Re: [PATCH v4 3/9] bus: mhi: core: Use helper API to trigger a non-blocking host resume

[bbhatt]

On 2020-07-04 07:47, Manivannan Sadhasivam wrote:
On Mon, Jun 29, 2020 at 09:39:36AM -0700, Bhaumik Bhatt wrote:
Autonomous low power mode support requires the MHI host to resume from
multiple places and post a wakeup source to exit system suspend. This
needs to be done in a non-blocking manner. Introduce a helper API to
trigger the host resume for data transfers and other non-blocking use
cases while supporting implementation of autonomous low power modes.

Why can't you use pm_wakeup_event() as done in __mhi_device_get_sync()?

Thanks,
Mani


I forgot to address the __mhi_device_get_sync() function. Thanks for 
pointing out.

Is it preferable to always post wakeup source with hard boolean set?
We do want to wakeup from Suspend-to-Idle if system suspend happens to 
go that route.

As of now, we just by default do regular wakeup event and not hard.
I figured at some point we might need to distinguish between hard vs 
regular, hence the option but
it can be eliminated in favor of one or another.

Thanks,
Bhaumik

Signed-off-by: Bhaumik Bhatt <bbh...@codeaurora.org>
---
 drivers/bus/mhi/core/internal.h |  8 ++++++++
 drivers/bus/mhi/core/main.c     | 21 +++++++--------------
 drivers/bus/mhi/core/pm.c       |  6 ++----
 3 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/bus/mhi/core/internal.h 
b/drivers/bus/mhi/core/internal.h
index bcfa7b6..cb32eaf 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -599,6 +599,14 @@ int mhi_queue_state_transition(struct 
mhi_controller *mhi_cntrl,
 int mhi_send_cmd(struct mhi_controller *mhi_cntrl, struct mhi_chan 
*mhi_chan,
                 enum mhi_cmd_type cmd);

+static inline void mhi_trigger_resume(struct mhi_controller 
*mhi_cntrl,
+                                     bool hard_wakeup)
+{
+       pm_wakeup_dev_event(&mhi_cntrl->mhi_dev->dev, 0, hard_wakeup);
+       mhi_cntrl->runtime_get(mhi_cntrl);
+       mhi_cntrl->runtime_put(mhi_cntrl);
+}
+
 /* Register access methods */
 void mhi_db_brstmode(struct mhi_controller *mhi_cntrl, struct db_cfg 
*db_cfg,
                     void __iomem *db_addr, dma_addr_t db_val);
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 1f622ce..8d6ec34 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -909,8 +909,7 @@ void mhi_ctrl_ev_task(unsigned long data)
                 * process it since we are probably in a suspended state,
                 * so trigger a resume.
                 */
-               mhi_cntrl->runtime_get(mhi_cntrl);
-               mhi_cntrl->runtime_put(mhi_cntrl);
+               mhi_trigger_resume(mhi_cntrl, false);

                return;
        }
@@ -971,10 +970,8 @@ int mhi_queue_skb(struct mhi_device *mhi_dev, 
enum dma_data_direction dir,
        }

        /* we're in M3 or transitioning to M3 */
-       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
-               mhi_cntrl->runtime_get(mhi_cntrl);
-               mhi_cntrl->runtime_put(mhi_cntrl);
-       }
+       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
+               mhi_trigger_resume(mhi_cntrl, false);

        /* Toggle wake to exit out of M2 */
        mhi_cntrl->wake_toggle(mhi_cntrl);
@@ -1032,10 +1029,8 @@ int mhi_queue_dma(struct mhi_device *mhi_dev, 
enum dma_data_direction dir,
        }

        /* we're in M3 or transitioning to M3 */
-       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
-               mhi_cntrl->runtime_get(mhi_cntrl);
-               mhi_cntrl->runtime_put(mhi_cntrl);
-       }
+       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
+               mhi_trigger_resume(mhi_cntrl, false);

        /* Toggle wake to exit out of M2 */
        mhi_cntrl->wake_toggle(mhi_cntrl);
@@ -1147,10 +1142,8 @@ int mhi_queue_buf(struct mhi_device *mhi_dev, 
enum dma_data_direction dir,
        read_lock_irqsave(&mhi_cntrl->pm_lock, flags);

        /* we're in M3 or transitioning to M3 */
-       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
-               mhi_cntrl->runtime_get(mhi_cntrl);
-               mhi_cntrl->runtime_put(mhi_cntrl);
-       }
+       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
+               mhi_trigger_resume(mhi_cntrl, false);

        /* Toggle wake to exit out of M2 */
        mhi_cntrl->wake_toggle(mhi_cntrl);
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 661d704..5e3994e 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -1139,10 +1139,8 @@ void mhi_device_put(struct mhi_device *mhi_dev)

        mhi_dev->dev_wake--;
        read_lock_bh(&mhi_cntrl->pm_lock);
-       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
-               mhi_cntrl->runtime_get(mhi_cntrl);
-               mhi_cntrl->runtime_put(mhi_cntrl);
-       }
+       if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
+               mhi_trigger_resume(mhi_cntrl, false);

        mhi_cntrl->wake_put(mhi_cntrl, false);
        read_unlock_bh(&mhi_cntrl->pm_lock);
--
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