[lkml]   [2018]   [Oct]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] mmc: tmio: simplify the DMA mode test
On Sat, Oct 13, 2018 at 12:03:08AM +0900, Masahiro Yamada wrote:
> host->chan_{rx,tx} represents the DMA capability of the platform.
> Even if DMA is supported, there are cases where we want to use PIO,
> for example, data length is short enough as commit 5f52c3552946
> ("mmc: tmio: use PIO for short transfers") mentioned.
> Regarding the hardware control flow, we are interested in whether DMA
> is currently enabled or not, instead of whether the platform has the
> DMA capability.
> Hence, the several conditionals in tmio_mmc_core.c end up with
> checking host->chan_{rx,tx} and !host->force_pio. This is not nice.
> Let's flip the flag host->force_pio into host->dma_on.
> host->dma_on represents whether the DMA is currently enabled or not.
> This flag is set false in the beginning of each command, then should
> be set true by tmio_mmc_start_dma() when the DMA is turned on.
> Signed-off-by: Masahiro Yamada <>

I like it. Much easier to read!

Reviewed-by: Wolfram Sang <>

Also here, I'd like to test this on Monday on some more devices.

[unhandled content-type:application/pgp-signature]
 \ /
  Last update: 2018-10-15 00:37    [W:0.134 / U:5.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site