linux-kernel - Re: [PATCH 2/5] dmaengine: omap-dma: Implement protection for invalid max

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Message-ID: <20170921171208.GF30097@localhost>
Date:   Thu, 21 Sep 2017 22:42:08 +0530
From:   Vinod Koul <vinod.koul@...el.com>
To:     Peter Ujfalusi <peter.ujfalusi@...com>
Cc:     dan.j.williams@...el.com, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, t-kristo@...com
Subject: Re: [PATCH 2/5] dmaengine: omap-dma: Implement protection for
 invalid max_burst

On Tue, Sep 12, 2017 at 01:44:21PM +0300, Peter Ujfalusi wrote:
> Set the device's max_burst to 16777215 (EN is 24bit unsigned value) so
> clients can take this into consideration when setting up the trasnfer.

ditto :D

> 
> During slave transfer preparation check if the requested maxburst is valid.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
> ---
>  drivers/dma/omap-dma.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
> index 8c1665c8fe33..f6dd849159d8 100644
> --- a/drivers/dma/omap-dma.c
> +++ b/drivers/dma/omap-dma.c
> @@ -1288,6 +1288,10 @@ static int omap_dma_slave_config(struct dma_chan *chan, struct dma_slave_config
>  	    cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
>  		return -EINVAL;
>  
> +	if (cfg->src_maxburst > chan->device->max_burst ||
> +	    cfg->dst_maxburst > chan->device->max_burst)
> +		return -EINVAL;
> +
>  	memcpy(&c->cfg, cfg, sizeof(c->cfg));
>  
>  	return 0;
> @@ -1482,6 +1486,7 @@ static int omap_dma_probe(struct platform_device *pdev)
>  	od->ddev.dst_addr_widths = OMAP_DMA_BUSWIDTHS;
>  	od->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
>  	od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
> +	od->ddev.max_burst = SZ_16M - 1; /* CCEN: 24bit unsigned */
>  	od->ddev.dev = &pdev->dev;
>  	INIT_LIST_HEAD(&od->ddev.channels);
>  	spin_lock_init(&od->lock);
> -- 
> 2.14.1
> 
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 
> 

-- 
~Vinod