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Date:   Thu, 13 Jun 2019 16:33:25 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     Peng Ma <peng.ma@nxp.com>
Cc:     "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
        Leo Li <leoyang.li@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>
Subject: Re: [EXT] Re: [V3 2/2] dmaengine: fsl-dpaa2-qdma: Add NXP dpaa2 qDMA
 controller driver for Layerscape SoCs
Message-ID: <20190613110325.GD9160@vkoul-mobl.Dlink>
References: <20190409072212.15860-1-peng.ma@nxp.com>
 <20190409072212.15860-2-peng.ma@nxp.com>
 <20190429053203.GF3845@vkoul-mobl.Dlink>
 <VI1PR04MB4431B87A1F712DC232A46ECBED130@VI1PR04MB4431.eurprd04.prod.outlook.com>
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On 10-06-19, 09:51, Peng Ma wrote:

> >> +                     goto err;
> >> +
> >> +             comp_temp->fl_virt_addr =
> >> +                     (void *)((struct dpaa2_fd *)
> >> +                             comp_temp->fd_virt_addr + 1);
> >
> >casts and pointer math, what could go wrong!! This doesnt smell right!
> >
> >> +             comp_temp->fl_bus_addr = comp_temp->fd_bus_addr +
> >> +                                     sizeof(struct dpaa2_fd);
> >
> >why not use fl_virt_addr and get the bus_address?
> What you mean is I should use virt_to_phys to get the bus_address?

Yes instead of maintaining both pointers, just use one and then when
required use one to get other. For bus address I would prefer
dma_map_single rather than virt_to_phys()
-- 
~Vinod