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

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Message-ID: <e7262e5d-a15c-8cb4-dc8b-c0e391f2a88b@hisilicon.com>
Date:	Tue, 19 Jul 2016 20:28:20 +0800
From:	Jinguojun <kid.jin@...ilicon.com>
To:	Jaehoon Chung <jh80.chung@...sung.com>, <ulf.hansson@...aro.org>,
	"Adrian Hunter" <adrian.hunter@...el.com>, <arnd@...db.de>,
	<rmk+kernel@....linux.org.uk>, <shawn.lin@...k-chips.com>,
	<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>
Subject: Re: [PATCH 1/2] Support SD UHS for hikey-mainline-rebase



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
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;
>>  }
>>  
>>
> 
> 
> .
>