MHI event ring priority updates
Subsystems (2)
PATCH v2 1/1 MHI event ring priority updates
Event ring priorities have remained out of use and are set to 1 by default. This series brings about an enum entry expanding use of the priority field by adding high priority tasklet scheduling to the menu.
In some cases, tasklet scheduling delays can be a nuisance. An example would be ath11k adding a610f3c65d3b ("bus: mhi: Wait for M2 state during system resume") in response to it. This issue can be potentially avoided if the controller uses a dedicated event ring for control packets with high priority tasklet scheduling in place.
There are no functional changes added to the controller (pci_generic or ath11k) drivers with this series and the only changes there are use of the enum in place of a harcoded value of "1". In the future, controllers can opt in to have any event ring scheduled in high priority.
Tested on: X86_64 architecture with SDX65 on Ubuntu 18.04 distribution.
v2:
-Remove enum and update kernel doc for priority simplifying the implementation -Drop patches for controller changes as they become unnecessary -Merge adding and enabling of support patches
Hemant Kumar (1):
bus: mhi: core: Add support for processing priority of event ring
drivers/bus/mhi/core/init.c | 3 +-- drivers/bus/mhi/core/main.c | 9 +++++++-- include/linux/mhi.h | 2 +- 3 files changed, 9 insertions(+), 5 deletions(-)
Signature · 2 lines
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PATCH v2 1/1 bus: mhi: core: Add support for processing priority of event ring
From: Hemant Kumar <[email protected]>
Event ring priorities are currently set to 1 and are unused. Default processing priority for event rings is set to regular tasklet. Controllers can choose to use high priority tasklet scheduling for certain event rings critical for processing such as ones transporting control information if they wish to avoid system scheduling delays for those packets. In order to support these use cases, allow controllers to set event ring priority to high.
--- drivers/bus/mhi/core/init.c | 3 +-- drivers/bus/mhi/core/main.c | 9 +++++++-- include/linux/mhi.h | 2 +- 3 files changed, 9 insertions(+), 5 deletions(-)
drivers/bus/mhi/core/init.c +1 -2
@@ -673,8 +673,7 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, &mhi_cntrl->mhi_chan[mhi_event->chan]; } -/* Priority is fixed to 1 for now */ - mhi_event->priority =1 ; + mhi_event->priority = event_cfg->priority; mhi_event->db_cfg.brstmode = event_cfg->mode;if (MHI_INVALID_BRSTMODE (mhi_event->db_cfg.brstmode))
drivers/bus/mhi/core/main.c +7 -2
@@ -454,10 +454,15 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)if (mhi_dev)mhi_notify (mhi_dev,MHI_CB_PENDING_DATA ); - }else { -tasklet_schedule (&mhi_event->task); + +return IRQ_HANDLED ; } +if (!mhi_event->priority) +tasklet_hi_schedule (&mhi_event->task); +else +tasklet_schedule (&mhi_event->task); +return IRQ_HANDLED ; }
include/linux/mhi.h +1 -1
@@ -250,7 +250,7 @@ struct mhi_channel_config {* @irq_moderation_ms: Delay irq for additional events to be aggregated * @irq: IRQ associated with this ring * @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring -* @priority: Priority of this ring. Use 1 for now +* @priority: Processing priority of this ring. 0 is high and 1 is regular * @mode: Doorbell mode * @data_type: Type of data this ring will process * @hardware_event: This ring is associated with hardware channels
Signature · 2 lines
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Re: [PATCH v2] bus: mhi: core: Add support for processing priority of event ring
Quoted 11 lines · Bhaumik Bhatt
From: Hemant Kumar <[email protected]>
Event ring priorities are currently set to 1 and are unused. Default processing priority for event rings is set to regular tasklet. Controllers can choose to use high priority tasklet scheduling for certain event rings critical for processing such as ones transporting control information if they wish to avoid system scheduling delays for those packets. In order to support these use cases, allow controllers to set event ring priority to high.
Quoted 2 lines
Signed-off-by Hemant Kumar <[email protected]>Signed-off-by Bhaumik Bhatt <[email protected]>
Thanks,
Mani
Quoted 59 lines
--- drivers/bus/mhi/core/init.c | 3 +-- drivers/bus/mhi/core/main.c | 9 +++++++-- include/linux/mhi.h | 2 +- 3 files changed, 9 insertions(+), 5 deletions(-)drivers/bus/mhi/core/init.c +1
-2@@ -673,8 +673,7 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, &mhi_cntrl->mhi_chan[mhi_event->chan]; } -/* Priority is fixed to 1 for now */ - mhi_event->priority =1 ; + mhi_event->priority = event_cfg->priority; mhi_event->db_cfg.brstmode = event_cfg->mode;if (MHI_INVALID_BRSTMODE (mhi_event->db_cfg.brstmode))drivers/bus/mhi/core/main.c +7
-2@@ -454,10 +454,15 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)if (mhi_dev)mhi_notify (mhi_dev,MHI_CB_PENDING_DATA ); - }else { -tasklet_schedule (&mhi_event->task); + +return IRQ_HANDLED ; } +if (!mhi_event->priority) +tasklet_hi_schedule (&mhi_event->task); +else +tasklet_schedule (&mhi_event->task); +return IRQ_HANDLED ; }include/linux/mhi.h +1
-1@@ -250,7 +250,7 @@ struct mhi_channel_config {* @irq_moderation_ms: Delay irq for additional events to be aggregated * @irq: IRQ associated with this ring * @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring -* @priority: Priority of this ring. Use 1 for now +* @priority: Processing priority of this ring. 0 is high and 1 is regular * @mode: Doorbell mode * @data_type: Type of data this ring will process * @hardware_event: This ring is associated with hardware channels Signature · 2 lines
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
Manivannan Sadhasivam
AppliedRe: [PATCH v2] bus: mhi: core: Add support for processing priority of event ring
In reply to Bhaumik BhattQuoted 11 lines · Bhaumik Bhatt
From: Hemant Kumar <[email protected]>
Event ring priorities are currently set to 1 and are unused. Default processing priority for event rings is set to regular tasklet. Controllers can choose to use high priority tasklet scheduling for certain event rings critical for processing such as ones transporting control information if they wish to avoid system scheduling delays for those packets. In order to support these use cases, allow controllers to set event ring priority to high.
Quoted 2 lines
Signed-off-by Hemant Kumar <[email protected]>Signed-off-by Bhaumik Bhatt <[email protected]>
Applied to mhi-next!
Thanks,
Mani
Quoted 59 lines
--- drivers/bus/mhi/core/init.c | 3 +-- drivers/bus/mhi/core/main.c | 9 +++++++-- include/linux/mhi.h | 2 +- 3 files changed, 9 insertions(+), 5 deletions(-)drivers/bus/mhi/core/init.c +1
-2@@ -673,8 +673,7 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, &mhi_cntrl->mhi_chan[mhi_event->chan]; } -/* Priority is fixed to 1 for now */ - mhi_event->priority =1 ; + mhi_event->priority = event_cfg->priority; mhi_event->db_cfg.brstmode = event_cfg->mode;if (MHI_INVALID_BRSTMODE (mhi_event->db_cfg.brstmode))drivers/bus/mhi/core/main.c +7
-2@@ -454,10 +454,15 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)if (mhi_dev)mhi_notify (mhi_dev,MHI_CB_PENDING_DATA ); - }else { -tasklet_schedule (&mhi_event->task); + +return IRQ_HANDLED ; } +if (!mhi_event->priority) +tasklet_hi_schedule (&mhi_event->task); +else +tasklet_schedule (&mhi_event->task); +return IRQ_HANDLED ; }include/linux/mhi.h +1
-1@@ -250,7 +250,7 @@ struct mhi_channel_config {* @irq_moderation_ms: Delay irq for additional events to be aggregated * @irq: IRQ associated with this ring * @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring -* @priority: Priority of this ring. Use 1 for now +* @priority: Processing priority of this ring. 0 is high and 1 is regular * @mode: Doorbell mode * @data_type: Type of data this ring will process * @hardware_event: This ring is associated with hardware channels Signature · 2 lines
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project