Date: Sat, 6 Nov 2021 13:05:40 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: arm@FreeBSD.org Subject: Re: huge emmc speed regression Message-ID: <67e6166d-a870-da60-efd4-9bd59fefca71@FreeBSD.org> In-Reply-To: <812ab31a-ce6e-d8ac-3539-39e6b20a01df@FreeBSD.org> References: <812ab31a-ce6e-d8ac-3539-39e6b20a01df@FreeBSD.org>
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On 06/11/2021 12:58, Andriy Gapon wrote:
>
> Upfront, I haven't tested the latest main / current yet.
> I should really test it but that's porbably for the next weekend.
>
> I see a huge emmc speed difference between the current from April 2021 and
> September 2021 (commit 5e79bba562bc303eed669dbd0d391b6c6a9c289b) on Orange Pi PC
> Plus using on-board eMMC card. I use MMCCAM in both cases.
>
> In the old environment I see expected read speeds (with sequential dd) of around
> 40 MB/s.
> In the new environment the speeds are around 300 KB/s (like a very good floppy
> disk of old).
>
> Some info from the old environment:
> # camcontrol mmcsdcmd 2:0:0 -I
> Host controller information
> Host OCR: 0x300000
> Min frequency: 400 KHz
> Max frequency: 52 MHz
[snip]
> Same command in the new environment looks a bit strange:
> # camcontrol mmcsdcmd 2:0:0 -I
> Host controller information
> Host OCR: 0x300000
> Min frequency: 400 KHz
> Max frequency: 0 MHz
[snip]
It seems that this is because the FDT does not have max-frequency property.
The old mmc_fdt_parse() code would leave f_max alone in that case and it was set
to 52 MHz by the driver.
However, the new code in mmc_fdt_parse(), or rather mmc_parse(), would reset
f_max to zero (despite the comment that was carried over):
/*
* max-frequency is optional, drivers should tweak this value
* if it's not present based on the clock that the mmc controller
* operates on
*/
max_freq = 0;
device_get_property(dev, "max-frequency", &max_freq, sizeof(uint64_t));
host->f_max = max_freq;
--
Andriy Gapon
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