[v2,0/6] dmaengine: ti: k3-udma: Fixes for 5.6
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Message ID 20200214091441.27535-1-peter.ujfalusi@ti.com
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  • dmaengine: ti: k3-udma: Fixes for 5.6
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Peter Ujfalusi Feb. 14, 2020, 9:14 a.m. UTC
Hi Vinod,

Recently we have uncovered silicon and driver issues which was not addressed in
the initial driver:

1. RX channel teardown will lock up the channel if we have stale data
in the DMA FIFOs and we don't have active transfer (no descriptor for UDMA).
The workaround is to use a dummy drain packet in these cases.

2. Early TX completion handling
The delayed work approach was not working efficiently causing the UART, SPI
performance to degrade, with the patch from Vignesh we see 10x performance
increase

3. TR setup for slave_sg
It was possible that the sg_len() was not multiple of 'burst * dev_width' and
because of this we ended up with incorrect TR setups.
Using a single function for TR setup makes things simpler and error prone among
slave_sg, cyclic and memcpy

4. Pause/Resume causes kernel crash
if it was called when we did not had active transfer the uc->desc was NULL.

5. The terminated cookie was never marked as completed
client will think that it is still in progress, which is not the case.
Also adding back the check for running channel in tx_status since if the channel
is not running then it implies that it has been terminated, so no transfer is
running.

Regards,
Peter
---
Peter Ujfalusi (5):
  dmaengine: ti: k3-udma: Workaround for RX teardown with stale data in
    peer
  dmaengine: ti: k3-udma: Move the TR counter calculation to helper
    function
  dmaengine: ti: k3-udma: Use the TR counter helper for slave_sg and
    cyclic
  dmaengine: ti: k3-udma: Use the channel direction in pause/resume
    functions
  dmaengine: ti: k3-udma: Fix terminated transfer handling

Vignesh Raghavendra (1):
  dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion
    check

 drivers/dma/ti/k3-udma.c | 493 ++++++++++++++++++++++++++++-----------
 1 file changed, 361 insertions(+), 132 deletions(-)

Comments

Vinod Koul Feb. 19, 2020, 7:39 a.m. UTC | #1
On 14-02-20, 11:14, Peter Ujfalusi wrote:
> Hi Vinod,
> 
> Recently we have uncovered silicon and driver issues which was not addressed in
> the initial driver:
> 
> 1. RX channel teardown will lock up the channel if we have stale data
> in the DMA FIFOs and we don't have active transfer (no descriptor for UDMA).
> The workaround is to use a dummy drain packet in these cases.
> 
> 2. Early TX completion handling
> The delayed work approach was not working efficiently causing the UART, SPI
> performance to degrade, with the patch from Vignesh we see 10x performance
> increase
> 
> 3. TR setup for slave_sg
> It was possible that the sg_len() was not multiple of 'burst * dev_width' and
> because of this we ended up with incorrect TR setups.
> Using a single function for TR setup makes things simpler and error prone among
> slave_sg, cyclic and memcpy
> 
> 4. Pause/Resume causes kernel crash
> if it was called when we did not had active transfer the uc->desc was NULL.
> 
> 5. The terminated cookie was never marked as completed
> client will think that it is still in progress, which is not the case.
> Also adding back the check for running channel in tx_status since if the channel
> is not running then it implies that it has been terminated, so no transfer is
> running.

Applied to fixes

Thanks