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From: Christian Loehle <CLoehle@hyperstone.com>
To: Richard Weinberger <richard@nod.at>
Cc: Biju Das <biju.das.jz@bp.renesas.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	linux-renesas-soc <linux-renesas-soc@vger.kernel.org>,
	wsa+renesas <wsa+renesas@sang-engineering.com>,
	ulf hansson <ulf.hansson@linaro.org>
Subject: RE: Poor write performance to boot area using rcar-gen3-sdhi
Date: Fri, 21 Apr 2023 16:23:25 +0000	[thread overview]
Message-ID: <398e244a4d3746f1bd7b4c32d1ea70e3@hyperstone.com> (raw)
In-Reply-To: <1273293952.226564.1682003880265.JavaMail.zimbra@nod.at>



-----Original Message-----
From: Richard Weinberger <richard@nod.at> 
Sent: Thursday, April 20, 2023 5:18 PM
To: Christian Loehle <CLoehle@hyperstone.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>; linux-mmc <linux-mmc@vger.kernel.org>; linux-renesas-soc <linux-renesas-soc@vger.kernel.org>; wsa+renesas <wsa+renesas@sang-engineering.com>; ulf hansson <ulf.hansson@linaro.org>
Subject: Re: Poor write performance to boot area using rcar-gen3-sdhi
> 
> I did further tracing and on Linux I see clearly that tmio_mmc_irq() always much later when writing to the boot area.
> 
> Another idea, since u-boot does not really support interrupts it polls various status bits to detect completion of commands and data transfers.
> Crazy idea: Maybe u-boot writes are faster than they should because it polls not always the right bits?
> 
> ...or Linux is too conservative and it matters for the boot area.
> 
> Thanks,
> //richard
> 

If u-boot does not wait until the card no longer signals busy, I would expect data loss.
There are probably some more differences if you really want to go down that rabbit hole,
like different bus modes for uboot and linux.
Anyway I don't really know how I could help you out here, if you could provide a trace showing the busy times,
that would be a smoking gun for the eMMC vendor.

Regards,
Christian

Hyperstone GmbH | Reichenaustr. 39a  | 78467 Konstanz
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  reply	other threads:[~2023-04-21 16:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-17 20:08 Poor write performance to boot area using rcar-gen3-sdhi Richard Weinberger
2023-04-18  6:09 ` Biju Das
2023-04-18  6:16   ` Richard Weinberger
2023-04-18  7:48     ` Christian Loehle
2023-04-18  8:11       ` Richard Weinberger
2023-04-18  8:36         ` Christian Loehle
2023-04-18 11:58           ` Richard Weinberger
2023-04-20 15:18             ` Richard Weinberger
2023-04-21 16:23               ` Christian Loehle [this message]
2023-05-09 11:28                 ` Richard Weinberger
2023-05-11  9:46                   ` Christian Loehle
2023-05-11 10:35                     ` Richard Weinberger
2023-04-18  8:12       ` Biju Das

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