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Subject[PATCH v3 5/7] bus: mhi: core: Add support for MHI suspend and resume
Date
Add support for MHI suspend and resume states. While at it, the
mhi_notify() function needs to be exported as well.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
drivers/bus/mhi/core/main.c | 3 +-
drivers/bus/mhi/core/pm.c | 143 ++++++++++++++++++++++++++++++++++++
include/linux/mhi.h | 19 +++++
3 files changed, 164 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index eb4256b81406..3e9aa3b2da77 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -267,7 +267,7 @@ int mhi_destroy_device(struct device *dev, void *data)
return 0;
}

-static void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
+void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
{
struct mhi_driver *mhi_drv;

@@ -279,6 +279,7 @@ static void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
if (mhi_drv->status_cb)
mhi_drv->status_cb(mhi_dev, cb_reason);
}
+EXPORT_SYMBOL_GPL(mhi_notify);

/* Bind MHI channels to MHI devices */
void mhi_create_devices(struct mhi_controller *mhi_cntrl)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 52690cb5c89c..3529419d076b 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -669,6 +669,149 @@ void mhi_pm_st_worker(struct work_struct *work)
}
}

+int mhi_pm_suspend(struct mhi_controller *mhi_cntrl)
+{
+ struct mhi_chan *itr, *tmp;
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_pm_state new_state;
+ int ret;
+
+ if (mhi_cntrl->pm_state == MHI_PM_DISABLE)
+ return -EINVAL;
+
+ if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
+ return -EIO;
+
+ /* Return busy if there are any pending resources */
+ if (atomic_read(&mhi_cntrl->dev_wake))
+ return -EBUSY;
+
+ /* Take MHI out of M2 state */
+ read_lock_bh(&mhi_cntrl->pm_lock);
+ mhi_cntrl->wake_get(mhi_cntrl, false);
+ read_unlock_bh(&mhi_cntrl->pm_lock);
+
+ ret = wait_event_timeout(mhi_cntrl->state_event,
+ mhi_cntrl->dev_state == MHI_STATE_M0 ||
+ mhi_cntrl->dev_state == MHI_STATE_M1 ||
+ MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
+ msecs_to_jiffies(mhi_cntrl->timeout_ms));
+
+ read_lock_bh(&mhi_cntrl->pm_lock);
+ mhi_cntrl->wake_put(mhi_cntrl, false);
+ read_unlock_bh(&mhi_cntrl->pm_lock);
+
+ if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
+ dev_err(dev,
+ "Could not enter M0/M1 state");
+ return -EIO;
+ }
+
+ write_lock_irq(&mhi_cntrl->pm_lock);
+
+ if (atomic_read(&mhi_cntrl->dev_wake)) {
+ write_unlock_irq(&mhi_cntrl->pm_lock);
+ return -EBUSY;
+ }
+
+ dev_info(dev, "Allowing M3 transition\n");
+ new_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3_ENTER);
+ if (new_state != MHI_PM_M3_ENTER) {
+ write_unlock_irq(&mhi_cntrl->pm_lock);
+ dev_err(dev,
+ "Error setting to PM state: %s from: %s\n",
+ to_mhi_pm_state_str(MHI_PM_M3_ENTER),
+ to_mhi_pm_state_str(mhi_cntrl->pm_state));
+ return -EIO;
+ }
+
+ /* Set MHI to M3 and wait for completion */
+ mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
+ write_unlock_irq(&mhi_cntrl->pm_lock);
+ dev_info(dev, "Wait for M3 completion\n");
+
+ ret = wait_event_timeout(mhi_cntrl->state_event,
+ mhi_cntrl->dev_state == MHI_STATE_M3 ||
+ MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
+ msecs_to_jiffies(mhi_cntrl->timeout_ms));
+
+ if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
+ dev_err(dev,
+ "Did not enter M3 state, MHI state: %s, PM state: %s\n",
+ TO_MHI_STATE_STR(mhi_cntrl->dev_state),
+ to_mhi_pm_state_str(mhi_cntrl->pm_state));
+ return -EIO;
+ }
+
+ /* Notify clients about entering LPM */
+ list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
+ mutex_lock(&itr->mutex);
+ if (itr->mhi_dev)
+ mhi_notify(itr->mhi_dev, MHI_CB_LPM_ENTER);
+ mutex_unlock(&itr->mutex);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mhi_pm_suspend);
+
+int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
+{
+ struct mhi_chan *itr, *tmp;
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_pm_state cur_state;
+ int ret;
+
+ dev_info(dev, "Entered with PM state: %s, MHI state: %s\n",
+ to_mhi_pm_state_str(mhi_cntrl->pm_state),
+ TO_MHI_STATE_STR(mhi_cntrl->dev_state));
+
+ if (mhi_cntrl->pm_state == MHI_PM_DISABLE)
+ return 0;
+
+ if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
+ return -EIO;
+
+ /* Notify clients about exiting LPM */
+ list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
+ mutex_lock(&itr->mutex);
+ if (itr->mhi_dev)
+ mhi_notify(itr->mhi_dev, MHI_CB_LPM_EXIT);
+ mutex_unlock(&itr->mutex);
+ }
+
+ write_lock_irq(&mhi_cntrl->pm_lock);
+ cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3_EXIT);
+ if (cur_state != MHI_PM_M3_EXIT) {
+ write_unlock_irq(&mhi_cntrl->pm_lock);
+ dev_info(dev,
+ "Error setting to PM state: %s from: %s\n",
+ to_mhi_pm_state_str(MHI_PM_M3_EXIT),
+ to_mhi_pm_state_str(mhi_cntrl->pm_state));
+ return -EIO;
+ }
+
+ /* Set MHI to M0 and wait for completion */
+ mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
+ write_unlock_irq(&mhi_cntrl->pm_lock);
+
+ ret = wait_event_timeout(mhi_cntrl->state_event,
+ mhi_cntrl->dev_state == MHI_STATE_M0 ||
+ MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
+ msecs_to_jiffies(mhi_cntrl->timeout_ms));
+
+ if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
+ dev_err(dev,
+ "Did not enter M0 state, MHI state: %s, PM state: %s\n",
+ TO_MHI_STATE_STR(mhi_cntrl->dev_state),
+ to_mhi_pm_state_str(mhi_cntrl->pm_state));
+ return -EIO;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mhi_pm_resume);
+
int __mhi_device_get_sync(struct mhi_controller *mhi_cntrl)
{
int ret;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index ad1996001965..a4288f4d656f 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -568,6 +568,13 @@ void mhi_driver_unregister(struct mhi_driver *mhi_drv);
void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
enum mhi_state state);

+/**
+ * mhi_notify - Notify the MHI client driver about client device status
+ * @mhi_dev: MHI device instance
+ * @cb_reason: MHI callback reason
+ */
+void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
+
/**
* mhi_prepare_for_power_up - Do pre-initialization before power up.
* This is optional, call this before power up if
@@ -604,6 +611,18 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
*/
void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl);

+/**
+ * mhi_pm_suspend - Move MHI into a suspended state
+ * @mhi_cntrl: MHI controller
+ */
+int mhi_pm_suspend(struct mhi_controller *mhi_cntrl);
+
+/**
+ * mhi_pm_resume - Resume MHI from suspended state
+ * @mhi_cntrl: MHI controller
+ */
+int mhi_pm_resume(struct mhi_controller *mhi_cntrl);
+
/**
* mhi_download_rddm_img - Download ramdump image from device for
* debugging purpose.
--
2.17.1
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