Patch "bus: mhi: core: Destroy SBL devices when moving to mission mode" has been added to the 5.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    bus: mhi: core: Destroy SBL devices when moving to mission mode

to the 5.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bus-mhi-core-destroy-sbl-devices-when-moving-to-miss.patch
and it can be found in the queue-5.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit a6f2f9c08718c73de21af72f0afe00b64e4e764b
Author: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Date:   Wed Feb 24 15:23:02 2021 -0800

    bus: mhi: core: Destroy SBL devices when moving to mission mode
    
    [ Upstream commit 925089c1900f588615db5bf4e1d9064a5f2c18c7 ]
    
    Currently, client devices are created in SBL or AMSS (mission
    mode) and only destroyed after power down or SYS ERROR. When
    moving between certain execution environments, such as from SBL
    to AMSS, no clean-up is required. This presents an issue where
    SBL-specific channels are left open and client drivers now run in
    an execution environment where they cannot operate. Fix this by
    expanding the mhi_destroy_device() to do an execution environment
    specific clean-up if one is requested. Close the gap and destroy
    devices in such scenarios that allow SBL client drivers to clean
    up once device enters mission mode.
    
    Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
    Reviewed-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
    Reviewed-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
    Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/1614208985-20851-2-git-send-email-bbhatt@xxxxxxxxxxxxxx
    Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 34dd430624e4..bd71a2b6f984 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -249,8 +249,10 @@ static bool is_valid_ring_ptr(struct mhi_ring *ring, dma_addr_t addr)
 
 int mhi_destroy_device(struct device *dev, void *data)
 {
+	struct mhi_chan *ul_chan, *dl_chan;
 	struct mhi_device *mhi_dev;
 	struct mhi_controller *mhi_cntrl;
+	enum mhi_ee_type ee = MHI_EE_MAX;
 
 	if (dev->bus != &mhi_bus_type)
 		return 0;
@@ -262,6 +264,17 @@ int mhi_destroy_device(struct device *dev, void *data)
 	if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
 		return 0;
 
+	ul_chan = mhi_dev->ul_chan;
+	dl_chan = mhi_dev->dl_chan;
+
+	/*
+	 * If execution environment is specified, remove only those devices that
+	 * started in them based on ee_mask for the channels as we move on to a
+	 * different execution environment
+	 */
+	if (data)
+		ee = *(enum mhi_ee_type *)data;
+
 	/*
 	 * For the suspend and resume case, this function will get called
 	 * without mhi_unregister_controller(). Hence, we need to drop the
@@ -269,11 +282,19 @@ int mhi_destroy_device(struct device *dev, void *data)
 	 * be sure that there will be no instances of mhi_dev left after
 	 * this.
 	 */
-	if (mhi_dev->ul_chan)
-		put_device(&mhi_dev->ul_chan->mhi_dev->dev);
+	if (ul_chan) {
+		if (ee != MHI_EE_MAX && !(ul_chan->ee_mask & BIT(ee)))
+			return 0;
 
-	if (mhi_dev->dl_chan)
-		put_device(&mhi_dev->dl_chan->mhi_dev->dev);
+		put_device(&ul_chan->mhi_dev->dev);
+	}
+
+	if (dl_chan) {
+		if (ee != MHI_EE_MAX && !(dl_chan->ee_mask & BIT(ee)))
+			return 0;
+
+		put_device(&dl_chan->mhi_dev->dev);
+	}
 
 	dev_dbg(&mhi_cntrl->mhi_dev->dev, "destroy device for chan:%s\n",
 		 mhi_dev->name);
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 36ab7aa14174..1edce7917b6b 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -377,6 +377,7 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
 {
 	struct mhi_event *mhi_event;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	enum mhi_ee_type current_ee = mhi_cntrl->ee;
 	int i, ret;
 
 	dev_dbg(dev, "Processing Mission Mode transition\n");
@@ -395,6 +396,8 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
 
 	wake_up_all(&mhi_cntrl->state_event);
 
+	device_for_each_child(&mhi_cntrl->mhi_dev->dev, &current_ee,
+			      mhi_destroy_device);
 	mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_EE_MISSION_MODE);
 
 	/* Force MHI to be in M0 state before continuing */