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Message-ID: <20190613110325.GD9160@vkoul-mobl.Dlink>
Date: Thu, 13 Jun 2019 16:33:25 +0530
From: Vinod Koul <vkoul@...nel.org>
To: Peng Ma <peng.ma@....com>
Cc: "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
Leo Li <leoyang.li@....com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"dmaengine@...r.kernel.org" <dmaengine@...r.kernel.org>
Subject: Re: [EXT] Re: [V3 2/2] dmaengine: fsl-dpaa2-qdma: Add NXP dpaa2 qDMA
controller driver for Layerscape SoCs
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
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