Date: Thu, 20 Aug 2015 10:50:14 +0530
From: Vinod Koul <vinod.koul@intel.com>
To: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dan Williams <dan.j.williams@intel.com>, linux-kernel@vger.kernel.org,
        Sudeep Dutt <sudeep.dutt@intel.com>, Nikhil Rao <nikhil.rao@intel.com>,
        Siva Yerramreddy <yshivakrishna@gmail.com>
Subject: Re: [PATCH char-misc-next 11/19] dma: Add support to program MIC
 x100 status descriptiors
Message-ID: <20150820052014.GU13546@localhost>
References: <cover.1438040669.git.ashutosh.dixit@intel.com>
 <0c2dec1519fdd81dfe6335efc2a1edb0b142639b.1438040669.git.ashutosh.dixit@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <0c2dec1519fdd81dfe6335efc2a1edb0b142639b.1438040669.git.ashutosh.dixit@intel.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1293
Lines: 45

On Mon, Jul 27, 2015 at 04:58:17PM -0700, Ashutosh Dixit wrote:
> +/* Program a status descriptor with phys as address and value to be written */
> +static int mic_dma_do_status_update(struct mic_dma_chan *ch, dma_addr_t phys,
> +				    u64 value)
> +{
> +	int ret = mic_dma_avail_desc_ring_space(ch, 4);
> +
> +	if (ret < 0)
> +		return ret;
> +	ret = 0;
?
> +	mic_dma_prep_status_desc(&ch->desc_ring[ch->head],
> +				 value, phys, false);
> +	mic_dma_hw_ring_inc_head(ch);
> +	return ret;

return 0 then?

> +}
> +
>  static inline void mic_dma_issue_pending(struct dma_chan *ch)
>  {
>  	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
> @@ -287,9 +310,28 @@ mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
>  		return NULL;
>  
>  	spin_lock(&mic_ch->prep_lock);
> +	if (len == 8) {
magic number?

> +		/*
> +		 * This is a hack to program status descriptor since
> +		 * DMA engine API doesn't have support for this.
> +		 */
what do you mean by programming status descriptor, what do you need to
program?

-- 
~Vinod

--
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/