From mboxrd@z Thu Jan  1 00:00:00 1970
From: Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH v5 06/12] mmc: sdhci-xenon: Add Marvell Xenon SDHC core
 functionality
Date: Thu, 26 Jan 2017 14:39:23 +0200
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To: Ulf Hansson <ulf.hansson@linaro.org>, Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>, Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>, Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>, Thomas Petazzoni <thomas.petazzoni@free-electrons.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, Mike Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@codeaurora.org>, linux-clk <linux-clk@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Rob Herring <robh+dt@kernel.org>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, Ziji Hu <huziji@marvell.com>, Jimmy Xu <zmxu@marvell.com>, Jisheng Zhang <jszhang@marvell.com>, Nadav Haklai <nadavh@marvell.com>, Ryan Gao <ygao@marvell.com>, Doug Jones <dougj>
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On 26/01/17 12:50, Ulf Hansson wrote:
> On 11 January 2017 at 18:19, Gregory CLEMENT
> <gregory.clement@free-electrons.com> wrote:
>> +                       priv->init_card_type = MMC_TYPE_MMC;
>> +                       mmc->caps |= MMC_CAP_NONREMOVABLE;
>> +
>> +                       /*
>> +                        * Force to clear BUS_TEST to
>> +                        * skip bus_test_pre and bus_test_post
>> +                        */
>> +                       mmc->caps &= ~MMC_CAP_BUS_WIDTH_TEST;
>> +                       mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ |
> 
> This cap is a bit strange. It was added several years ago by Adrian
> Hunter, but I am wondering about the reason to why it's needed.
> 

MMC_CAP2_HC_ERASE_SZ relates to EXT-CSD ERASE_GROUP_DEF.

I think it was added to enable people to choose whether they wanted a large
or small erase granularity.  That probably doesn't matter if the card
supports TRIM.