Re: [PATCH v2] dmaengine: dma-jz4780: Break descriptor chains on JZ4740
From: Vinod Koul
Date: Thu Jul 25 2019 - 14:06:34 EST
On 14-07-19, 17:55, Paul Cercueil wrote:
> The current driver works perfectly fine on every generation of the
> JZ47xx SoCs, except on the JZ4740.
> There, when hardware descriptors are chained together (with the LINK
> bit set), the next descriptor isn't automatically fetched as it should -
> instead, an interrupt is raised, even if the TIE bit (Transfer Interrupt
> Enable) bit is cleared. When it happens, the DMA transfer seems to be
> stopped (it doesn't chain), and it's uncertain how many bytes have
> actually been transferred.
> Until somebody smarter than me can figure out how to make chained
> descriptors work on the JZ4740, we now disable chained descriptors on
> that particular SoC.