Updates to MHI channel handling
Subsystems (2)
v3 cover Updates to MHI channel handling
MHI specification shows a state machine with support for STOP channel command and the validity of certain state transitions. MHI host currently does not provide any mechanism to stop a channel and restart it without resetting it. There are also times when the device moves on to a different execution environment while client drivers on the host are unaware of it and still attempt to reset the channels facing unnecessary timeouts.
This series addresses the above areas to provide support for stopping an MHI channel, resuming it back, improved documentation and improving upon channel state machine handling in general.
This set of patches was tested on arm64 architecture.
v3:
-Updated documentation for channel transfer APIs to highlight differences -Create separate patch for "allowing channel to be disabled from stopped state"
v2:
-Renamed the newly introduced APIs to mhi_start_transfer() / mhi_stop_transfer() -Added improved documentation to avoid confusion with the new APIs -Removed the __ prefix from mhi_unprepare_channel() API for consistency.
Bhaumik Bhatt (7):
bus: mhi: core: Allow receiving a STOP channel command response
bus: mhi: core: Allow channel to be disabled from stopped state
bus: mhi: core: Improvements to the channel handling state machine
bus: mhi: core: Add support to stop or start channel data transfers
bus: mhi: core: Check execution environment for channel before issuing
reset
bus: mhi: core: Remove __ prefix for MHI channel unprepare function
bus: mhi: Improve documentation on channel transfer setup APIs
drivers/bus/mhi/core/init.c | 9 +- drivers/bus/mhi/core/internal.h | 12 +++ drivers/bus/mhi/core/main.c | 229 +++++++++++++++++++++++++++------------- include/linux/mhi.h | 45 +++++++- 4 files changed, 220 insertions(+), 75 deletions(-)
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PATCH v3 1/7 bus: mhi: core: Allow receiving a STOP channel command response
Add support to receive the response to a STOP channel command to the MHI bus. If a client would like to STOP a channel instead of issuing a RESET to it, this would provide support for it.
--- drivers/bus/mhi/core/main.c | 5 +++++ 1 file changed, 5 insertions(+)
drivers/bus/mhi/core/main.c +5 -0
@@ -1193,6 +1193,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl, cmd_tre->dword[0 ] =MHI_TRE_CMD_RESET_DWORD0 ; cmd_tre->dword[1 ] =MHI_TRE_CMD_RESET_DWORD1 (chan);break ; +case MHI_CMD_STOP_CHAN : + cmd_tre->ptr =MHI_TRE_CMD_STOP_PTR ; + cmd_tre->dword[0 ] =MHI_TRE_CMD_STOP_DWORD0 ; + cmd_tre->dword[1 ] =MHI_TRE_CMD_STOP_DWORD1 (chan); +break ;case MHI_CMD_START_CHAN : cmd_tre->ptr =MHI_TRE_CMD_START_PTR ; cmd_tre->dword[0 ] =MHI_TRE_CMD_START_DWORD0 ;
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Re: [PATCH v3 1/7] bus: mhi: core: Allow receiving a STOP channel command response
Hi Bhaumik,
Quoted 1 line · Bhaumik Bhatt
Add support to receive the response to a STOP channel command to the
How about saying "Add support to send the STOP channel command ?
Quoted 15 lines
MHI bus. If a client would like to STOP a channel instead of issuing a RESET to it, this would provide support for it.
Signed-off-by Bhaumik Bhatt <[email protected]>--- drivers/bus/mhi/core/main.c | 5 +++++ 1 file changed, 5 insertions(+)drivers/bus/mhi/core/main.c +0
-0@@ -1193,6 +1193,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl, cmd_tre->dword[0 ] =MHI_TRE_CMD_RESET_DWORD0 ;
drivers/bus/mhi/core/main.c int mhi_send_cmd(struct mhi_controller *mhi_cntrl, · line 1203
Quoted 10 lines
drivers/bus/mhi/core/main.c +5
-0cmd_tre->dword[1 ] =MHI_TRE_CMD_RESET_DWORD1 (chan);break ; +case MHI_CMD_STOP_CHAN : + cmd_tre->ptr =MHI_TRE_CMD_STOP_PTR ; + cmd_tre->dword[0 ] =MHI_TRE_CMD_STOP_DWORD0 ; + cmd_tre->dword[1 ] =MHI_TRE_CMD_STOP_DWORD1 (chan); +break ;case MHI_CMD_START_CHAN : cmd_tre->ptr =MHI_TRE_CMD_START_PTR ; cmd_tre->dword[0 ] =MHI_TRE_CMD_START_DWORD0 ;
Thanks,
Hemant
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Re: [PATCH v3 1/7] bus: mhi: core: Allow receiving a STOP channel command response
Quoted 5 lines · Hemant Kumar
Hi Bhaumik,
Quoted 1 line · Bhaumik Bhatt
Add support to receive the response to a STOP channel command to the
How about saying "Add support to send the STOP channel command ?
Addressed in v4.
Quoted 21 lines
Quoted 21 lines
MHI bus. If a client would like to STOP a channel instead of issuing a RESET to it, this would provide support for it.
Signed-off-by Bhaumik Bhatt <[email protected]>--- drivers/bus/mhi/core/main.c | 5 +++++ 1 file changed, 5 insertions(+)drivers/bus/mhi/core/main.c +4
-0@@ -1193,6 +1193,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl, cmd_tre->dword[0 ] =MHI_TRE_CMD_RESET_DWORD0 ; cmd_tre->dword[1 ] =MHI_TRE_CMD_RESET_DWORD1 (chan);break ; +case MHI_CMD_STOP_CHAN : + cmd_tre->ptr =MHI_TRE_CMD_STOP_PTR ; + cmd_tre->dword[0 ] =MHI_TRE_CMD_STOP_DWORD0 ; + cmd_tre->dword[1 ] =MHI_TRE_CMD_STOP_DWORD1 (chan);
Quoted 8 lines
Quoted 5 lines
drivers/bus/mhi/core/main.c +1
-0+break ;case MHI_CMD_START_CHAN : cmd_tre->ptr =MHI_TRE_CMD_START_PTR ;cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;Thanks,
Hemant
Thanks,
Bhaumik
---
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PATCH v3 2/7 bus: mhi: core: Allow channel to be disabled from stopped state
In reply to Bhaumik BhattIf a channel was explicitly stopped but not reset, allow it to move to a disabled state so the channel context can be cleaned up. As the channel remained in a stopped state, its context was not reset and cleared, which needs to be done if a client driver module is unloaded or a device crash occurs.
--- drivers/bus/mhi/core/init.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/bus/mhi/core/init.c +2 -1
@@ -1288,7 +1288,8 @@ static int mhi_driver_remove(struct device *dev)mutex_lock (&mhi_chan->mutex); -if (ch_state[dir] ==MHI_CH_STATE_ENABLED && +if ((ch_state[dir] ==MHI_CH_STATE_ENABLED || + ch_state[dir] ==MHI_CH_STATE_STOP ) && !mhi_chan->offload_ch)mhi_deinit_chan_ctxt (mhi_cntrl, mhi_chan);
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Re: [PATCH v3 2/7] bus: mhi: core: Allow channel to be disabled from stopped state
Quoted 8 lines · Bhaumik Bhatt
If a channel was explicitly stopped but not reset, allow it to move to a disabled state so the channel context can be cleaned up. As the channel remained in a stopped state, its context was not reset and cleared, which needs to be done if a client driver module is unloaded or a device crash occurs.
Signed-off-by Bhaumik Bhatt <[email protected]>---
Signature · 2 lines
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PATCH v3 3/7 bus: mhi: core: Improvements to the channel handling state machine
In reply to Bhaumik BhattAdd support to enable sending the stop channel command and improve the channel handling state machine such that all commands go through a common function. This can help ensure that the state machine is not violated in any way and adheres to the MHI specification.
--- drivers/bus/mhi/core/init.c | 6 ++ drivers/bus/mhi/core/internal.h | 12 +++ drivers/bus/mhi/core/main.c | 166 +++++++++++++++++++++++----------------- 3 files changed, 114 insertions(+), 70 deletions(-)
drivers/bus/mhi/core/init.c +6 -0
@@ -54,6 +54,12 @@ const char * const mhi_state_str[MHI_STATE_MAX] = { [MHI_STATE_SYS_ERR] = "SYS_ERR", }; +const char *const mhi_ch_state_type_str[MHI_CH_STATE_TYPE_MAX ] = { + [MHI_CH_STATE_TYPE_RESET ] ="RESET" , + [MHI_CH_STATE_TYPE_STOP ] ="STOP" , + [MHI_CH_STATE_TYPE_START ] ="START" , +}; +static const char *const mhi_pm_state_str[] = { [MHI_PM_STATE_DISABLE ] ="DISABLE" , [MHI_PM_STATE_POR ] ="POR" ,
drivers/bus/mhi/core/internal.h +12 -0
@@ -369,6 +369,18 @@ enum mhi_ch_state { MHI_CH_STATE_ERROR = 0x5, }; +enum mhi_ch_state_type { +MHI_CH_STATE_TYPE_RESET , +MHI_CH_STATE_TYPE_STOP , +MHI_CH_STATE_TYPE_START , +MHI_CH_STATE_TYPE_MAX , +}; + +extern const char *const mhi_ch_state_type_str[MHI_CH_STATE_TYPE_MAX ]; +#define TO_CH_STATE_TYPE_STR (state) (((state) >= MHI_CH_STATE_TYPE_MAX) ? \ + "INVALID_STATE" : \ + mhi_ch_state_type_str[state]) +#define MHI_INVALID_BRSTMODE (mode) (mode != MHI_DB_BRST_DISABLE && \ mode != MHI_DB_BRST_ENABLE)
drivers/bus/mhi/core/main.c +96 -70
217 lines not on this page · raw message
Signature · 2 lines
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Re: [PATCH v3 3/7] bus: mhi: core: Improvements to the channel handling state machine
Quoted 8 lines · Bhaumik Bhatt
Add support to enable sending the stop channel command and improve the channel handling state machine such that all commands go through a common function. This can help ensure that the state machine is not violated in any way and adheres to the MHI specification.
Signed-off-by Bhaumik Bhatt <[email protected]>---
Signature · 2 lines
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PATCH v3 4/7 bus: mhi: core: Add support to stop or start channel data transfers
In reply to Bhaumik BhattSome MHI client drivers may want to request a pause or halt of data transfer activity on their channels. Support for this does not exist and must be introduced, wherein the channel context is not reset or cleared but only the STOP channel command is issued. This would need to be paired with an API that allows resuming the data transfer activity on channels by use of the START channel command. This API assumes that the context information is already setup. Enable this using two new APIs, mhi_start_transfer() and mhi_stop_transfer().
--- drivers/bus/mhi/core/main.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/mhi.h | 19 +++++++++++++++++++ 2 files changed, 60 insertions(+)
drivers/bus/mhi/core/main.c +41 -0
@@ -1552,6 +1552,47 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev) }EXPORT_SYMBOL_GPL (mhi_unprepare_from_transfer); +static int mhi_update_transfer_state (struct mhi_device *mhi_dev, +enum mhi_ch_state_type to_state) +{ +struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; +struct mhi_chan *mhi_chan; +int dir, ret; + +for (dir =0 ; dir <2 ; dir++) { + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan; + +if (!mhi_chan) +continue ; + +/* +* Bail out if one of the channels fail as client will reset +* both upon failure +*/ +mutex_lock (&mhi_chan->mutex); + ret =mhi_update_channel_state (mhi_cntrl, mhi_chan, to_state); +if (ret) { +mutex_unlock (&mhi_chan->mutex); +return ret; + } +mutex_unlock (&mhi_chan->mutex); + } + +return 0 ; +} + +int mhi_stop_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_STOP ); +} +EXPORT_SYMBOL_GPL (mhi_stop_transfer); + +int mhi_start_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_START ); +} +EXPORT_SYMBOL_GPL (mhi_start_transfer); +int mhi_poll (struct mhi_device *mhi_dev,u32 budget) {struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
include/linux/mhi.h +19 -0
@@ -704,6 +704,25 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);void mhi_unprepare_from_transfer (struct mhi_device *mhi_dev);/** +* mhi_stop_transfer - Pauses ongoing channel activity by issuing the STOP +* channel command to both UL and DL channels. This command +* does not reset the channel context and the client drivers +* can issue mhi_start_transfer to resume activity. +* @mhi_dev: Device associated with the channels +*/ +int mhi_stop_transfer (struct mhi_device *mhi_dev); + +/** +* mhi_start_transfer - Resumes channel activity by issuing the START channel +* command to both UL and DL channels. This command assumes +* the channel context is already setup and the client +* drivers can issue mhi_stop_transfer to pause activity if +* required. +* @mhi_dev: Device associated with the channels +*/ +int mhi_start_transfer (struct mhi_device *mhi_dev); + +/** * mhi_poll - Poll for any available data in DL direction * @mhi_dev: Device associated with the channels * @budget: # of events to process
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Re: [PATCH v3 4/7] bus: mhi: core: Add support to stop or start channel data transfers
Hi Bhaumik,
Quoted 7 lines · Bhaumik Bhatt
Some MHI client drivers may want to request a pause or halt of data transfer activity on their channels. Support for this does not exist and must be introduced, wherein the channel context is not reset or cleared but only the STOP channel command is issued. This would need to be paired with an API that allows resuming the data transfer activity on channels by use of the START channel command. This API assumes that the context information is already
is it a better option to make sure channel context is setup as this is an exported API. Hence check for channel context bail out in case channel context is not setup with an err msg ?
Quoted 82 lines
setup. Enable this using two new APIs,
mhi_start_transfer()andmhi_stop_transfer().Signed-off-by Bhaumik Bhatt <[email protected]>--- drivers/bus/mhi/core/main.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/mhi.h | 19 +++++++++++++++++++ 2 files changed, 60 insertions(+)drivers/bus/mhi/core/main.c +41
-0@@ -1552,6 +1552,47 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev) }EXPORT_SYMBOL_GPL (mhi_unprepare_from_transfer); +static int mhi_update_transfer_state (struct mhi_device *mhi_dev, +enum mhi_ch_state_type to_state) +{ +struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; +struct mhi_chan *mhi_chan; +int dir, ret; + +for (dir =0 ; dir <2 ; dir++) { + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan; + +if (!mhi_chan) +continue ; + +/* +* Bail out if one of the channels fail as client will reset +* both upon failure +*/ +mutex_lock (&mhi_chan->mutex); + ret =mhi_update_channel_state (mhi_cntrl, mhi_chan, to_state); +if (ret) { +mutex_unlock (&mhi_chan->mutex); +return ret; + } +mutex_unlock (&mhi_chan->mutex); + } + +return 0 ; +} + +int mhi_stop_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_STOP ); +} +EXPORT_SYMBOL_GPL (mhi_stop_transfer); + +int mhi_start_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_START ); +} +EXPORT_SYMBOL_GPL (mhi_start_transfer); +int mhi_poll (struct mhi_device *mhi_dev,u32 budget) {struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;include/linux/mhi.h +12
-0@@ -704,6 +704,25 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);void mhi_unprepare_from_transfer (struct mhi_device *mhi_dev);/** +* mhi_stop_transfer - Pauses ongoing channel activity by issuing the STOP +* channel command to both UL and DL channels. This command +* does not reset the channel context and the client drivers +* can issue mhi_start_transfer to resume activity. +* @mhi_dev: Device associated with the channels +*/ +int mhi_stop_transfer (struct mhi_device *mhi_dev); + +/** +* mhi_start_transfer - Resumes channel activity by issuing the START channel +* command to both UL and DL channels. This command assumes +* the channel context is already setup and the client
include/linux/mhi.h int mhi_prepare_for_transfer(struct mhi_device *mhi_dev); · line 728
Quoted 10 lines
include/linux/mhi.h +7
-0+* drivers can issue mhi_stop_transfer to pause activity if +* required. +* @mhi_dev: Device associated with the channels +*/ +int mhi_start_transfer (struct mhi_device *mhi_dev); + +/** * mhi_poll - Poll for any available data in DL direction * @mhi_dev: Device associated with the channels * @budget: # of events to process
Overall change looks good.
Thanks,
Hemant
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Re: [PATCH v3 4/7] bus: mhi: core: Add support to stop or start channel data transfers
Quoted 11 lines · Hemant Kumar
Hi Bhaumik,
Quoted 7 lines · Bhaumik Bhatt
Some MHI client drivers may want to request a pause or halt of data transfer activity on their channels. Support for this does not exist and must be introduced, wherein the channel context is not reset or cleared but only the STOP channel command is issued. This would need to be paired with an API that allows resuming the data transfer activity on channels by use of the START channel command. This API assumes that the context information is already
Quoted 4 lines
is it a better option to make sure channel context is setup as this is an exported API. Hence check for channel context bail out in case channel context is not setup with an err msg ?
This is a better method, yes. Addressed in v4.
Quoted 103 lines
Quoted 95 lines
setup. Enable this using two new APIs,
mhi_start_transfer()andmhi_stop_transfer().Signed-off-by Bhaumik Bhatt <[email protected]>--- drivers/bus/mhi/core/main.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/mhi.h | 19 +++++++++++++++++++ 2 files changed, 60 insertions(+)drivers/bus/mhi/core/main.c +40
-0@@ -1552,6 +1552,47 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev) }EXPORT_SYMBOL_GPL (mhi_unprepare_from_transfer); +static int mhi_update_transfer_state(struct mhi_device *mhi_dev, +enum mhi_ch_state_type to_state) +{ +struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; +struct mhi_chan *mhi_chan; +int dir, ret; + +for (dir =0 ; dir <2 ; dir++) { + mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan; + +if (!mhi_chan) +continue ; + +/* +* Bail out if one of the channels fail as client will reset +* both upon failure +*/ +mutex_lock (&mhi_chan->mutex); + ret =mhi_update_channel_state (mhi_cntrl, mhi_chan, to_state); +if (ret) { +mutex_unlock (&mhi_chan->mutex); +return ret; + } +mutex_unlock (&mhi_chan->mutex); + } + +return 0 ; +} + +int mhi_stop_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_STOP ); +} +EXPORT_SYMBOL_GPL (mhi_stop_transfer); + +int mhi_start_transfer (struct mhi_device *mhi_dev) +{ +return mhi_update_transfer_state (mhi_dev,MHI_CH_STATE_TYPE_START ); +} +EXPORT_SYMBOL_GPL (mhi_start_transfer); +int mhi_poll (struct mhi_device *mhi_dev,u32 budget) {struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;include/linux/mhi.h +1
-0@@ -704,6 +704,25 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);void mhi_unprepare_from_transfer (struct mhi_device *mhi_dev);/** +* mhi_stop_transfer - Pauses ongoing channel activity by issuing the STOP
+ * channel command to both UL and DL channels.
This command
+ * does not reset the channel context and the
client drivers
+ * can issuemhi_start_transferto resume
activity.
+ * @mhi_dev: Device associated with the channels
+ */include/linux/mhi.h +4
-0+int mhi_stop_transfer (struct mhi_device *mhi_dev); + +/** +* mhi_start_transfer - Resumes channel activity by issuing the START channel
+ * command to both UL and DL channels. This
command assumes
+ * the channel context is already setup and the
client
+ * drivers can issuemhi_stop_transferto pause
activity if
+ * required.
+ * @mhi_dev: Device associated with the channels
+ */include/linux/mhi.h int mhi_prepare_for_transfer(struct mhi_device *mhi_dev); · line 728
Quoted 6 lines
include/linux/mhi.h +3
-0+int mhi_start_transfer (struct mhi_device *mhi_dev); + +/** * mhi_poll - Poll for any available data in DL direction * @mhi_dev: Device associated with the channels * @budget: # of events to process Overall change looks good.
Quoted 2 lines
Thanks,
Hemant
Thanks,
Bhaumik
---
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PATCH v3 5/7 bus: mhi: core: Check execution environment for channel before issuing reset
In reply to Bhaumik BhattA client can attempt to unprepare certain channels for transfer even after the execution environment they are supposed to run in has changed. In the event that happens, the device need not be notified of the reset and the host can proceed with clean up for the channel context and memory allocated for it on the host.
--- drivers/bus/mhi/core/main.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
drivers/bus/mhi/core/main.c +13 -0
@@ -1320,11 +1320,24 @@ static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,/* no more processing events for this channel */ mutex_lock (&mhi_chan->mutex); +if (!(BIT (mhi_cntrl->ee) & mhi_chan->ee_mask)) { +dev_err (dev, +"Current EE: %s Required EE Mask: 0x%x for chan: %s\n" , +TO_MHI_EXEC_STR (mhi_cntrl->ee), mhi_chan->ee_mask, + mhi_chan->name); + goto exit_unprepare_channel; + } + ret =mhi_update_channel_state (mhi_cntrl, mhi_chan,MHI_CH_STATE_TYPE_RESET );if (ret)dev_err (dev,"Failed to reset channel, still resetting\n" ); +exit_unprepare_channel: +write_lock_irq (&mhi_chan->lock); + mhi_chan->ch_state =MHI_CH_STATE_DISABLED ; +write_unlock_irq (&mhi_chan->lock); +if (!mhi_chan->offload_ch) {mhi_reset_chan (mhi_cntrl, mhi_chan);mhi_deinit_chan_ctxt (mhi_cntrl, mhi_chan);
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Re: [PATCH v3 5/7] bus: mhi: core: Check execution environment for channel before issuing reset
Quoted 7 lines · Bhaumik Bhatt
A client can attempt to unprepare certain channels for transfer even after the execution environment they are supposed to run in has changed. In the event that happens, the device need not be notified of the reset and the host can proceed with clean up for the channel context and memory allocated for it on the host.
Signed-off-by Bhaumik Bhatt <[email protected]>
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PATCH v3 6/7 bus: mhi: core: Remove __ prefix for MHI channel unprepare function
In reply to Bhaumik BhattThe __mhi_unprepare_channel() API does not require the __ prefix. Get rid of it and make the internal function consistent with the other function names.
--- drivers/bus/mhi/core/main.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
drivers/bus/mhi/core/main.c +5 -5
@@ -1311,8 +1311,8 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,return -EINVAL ; } -static void __mhi_unprepare_channel (struct mhi_controller *mhi_cntrl, -struct mhi_chan *mhi_chan) +static void mhi_unprepare_channel (struct mhi_controller *mhi_cntrl, +struct mhi_chan *mhi_chan) {int ret;struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -1425,7 +1425,7 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl, error_pre_alloc:mutex_unlock (&mhi_chan->mutex); -__mhi_unprepare_channel (mhi_cntrl, mhi_chan); +mhi_unprepare_channel (mhi_cntrl, mhi_chan);return ret; }
@@ -1542,7 +1542,7 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)if (!mhi_chan)continue ; -__mhi_unprepare_channel (mhi_cntrl, mhi_chan); +mhi_unprepare_channel (mhi_cntrl, mhi_chan); }return ret;
@@ -1560,7 +1560,7 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)if (!mhi_chan)continue ; -__mhi_unprepare_channel (mhi_cntrl, mhi_chan); +mhi_unprepare_channel (mhi_cntrl, mhi_chan); } }EXPORT_SYMBOL_GPL (mhi_unprepare_from_transfer);
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Re: [PATCH v3 6/7] bus: mhi: core: Remove __ prefix for MHI channel unprepare function
Quoted 6 lines · Bhaumik Bhatt
The
__mhi_unprepare_channel()API does not require the __ prefix. Get rid of it and make the internal function consistent with the other function names.Signed-off-by Bhaumik Bhatt <[email protected]>Reviewed-by Manivannan Sadhasivam <[email protected]>
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PATCH v3 7/7 bus: mhi: Improve documentation on channel transfer setup APIs
In reply to Bhaumik BhattThe mhi_prepare_for_transfer() and mhi_unprepare_from_transfer() APIs could use better explanation, especially with the addition of two new APIs to start and stop the transfers on channels. Add better set of information for those APIs.
--- include/linux/mhi.h | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)
include/linux/mhi.h +24 -2
@@ -692,13 +692,35 @@ int mhi_device_get_sync(struct mhi_device *mhi_dev);void mhi_device_put (struct mhi_device *mhi_dev);/** -* mhi_prepare_for_transfer - Setup channel for data transfer +* mhi_prepare_for_transfer - Setup UL and DL channels for data transfer. +* Allocate and initialize the channel context and +* also issue the START channel command to both +* channels. Channels can be started only if both +* host and device execution environments match and +* channels are in a DISABLED state. Calling the +* mhi_start_transfer() function is not required +* afterwards as channels are already started. This +* function also initializes the channel context +* whereas mhi_start_transfer() can only be used to +* issue the start channel command once the context +* is setup. * @mhi_dev: Device associated with the channels */ int mhi_prepare_for_transfer (struct mhi_device *mhi_dev);/** -* mhi_unprepare_from_transfer - Unprepare the channels +* mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer. +* Issue the RESET channel command and let the +* device clean-up the context so no incoming +* transfers are seen on the host. Free memory +* associated with the context on host. If device +* is unresponsive, only perform a host side +* clean-up. Channels can be reset only if both +* host and device execution environments match +* and channels are in an ENABLED, STOPPED or +* SUSPENDED state. Calling mhi_stop_transfer() is +* not required before calling this function as it +* will only stop transfers, not reset channels. * @mhi_dev: Device associated with the channels */ void mhi_unprepare_from_transfer (struct mhi_device *mhi_dev);
Signature · 2 lines
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Re: [PATCH v3 7/7] bus: mhi: Improve documentation on channel transfer setup APIs
Quoted 7 lines · Bhaumik Bhatt
The
mhi_prepare_for_transfer()andmhi_unprepare_from_transfer()APIs could use better explanation, especially with the addition of two new APIs to start and stop the transfers on channels. Add better set of information for those APIs.Signed-off-by Bhaumik Bhatt <[email protected]>---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project