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author | Bhaumik Bhatt <bbhatt@codeaurora.org> | 2020-11-09 12:47:30 -0800 |
---|---|---|
committer | Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> | 2020-11-18 15:20:34 +0530 |
commit | a03c7a86e12721da9f6bb509dddda19fd9ae8c6c (patch) | |
tree | a35d6003804a3dd33606259d719173cff6affd89 | |
parent | 556bbb442bbb44f429dbaa9f8b48e0b4cda6e088 (diff) | |
download | linux-a03c7a86e12721da9f6bb509dddda19fd9ae8c6c.tar.bz2 |
bus: mhi: core: Mark and maintain device states early on after power down
mhi_power_down() does not ensure that the PM state is moved to an
inaccessible state soon enough as the system can encounter
scheduling delays till mhi_pm_disable_transition() gets called.
Additionally, if an MHI controller decides that the device is now
inaccessible and issues a power down, the register inaccessible
state is not maintained by moving from MHI_PM_LD_ERR_FATAL_DETECT
to MHI_PM_SHUTDOWN_PROCESS. This can result in bus errors if a
client driver attempted to read registers when powering down.
Close these gaps and avoid any race conditions to prevent such
activity.
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>
-rw-r--r-- | drivers/bus/mhi/core/pm.c | 77 |
1 files changed, 33 insertions, 44 deletions
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 347ae7dd6cf8..ffbf6f539510 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -37,9 +37,10 @@ * M0 -> FW_DL_ERR * M0 -> M3_ENTER -> M3 -> M3_EXIT --> M0 * L1: SYS_ERR_DETECT -> SYS_ERR_PROCESS --> POR - * L2: SHUTDOWN_PROCESS -> DISABLE + * L2: SHUTDOWN_PROCESS -> LD_ERR_FATAL_DETECT + * SHUTDOWN_PROCESS -> DISABLE * L3: LD_ERR_FATAL_DETECT <--> LD_ERR_FATAL_DETECT - * LD_ERR_FATAL_DETECT -> SHUTDOWN_PROCESS + * LD_ERR_FATAL_DETECT -> DISABLE */ static struct mhi_pm_transitions const dev_state_transitions[] = { /* L0 States */ @@ -72,7 +73,7 @@ static struct mhi_pm_transitions const dev_state_transitions[] = { { MHI_PM_M3, MHI_PM_M3_EXIT | MHI_PM_SYS_ERR_DETECT | - MHI_PM_SHUTDOWN_PROCESS | MHI_PM_LD_ERR_FATAL_DETECT + MHI_PM_LD_ERR_FATAL_DETECT }, { MHI_PM_M3_EXIT, @@ -103,7 +104,7 @@ static struct mhi_pm_transitions const dev_state_transitions[] = { /* L3 States */ { MHI_PM_LD_ERR_FATAL_DETECT, - MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_SHUTDOWN_PROCESS + MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_DISABLE }, }; @@ -445,10 +446,9 @@ error_mission_mode: } /* Handle shutdown transitions */ -static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, - enum mhi_pm_state transition_state) +static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) { - enum mhi_pm_state cur_state, prev_state; + enum mhi_pm_state cur_state; struct mhi_event *mhi_event; struct mhi_cmd_ctxt *cmd_ctxt; struct mhi_cmd *mhi_cmd; @@ -456,33 +456,13 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, struct device *dev = &mhi_cntrl->mhi_dev->dev; int ret, i; - dev_dbg(dev, "Transitioning from PM state: %s to: %s\n", - to_mhi_pm_state_str(mhi_cntrl->pm_state), - to_mhi_pm_state_str(transition_state)); + dev_dbg(dev, "Processing disable transition with PM state: %s\n", + to_mhi_pm_state_str(mhi_cntrl->pm_state)); mutex_lock(&mhi_cntrl->pm_mutex); - write_lock_irq(&mhi_cntrl->pm_lock); - prev_state = mhi_cntrl->pm_state; - cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); - if (cur_state == transition_state) { - mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION; - mhi_cntrl->dev_state = MHI_STATE_RESET; - } - write_unlock_irq(&mhi_cntrl->pm_lock); - - /* Wake up threads waiting for state transition */ - wake_up_all(&mhi_cntrl->state_event); - - if (cur_state != transition_state) { - dev_err(dev, "Failed to transition to state: %s from: %s\n", - to_mhi_pm_state_str(transition_state), - to_mhi_pm_state_str(cur_state)); - mutex_unlock(&mhi_cntrl->pm_mutex); - return; - } /* Trigger MHI RESET so that the device will not access host memory */ - if (MHI_REG_ACCESS_VALID(prev_state)) { + if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) { u32 in_reset = -1; unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms); @@ -785,8 +765,7 @@ void mhi_pm_st_worker(struct work_struct *work) mhi_pm_sys_error_transition(mhi_cntrl); break; case DEV_ST_TRANSITION_DISABLE: - mhi_pm_disable_transition - (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); + mhi_pm_disable_transition(mhi_cntrl); break; default: break; @@ -1153,23 +1132,33 @@ EXPORT_SYMBOL_GPL(mhi_async_power_up); void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) { - enum mhi_pm_state cur_state; + enum mhi_pm_state cur_state, transition_state; struct device *dev = &mhi_cntrl->mhi_dev->dev; /* If it's not a graceful shutdown, force MHI to linkdown state */ - if (!graceful) { - mutex_lock(&mhi_cntrl->pm_mutex); - write_lock_irq(&mhi_cntrl->pm_lock); - cur_state = mhi_tryset_pm_state(mhi_cntrl, - MHI_PM_LD_ERR_FATAL_DETECT); - write_unlock_irq(&mhi_cntrl->pm_lock); - mutex_unlock(&mhi_cntrl->pm_mutex); - if (cur_state != MHI_PM_LD_ERR_FATAL_DETECT) - dev_dbg(dev, "Failed to move to state: %s from: %s\n", - to_mhi_pm_state_str(MHI_PM_LD_ERR_FATAL_DETECT), - to_mhi_pm_state_str(mhi_cntrl->pm_state)); + transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS : + MHI_PM_LD_ERR_FATAL_DETECT; + + mutex_lock(&mhi_cntrl->pm_mutex); + write_lock_irq(&mhi_cntrl->pm_lock); + cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state); + if (cur_state != transition_state) { + dev_err(dev, "Failed to move to state: %s from: %s\n", + to_mhi_pm_state_str(transition_state), + to_mhi_pm_state_str(mhi_cntrl->pm_state)); + /* Force link down or error fatal detected state */ + mhi_cntrl->pm_state = MHI_PM_LD_ERR_FATAL_DETECT; } + /* mark device inactive to avoid any further host processing */ + mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION; + mhi_cntrl->dev_state = MHI_STATE_RESET; + + wake_up_all(&mhi_cntrl->state_event); + + write_unlock_irq(&mhi_cntrl->pm_lock); + mutex_unlock(&mhi_cntrl->pm_mutex); + mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); /* Wait for shutdown to complete */ |