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538603c602
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 73a47bd0da ("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: 73a47bd0da ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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