linux-kernel - Re: [PATCH v3 1/2] dmaengine: vdma: Add 64 bit addressing support for the axi dma

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Message-ID: <20160621053551.GX16910@localhost>
Date:	Tue, 21 Jun 2016 11:05:52 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	Kedareswara rao Appana <appana.durga.rao@...inx.com>
Cc:	dan.j.williams@...el.com, svemula@...inx.com, anirudh@...inx.com,
	michal.simek@...inx.com, soren.brinkmann@...inx.com,
	appanad@...inx.com, moritz.fischer@...us.com,
	laurent.pinchart@...asonboard.com, luis@...ethencourt.com,
	dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] dmaengine: vdma: Add 64 bit addressing support
 for the axi dma

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