linux-kernel - Re: [PATCH 1/5] dmaengine: edma: Implement protection for invalid max

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Date:   Thu, 21 Sep 2017 22:40:18 +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 1/5] dmaengine: edma: Implement protection for invalid
 max_burst

On Tue, Sep 12, 2017 at 01:44:20PM +0300, Peter Ujfalusi wrote:
> Set the device's max_burst to 32767 (CIDX is 16bit signed value) so clients
> can take this into consideration when setting up the trasnfer.

/s/trasnfer/transfer

> 
> During slave transfer preparation check if the requested maxburst is valid.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
> ---
>  drivers/dma/edma.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
> index 3879f80a4815..6970355abdc9 100644
> --- a/drivers/dma/edma.c
> +++ b/drivers/dma/edma.c
> @@ -891,6 +891,10 @@ static int edma_slave_config(struct dma_chan *chan,
>  	    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(&echan->cfg, cfg, sizeof(echan->cfg));
>  
>  	return 0;
> @@ -1855,6 +1859,7 @@ static void edma_dma_init(struct edma_cc *ecc, bool legacy_mode)
>  	s_ddev->dst_addr_widths = EDMA_DMA_BUSWIDTHS;
>  	s_ddev->directions |= (BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV));
>  	s_ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
> +	s_ddev->max_burst = SZ_32K - 1; /* CIDX: 16bit signed */
>  
>  	s_ddev->dev = ecc->dev;
>  	INIT_LIST_HEAD(&s_ddev->channels);
> -- 
> 2.14.1
> 
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 
> 

-- 
~Vinod