bus: mhi: core: Move to using high priority workqueue

MHI work is currently scheduled on the global/system workqueue and can
encounter delays on a stressed system. To avoid those unforeseen
delays which can hamper bootup or shutdown times, use a dedicated high
priority workqueue instead of the global/system workqueue.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 8cefa359fccd81be8491ab2c5ae46ce5e33b7471..877e40c86801a7b954d502187e7c9a617ba68588 100644 (file)
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -880,6 +880,13 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
        INIT_WORK(&mhi_cntrl->st_worker, mhi_pm_st_worker);
        init_waitqueue_head(&mhi_cntrl->state_event);
 
+       mhi_cntrl->hiprio_wq = alloc_ordered_workqueue
+                               ("mhi_hiprio_wq", WQ_MEM_RECLAIM | WQ_HIGHPRI);
+       if (!mhi_cntrl->hiprio_wq) {
+               dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate workqueue\n");
+               goto error_alloc_cmd;
+       }
+
        mhi_cmd = mhi_cntrl->mhi_cmd;
        for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++)
                spin_lock_init(&mhi_cmd->lock);
@@ -969,6 +976,7 @@ error_alloc_dev:
 error_alloc_cmd:
        vfree(mhi_cntrl->mhi_chan);
        kfree(mhi_cntrl->mhi_event);
+       destroy_workqueue(mhi_cntrl->hiprio_wq);
 
        return ret;
 }
@@ -982,6 +990,7 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 
        mhi_destroy_debugfs(mhi_cntrl);
 
+       destroy_workqueue(mhi_cntrl->hiprio_wq);
        kfree(mhi_cntrl->mhi_cmd);
        kfree(mhi_cntrl->mhi_event);
 

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 3de7b1639ec6a5c27b7c1bc8f91ed7c43668adb2..805b6fa748f01d96e0bce090415df1ed193528f6 100644 (file)
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -597,7 +597,7 @@ int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
        list_add_tail(&item->node, &mhi_cntrl->transition_list);
        spin_unlock_irqrestore(&mhi_cntrl->transition_lock, flags);
 
-       schedule_work(&mhi_cntrl->st_worker);
+       queue_work(mhi_cntrl->hiprio_wq, &mhi_cntrl->st_worker);
 
        return 0;
 }

diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 52b3c60bf9bb46e9b42065bf8dd0e303033bb583..1ed5f2aa224bdfef510d805bcbcdd8f9251a2ae8 100644 (file)
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -337,6 +337,7 @@ struct mhi_controller_config {
  * @wlock: Lock for protecting device wakeup
  * @mhi_link_info: Device bandwidth info
  * @st_worker: State transition worker
+ * @hiprio_wq: High priority workqueue for MHI work such as state transitions
  * @state_event: State change event
  * @status_cb: CB function to notify power states of the device (required)
  * @wake_get: CB function to assert device wake (optional)
@@ -419,6 +420,7 @@ struct mhi_controller {
        spinlock_t wlock;
        struct mhi_link_info mhi_link_info;
        struct work_struct st_worker;
+       struct workqueue_struct *hiprio_wq;
        wait_queue_head_t state_event;
 
        void (*status_cb)(struct mhi_controller *mhi_cntrl,