Subject: Re: [PATCH] pasemi_dma: Driver for PA Semi PWRficient on-chip
	DMAengine
From: Dan Williams <dan.j.williams@intel.com>
To: Olof Johansson <olof@lixom.net>
Cc: "Nelson, Shannon" <shannon.nelson@intel.com>, linux-kernel@vger.kernel.org,
       pasemi-linux@ozlabs.org, linuxppc-dev@ozlabs.org, hskinnemoen@atmel.com
In-Reply-To: <20080306233900.GA3969@lixom.net>
References: <20080306233900.GA3969@lixom.net>
Content-Type: text/plain
Date: Tue, 11 Mar 2008 10:04:11 -0700
Message-Id: <1205255051.26723.19.camel@dwillia2-linux.ch.intel.com>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1495
Lines: 43

On Thu, 2008-03-06 at 16:39 -0700, Olof Johansson wrote:
> pasemi_dma: Driver for PA Semi PWRficient on-chip DMA engine
>    
> First cut at a dma copy offload driver for PA Semi PWRficient. It uses the
> platform-specific functions to allocate channels, etc.
> 
> Signed-off-by: Olof Johansson <olof@lixom.net>
> 
> 
> ---
> 
> This has some dependencies on other patches currently queued up in the
> powerpc git trees for 2.6.26. I'd appreciate reviews and acked-bys, but
> it might be easiest to just merge it up the powerpc path due to the
> dependencies.
> 
Apologies for not getting to this sooner.

I notice that the driver does not handle callbacks in its descriptor
cleanup path.  This could be ok if your intent is only to support the
net_dma style polled operations, but this will not work for the
raid-offload async_tx case.  I think the solution is for async_tx to
ignore channels without the DMA_INTERRUPT capability.

> +static void pasemi_dma_clean(struct pasemi_dma_chan *chan)
> +{
> +       int old, new, i;
> +       unsigned long flags;
> +       struct pasemi_dma_desc *desc;
> +       spin_lock_irqsave(&chan->desc_lock, flags);

Is spin_lock_bh() insufficient here?

...that's all that jumps out at the moment.

Regards,
Dan

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