Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Sat, 20 Aug 2022 23:17:44 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Vadym Kochan <vadym.kochan@plvision.eu>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Christoph Hellwig <hch@infradead.org>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Hu Ziji <huziji@marvell.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Elad Nachman <enachman@marvell.com>, iommu@lists.linux.dev,
        Mickey Rachamim <mickeyr@marvell.com>
Subject: Re: [PATCH] mmc: sdhci-xenon: Fix 2G limitation on AC5 SoC
Message-ID: <YwHOCHmKaf7yfgOD@infradead.org>
References: <20220808095237.GA15939@plvision.eu>
 <6c94411c-4847-526c-d929-c9523aa65c11@intel.com>
 <20220808122652.GA6599@plvision.eu>
 <3f96b382-aede-1f52-33cb-5f95715bdf59@intel.com>
 <3d16ebad-ea6c-555e-2481-ca5fb08a6c66@arm.com>
 <20220816205129.GA6438@plvision.eu>
 <94888b3b-8f54-367d-c6b4-5ebfeeafe4c4@arm.com>
 <20220817160730.GA17202@plvision.eu>
 <80d2538c-bac4-cc4f-85ae-352fcf86321d@arm.com>
 <20220818120740.GA21548@plvision.eu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220818120740.GA21548@plvision.eu>
Precedence: bulk

On Thu, Aug 18, 2022 at 03:07:40PM +0300, Vadym Kochan wrote:
> It works with the following changes:
> 
>     #1 dma-ranges = <0x0 0x0 0x2 0x0 0x0 0x80000000>;
> 
>     #3 swiotlb="force"
> 
> Is it OK to force the memory allocation from the start for the swiotlb ?

It should be ok, but isn't really optimal.

I wonder if we should just allow DT to specify the swiotlb buffer
location.  Basically have yet another RESERVEDMEM_OF_DECLARE variant
for it, which shouldn't be all that much work except for figuring
out the interaction with the various kernel command line options.