diff options
| author | Sekhar Nori <[email protected]> | 2014-03-19 11:25:50 +0530 |
|---|---|---|
| committer | Vinod Koul <[email protected]> | 2014-04-14 09:29:55 +0530 |
| commit | 5fc68a6cad658e45dca3e0a6607df3a8e5df4ef9 (patch) | |
| tree | ab4dc89221cfeb0f7cf7c6c3551b5e2856bef6cf /net/lapb/lapb_out.c | |
| parent | c9eaa447e77efe77b7fa4c953bd62de8297fd6c5 (diff) | |
dma: edma: fix incorrect SG list handling
The code to handle any length SG lists calls edma_resume()
even before edma_start() is called. This is incorrect
because edma_resume() enables edma events on the channel
after which CPU (in edma_start) cannot clear posted
events by writing to ECR (per the EDMA user's guide).
Because of this EDMA transfers fail to start if due
to some reason there is a pending EDMA event registered
even before EDMA transfers are started. This can happen if
an EDMA event is a byproduct of device initialization.
Fix this by calling edma_resume() only if it is not the
first batch of MAX_NR_SG elements.
Without this patch, MMC/SD fails to function on DA850 EVM
with DMA. The behaviour is triggered by specific IP and
this can explain why the issue was not reported before
(example with MMC/SD on AM335x).
Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card.
Cc: [email protected] # v3.12.x+
Cc: Joel Fernandes <[email protected]>
Acked-by: Joel Fernandes <[email protected]>
Tested-by: Jon Ringle <[email protected]>
Tested-by: Alexander Holler <[email protected]>
Reported-by: Jon Ringle <[email protected]>
Signed-off-by: Sekhar Nori <[email protected]>
Signed-off-by: Vinod Koul <[email protected]>
Diffstat (limited to 'net/lapb/lapb_out.c')
0 files changed, 0 insertions, 0 deletions