Re: [PATCH v3 03/16] bus: mhi: core: Add support for registering MHI client drivers

From: Greg KH
Date: Wed Mar 18 2020 - 09:36:32 EST


On Thu, Feb 20, 2020 at 03:28:41PM +0530, Manivannan Sadhasivam wrote:
> This commit adds support for registering MHI client drivers with the
> MHI stack. MHI client drivers binds to one or more MHI devices inorder
> to sends and receive the upper-layer protocol packets like IP packets,
> modem control messages, and diagnostics messages over MHI bus.
>
> This is based on the patch submitted by Sujeev Dias:
> https://lkml.org/lkml/2018/7/9/987
>
> Signed-off-by: Sujeev Dias <sdias@xxxxxxxxxxxxxx>
> Signed-off-by: Siddartha Mohanadoss <smohanad@xxxxxxxxxxxxxx>
> [mani: splitted and cleaned up for upstream]
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
> Tested-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
> ---
> drivers/bus/mhi/core/init.c | 149 ++++++++++++++++++++++++++++++++++++
> include/linux/mhi.h | 39 ++++++++++
> 2 files changed, 188 insertions(+)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 6f24c21284ec..12e386862b3f 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -374,8 +374,157 @@ struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl)
> return mhi_dev;
> }
>
> +static int mhi_driver_probe(struct device *dev)
> +{
> + struct mhi_device *mhi_dev = to_mhi_device(dev);
> + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
> + struct device_driver *drv = dev->driver;
> + struct mhi_driver *mhi_drv = to_mhi_driver(drv);
> + struct mhi_event *mhi_event;
> + struct mhi_chan *ul_chan = mhi_dev->ul_chan;
> + struct mhi_chan *dl_chan = mhi_dev->dl_chan;
> +
> + if (ul_chan) {
> + /*
> + * If channel supports LPM notifications then status_cb should
> + * be provided
> + */
> + if (ul_chan->lpm_notify && !mhi_drv->status_cb)
> + return -EINVAL;
> +
> + /* For non-offload channels then xfer_cb should be provided */
> + if (!ul_chan->offload_ch && !mhi_drv->ul_xfer_cb)
> + return -EINVAL;
> +
> + ul_chan->xfer_cb = mhi_drv->ul_xfer_cb;
> + }
> +
> + if (dl_chan) {
> + /*
> + * If channel supports LPM notifications then status_cb should
> + * be provided
> + */
> + if (dl_chan->lpm_notify && !mhi_drv->status_cb)
> + return -EINVAL;
> +
> + /* For non-offload channels then xfer_cb should be provided */
> + if (!dl_chan->offload_ch && !mhi_drv->dl_xfer_cb)
> + return -EINVAL;
> +
> + mhi_event = &mhi_cntrl->mhi_event[dl_chan->er_index];
> +
> + /*
> + * If the channel event ring is managed by client, then
> + * status_cb must be provided so that the framework can
> + * notify pending data
> + */
> + if (mhi_event->cl_manage && !mhi_drv->status_cb)
> + return -EINVAL;
> +
> + dl_chan->xfer_cb = mhi_drv->dl_xfer_cb;
> + }
> +
> + /* Call the user provided probe function */
> + return mhi_drv->probe(mhi_dev, mhi_dev->id);
> +}
> +
> +static int mhi_driver_remove(struct device *dev)
> +{
> + struct mhi_device *mhi_dev = to_mhi_device(dev);
> + struct mhi_driver *mhi_drv = to_mhi_driver(dev->driver);
> + struct mhi_chan *mhi_chan;
> + enum mhi_ch_state ch_state[] = {
> + MHI_CH_STATE_DISABLED,
> + MHI_CH_STATE_DISABLED
> + };
> + int dir;
> +
> + /* Skip if it is a controller device */
> + if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
> + return 0;
> +
> + /* Reset both channels */
> + for (dir = 0; dir < 2; dir++) {
> + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan;
> +
> + if (!mhi_chan)
> + continue;
> +
> + /* Wake all threads waiting for completion */
> + write_lock_irq(&mhi_chan->lock);
> + mhi_chan->ccs = MHI_EV_CC_INVALID;
> + complete_all(&mhi_chan->completion);
> + write_unlock_irq(&mhi_chan->lock);
> +
> + /* Set the channel state to disabled */
> + mutex_lock(&mhi_chan->mutex);
> + write_lock_irq(&mhi_chan->lock);
> + ch_state[dir] = mhi_chan->ch_state;
> + mhi_chan->ch_state = MHI_CH_STATE_SUSPENDED;
> + write_unlock_irq(&mhi_chan->lock);
> +
> + mutex_unlock(&mhi_chan->mutex);
> + }
> +
> + mhi_drv->remove(mhi_dev);
> +
> + /* De-init channel if it was enabled */
> + for (dir = 0; dir < 2; dir++) {
> + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan;
> +
> + if (!mhi_chan)
> + continue;
> +
> + mutex_lock(&mhi_chan->mutex);
> +
> + mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
> +
> + mutex_unlock(&mhi_chan->mutex);
> + }
> +
> + return 0;
> +}
> +
> +int mhi_driver_register(struct mhi_driver *mhi_drv)
> +{
> + struct device_driver *driver = &mhi_drv->driver;
> +
> + if (!mhi_drv->probe || !mhi_drv->remove)
> + return -EINVAL;
> +
> + driver->bus = &mhi_bus_type;
> + driver->probe = mhi_driver_probe;
> + driver->remove = mhi_driver_remove;
> +
> + return driver_register(driver);
> +}
> +EXPORT_SYMBOL_GPL(mhi_driver_register);

You don't care about module owners of the driver? Odd :(

(hint, you probably should...)

greg k-h