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Date:   Fri, 14 Sep 2018 16:29:23 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Masahiro Yamada <yamada.masahiro@socionext.com>
Cc:     linux-mtd@lists.infradead.org,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        Steffen Trumtrar <s.trumtrar@pengutronix.de>,
        linux-kernel@vger.kernel.org, Marek Vasut <marek.vasut@gmail.com>,
        Brian Norris <computersforpeace@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] mtd: rawnand: denali: fix a race condition when DMA is
 kicked
Message-ID: <20180914162923.05c44fcc@xps13>
In-Reply-To: <1536818329-11068-1-git-send-email-yamada.masahiro@socionext.com>
References: <1536818329-11068-1-git-send-email-yamada.masahiro@socionext.com>
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Hello,

Masahiro Yamada <yamada.masahiro@socionext.com> wrote on Thu, 13 Sep
2018 14:58:49 +0900:

> I thought the read-back of the DMA_ENABLE register was unnecessary
> (at least it is working on my boards), then deleted it in commit
> 586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper
> into caller").  Sorry, I was wrong - it caused a timing issue on
> Cyclone5 SoCFPGAs.
> 
> Revive the register read-back, commenting why this is necessary.
> 
> Fixes: 586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper into caller")
> Reported-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>


Thanks,
Miquèl