@@ -19,4 +19,18 @@ config WWAN_CORE
To compile this driver as a module, choose M here: the module will be
called wwan.
+config MHI_WWAN_CTRL
+ tristate "MHI WWAN control driver for QCOM-based PCIe modems"
+ select WWAN_CORE
+ depends on MHI_BUS
+ help
+ MHI WWAN CTRL allows QCOM-based PCIe modems to expose different modem
+ control protocols/ports to userspace, including AT, MBIM, QMI, DIAG
+ and FIREHOSE. These protocols can be accessed directly from userspace
+ (e.g. AT commands) or via libraries/tools (e.g. libmbim, libqmi,
+ libqcdm...).
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_wwan_ctrl
+
endif # WWAN
@@ -5,3 +5,5 @@
obj-$(CONFIG_WWAN_CORE) += wwan.o
wwan-objs += wwan_core.o
+
+obj-$(CONFIG_MHI_WWAN_CTRL) += mhi_wwan_ctrl.o
new file mode 100644
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2018-2021, The Linux Foundation. All rights reserved.*/
+
+#include <linux/kernel.h>
+#include <linux/mhi.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/wwan.h>
+
+/* MHI wwan device flags */
+#define MHI_WWAN_DL_CAP BIT(0)
+#define MHI_WWAN_UL_CAP BIT(1)
+#define MHI_WWAN_CONNECTED BIT(2)
+#define MHI_WWAN_TX_FULL BIT(3)
+
+#define MHI_WWAN_MAX_MTU 0x8000
+
+struct mhi_wwan_buf {
+ struct list_head node;
+ void *data;
+ size_t len;
+ size_t consumed;
+};
+
+struct mhi_wwan_dev {
+ /* Lower level is a mhi dev, upper level is a wwan port */
+ struct mhi_device *mhi_dev;
+ struct wwan_port *wwan_port;
+
+ /* Protect mhi device against concurrent accesses (queue, remove...) */
+ struct mutex mhi_dev_lock;
+ unsigned int mhi_dev_start_count;
+
+ /* read/write wait queues */
+ wait_queue_head_t ul_wq;
+ wait_queue_head_t dl_wq;
+
+ /* Protect local download queue against concurent update (read/xfer_cb) */
+ spinlock_t dl_queue_lock;
+ struct list_head dl_queue;
+
+ unsigned long flags;
+ size_t mtu;
+
+ /* kref is used to safely refcount and release a mhi_wwan_dev instance,
+ * which is shared between mhi-dev probe/remove and wwan-port fops.
+ */
+ struct kref refcnt;
+};
+
+static void mhi_wwan_ctrl_dev_release(struct kref *ref)
+{
+ struct mhi_wwan_dev *mhiwwan = container_of(ref, struct mhi_wwan_dev, refcnt);
+ struct mhi_wwan_buf *buf_itr, *tmp;
+
+ /* Release non consumed buffers (lock-free safe in release) */
+ list_for_each_entry_safe(buf_itr, tmp, &mhiwwan->dl_queue, node) {
+ list_del(&buf_itr->node);
+ kfree(buf_itr->data);
+ }
+
+ mutex_destroy(&mhiwwan->mhi_dev_lock);
+
+ kfree(mhiwwan);
+}
+
+static int mhi_wwan_ctrl_fill_inbound(struct mhi_wwan_dev *mhiwwan)
+{
+ struct mhi_device *mhi_dev = mhiwwan->mhi_dev;
+ int nr_desc, ret = -EIO;
+
+ lockdep_assert_held(&mhiwwan->mhi_dev_lock);
+
+ /* skip queuing without error if dl channel is not supported. This
+ * allows open to succeed for devices supporting ul channels only.
+ */
+ if (!mhi_dev->dl_chan)
+ return 0;
+
+ nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
+
+ while (nr_desc--) {
+ struct mhi_wwan_buf *mhibuf;
+ void *buf;
+
+ buf = kmalloc(mhiwwan->mtu + sizeof(*mhibuf), GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ /* save mhi_wwan_buf meta info at the end of the buffer */
+ mhibuf = buf + mhiwwan->mtu;
+ mhibuf->data = buf;
+
+ ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, mhiwwan->mtu, MHI_EOT);
+ if (ret) {
+ dev_err(&mhi_dev->dev, "Failed to queue buffer\n");
+ kfree(buf);
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+static int mhi_wwan_ctrl_start(struct mhi_wwan_dev *mhiwwan)
+{
+ struct mhi_device *mhi_dev;
+ int ret = 0;
+
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+
+ mhi_dev = mhiwwan->mhi_dev;
+ if (!mhi_dev) { /* mhi dev got hot-unplugged */
+ ret = -ENODEV;
+ goto exit_unlock;
+ }
+
+ /* Do not start if already started (by previous open) */
+ if (mhiwwan->mhi_dev_start_count)
+ goto exit_started;
+
+ /* Start mhi device's channel(s) */
+ ret = mhi_prepare_for_transfer(mhi_dev);
+ if (ret)
+ goto exit_unlock;
+
+ /* Add buffers to inbound queue */
+ ret = mhi_wwan_ctrl_fill_inbound(mhiwwan);
+ if (ret) {
+ mhi_unprepare_from_transfer(mhi_dev);
+ goto exit_unlock;
+ }
+
+exit_started:
+ mhiwwan->mhi_dev_start_count++;
+exit_unlock:
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+ return ret;
+}
+
+static void mhi_wwan_ctrl_stop(struct mhi_wwan_dev *mhiwwan)
+{
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+
+ mhiwwan->mhi_dev_start_count--;
+
+ if (mhiwwan->mhi_dev && !mhiwwan->mhi_dev_start_count)
+ mhi_unprepare_from_transfer(mhiwwan->mhi_dev);
+
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+}
+
+static int mhi_wwan_ctrl_open(struct inode *inode, struct file *filp)
+{
+ struct mhi_wwan_dev *mhiwwan = filp->private_data;
+ int ret = 0;
+
+ kref_get(&mhiwwan->refcnt);
+
+ ret = mhi_wwan_ctrl_start(mhiwwan);
+ if (ret)
+ kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release);
+
+ return ret;
+}
+
+static int mhi_wwan_ctrl_release(struct inode *inode, struct file *filp)
+{
+ struct mhi_wwan_dev *mhiwwan = filp->private_data;
+
+ mhi_wwan_ctrl_stop(mhiwwan);
+ kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release);
+
+ return 0;
+}
+
+static __poll_t mhi_wwan_ctrl_poll(struct file *filp, poll_table *wait)
+{
+ struct mhi_wwan_dev *mhiwwan = filp->private_data;
+ __poll_t mask = 0;
+
+ poll_wait(filp, &mhiwwan->ul_wq, wait);
+ poll_wait(filp, &mhiwwan->dl_wq, wait);
+
+ /* Any buffer in the DL queue ? */
+ spin_lock_bh(&mhiwwan->dl_queue_lock);
+ if (!list_empty(&mhiwwan->dl_queue))
+ mask |= EPOLLIN | EPOLLRDNORM;
+ spin_unlock_bh(&mhiwwan->dl_queue_lock);
+
+ /* If MHI queue is not full, write is possible */
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+ if (!mhiwwan->mhi_dev) /* mhi dev got hot-unplugged */
+ mask = EPOLLHUP;
+ else if (!mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+
+ return mask;
+}
+
+static bool is_write_blocked(struct mhi_wwan_dev *mhiwwan)
+{
+ return test_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags) &&
+ test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags);
+}
+
+static int mhi_wwan_wait_writable(struct mhi_wwan_dev *mhiwwan, bool nonblock)
+{
+ int ret;
+
+ if (is_write_blocked(mhiwwan)) {
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(mhiwwan->ul_wq,
+ !is_write_blocked(mhiwwan));
+ if (ret < 0)
+ return -ERESTARTSYS;
+ }
+
+ if (!test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags))
+ return -ENODEV;
+
+ return 0;
+}
+
+static ssize_t mhi_wwan_ctrl_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct mhi_wwan_dev *mhiwwan = filp->private_data;
+ size_t xfer_size = min_t(size_t, count, mhiwwan->mtu);
+ void *kbuf;
+ int ret;
+
+ if (!test_bit(MHI_WWAN_UL_CAP, &mhiwwan->flags))
+ return -EOPNOTSUPP;
+
+ if (!buf || !count)
+ return -EINVAL;
+
+ ret = mhi_wwan_wait_writable(mhiwwan, filp->f_flags & O_NONBLOCK);
+ if (ret)
+ return ret;
+
+ kbuf = kmalloc(xfer_size, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+
+ if (copy_from_user(kbuf, buf, xfer_size)) {
+ ret = -EFAULT;
+ goto exit_free_buf;
+ }
+
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+
+ if (!mhiwwan->mhi_dev) { /* mhi dev got hot-unplugged */
+ ret = -ENODEV;
+ goto exit_unlock;
+ }
+
+ ret = mhi_queue_buf(mhiwwan->mhi_dev, DMA_TO_DEVICE, kbuf, xfer_size, MHI_EOT);
+ if (ret)
+ goto exit_unlock;
+
+ kbuf = NULL; /* Buffer is owned by MHI core now, prevent freeing */
+
+ if (mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE))
+ set_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags);
+
+exit_unlock:
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+exit_free_buf:
+ kfree(kbuf);
+
+ return ret ? ret : xfer_size;
+}
+
+static void mhi_wwan_ctrl_recycle_mhibuf(struct mhi_wwan_dev *mhiwwan,
+ struct mhi_wwan_buf *mhibuf)
+{
+ struct mhi_device *mhi_dev;
+ int ret;
+
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+
+ mhi_dev = mhiwwan->mhi_dev;
+ if (!mhi_dev) /* mhi dev got hot-unplugged */
+ kfree(mhibuf->data);
+
+ ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, mhibuf->data,
+ mhiwwan->mtu, MHI_EOT);
+ if (ret) {
+ dev_warn(&mhi_dev->dev, "Unable to recycle buffer (%d)\n", ret);
+ kfree(mhibuf->data);
+ }
+
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+}
+
+static bool is_read_blocked(struct mhi_wwan_dev *mhiwwan)
+{
+ return test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags) &&
+ list_empty(&mhiwwan->dl_queue);
+}
+
+/* Called with dl_queue lock to wait for buffer in the dl_queue */
+static int mhi_wwan_wait_dlqueue_lock_irq(struct mhi_wwan_dev *mhiwwan, bool nonblock)
+{
+ int ret;
+
+ lockdep_assert_held(&mhiwwan->dl_queue_lock);
+
+ if (is_read_blocked(mhiwwan)) {
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible_lock_irq(mhiwwan->dl_wq,
+ !is_read_blocked(mhiwwan),
+ mhiwwan->dl_queue_lock);
+ if (ret < 0)
+ return -ERESTARTSYS;
+ }
+
+ if (!test_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags))
+ return -ENODEV;
+
+ return 0;
+}
+
+static ssize_t mhi_wwan_ctrl_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct mhi_wwan_dev *mhiwwan = filp->private_data;
+ struct mhi_wwan_buf *mhibuf;
+ size_t copy_len;
+ char *copy_ptr;
+ int ret = 0;
+
+ if (!test_bit(MHI_WWAN_DL_CAP, &mhiwwan->flags))
+ return -EOPNOTSUPP;
+
+ if (!buf)
+ return -EINVAL;
+
+ /* _irq variant to use wait_event_interruptible_lock_irq() */
+ spin_lock_irq(&mhiwwan->dl_queue_lock);
+
+ ret = mhi_wwan_wait_dlqueue_lock_irq(mhiwwan, filp->f_flags & O_NONBLOCK);
+ if (ret)
+ goto err_unlock;
+
+ mhibuf = list_first_entry_or_null(&mhiwwan->dl_queue, struct mhi_wwan_buf, node);
+ if (!mhibuf) {
+ ret = -EIO;
+ goto err_unlock;
+ }
+
+ /* Consume the buffer */
+ copy_len = min_t(size_t, count, mhibuf->len - mhibuf->consumed);
+ copy_ptr = mhibuf->data + mhibuf->consumed;
+ mhibuf->consumed += copy_len;
+
+ if (mhibuf->consumed != mhibuf->len) {
+ /* buffer has not been fully consumed, and stay in the local
+ * dl_queue.
+ */
+ if (copy_to_user(buf, copy_ptr, copy_len))
+ ret = -EFAULT;
+ spin_unlock_irq(&mhiwwan->dl_queue_lock);
+ } else {
+ /* buffer has been fully consumed, it can be removed from
+ * the local dl queue and recycled for a new mhi transfer.
+ */
+ list_del(&mhibuf->node);
+ spin_unlock_irq(&mhiwwan->dl_queue_lock);
+
+ if (copy_to_user(buf, copy_ptr, copy_len))
+ ret = -EFAULT;
+
+ mhi_wwan_ctrl_recycle_mhibuf(mhiwwan, mhibuf);
+ }
+
+ return ret ? ret : copy_len;
+
+err_unlock:
+ spin_unlock_irq(&mhiwwan->dl_queue_lock);
+
+ return ret;
+}
+
+static const struct file_operations mhidev_fops = {
+ .owner = THIS_MODULE,
+ .open = mhi_wwan_ctrl_open,
+ .release = mhi_wwan_ctrl_release,
+ .read = mhi_wwan_ctrl_read,
+ .write = mhi_wwan_ctrl_write,
+ .poll = mhi_wwan_ctrl_poll,
+};
+
+static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev,
+ struct mhi_result *mhi_result)
+{
+ struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev);
+
+ dev_dbg(&mhi_dev->dev, "%s: status: %d xfer_len: %zu\n", __func__,
+ mhi_result->transaction_status, mhi_result->bytes_xferd);
+
+ kfree(mhi_result->buf_addr);
+
+ if (!mhi_queue_is_full(mhiwwan->mhi_dev, DMA_TO_DEVICE)) {
+ clear_bit(MHI_WWAN_TX_FULL, &mhiwwan->flags);
+ wake_up_interruptible(&mhiwwan->ul_wq);
+ }
+}
+
+static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev,
+ struct mhi_result *mhi_result)
+{
+ struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev);
+ struct mhi_wwan_buf *mhibuf;
+
+ dev_dbg(&mhi_dev->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;
+ }
+
+ /* mhibuf is placed at the end of the buffer (cf mhi_wwan_ctrl_fill_inbound) */
+ mhibuf = mhi_result->buf_addr + mhiwwan->mtu;
+ mhibuf->data = mhi_result->buf_addr;
+ mhibuf->len = mhi_result->bytes_xferd;
+ mhibuf->consumed = 0;
+
+ spin_lock_bh(&mhiwwan->dl_queue_lock);
+ list_add_tail(&mhibuf->node, &mhiwwan->dl_queue);
+ spin_unlock_bh(&mhiwwan->dl_queue_lock);
+
+ wake_up_interruptible(&mhiwwan->dl_wq);
+}
+
+static int mhi_wwan_ctrl_probe(struct mhi_device *mhi_dev,
+ const struct mhi_device_id *id)
+{
+ struct mhi_controller *cntrl = mhi_dev->mhi_cntrl;
+ struct mhi_wwan_dev *mhiwwan;
+
+ /* Create mhi_wwan data context */
+ mhiwwan = kzalloc(sizeof(*mhiwwan), GFP_KERNEL);
+ if (!mhiwwan)
+ return -ENOMEM;
+
+ /* Init mhi_wwan data */
+ kref_init(&mhiwwan->refcnt);
+ mutex_init(&mhiwwan->mhi_dev_lock);
+ init_waitqueue_head(&mhiwwan->ul_wq);
+ init_waitqueue_head(&mhiwwan->dl_wq);
+ spin_lock_init(&mhiwwan->dl_queue_lock);
+ INIT_LIST_HEAD(&mhiwwan->dl_queue);
+ mhiwwan->mhi_dev = mhi_dev;
+ mhiwwan->mtu = MHI_WWAN_MAX_MTU;
+ set_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags);
+
+ if (mhi_dev->dl_chan)
+ set_bit(MHI_WWAN_DL_CAP, &mhiwwan->flags);
+ if (mhi_dev->ul_chan)
+ set_bit(MHI_WWAN_UL_CAP, &mhiwwan->flags);
+
+ dev_set_drvdata(&mhi_dev->dev, mhiwwan);
+
+ /* Register as a wwan port, id->driver_data contains wwan port type */
+ mhiwwan->wwan_port = wwan_create_port(&cntrl->mhi_dev->dev,
+ id->driver_data,
+ &mhidev_fops, mhiwwan);
+ if (IS_ERR(mhiwwan->wwan_port)) {
+ mutex_destroy(&mhiwwan->mhi_dev_lock);
+ kfree(mhiwwan);
+ return PTR_ERR(mhiwwan->wwan_port);
+ }
+
+ return 0;
+};
+
+static void mhi_wwan_ctrl_remove(struct mhi_device *mhi_dev)
+{
+ struct mhi_wwan_dev *mhiwwan = dev_get_drvdata(&mhi_dev->dev);
+
+ wwan_remove_port(mhiwwan->wwan_port);
+ dev_set_drvdata(&mhi_dev->dev, NULL);
+ clear_bit(MHI_WWAN_CONNECTED, &mhiwwan->flags);
+
+ /* Unlink mhi_dev from mhi_wwan_dev */
+ mutex_lock(&mhiwwan->mhi_dev_lock);
+ mhiwwan->mhi_dev = NULL;
+ mutex_unlock(&mhiwwan->mhi_dev_lock);
+
+ /* wake up any blocked user */
+ wake_up_interruptible(&mhiwwan->dl_wq);
+ wake_up_interruptible(&mhiwwan->ul_wq);
+
+ kref_put(&mhiwwan->refcnt, mhi_wwan_ctrl_dev_release);
+}
+
+static const struct mhi_device_id mhi_wwan_ctrl_match_table[] = {
+ { .chan = "DUN", .driver_data = WWAN_PORT_AT },
+ { .chan = "MBIM", .driver_data = WWAN_PORT_MBIM },
+ { .chan = "QMI", .driver_data = WWAN_PORT_QMI },
+ { .chan = "DIAG", .driver_data = WWAN_PORT_QCDM },
+ { .chan = "FIREHOSE", .driver_data = WWAN_PORT_FIREHOSE },
+ {},
+};
+MODULE_DEVICE_TABLE(mhi, mhi_wwan_ctrl_match_table);
+
+static struct mhi_driver mhi_wwan_ctrl_driver = {
+ .id_table = mhi_wwan_ctrl_match_table,
+ .remove = mhi_wwan_ctrl_remove,
+ .probe = mhi_wwan_ctrl_probe,
+ .ul_xfer_cb = mhi_ul_xfer_cb,
+ .dl_xfer_cb = mhi_dl_xfer_cb,
+ .driver = {
+ .name = "mhi_wwan_ctrl",
+ },
+};
+
+module_mhi_driver(mhi_wwan_ctrl_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MHI WWAN CTRL Driver");
+MODULE_AUTHOR("Hemant Kumar <hemantk@codeaurora.org>");
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
The MHI WWWAN control driver allows MHI QCOM-based modems to expose different modem control protocols/ports to userspace, so that userspace modem tools or daemon (e.g. ModemManager) can control WWAN config and state (APN config, SMS, provider selection...). A QCOM-based modem can expose one or several of the following protocols: - AT: Well known AT commands interactive protocol (microcom, minicom...) - MBIM: Mobile Broadband Interface Model (libmbim, mbimcli) - QMI: QCOM MSM/Modem Interface (libqmi, qmicli) - QCDM: QCOM Modem diagnostic interface (libqcdm) - FIREHOSE: XML-based protocol for Modem firmware management (qmi-firmware-update) The different interfaces are exposed as character devices through the WWAN subsystem, in a similar way as for USB modem variants (cdc-wdm). Note that this patch is mostly a rework of the earlier MHI UCI tentative that was a generic interface for accessing MHI bus from userspace. As suggested, this new version is WWAN specific and is dedicated to only expose channels used for controlling a modem, and for which related opensource userpace support exist. Signed-off-by: Loic Poulain <loic.poulain@linaro.org> --- v2: not part of the series v3: not part of the series v4: Introduce WWAN framework/subsystem v5: Specify WWAN_CORE module name in Kconfig v6: - Move to unified wwan_core.c file - Make wwan_port a device - Get rid of useless various dev lists (use wwan class) - Get rid of useless wwan dev usage counter and mutex - do not expose wwan_create_device, it's indirectly called via create_port - Increase minor count to the whole available minor range - private_data as wwan_create_port parameter drivers/net/wwan/Kconfig | 14 + drivers/net/wwan/Makefile | 2 + drivers/net/wwan/mhi_wwan_ctrl.c | 534 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 550 insertions(+) create mode 100644 drivers/net/wwan/mhi_wwan_ctrl.c