bus: mhi: ep: Add support for suspending and resuming channels

Add support for suspending and resuming the channels in MHI endpoint stack.
The channels will be moved to the suspended state during M3 state
transition and will be resumed during M0 transition.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/ep/internal.h b/drivers/bus/mhi/ep/internal.h
index d201d755560c176fa68b6e79a7e649d99851523a..a2125fa5fe2f97e5240c62f9503b7fb39e2ad3a2 100644 (file)
--- a/drivers/bus/mhi/ep/internal.h
+++ b/drivers/bus/mhi/ep/internal.h
@@ -212,5 +212,7 @@ int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl);
 int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl);
 int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl);
 void mhi_ep_handle_syserr(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_resume_channels(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_suspend_channels(struct mhi_ep_cntrl *mhi_cntrl);
 
 #endif

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 660d1e9791d3c5e53cff8f5787cf0dee4825c1e4..bae5f40ec15e50e7fa5193835556ecb0d2c7e186 100644 (file)
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -1097,6 +1097,64 @@ void mhi_ep_power_down(struct mhi_ep_cntrl *mhi_cntrl)
 }
 EXPORT_SYMBOL_GPL(mhi_ep_power_down);
 
+void mhi_ep_suspend_channels(struct mhi_ep_cntrl *mhi_cntrl)
+{
+       struct mhi_ep_chan *mhi_chan;
+       u32 tmp;
+       int i;
+
+       for (i = 0; i < mhi_cntrl->max_chan; i++) {
+               mhi_chan = &mhi_cntrl->mhi_chan[i];
+
+               if (!mhi_chan->mhi_dev)
+                       continue;
+
+               mutex_lock(&mhi_chan->lock);
+               /* Skip if the channel is not currently running */
+               tmp = le32_to_cpu(mhi_cntrl->ch_ctx_cache[i].chcfg);
+               if (FIELD_GET(CHAN_CTX_CHSTATE_MASK, tmp) != MHI_CH_STATE_RUNNING) {
+                       mutex_unlock(&mhi_chan->lock);
+                       continue;
+               }
+
+               dev_dbg(&mhi_chan->mhi_dev->dev, "Suspending channel\n");
+               /* Set channel state to SUSPENDED */
+               tmp &= ~CHAN_CTX_CHSTATE_MASK;
+               tmp |= FIELD_PREP(CHAN_CTX_CHSTATE_MASK, MHI_CH_STATE_SUSPENDED);
+               mhi_cntrl->ch_ctx_cache[i].chcfg = cpu_to_le32(tmp);
+               mutex_unlock(&mhi_chan->lock);
+       }
+}
+
+void mhi_ep_resume_channels(struct mhi_ep_cntrl *mhi_cntrl)
+{
+       struct mhi_ep_chan *mhi_chan;
+       u32 tmp;
+       int i;
+
+       for (i = 0; i < mhi_cntrl->max_chan; i++) {
+               mhi_chan = &mhi_cntrl->mhi_chan[i];
+
+               if (!mhi_chan->mhi_dev)
+                       continue;
+
+               mutex_lock(&mhi_chan->lock);
+               /* Skip if the channel is not currently suspended */
+               tmp = le32_to_cpu(mhi_cntrl->ch_ctx_cache[i].chcfg);
+               if (FIELD_GET(CHAN_CTX_CHSTATE_MASK, tmp) != MHI_CH_STATE_SUSPENDED) {
+                       mutex_unlock(&mhi_chan->lock);
+                       continue;
+               }
+
+               dev_dbg(&mhi_chan->mhi_dev->dev, "Resuming channel\n");
+               /* Set channel state to RUNNING */
+               tmp &= ~CHAN_CTX_CHSTATE_MASK;
+               tmp |= FIELD_PREP(CHAN_CTX_CHSTATE_MASK, MHI_CH_STATE_RUNNING);
+               mhi_cntrl->ch_ctx_cache[i].chcfg = cpu_to_le32(tmp);
+               mutex_unlock(&mhi_chan->lock);
+       }
+}
+
 static void mhi_ep_release_device(struct device *dev)
 {
        struct mhi_ep_device *mhi_dev = to_mhi_ep_device(dev);

diff --git a/drivers/bus/mhi/ep/sm.c b/drivers/bus/mhi/ep/sm.c
index e3865b85399d115d4122c7e112212b7c7c02bc5a..3655c19e23c7b5f0c86f5bda14212016c3a3f317 100644 (file)
--- a/drivers/bus/mhi/ep/sm.c
+++ b/drivers/bus/mhi/ep/sm.c
@@ -62,8 +62,11 @@ int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl)
        enum mhi_state old_state;
        int ret;
 
+       /* If MHI is in M3, resume suspended channels */
        spin_lock_bh(&mhi_cntrl->state_lock);
        old_state = mhi_cntrl->mhi_state;
+       if (old_state == MHI_STATE_M3)
+               mhi_ep_resume_channels(mhi_cntrl);
 
        ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
        spin_unlock_bh(&mhi_cntrl->state_lock);
@@ -106,6 +109,8 @@ int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl)
                return ret;
        }
 
+       mhi_ep_suspend_channels(mhi_cntrl);
+
        /* Signal host that the device moved to M3 */
        ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M3);
        if (ret) {