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From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] i.MX28: Enable SD DMA only if DCache enabled
Date: Thu, 5 Apr 2012 02:48:31 +0200	[thread overview]
Message-ID: <201204050248.31903.marex@denx.de> (raw)
In-Reply-To: <CAOMZO5Di5DD7PUsa+PJYdH3c9-7FWC69hr2Ef7Lc6FiYJBkUag@mail.gmail.com>

Dear Fabio Estevam,

> On Wed, Apr 4, 2012 at 6:51 PM, Marek Vasut <marex@denx.de> wrote:
> > +/* Enable DMA transfers only if DCache is on. */
> > +#ifndef CONFIG_SYS_DCACHE_OFF
> > +#define CONFIG_MXS_MMC_DMA
> > +#endif
> 
> Your patch makes sense, but I would prefer not to couple
> CONFIG_MXS_MMC_DMA with DCACHE support.
> 
> Someone may want to enable cache, but still uses MMC driver in PIO mode.

You don't, it's slow as crap then.

> IMHO CONFIG_MXS_MMC_DMA could be defined in configs/board.h when needed.
> 
> Yesterday I was running MMC DMA without DCACHE support and it did work
> (after the mxs_dma_init changes).

I have some obscure card now and I'm seeing breakage (DMA transfer timeout).

btw. Fabio, can you ping me on jabber please?

Best regards,
Marek Vasut

  reply	other threads:[~2012-04-05  0:48 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-04 21:51 [U-Boot] [PATCH] i.MX28: Enable SD DMA only if DCache enabled Marek Vasut
2012-04-04 23:12 ` Fabio Estevam
2012-04-05  0:48   ` Marek Vasut [this message]
2012-04-05  3:36     ` Fabio Estevam
2012-04-05 10:08       ` Marek Vasut
2012-04-06  0:34     ` Fabio Estevam
2012-04-06  1:03       ` Marek Vasut
2012-04-05 10:24 ` [U-Boot] [PATCH] i.MX28: Allow coexistence of PIO and DMA mode for SD/MMC Marek Vasut
2012-04-05 12:12   ` Stefano Babic
2012-04-05 12:17     ` Marek Vasut
2012-04-05 12:28       ` Stefano Babic
2012-04-05 13:30   ` [U-Boot] [PATCH V3] " Marek Vasut
2012-04-09 10:57     ` Stefano Babic

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