linux-kernel - Re: [PATCH] dmaengine: ti: omap-dma: Configure LCH

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]

Date:   Mon, 17 Dec 2018 21:16:58 +0200
From:   Aaro Koskinen <aaro.koskinen@....fi>
To:     Russell King - ARM Linux <linux@...linux.org.uk>,
        Peter Ujfalusi <peter.ujfalusi@...com>
Cc:     vkoul@...nel.org, dan.j.williams@...el.com,
        dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        tony@...mide.com, linux-omap@...r.kernel.org
Subject: Re: [PATCH] dmaengine: ti: omap-dma: Configure LCH_TYPE for OMAP1

On Thu, Nov 22, 2018 at 03:12:36PM +0000, Russell King - ARM Linux wrote:
> Also we can't deal with the omap_set_dma_dest_burst_mode() setting -
> DMAengine always uses a 64 byte burst, but udc wants a smaller burst
> setting.  Does this matter?

Looking at OMAP1 docs, it seems it supports only 16 bytes. Then checking
DMAengine code, I don't think these CSDP bit values are not valid
for OMAP1:

        CSDP_SRC_BURST_1        = 0 << 7,
        CSDP_SRC_BURST_16       = 1 << 7,
        CSDP_SRC_BURST_32       = 2 << 7,
        CSDP_SRC_BURST_64       = 3 << 7,

>From TI SPRU674 document, pages 50-51:

	0	single access (no burst)
	1	single access (no burst)
	2	burst 4
	3	reserved (do not use this setting)

So if CSDP_SRC_BURST_64 (3) gets programmed OMAP1, I wonder what is the
end result, no burst or burst 4...

A.