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From: joelf@ti.com (Joel Fernandes)
To: linux-arm-kernel@lists.infradead.org
Subject: [patch V2 5/6] edma: Make reading the position of active channels work
Date: Mon, 28 Apr 2014 11:11:18 -0500	[thread overview]
Message-ID: <535E7DA6.7010506@ti.com> (raw)
In-Reply-To: <20140428104643.215725974@linutronix.de>

On 04/28/2014 05:49 AM, Thomas Gleixner wrote:
> As Joel pointed out, edma_read_position() uses memcpy_fromio() to read
> the parameter ram. That's not synchronized with the internal update as
> it does a byte by byte copy. We need to do a 32bit read to get a
> consistent value.
> 
> Further reading destination and source is pointless. In DEV_TO_MEM
> transfers we are only interested in the destination, in MEM_TO_DEV we
> care about the source. In MEM_TO_MEM it really does not matter which
> one you read.
> 
> Simple solution: Remove the pointers, select dest/source via a bool
> and return the read value.
> 
> Remove the export of this function while at it. The only potential
> user is the dmaengine and that's always builtin.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Thanks, this looks good.

Acked-by: Joel Fernandes <joelf@ti.com>


Regards,
-Joel

  parent reply	other threads:[~2014-04-28 16:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-28 10:49 [patch V2 0/6] dma: edma: Provide granular residue accounting Thomas Gleixner
2014-04-28 10:49 ` [patch V2 1/6] dma: edma: Sanitize residue reporting Thomas Gleixner
2014-04-28 10:49 ` [patch V2 2/6] dma: edma: Check the current decriptor first in tx_status() Thomas Gleixner
2014-04-28 10:49 ` [patch V2 3/6] dma: edma: Create private pset struct Thomas Gleixner
2014-04-28 10:49 ` [patch V2 5/6] edma: Make reading the position of active channels work Thomas Gleixner
2014-04-28 14:44   ` Sekhar Nori
2014-04-28 16:11   ` Joel Fernandes [this message]
2014-04-28 10:49 ` [patch V2 4/6] dma: edma: Store transfer data in edma_desc and edma_pset Thomas Gleixner
2014-04-28 10:49 ` [patch V2 6/6] dma: edma: Provide granular accounting Thomas Gleixner
2014-04-28 20:47 ` [patch V2 0/6] dma: edma: Provide granular residue accounting Joel Fernandes
2014-04-29  8:46   ` Vinod Koul
2014-04-30  4:25     ` Joel Fernandes
2014-04-30  5:08       ` Vinod Koul
2014-05-01  1:57         ` Joel Fernandes

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