linux-kernel - Re: [PATCH 1/2] Support SD UHS for hikey-mainline-rebase

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Date:	Wed, 20 Jul 2016 09:09:45 +0800
From:	Shawn Lin <shawn.lin@...k-chips.com>
To:	Jinguojun <kid.jin@...ilicon.com>,
	Jaehoon Chung <jh80.chung@...sung.com>, ulf.hansson@...aro.org,
	Adrian Hunter <adrian.hunter@...el.com>, arnd@...db.de,
	rmk+kernel@....linux.org.uk, linux-mmc@...r.kernel.org,
	linux-kernel@...r.kernel.org, xuwei5@...ilicon.com,
	robh+dt@...nel.org, ijc+devicetree@...lion.org.uk,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linuxarm@...wei.com, suzhuangluan@...ilicon.com,
	kongfei@...ilicon.com, CPGS <cpgs@...sung.com>
Cc:	shawn.lin@...k-chips.com
Subject: Re: [PATCH 1/2] Support SD UHS for hikey-mainline-rebase

在 2016/7/19 20:28, Jinguojun 写道:
>
>
> On 2016/7/19 16:13, Jaehoon Chung wrote:
>> Hi,
>>
>> Removed the unnecessary CC'd.
>>
>> On 07/19/2016 04:51 PM, Jin Guojun wrote:
>>> From: j00226943 <j00226943@...esmail.huawei.com>
>>
>> What is j00226943?
>>
>> When you send the patch for dw_mmc controller, plz use the prefix "mmc: dw_mmc: ".
>>
>>>
>>> Two more changes:
>>>
>>> Before we send cmd,we need to set CMD bit29 to
>>> 1 so that CMD and DATA sent to card through the HOLD Register,
>>> This is the explication in synosys host:To meet the relatively
>>> high Input Hold Time requirement for SDR12, SDR25, and other MMC
>>> speed modes, you should program bit[29]use_hold_Reg of the CMD
>>> register to 1'b1; the output data is then registered again in the
>>> cclk_in_drv domain by using the Hold Register as shown in Path B
>>> of Figure 10-8. However, for the higher speed modes of SDR104, SDR50
>>> and DDR50, you can meet the much smaller Input Hold Time requirement
>>> of 0.8ns by bypassing the Hold Register (Path A in Figure 10-8,
>>> programming CMD.use_hold_reg = 1'b0) and then adding delay elements
>>> on the output path as indicated
>>>
>>> We have no tuning function in our drivers,so we must do the
>>> Function piling when we init UHS card.
>
> 1.For hikey we cant support UHS for SD card in https://github.com/96boards-hikey/linux/tree/hikey-mainline-rebase
> 2.I have no SDMMC_CMD_USE_HOLD_REG in Dw_mmc-k3.c
>
>>
>> Sorry..this patch is NACK.
>> SDMMC_CMD_USE_HOLD_REG is already used by default in dw_mmc.c
>> Which kernel version did you use?
>>
>>>
>>> Signed-off-by: Jin Guojun <kid.jin@...ilicon.com>
>>> ---
>>>  drivers/mmc/host/dw_mmc-k3.c | 6 ++++++
>>>  drivers/mmc/host/dw_mmc.c    | 2 ++
>>>  2 files changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c
>>> index 63c2e2e..2cbfcc7 100644
>>> --- a/drivers/mmc/host/dw_mmc-k3.c
>>> +++ b/drivers/mmc/host/dw_mmc-k3.c
>>> @@ -125,10 +125,16 @@ static void dw_mci_hi6220_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>>>  	host->bus_hz = clk_get_rate(host->biu_clk);
>>>  }
>>>
>>> +static void dw_mci_hi6220_prepare_command(struct dw_mci *host, u32 *cmdr)
>>> +{
>>> +	*cmdr |= SDMMC_CMD_USE_HOLD_REG;
>>> +}
>>> +
>>>  static const struct dw_mci_drv_data hi6220_data = {
>>>  	.switch_voltage		= dw_mci_hi6220_switch_voltage,
>>>  	.set_ios		= dw_mci_hi6220_set_ios,
>>>  	.parse_dt		= dw_mci_hi6220_parse_dt,
>>> +	.prepare_command        = dw_mci_hi6220_prepare_command,
>>>  };
> Hi,thank you for your review
>
> 1.We do the prepare_command in dw_mci_prepare_command before we send CMD in dw_mmc.c

please clone Ulf's tree[0] and rebase your any patches on its next
branch, thanks.


[0] git://git.linaro.org/people/ulf.hansson/mmc

> 2.I can find the same drivers in dw_mmc-exynos.c
> 3.For hikey we do the initialization from Dw_mmc-k3.c,so I need to do the prepare_command in hi6220 drivers
>
>>
>> There is no "prepare_command" hooks.
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>>  static const struct of_device_id dw_mci_k3_match[] = {
>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>> index 9dd1bd3..047e116 100644
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -1564,6 +1564,8 @@ static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>>
>>>  	if (drv_data && drv_data->execute_tuning)
>>>  		err = drv_data->execute_tuning(slot, opcode);
>>> +	else
>>> +		err = 0;
>>>  	return err;
>>>  }
>>>
>>>
>>
>>
>> .
>>
>
>
>
>


-- 
Best Regards
Shawn Lin