From: Vinod Koul <vinod.koul@intel.com>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: "Stefan Brüns" <stefan.bruens@rwth-aachen.de>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
"Dan Williams" <dan.j.williams@intel.com>
Subject: Re: [PATCH] dmaengine: edma: Reject slave configs using a buswidth of 8 and larger
Date: Fri, 22 Sep 2017 14:13:35 +0530 [thread overview]
Message-ID: <20170922084335.GQ30097@localhost> (raw)
In-Reply-To: <83394991-4b17-46e6-aa4f-89c60b43e10a@ti.com>
On Fri, Sep 22, 2017 at 09:16:13AM +0300, Peter Ujfalusi wrote:
> Stefan, Vinod,
>
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
> On 2017-09-21 21:29, Peter Ujfalusi wrote:
> >
> >
> > On 2017-09-21 20:17, Vinod Koul wrote:
> >> On Sun, Sep 17, 2017 at 04:25:10PM +0200, Stefan Brüns wrote:
> >>> The driver would happily accept buswidth of 16/32/64 bytes and program
> >>> garbage to its registers.
> >>
> >> Peter?
> >
> > Well, eDMA as such has no limitation on the buswidth, the addr_width
> > become ACNT, counter for the inner loop - which we use to represent the
> > word length. In theory we could support 32K-1 long word with eDMA, which
> > we actually do in case of memcpy.
> >
> > But the driver does state that it supports bus width of 1, 2, 3 and 4 bytes.
> >
> > These are form the past and I never felt the need to check them.
> >
> > I think it is fine to reject salve config when asking for longer dev
> > width. I might revisit later if the need comes..
> >
> > Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>
> If it is not too late, I have second thoughts about this..
> It might be better to remove the src_addr_width/dst_addr_width check
> from edma_slave_config() and add all DMA_SLAVE_BUSWIDTH_* to
> EDMA_DMA_BUSWIDTHS.
fine by me, pls send updated..
--
~Vinod
prev parent reply other threads:[~2017-09-22 8:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-17 14:25 [PATCH] dmaengine: edma: Reject slave configs using a buswidth of 8 and larger Stefan Brüns
2017-09-21 17:17 ` Vinod Koul
2017-09-21 18:29 ` Peter Ujfalusi
2017-09-22 6:16 ` Peter Ujfalusi
2017-09-22 8:43 ` Vinod Koul [this message]
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