| Message ID | 1600480955-16827-7-git-send-email-bbhatt@codeaurora.org |
|---|---|
| State | New |
| Headers | show |
| Series | Bug fixes and improvements for MHI power operations | expand |
On Fri, Sep 18, 2020 at 07:02:31PM -0700, Bhaumik Bhatt wrote: > If MHI were to attempt a device shutdown following an assumption MHI host? And is this really an assumption or it is definite that the link is inaccessible. Please clarify! > that the device is inaccessible, the host currently moves to a state > where device register accesses are allowed when they should not be. > This would end up allowing accesses to the device register space when > the link is inaccessible and can result in bus errors observed on the > host. Improve shutdown handling to prevent these outcomes and do not > move the MHI PM state to a register accessible state after device is > assumed to be inaccessible. > Apparently you are introducing a new device transition state but your commit description doesn't state that :/ Thanks, Mani > Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> > --- > drivers/bus/mhi/core/init.c | 1 + > drivers/bus/mhi/core/internal.h | 1 + > drivers/bus/mhi/core/pm.c | 18 +++++++++++++----- > 3 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > index 9ae4c19..fa33dde 100644 > --- a/drivers/bus/mhi/core/init.c > +++ b/drivers/bus/mhi/core/init.c > @@ -37,6 +37,7 @@ const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX] = { > [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE", > [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR", > [DEV_ST_TRANSITION_DISABLE] = "DISABLE", > + [DEV_ST_TRANSITION_FATAL] = "FATAL SHUTDOWN", > }; > > const char * const mhi_state_str[MHI_STATE_MAX] = { > diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h > index 7989269..f3b9e5a 100644 > --- a/drivers/bus/mhi/core/internal.h > +++ b/drivers/bus/mhi/core/internal.h > @@ -388,6 +388,7 @@ enum dev_st_transition { > DEV_ST_TRANSITION_MISSION_MODE, > DEV_ST_TRANSITION_SYS_ERR, > DEV_ST_TRANSITION_DISABLE, > + DEV_ST_TRANSITION_FATAL, > DEV_ST_TRANSITION_MAX, > }; > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index 3462d82..bce1f62 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 > }, > }; > > @@ -670,6 +671,10 @@ void mhi_pm_st_worker(struct work_struct *work) > mhi_pm_disable_transition > (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); > break; > + case DEV_ST_TRANSITION_FATAL: > + mhi_pm_disable_transition > + (mhi_cntrl, MHI_PM_LD_ERR_FATAL_DETECT); > + break; > default: > break; > } > @@ -1039,6 +1044,7 @@ 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 dev_st_transition next_state = DEV_ST_TRANSITION_DISABLE; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > > /* If it's not a graceful shutdown, force MHI to linkdown state */ > @@ -1053,9 +1059,11 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > 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)); > + else > + next_state = DEV_ST_TRANSITION_FATAL; > } > > - mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); > + mhi_queue_state_transition(mhi_cntrl, next_state); > > /* Wait for shutdown to complete */ > flush_work(&mhi_cntrl->st_worker); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
On 9/19/2020 7:32 AM, Bhaumik Bhatt wrote: > If MHI were to attempt a device shutdown following an assumption > that the device is inaccessible, the host currently moves to a state > where device register accesses are allowed when they should not be. > This would end up allowing accesses to the device register space when > the link is inaccessible and can result in bus errors observed on the > host. Improve shutdown handling to prevent these outcomes and do not > move the MHI PM state to a register accessible state after device is Which state are you referring to when you say 'register accessible state'? Would it be possible to provide more details on current handling here? > assumed to be inaccessible. > > Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> > --- > drivers/bus/mhi/core/init.c | 1 + > drivers/bus/mhi/core/internal.h | 1 + > drivers/bus/mhi/core/pm.c | 18 +++++++++++++----- > 3 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > index 9ae4c19..fa33dde 100644 > --- a/drivers/bus/mhi/core/init.c > +++ b/drivers/bus/mhi/core/init.c > @@ -37,6 +37,7 @@ const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX] = { > [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE", > [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR", > [DEV_ST_TRANSITION_DISABLE] = "DISABLE", > + [DEV_ST_TRANSITION_FATAL] = "FATAL SHUTDOWN", > }; > > const char * const mhi_state_str[MHI_STATE_MAX] = { > diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h > index 7989269..f3b9e5a 100644 > --- a/drivers/bus/mhi/core/internal.h > +++ b/drivers/bus/mhi/core/internal.h > @@ -388,6 +388,7 @@ enum dev_st_transition { > DEV_ST_TRANSITION_MISSION_MODE, > DEV_ST_TRANSITION_SYS_ERR, > DEV_ST_TRANSITION_DISABLE, > + DEV_ST_TRANSITION_FATAL, > DEV_ST_TRANSITION_MAX, > }; > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index 3462d82..bce1f62 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 > }, > }; > > @@ -670,6 +671,10 @@ void mhi_pm_st_worker(struct work_struct *work) > mhi_pm_disable_transition > (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); > break; > + case DEV_ST_TRANSITION_FATAL: > + mhi_pm_disable_transition > + (mhi_cntrl, MHI_PM_LD_ERR_FATAL_DETECT); > + break; > default: > break; > } > @@ -1039,6 +1044,7 @@ 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 dev_st_transition next_state = DEV_ST_TRANSITION_DISABLE; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > > /* If it's not a graceful shutdown, force MHI to linkdown state */ > @@ -1053,9 +1059,11 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > 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)); > + else > + next_state = DEV_ST_TRANSITION_FATAL; > } > > - mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); > + mhi_queue_state_transition(mhi_cntrl, next_state); > > /* Wait for shutdown to complete */ > flush_work(&mhi_cntrl->st_worker); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index 9ae4c19..fa33dde 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -37,6 +37,7 @@ const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX] = { [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE", [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR", [DEV_ST_TRANSITION_DISABLE] = "DISABLE", + [DEV_ST_TRANSITION_FATAL] = "FATAL SHUTDOWN", }; const char * const mhi_state_str[MHI_STATE_MAX] = { diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h index 7989269..f3b9e5a 100644 --- a/drivers/bus/mhi/core/internal.h +++ b/drivers/bus/mhi/core/internal.h @@ -388,6 +388,7 @@ enum dev_st_transition { DEV_ST_TRANSITION_MISSION_MODE, DEV_ST_TRANSITION_SYS_ERR, DEV_ST_TRANSITION_DISABLE, + DEV_ST_TRANSITION_FATAL, DEV_ST_TRANSITION_MAX, }; diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index 3462d82..bce1f62 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 }, }; @@ -670,6 +671,10 @@ void mhi_pm_st_worker(struct work_struct *work) mhi_pm_disable_transition (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS); break; + case DEV_ST_TRANSITION_FATAL: + mhi_pm_disable_transition + (mhi_cntrl, MHI_PM_LD_ERR_FATAL_DETECT); + break; default: break; } @@ -1039,6 +1044,7 @@ 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 dev_st_transition next_state = DEV_ST_TRANSITION_DISABLE; struct device *dev = &mhi_cntrl->mhi_dev->dev; /* If it's not a graceful shutdown, force MHI to linkdown state */ @@ -1053,9 +1059,11 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) 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)); + else + next_state = DEV_ST_TRANSITION_FATAL; } - mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); + mhi_queue_state_transition(mhi_cntrl, next_state); /* Wait for shutdown to complete */ flush_work(&mhi_cntrl->st_worker);
If MHI were to attempt a device shutdown following an assumption that the device is inaccessible, the host currently moves to a state where device register accesses are allowed when they should not be. This would end up allowing accesses to the device register space when the link is inaccessible and can result in bus errors observed on the host. Improve shutdown handling to prevent these outcomes and do not move the MHI PM state to a register accessible state after device is assumed to be inaccessible. Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> --- drivers/bus/mhi/core/init.c | 1 + drivers/bus/mhi/core/internal.h | 1 + drivers/bus/mhi/core/pm.c | 18 +++++++++++++----- 3 files changed, 15 insertions(+), 5 deletions(-)