linux-kernel - Re: [PATCH 06/10] MXS-DMA : add more flags for MXS-DMA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4F17E2E7.2080300@freescale.com>
Date:	Thu, 19 Jan 2012 17:31:19 +0800
From:	Huang Shijie <b32955@...escale.com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
CC:	<vinod.koul@...el.com>, <alsa-devel@...a-project.org>,
	<artem.bityutskiy@...el.com>, <b29396@...escale.com>,
	<linux-mmc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<w.sang@...gutronix.de>, <linux-mtd@...ts.infradead.org>,
	<shawn.guo@...aro.org>, <shijie8@...il.com>,
	<linux-arm-kernel@...ts.infradead.org>, <LW@...O-electronics.de>
Subject: Re: [PATCH 06/10] MXS-DMA : add more flags for MXS-DMA

hi,
> Err, the 'flags' argument to device_prep_slave_sg() is supposed to be
> from the set of enum dma_ctrl_flags.  What this means is that your
> MXS_DMA_F_APPEND is equivalent to DMA_PREP_INTERRUPT, and
> MXS_DMA_F_WAIT4END is equivalent to DMA_CTRL_ACK.
>
thanks a lot.
I will reuse the dma_ctrl_flags in the next version.
> What this does is make your drivers completely dependent on your DMA
> engine implementation.  That's not a good idea when devices get
> reused in different SoCs.
>
Frankly speaking, the APBH-DMA is more coupled with the GPMI  then any 
other modules.
In the MX6Q, the GPMI is the ONLY user of APBH-DMA.
You even can see the NAND_LOCK bit in the DMA command structure which is 
only used by the GPMI
NAND controller,.


To Shawn & Wolfram:
    thanks very much for your comments.

Best Regards
Huang Shijie

> If you need to supply extra flags which aren't in the dma_ctrl_flags,
> at least make sure that they're using different bits.  For bonus points,
> also have your driver_check_  the DMA engine it's connected to before
> it passes these flags.
>


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