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Re: [Qemu-arm] [PATCH 12/13] sdhci: Add i.MX specific subtype of SDHCI
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-arm] [PATCH 12/13] sdhci: Add i.MX specific subtype of SDHCI |
Date: |
Thu, 14 Dec 2017 13:17:21 -0300 |
On Thu, Dec 14, 2017 at 1:05 PM, Andrey Smirnov
<address@hidden> wrote:
> On Thu, Dec 14, 2017 at 7:32 AM, Philippe Mathieu-Daudé <address@hidden>
> wrote:
>> [...]
>>>>> + case ESDHC_DLL_CTRL:
>>>>> + case ESDHC_TUNE_CTRL_STATUS:
>>>>> + case 0x6c:
>>>>
>>>> Isn't there a name we can give 0x6c ?
>>>>
>>>
>>> Unfortunately, not that I know of. It's a mystery register not listed
>>> in RM and the only place I can found it being mentioned is in Linux
>>> driver as a part of errata ESDHC_FLAG_ERR004536 fix, where it is used
>>> nameless as well.
>>
>> This sets the SD CLK/RCLK frequency (10-bit) for the 104MB/sec bus speed
>> (UHS-I mode).
>>
>> The "Sampling Clock Tuning Procedure" figure in the Spec v3 is helpful.
>>
>
> I am a bit hesitant to agree that this is indeed the case. ERR004536
> errata's title is "uSDHC: ADMA Length Mismatch Error may occur for
> longer read latencies" and recommented workaround is "Use SDMA (or
> ADMA1) in case the AHB latency is larger than the “minimal time for
> one block”. On top of that corresponding code in Linux
> (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/mmc/host/sdhci-esdhc-imx.c?h=v4.15-rc3#n1061)
> doesn't seem to use it as a 10-bit frequency field, treating it more
> like a single-bit flag.
Ok, I'll have a better look when applying these SD patches on top of
my current SD tree.
Regards,
Phil.
- [Qemu-arm] [PATCH 08/13] imx_fec: Add support for multiple Tx DMA rings, (continued)
- [Qemu-arm] [PATCH 08/13] imx_fec: Add support for multiple Tx DMA rings, Andrey Smirnov, 2017/12/11
- [Qemu-arm] [PATCH 09/13] imx_fec: Use correct length for packet size, Andrey Smirnov, 2017/12/11
- [Qemu-arm] [PATCH 13/13] sdhci: Implement write method of ACMD12ERRSTS register, Andrey Smirnov, 2017/12/11
- [Qemu-arm] [PATCH 11/13] imx_fec: Reserve full FSL_IMX25_FEC_SIZE page for the register file, Andrey Smirnov, 2017/12/11
- [Qemu-arm] [PATCH 12/13] sdhci: Add i.MX specific subtype of SDHCI, Andrey Smirnov, 2017/12/11
[Qemu-arm] [PATCH 10/13] imx_fec: Fix a typo in imx_enet_receive(), Andrey Smirnov, 2017/12/11
Re: [Qemu-arm] [PATCH 00/13] i.MX FEC and SD changes, Peter Maydell, 2017/12/12