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> --- 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 a00f1547d252..999a675a5f0e 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -379,8 +379,157 @@ 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); + +void mhi_driver_unregister(struct mhi_driver *mhi_drv) +{ + driver_unregister(&mhi_drv->driver); +} +EXPORT_SYMBOL_GPL(mhi_driver_unregister); + static int mhi_match(struct device *dev, struct device_driver *drv) { + struct mhi_device *mhi_dev = to_mhi_device(dev); + struct mhi_driver *mhi_drv = to_mhi_driver(drv); + const struct mhi_device_id *id; + + /* + * If the device is a controller type then there is no client driver + * associated with it + */ + if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER) + return 0; + + for (id = mhi_drv->id_table; id->chan[0]; id++) + if (!strcmp(mhi_dev->chan_name, id->chan)) { + mhi_dev->id = id; + return 1; + } + return 0; }; diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 02330236ced8..137f1891701f 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -372,6 +372,8 @@ struct mhi_controller { * @dl_chan: DL channel for the device * @dev: Driver model device node for the MHI device * @dev_type: MHI device type + * @ul_chan_id: MHI channel id for UL transfer + * @dl_chan_id: MHI channel id for DL transfer * @tiocm: Device current terminal settings * @dev_wake: Device wakeup counter */ @@ -383,6 +385,8 @@ struct mhi_device { struct mhi_chan *dl_chan; struct device dev; enum mhi_device_type dev_type; + int ul_chan_id; + int dl_chan_id; u32 tiocm; u32 dev_wake; }; @@ -401,6 +405,29 @@ struct mhi_result { int transaction_status; }; +/** + * struct mhi_driver - Structure representing a MHI client driver + * @probe: CB function for client driver probe function + * @remove: CB function for client driver remove function + * @ul_xfer_cb: CB function for UL data transfer + * @dl_xfer_cb: CB function for DL data transfer + * @status_cb: CB functions for asynchronous status + * @driver: Device driver model driver + */ +struct mhi_driver { + const struct mhi_device_id *id_table; + int (*probe)(struct mhi_device *mhi_dev, + const struct mhi_device_id *id); + void (*remove)(struct mhi_device *mhi_dev); + void (*ul_xfer_cb)(struct mhi_device *mhi_dev, + struct mhi_result *result); + void (*dl_xfer_cb)(struct mhi_device *mhi_dev, + struct mhi_result *result); + void (*status_cb)(struct mhi_device *mhi_dev, enum mhi_callback mhi_cb); + struct device_driver driver; +}; + +#define to_mhi_driver(drv) container_of(drv, struct mhi_driver, driver) #define to_mhi_device(dev) container_of(dev, struct mhi_device, dev) /** @@ -417,4 +444,16 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, */ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl); +/** + * mhi_driver_register - Register driver with MHI framework + * @mhi_drv: Driver associated with the device + */ +int mhi_driver_register(struct mhi_driver *mhi_drv); + +/** + * mhi_driver_unregister - Unregister a driver for mhi_devices + * @mhi_drv: Driver associated with the device + */ +void mhi_driver_unregister(struct mhi_driver *mhi_drv); + #endif /* _MHI_H_ */ -- 2.17.1
