send-email-hemantk@codeaurora.org> References: <1591899224-3403-1-git-send-email-hemantk@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This MHI client driver allows user space clients to transfer data between MHI device and host using standard file operations. Device file node is created with format /dev/mhi__ Currently it supports loopback client. Signed-off-by: Hemant Kumar --- drivers/bus/mhi/Kconfig | 2 + drivers/bus/mhi/Makefile | 1 + drivers/bus/mhi/clients/Kconfig | 16 + drivers/bus/mhi/clients/Makefile | 3 + drivers/bus/mhi/clients/uci.c | 652 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 674 insertions(+) create mode 100644 drivers/bus/mhi/clients/Kconfig create mode 100644 drivers/bus/mhi/clients/Makefile create mode 100644 drivers/bus/mhi/clients/uci.c diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig index 6a217ff..f224be8 100644 --- a/drivers/bus/mhi/Kconfig +++ b/drivers/bus/mhi/Kconfig @@ -20,3 +20,5 @@ 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. + +source "drivers/bus/mhi/clients/Kconfig" diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile index 19e6443..48f6028 100644 --- a/drivers/bus/mhi/Makefile +++ b/drivers/bus/mhi/Makefile @@ -1,2 +1,3 @@ # core layer obj-y += core/ +obj-y += clients/ diff --git a/drivers/bus/mhi/clients/Kconfig b/drivers/bus/mhi/clients/Kconfig new file mode 100644 index 0000000..cd84419 --- /dev/null +++ b/drivers/bus/mhi/clients/Kconfig @@ -0,0 +1,16 @@ +# SPDX-License-Identifier: GPL-2.0-only + +menu "MHI clients support" + depends on MHI_BUS + +config MHI_UCI + tristate "MHI UCI" + depends on MHI_BUS + help + MHI based userspace client interface driver is for transferring + data between host and device using standard file operations from + user space. 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. + +endmenu diff --git a/drivers/bus/mhi/clients/Makefile b/drivers/bus/mhi/clients/Makefile new file mode 100644 index 0000000..dd2930c --- /dev/null +++ b/drivers/bus/mhi/clients/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only + +obj-$(CONFIG_MHI_UCI) +=uci.o diff --git a/drivers/bus/mhi/clients/uci.c b/drivers/bus/mhi/clients/uci.c new file mode 100644 index 0000000..8f36fb0 --- /dev/null +++ b/drivers/bus/mhi/clients/uci.c @@ -0,0 +1,652 @@ +// 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_DEVICES (64) + +struct uci_chan { + wait_queue_head_t wq; + + /* locks ul/dl uci device channel */ + spinlock_t lock; + + /* user space waiting to read */ + struct list_head pending; + + /* current buffer user space reading */ + struct uci_buf *cur_buf; + size_t rx_size; +}; + +struct uci_buf { + void *data; + size_t len; + struct list_head node; +}; + +struct mhi_uci_drv { + struct list_head head; + + /* uci driver lock to sync open, probe and remove */ + struct mutex lock; + struct class *class; + int major; + dev_t dev_t; +}; + +struct uci_dev { + struct list_head node; + dev_t devt; + struct device *dev; + struct mhi_device *mhi_dev; + const char *chan; + + /* sync open and close */ + struct mutex mutex; + struct uci_chan ul_chan; + struct uci_chan dl_chan; + size_t mtu; + + /* maximum size of incoming buffer */ + size_t actual_mtu; + int ref_count; + bool enabled; +}; + +static DECLARE_BITMAP(uci_minors, MAX_UCI_DEVICES); +static struct mhi_uci_drv mhi_uci_drv; + +static int mhi_queue_inbound(struct uci_dev *uci_dev) +{ + struct mhi_device *mhi_dev = uci_dev->mhi_dev; + struct device *dev = &mhi_dev->dev; + int nr_trbs = mhi_get_no_free_descriptors(mhi_dev, DMA_FROM_DEVICE); + size_t mtu = uci_dev->mtu; + size_t actual_mtu = uci_dev->actual_mtu; + void *buf; + struct uci_buf *uci_buf; + int ret = -EIO, i; + + for (i = 0; i < nr_trbs; i++) { + buf = kmalloc(mtu, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + uci_buf = buf + actual_mtu; + uci_buf->data = buf; + + dev_dbg(dev, "Allocated buf %d of %d size %ld\n", i, nr_trbs, + actual_mtu); + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, actual_mtu, + MHI_EOT); + if (ret) { + kfree(buf); + dev_err(dev, "Failed to queue buffer %d\n", i); + return ret; + } + } + + return ret; +} + +static int mhi_uci_release(struct inode *inode, struct file *file) +{ + struct uci_dev *uci_dev = file->private_data; + + mutex_lock(&uci_dev->mutex); + uci_dev->ref_count--; + if (!uci_dev->ref_count) { + struct uci_buf *itr, *tmp; + struct uci_chan *uci_chan; + + if (uci_dev->enabled) + mhi_unprepare_from_transfer(uci_dev->mhi_dev); + + /* clean inbound channel */ + uci_chan = &uci_dev->dl_chan; + list_for_each_entry_safe(itr, tmp, &uci_chan->pending, node) { + list_del(&itr->node); + kfree(itr->data); + } + if (uci_chan->cur_buf) + kfree(uci_chan->cur_buf->data); + + uci_chan->cur_buf = NULL; + + if (!uci_dev->enabled) { + mutex_unlock(&uci_dev->mutex); + mutex_destroy(&uci_dev->mutex); + clear_bit(MINOR(uci_dev->devt), uci_minors); + kfree(uci_dev); + return 0; + } + } + + mutex_unlock(&uci_dev->mutex); + + return 0; +} + +static __poll_t mhi_uci_poll(struct file *file, poll_table *wait) +{ + struct uci_dev *uci_dev = file->private_data; + struct mhi_device *mhi_dev = uci_dev->mhi_dev; + struct device *dev = &mhi_dev->dev; + struct uci_chan *uci_chan; + __poll_t mask = 0; + + poll_wait(file, &uci_dev->dl_chan.wq, wait); + poll_wait(file, &uci_dev->ul_chan.wq, wait); + + uci_chan = &uci_dev->dl_chan; + spin_lock_bh(&uci_chan->lock); + if (!uci_dev->enabled) { + mask = EPOLLERR; + } else { + if (!list_empty(&uci_chan->pending) || uci_chan->cur_buf) { + dev_dbg(dev, "Client can read from node\n"); + mask |= EPOLLIN | EPOLLRDNORM; + } + } + spin_unlock_bh(&uci_chan->lock); + + uci_chan = &uci_dev->ul_chan; + spin_lock_bh(&uci_chan->lock); + if (!uci_dev->enabled) { + mask |= EPOLLERR; + } else if (mhi_get_no_free_descriptors(mhi_dev, DMA_TO_DEVICE) > 0) { + dev_dbg(dev, "Client can write to node\n"); + mask |= EPOLLOUT | EPOLLWRNORM; + } + spin_unlock_bh(&uci_chan->lock); + + dev_dbg(dev, "Client attempted to poll, returning mask 0x%x\n", mask); + + return mask; +} + +static ssize_t mhi_uci_write(struct file *file, + const char __user *buf, + size_t count, + loff_t *offp) +{ + struct uci_dev *uci_dev = file->private_data; + struct mhi_device *mhi_dev = uci_dev->mhi_dev; + struct device *dev = &mhi_dev->dev; + struct uci_chan *uci_chan = &uci_dev->ul_chan; + size_t bytes_xfered = 0; + int ret, nr_avail; + + if (!buf || !count) + return -EINVAL; + + /* confirm channel is active */ + spin_lock_bh(&uci_chan->lock); + if (!uci_dev->enabled) { + spin_unlock_bh(&uci_chan->lock); + return -ERESTARTSYS; + } + + dev_dbg(dev, "Enter: to xfer:%lu bytes\n", count); + + while (count) { + size_t xfer_size; + void *kbuf; + enum mhi_flags flags; + + spin_unlock_bh(&uci_chan->lock); + + /* wait for free descriptors */ + ret = wait_event_interruptible(uci_chan->wq, + (!uci_dev->enabled) || + (nr_avail = mhi_get_no_free_descriptors(mhi_dev, + DMA_TO_DEVICE)) > 0); + + if (ret == -ERESTARTSYS || !uci_dev->enabled) { + dev_dbg(dev, "Exit signal caught for node or not enabled\n"); + return -ERESTARTSYS; + } + + xfer_size = min_t(size_t, count, uci_dev->mtu); + kbuf = kmalloc(xfer_size, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + ret = copy_from_user(kbuf, buf, xfer_size); + if (unlikely(ret)) { + kfree(kbuf); + return ret; + } + + spin_lock_bh(&uci_chan->lock); + + /* if ring is full after this force EOT */ + if (nr_avail > 1 && (count - xfer_size)) + flags = MHI_CHAIN; + else + flags = MHI_EOT; + + if (uci_dev->enabled) + ret = mhi_queue_buf(mhi_dev, DMA_TO_DEVICE, kbuf, + xfer_size, flags); + else + ret = -ERESTARTSYS; + + if (ret) { + kfree(kbuf); + goto sys_interrupt; + } + + bytes_xfered += xfer_size; + count -= xfer_size; + buf += xfer_size; + } + + spin_unlock_bh(&uci_chan->lock); + dev_dbg(dev, "Exit: Number of bytes xferred:%lu\n", bytes_xfered); + + return bytes_xfered; + +sys_interrupt: + spin_unlock_bh(&uci_chan->lock); + + return ret; +} + +static ssize_t mhi_uci_read(struct file *file, + char __user *buf, + size_t count, + loff_t *ppos) +{ + struct uci_dev *uci_dev = file->private_data; + struct mhi_device *mhi_dev = uci_dev->mhi_dev; + struct uci_chan *uci_chan = &uci_dev->dl_chan; + struct device *dev = &mhi_dev->dev; + struct uci_buf *uci_buf; + char *ptr; + size_t to_copy; + int ret = 0; + + if (!buf) + return -EINVAL; + + dev_dbg(dev, "Client provided buf len:%lu\n", count); + + mutex_lock(&uci_dev->mutex); + /* confirm channel is active */ + spin_lock_bh(&uci_chan->lock); + if (!uci_dev->enabled) { + spin_unlock_bh(&uci_chan->lock); + mutex_unlock(&uci_dev->mutex); + return -ERESTARTSYS; + } + + /* No data available to read, wait */ + if (!uci_chan->cur_buf && list_empty(&uci_chan->pending)) { + dev_dbg(dev, "No data available to read waiting\n"); + + spin_unlock_bh(&uci_chan->lock); + mutex_unlock(&uci_dev->mutex); + ret = wait_event_interruptible(uci_chan->wq, + (!uci_dev->enabled || + !list_empty(&uci_chan->pending))); + if (ret == -ERESTARTSYS) { + dev_dbg(dev, "Exit signal caught for node\n"); + return -ERESTARTSYS; + } + + mutex_lock(&uci_dev->mutex); + spin_lock_bh(&uci_chan->lock); + if (!uci_dev->enabled) { + dev_dbg(dev, "node is disabled\n"); + ret = -ERESTARTSYS; + goto read_error; + } + } + + /* new read, get the next descriptor from the list */ + if (!uci_chan->cur_buf) { + uci_buf = list_first_entry_or_null(&uci_chan->pending, + struct uci_buf, node); + if (unlikely(!uci_buf)) { + ret = -EIO; + goto read_error; + } + + list_del(&uci_buf->node); + uci_chan->cur_buf = uci_buf; + uci_chan->rx_size = uci_buf->len; + dev_dbg(dev, "Got pkt of size:%zu\n", uci_chan->rx_size); + } + + uci_buf = uci_chan->cur_buf; + + /* Copy the buffer to user space */ + to_copy = min_t(size_t, count, uci_chan->rx_size); + ptr = uci_buf->data + (uci_buf->len - uci_chan->rx_size); + spin_unlock_bh(&uci_chan->lock); + + ret = copy_to_user(buf, ptr, to_copy); + if (ret) + goto err_unlock_mtx; + + spin_lock_bh(&uci_chan->lock); + + dev_dbg(dev, "Copied %lu of %lu bytes\n", to_copy, uci_chan->rx_size); + uci_chan->rx_size -= to_copy; + + /* we finished with this buffer, queue it back to hardware */ + if (!uci_chan->rx_size) { + uci_chan->cur_buf = NULL; + + if (uci_dev->enabled) + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, + uci_buf->data, + uci_dev->actual_mtu, MHI_EOT); + else + ret = -ERESTARTSYS; + + if (ret) { + dev_err(dev, "Failed to recycle element\n"); + kfree(uci_buf->data); + goto read_error; + } + } + spin_unlock_bh(&uci_chan->lock); + mutex_unlock(&uci_dev->mutex); + + dev_dbg(dev, "Returning %lu bytes\n", to_copy); + + return to_copy; + +read_error: + spin_unlock_bh(&uci_chan->lock); +err_unlock_mtx: + mutex_unlock(&uci_dev->mutex); + return ret; +} + +static int mhi_uci_open(struct inode *inode, struct file *filp) +{ + struct uci_dev *uci_dev = NULL, *tmp_dev; + int ret = -EIO; + struct uci_buf *buf_itr, *tmp; + struct uci_chan *dl_chan; + struct mhi_device *mhi_dev; + struct device *dev; + + mutex_lock(&mhi_uci_drv.lock); + list_for_each_entry(tmp_dev, &mhi_uci_drv.head, node) { + if (tmp_dev->devt == inode->i_rdev) { + uci_dev = tmp_dev; + break; + } + } + + /* could not find a minor node */ + if (!uci_dev) + goto error_exit; + + mhi_dev = uci_dev->mhi_dev; + dev = &mhi_dev->dev; + + mutex_lock(&uci_dev->mutex); + if (!uci_dev->enabled) { + dev_info(dev, "Node exist, but not in active state!\n"); + goto error_open_chan; + } + + uci_dev->ref_count++; + + dev_dbg(dev, "Node open, ref counts %u\n", uci_dev->ref_count); + + if (uci_dev->ref_count == 1) { + dev_dbg(dev, "Starting channel\n"); + ret = mhi_prepare_for_transfer(uci_dev->mhi_dev); + if (ret) { + dev_err(dev, "Error starting transfer channels\n"); + uci_dev->ref_count--; + goto error_open_chan; + } + + ret = mhi_queue_inbound(uci_dev); + if (ret) + goto error_rx_queue; + } + + filp->private_data = uci_dev; + mutex_unlock(&uci_dev->mutex); + mutex_unlock(&mhi_uci_drv.lock); + + return 0; + +error_rx_queue: + dl_chan = &uci_dev->dl_chan; + mhi_unprepare_from_transfer(uci_dev->mhi_dev); + list_for_each_entry_safe(buf_itr, tmp, &dl_chan->pending, node) { + list_del(&buf_itr->node); + kfree(buf_itr->data); + } + +error_open_chan: + mutex_unlock(&uci_dev->mutex); + +error_exit: + mutex_unlock(&mhi_uci_drv.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 *uci_dev = dev_get_drvdata(&mhi_dev->dev); + struct uci_chan *uci_chan = &uci_dev->ul_chan; + struct device *dev = &mhi_dev->dev; + + dev_dbg(dev, "status:%d xfer_len:%zu\n", mhi_result->transaction_status, + mhi_result->bytes_xferd); + + kfree(mhi_result->buf_addr); + if (!mhi_result->transaction_status) + wake_up(&uci_chan->wq); +} + +static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct uci_dev *uci_dev = dev_get_drvdata(&mhi_dev->dev); + struct uci_chan *uci_chan = &uci_dev->dl_chan; + struct device *dev = &mhi_dev->dev; + unsigned long flags; + struct uci_buf *buf; + + dev_dbg(dev, "status:%d receive_len:%zu\n", + mhi_result->transaction_status, mhi_result->bytes_xferd); + + if (mhi_result->transaction_status == -ENOTCONN) { + kfree(mhi_result->buf_addr); + return; + } + + spin_lock_irqsave(&uci_chan->lock, flags); + buf = mhi_result->buf_addr + uci_dev->actual_mtu; + buf->data = mhi_result->buf_addr; + buf->len = mhi_result->bytes_xferd; + list_add_tail(&buf->node, &uci_chan->pending); + spin_unlock_irqrestore(&uci_chan->lock, flags); + + wake_up(&uci_chan->wq); +} + +static int mhi_uci_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + struct uci_dev *uci_dev; + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; + struct device *dev = &mhi_dev->dev; + int minor; + int dir; + + uci_dev = kzalloc(sizeof(*uci_dev), GFP_KERNEL); + if (!uci_dev) + return -ENOMEM; + + mutex_init(&uci_dev->mutex); + uci_dev->mhi_dev = mhi_dev; + + mutex_lock(&uci_dev->mutex); + mutex_lock(&mhi_uci_drv.lock); + + minor = find_first_zero_bit(uci_minors, MAX_UCI_DEVICES); + if (minor >= MAX_UCI_DEVICES) { + mutex_unlock(&mhi_uci_drv.lock); + mutex_unlock(&uci_dev->mutex); + kfree(uci_dev); + return -ENOSPC; + } + + uci_dev->devt = MKDEV(mhi_uci_drv.major, minor); + uci_dev->dev = device_create(mhi_uci_drv.class, &mhi_dev->dev, + uci_dev->devt, uci_dev, + DEVICE_NAME "_%s_%s", + dev_name(mhi_cntrl->cntrl_dev), + mhi_dev->name); + set_bit(minor, uci_minors); + + for (dir = 0; dir < 2; dir++) { + struct uci_chan *uci_chan = (dir) ? + &uci_dev->ul_chan : &uci_dev->dl_chan; + spin_lock_init(&uci_chan->lock); + init_waitqueue_head(&uci_chan->wq); + INIT_LIST_HEAD(&uci_chan->pending); + } + + uci_dev->mtu = min_t(size_t, id->driver_data, MHI_MAX_MTU); + uci_dev->actual_mtu = uci_dev->mtu - sizeof(struct uci_buf); + dev_set_drvdata(&mhi_dev->dev, uci_dev); + uci_dev->enabled = true; + + list_add(&uci_dev->node, &mhi_uci_drv.head); + mutex_unlock(&mhi_uci_drv.lock); + mutex_unlock(&uci_dev->mutex); + + dev_info(dev, "channel:%s successfully probed\n", mhi_dev->name); + + return 0; +}; + +static void mhi_uci_remove(struct mhi_device *mhi_dev) +{ + struct uci_dev *uci_dev = dev_get_drvdata(&mhi_dev->dev); + struct device *dev = &mhi_dev->dev; + + dev_dbg(dev, "%s: enter\n", __func__); + + mutex_lock(&mhi_uci_drv.lock); + mutex_lock(&uci_dev->mutex); + + /* disable the node */ + spin_lock_irq(&uci_dev->dl_chan.lock); + spin_lock_irq(&uci_dev->ul_chan.lock); + uci_dev->enabled = false; + spin_unlock_irq(&uci_dev->ul_chan.lock); + spin_unlock_irq(&uci_dev->dl_chan.lock); + wake_up(&uci_dev->dl_chan.wq); + wake_up(&uci_dev->ul_chan.wq); + + /* delete the node to prevent new opens */ + device_destroy(mhi_uci_drv.class, uci_dev->devt); + uci_dev->dev = NULL; + list_del(&uci_dev->node); + + /* safe to free memory only if all file nodes are closed */ + if (!uci_dev->ref_count) { + mutex_unlock(&uci_dev->mutex); + mutex_destroy(&uci_dev->mutex); + clear_bit(MINOR(uci_dev->devt), uci_minors); + dev_set_drvdata(&mhi_dev->dev, NULL); + kfree(uci_dev); + mutex_unlock(&mhi_uci_drv.lock); + return; + } + + mutex_unlock(&uci_dev->mutex); + mutex_unlock(&mhi_uci_drv.lock); + + dev_dbg(dev, "%s: exit\n", __func__); +} + +/* .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 mhi_uci_init(void) +{ + int ret; + + ret = register_chrdev(0, MHI_UCI_DRIVER_NAME, &mhidev_fops); + if (ret < 0) + return ret; + + mhi_uci_drv.major = ret; + mhi_uci_drv.class = class_create(THIS_MODULE, MHI_UCI_DRIVER_NAME); + if (IS_ERR(mhi_uci_drv.class)) { + unregister_chrdev(mhi_uci_drv.major, MHI_UCI_DRIVER_NAME); + return -ENODEV; + } + + mutex_init(&mhi_uci_drv.lock); + INIT_LIST_HEAD(&mhi_uci_drv.head); + + ret = mhi_driver_register(&mhi_uci_driver); + if (ret) { + class_destroy(mhi_uci_drv.class); + unregister_chrdev(mhi_uci_drv.major, MHI_UCI_DRIVER_NAME); + } + + return ret; +} + +static void __exit mhi_uci_exit(void) +{ + mhi_driver_unregister(&mhi_uci_driver); + class_destroy(mhi_uci_drv.class); + unregister_chrdev(mhi_uci_drv.major, MHI_UCI_DRIVER_NAME); +} + +module_init(mhi_uci_init); +module_exit(mhi_uci_exit); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MHI UCI Driver");