dmaengine: ep93xx: Don't drain the transfers in terminate_all()
Draining the transfers in terminate_all callback happens with IRQs disabled,
therefore induces huge latency:
irqsoff latency trace v1.1.5 on 4.11.0
--------------------------------------------------------------------
latency: 39770 us, #57/57, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0)
-----------------
| task: process-129 (uid:0 nice:0 policy:2 rt_prio:50)
-----------------
=> started at: _snd_pcm_stream_lock_irqsave
=> ended at: snd_pcm_stream_unlock_irqrestore
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| / delay
cmd pid ||||| time | caller
\ / ||||| \ | /
process-129 0d.s. 3us : _snd_pcm_stream_lock_irqsave
process-129 0d.s1 9us : snd_pcm_stream_lock <-_snd_pcm_stream_lock_irqsave
process-129 0d.s1 15us : preempt_count_add <-snd_pcm_stream_lock
process-129 0d.s2 22us : preempt_count_add <-snd_pcm_stream_lock
process-129 0d.s3 32us : snd_pcm_update_hw_ptr0 <-snd_pcm_period_elapsed
process-129 0d.s3 41us : soc_pcm_pointer <-snd_pcm_update_hw_ptr0
process-129 0d.s3 50us : dmaengine_pcm_pointer <-soc_pcm_pointer
process-129 0d.s3 58us+: snd_dmaengine_pcm_pointer_no_residue <-dmaengine_pcm_pointer
process-129 0d.s3 96us : update_audio_tstamp <-snd_pcm_update_hw_ptr0
process-129 0d.s3 103us : snd_pcm_update_state <-snd_pcm_update_hw_ptr0
process-129 0d.s3 112us : xrun <-snd_pcm_update_state
process-129 0d.s3 119us : snd_pcm_stop <-xrun
process-129 0d.s3 126us : snd_pcm_action <-snd_pcm_stop
process-129 0d.s3 134us : snd_pcm_action_single <-snd_pcm_action
process-129 0d.s3 141us : snd_pcm_pre_stop <-snd_pcm_action_single
process-129 0d.s3 150us : snd_pcm_do_stop <-snd_pcm_action_single
process-129 0d.s3 157us : soc_pcm_trigger <-snd_pcm_do_stop
process-129 0d.s3 166us : snd_dmaengine_pcm_trigger <-soc_pcm_trigger
process-129 0d.s3 175us : ep93xx_dma_terminate_all <-snd_dmaengine_pcm_trigger
process-129 0d.s3 182us : preempt_count_add <-ep93xx_dma_terminate_all
process-129 0d.s4 189us*: m2p_hw_shutdown <-ep93xx_dma_terminate_all
process-129 0d.s4 39472us : m2p_hw_setup <-ep93xx_dma_terminate_all
... rest skipped...
process-129 0d.s. 40080us : <stack trace>
=> ep93xx_dma_tasklet
=> tasklet_action
=> __do_softirq
=> irq_exit
=> __handle_domain_irq
=> vic_handle_irq
=> __irq_usr
=> 0xb66c6668
Just abort the transfers and warn if the HW state is not what we expect.
Move draining into device_synchronize callback.
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Alexander Sverdlin
Vinod Koul
parent
0037ae4781
commit
98f9de366f
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@ -201,6 +201,7 @@ struct ep93xx_dma_engine {
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struct dma_device dma_dev;
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bool m2m;
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int (*hw_setup)(struct ep93xx_dma_chan *);
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void (*hw_synchronize)(struct ep93xx_dma_chan *);
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void (*hw_shutdown)(struct ep93xx_dma_chan *);
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void (*hw_submit)(struct ep93xx_dma_chan *);
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int (*hw_interrupt)(struct ep93xx_dma_chan *);
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@ -333,21 +334,27 @@ static inline u32 m2p_channel_state(struct ep93xx_dma_chan *edmac)
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return (readl(edmac->regs + M2P_STATUS) >> 4) & 0x3;
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}
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static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac)
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static void m2p_hw_synchronize(struct ep93xx_dma_chan *edmac)
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{
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unsigned long flags;
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u32 control;
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spin_lock_irqsave(&edmac->lock, flags);
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control = readl(edmac->regs + M2P_CONTROL);
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control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT);
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m2p_set_control(edmac, control);
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spin_unlock_irqrestore(&edmac->lock, flags);
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while (m2p_channel_state(edmac) >= M2P_STATE_ON)
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cpu_relax();
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schedule();
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}
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static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac)
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{
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m2p_set_control(edmac, 0);
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while (m2p_channel_state(edmac) == M2P_STATE_STALL)
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cpu_relax();
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while (m2p_channel_state(edmac) != M2P_STATE_IDLE)
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dev_warn(chan2dev(edmac), "M2P: Not yet IDLE\n");
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}
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static void m2p_fill_desc(struct ep93xx_dma_chan *edmac)
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@ -1162,6 +1169,26 @@ fail:
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return NULL;
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}
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/**
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* ep93xx_dma_synchronize - Synchronizes the termination of transfers to the
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* current context.
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* @chan: channel
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*
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* Synchronizes the DMA channel termination to the current context. When this
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* function returns it is guaranteed that all transfers for previously issued
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* descriptors have stopped and and it is safe to free the memory associated
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* with them. Furthermore it is guaranteed that all complete callback functions
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* for a previously submitted descriptor have finished running and it is safe to
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* free resources accessed from within the complete callbacks.
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*/
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static void ep93xx_dma_synchronize(struct dma_chan *chan)
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{
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struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
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if (edmac->edma->hw_synchronize)
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edmac->edma->hw_synchronize(edmac);
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}
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/**
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* ep93xx_dma_terminate_all - terminate all transactions
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* @chan: channel
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@ -1325,6 +1352,7 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
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dma_dev->device_prep_slave_sg = ep93xx_dma_prep_slave_sg;
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dma_dev->device_prep_dma_cyclic = ep93xx_dma_prep_dma_cyclic;
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dma_dev->device_config = ep93xx_dma_slave_config;
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dma_dev->device_synchronize = ep93xx_dma_synchronize;
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dma_dev->device_terminate_all = ep93xx_dma_terminate_all;
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dma_dev->device_issue_pending = ep93xx_dma_issue_pending;
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dma_dev->device_tx_status = ep93xx_dma_tx_status;
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@ -1342,6 +1370,7 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
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} else {
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dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
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edma->hw_synchronize = m2p_hw_synchronize;
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edma->hw_setup = m2p_hw_setup;
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edma->hw_shutdown = m2p_hw_shutdown;
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edma->hw_submit = m2p_hw_submit;
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