On 02-07-18, 18:18, Yoshihiro Shimoda wrote:
> This patch fixes an issue that unexpected retransfering happens
> if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to
> the CHCR register. For example, sh-sci driver can reproduce this
> issue like below:
>
> In rx_timer_fn(): /* CHCR DE bit may be set to 1 */
> dmaengine_tx_status()
> rcar_dmac_tx_status()
> rcar_dmac_chan_get_residue()
> rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */
>
> According to the description of commit 73a47bd0da66 ("dmaengine:
> rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data
> will be transferred if CHCR::DE bit was cleared". So, this patch
> doesn't need to check TCRB register.
>
> Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for
> residue")
> Signed-off-by: Yoshihiro Shimoda <[email protected]>
> ---
> This patch is based on the latest slave-dma / fixes branch.
>
> This issue can be reproduced by the following commands on r8a7795
> Salvator-XS and Windows Teraterm :) :
> # stty 921600
> (Change Teraterm baud rate)
> # cat > rx.txt
> (Send 5MiB file by Teraterm. After a few minutes later, we cannot
> input any commands by the serial console.)
Applied after fixing subsystem name
--
~Vinod
