lkml.org 
[lkml]   [2013]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC 2/4] dma: add dmaengine driver for Samsung s3c24xx SoCs
From
On Wed, May 15, 2013 at 10:31 PM, Heiko Stübner <heiko@sntech.de> wrote:

> If I understand the writel semantics and the thread from you from 2011 [0]
> correctly, only the writel to DMASKTRIG mustn't be relaxed to make sure the
> settings registers are written to before, so like:
>
> writel_relaxed(txd->src_addr, phy->base + DISRC);
> writel_relaxed(txd->disrcc, phy->base + DISRCC);
> writel_relaxed(txd->dst_addr, phy->base + DIDST);
> writel_relaxed(txd->didstc, phy->base + DIDSTC);
> writel_relaxed(dcon, phy->base + DCON);
>
> val = readl_relaxed(phy->base + DMASKTRIG);
> val &= ~DMASKTRIG_STOP;
> val |= DMASKTRIG_ON;
> writel(val, phy->base + DMASKTRIG);

Yep. That will drain write buffers etc and make sure all outstanding writes hit
the hardware.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2013-05-17 15:01    [W:0.095 / U:0.280 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site