From c6dba8924201079093e1187a61934c6863b9efc1 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Mon, 29 Nov 2021 13:59:16 +0530 Subject: bus: mhi: ep: Add support for powering down the MHI endpoint stack Add support for MHI endpoint power_down that includes stopping all available channels, destroying the channels, resetting the event and transfer rings and freeing the host cache. The stack will be powered down whenever the physical bus link goes down. Reviewed-by: Alex Elder Signed-off-by: Manivannan Sadhasivam --- drivers/bus/mhi/ep/main.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) (limited to 'drivers/bus/mhi') diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c index 20d579733486..968025e4d3ac 100644 --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -22,6 +22,8 @@ static DEFINE_IDA(mhi_ep_cntrl_ida); +static int mhi_ep_destroy_device(struct device *dev, void *data); + static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx, struct mhi_ring_element *el, bool bei) { @@ -400,6 +402,68 @@ static irqreturn_t mhi_ep_irq(int irq, void *data) return IRQ_HANDLED; } +static void mhi_ep_abort_transfer(struct mhi_ep_cntrl *mhi_cntrl) +{ + struct mhi_ep_ring *ch_ring, *ev_ring; + struct mhi_result result = {}; + struct mhi_ep_chan *mhi_chan; + int i; + + /* Stop all the channels */ + for (i = 0; i < mhi_cntrl->max_chan; i++) { + mhi_chan = &mhi_cntrl->mhi_chan[i]; + if (!mhi_chan->ring.started) + continue; + + mutex_lock(&mhi_chan->lock); + /* Send channel disconnect status to client drivers */ + if (mhi_chan->xfer_cb) { + result.transaction_status = -ENOTCONN; + result.bytes_xferd = 0; + mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); + } + + mhi_chan->state = MHI_CH_STATE_DISABLED; + mutex_unlock(&mhi_chan->lock); + } + + flush_workqueue(mhi_cntrl->wq); + + /* Destroy devices associated with all channels */ + device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_ep_destroy_device); + + /* Stop and reset the transfer rings */ + for (i = 0; i < mhi_cntrl->max_chan; i++) { + mhi_chan = &mhi_cntrl->mhi_chan[i]; + if (!mhi_chan->ring.started) + continue; + + ch_ring = &mhi_cntrl->mhi_chan[i].ring; + mutex_lock(&mhi_chan->lock); + mhi_ep_ring_reset(mhi_cntrl, ch_ring); + mutex_unlock(&mhi_chan->lock); + } + + /* Stop and reset the event rings */ + for (i = 0; i < mhi_cntrl->event_rings; i++) { + ev_ring = &mhi_cntrl->mhi_event[i].ring; + if (!ev_ring->started) + continue; + + mutex_lock(&mhi_cntrl->event_lock); + mhi_ep_ring_reset(mhi_cntrl, ev_ring); + mutex_unlock(&mhi_cntrl->event_lock); + } + + /* Stop and reset the command ring */ + mhi_ep_ring_reset(mhi_cntrl, &mhi_cntrl->mhi_cmd->ring); + + mhi_ep_free_host_cfg(mhi_cntrl); + mhi_ep_mmio_mask_interrupts(mhi_cntrl); + + mhi_cntrl->enabled = false; +} + int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) { struct device *dev = &mhi_cntrl->mhi_dev->dev; @@ -454,6 +518,16 @@ err_free_event: } EXPORT_SYMBOL_GPL(mhi_ep_power_up); +void mhi_ep_power_down(struct mhi_ep_cntrl *mhi_cntrl) +{ + if (mhi_cntrl->enabled) + mhi_ep_abort_transfer(mhi_cntrl); + + kfree(mhi_cntrl->mhi_event); + disable_irq(mhi_cntrl->irq); +} +EXPORT_SYMBOL_GPL(mhi_ep_power_down); + static void mhi_ep_release_device(struct device *dev) { struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev); @@ -733,6 +807,10 @@ err_free_ch: } EXPORT_SYMBOL_GPL(mhi_ep_register_controller); +/* + * It is expected that the controller drivers will power down the MHI EP stack + * using "mhi_ep_power_down()" before calling this function to unregister themselves. + */ void mhi_ep_unregister_controller(struct mhi_ep_cntrl *mhi_cntrl) { struct mhi_ep_device *mhi_dev = mhi_cntrl->mhi_dev; -- cgit v1.2.3