Re: [PATCH v3 1/2] dmaengine: vdma: Add 64 bit addressing support for the axi dma
From: Vinod Koul
Date: Tue Jun 21 2016 - 01:32:17 EST
On Tue, Jun 07, 2016 at 07:21:15PM +0530, Kedareswara rao Appana wrote:
> The AXI DMA is a soft ip, which can be programmed to support
> 32 bit addressing or greater than 32 bit addressing.
>
> When the AXI DMA ip is configured for 32 bit address space
> in simple dma mode the buffer address is specified by a single register
> (18h for MM2S channel and 48h for S2MM channel). When configured in SG mode
> The current descriptor and tail descriptor are specified by a single
> Register(08h for curdesc 10h for tail desc for MM2S channel and 38h for
> Curdesc and 40h for tail desc for S2MM).
>
> When the AXI DMA core is configured for an address space greater
> than 32 then each buffer address or descriptor address is specified by
> a combination of two registers.
>
> The first register specifies the LSB 32 bits of address,
> while the next register specifies the MSB 32 bits of address.
>
> For example, 48h will specify the LSB 32 bits while 4Ch will
> specify the MSB 32 bits of the first start address.
> So we need to program two registers at a time.
>
> This patch adds the 64 bit addressing support for the axidma
> IP in the driver.
Applied both, thanks
--
~Vinod