From: nsekhar@ti•com (Sekhar Nori)
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 20:14:03 +0530 [thread overview]
Message-ID: <535E6933.2020509@ti.com> (raw)
In-Reply-To: <20140428104643.215725974@linutronix.de>
On Monday 28 April 2014 04:19 PM, 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.
While this is true today, there are other DMA drivers which
are modules.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix•de>
Irrespective of above,
Acked-by: Sekhar Nori <nsekhar@ti•com>
Thanks,
Sekhar
next prev parent reply other threads:[~2014-04-28 14:44 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 4/6] dma: edma: Store transfer data in edma_desc and edma_pset 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 [this message]
2014-04-28 16:11 ` Joel Fernandes
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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