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Subject: Re: [PATCH] mtd: nand: Fix build error while
 CONFIG_MTD_NAND_ECC_SW_BCH is set to module
To:     Boris Brezillon <boris.brezillon@collabora.com>
References: <20190410130747.35692-1-yuehaibing@huawei.com>
 <20190410153920.68267a1a@collabora.com>
 <20190410155856.655122c8@collabora.com>
 <8b020124-4008-6081-c04c-eaefb7875878@huawei.com>
 <20190410162927.17ea678b@collabora.com>
CC:     <miquel.raynal@bootlin.com>, <richard@nod.at>,
        <computersforpeace@gmail.com>, <marek.vasut@gmail.com>,
        <paul.burton@mips.com>, <bbrezillon@kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>
From:   YueHaibing <yuehaibing@huawei.com>
Message-ID: <41165c39-da0c-0f15-87f9-4fb588b77dcc@huawei.com>
Date:   Wed, 10 Apr 2019 23:03:24 +0800
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On 2019/4/10 22:29, Boris Brezillon wrote:
> On Wed, 10 Apr 2019 22:22:16 +0800
> YueHaibing <yuehaibing@huawei.com> wrote:
> 
>> On 2019/4/10 21:58, Boris Brezillon wrote:
>>> On Wed, 10 Apr 2019 15:39:28 +0200
>>> Boris Brezillon <boris.brezillon@collabora.com> wrote:
>>>   
>>>> On Wed, 10 Apr 2019 21:07:47 +0800
>>>> Yue Haibing <yuehaibing@huawei.com> wrote:
>>>>  
>>>>> From: YueHaibing <yuehaibing@huawei.com>
>>>>>
>>>>> Fix gcc build error while CONFIG_MTD_NAND_ECC_SW_BCH
>>>>> is set to module:
>>>>>
>>>>> drivers/mtd/nand/raw/nand_base.o: In function `nand_cleanup':
>>>>> (.text+0xef6): undefined reference to `nand_bch_free'
>>>>> drivers/mtd/nand/raw/nand_base.o: In function `nand_scan_tail':
>>>>> nand_base.c:(.text+0xa101): undefined reference to `nand_bch_calculate_ecc'
>>>>> nand_base.c:(.text+0xa120): undefined reference to `nand_bch_correct_data'
>>>>> nand_base.c:(.text+0xa269): undefined reference to `nand_bch_init'
>>>>>
>>>>> CONFIG_MTD_NAND_ECC_SW_BCH should not be set to M,
>>>>> because MTD_RAW_NAND need it while linked.
>>>>>
>>>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>>>> Fixes: 193bd4002644 ("mtd: nand: add software BCH ECC support"    
>>>>
>>>> Nope, it's not this one that introduced the regression.
>>>>
>>>>
>>>>  
>>>>> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
>>>>> ---
>>>>>  drivers/mtd/nand/raw/Kconfig | 2 +-
>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>>>>> index 615d738..0500c42 100644
>>>>> --- a/drivers/mtd/nand/raw/Kconfig
>>>>> +++ b/drivers/mtd/nand/raw/Kconfig
>>>>> @@ -22,7 +22,7 @@ menuconfig MTD_RAW_NAND
>>>>>  if MTD_RAW_NAND
>>>>>  
>>>>>  config MTD_NAND_ECC_SW_BCH
>>>>> -	tristate "Support software BCH ECC"
>>>>> +	bool "Support software BCH ECC"
>>>>>  	select BCH
>>>>>  	default n
>>>>>  	help    
>>>>
>>>> Should be fixed with the following diff squashed into:
>>>>
>>>> 51ef1d0b2095 ("mtd: nand: Clarify Kconfig entry for software BCH ECC algorithm")
>>>>  
>>>> --->8---    
>>>> diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h
>>>> index b8106651f807..06ce2b655c13 100644
>>>> --- a/include/linux/mtd/nand_bch.h
>>>> +++ b/include/linux/mtd/nand_bch.h
>>>> @@ -15,7 +15,7 @@ struct mtd_info;
>>>>  struct nand_chip;
>>>>  struct nand_bch_control;
>>>>  
>>>> -#if defined(CONFIG_MTD_NAND_ECC_BCH)
>>>> +#if defined(CONFIG_MTD_NAND_ECC_SW_BCH)
>>>>  
>>>>  static inline int mtd_nand_has_bch(void) { return 1; }
>>>>  
>>>> @@ -39,7 +39,7 @@ struct nand_bch_control *nand_bch_init(struct mtd_info *mtd);
>>>>   */
>>>>  void nand_bch_free(struct nand_bch_control *nbc);
>>>>  
>>>> -#else /* !CONFIG_MTD_NAND_ECC_BCH */
>>>> +#else /* !CONFIG_MTD_NAND_ECC_SW_BCH */
>>>>  
>>>>  static inline int mtd_nand_has_bch(void) { return 0; }
>>>>  
>>>> @@ -64,6 +64,6 @@ static inline struct nand_bch_control *nand_bch_init(struct mtd_info *mtd)
>>>>  
>>>>  static inline void nand_bch_free(struct nand_bch_control *nbc) {}
>>>>  
>>>> -#endif /* CONFIG_MTD_NAND_ECC_BCH */
>>>> +#endif /* CONFIG_MTD_NAND_ECC_SW_BCH */
>>>>  
>>>>  #endif /* __MTD_NAND_BCH_H__ */  
>>>
>>> Sorry, I didn't look at the right branch, this part of the code was
>>> correct, but we still have a problem to express the RAW_NAND(y) ->
>>> SW_BCH(y) dependency.  
>>
>> It seems this dependency is not always need,
>>
>> case MTD_RAW_NAND set to y works well while CONFIG_MTD_NAND_ECC_SW_BCH is not set.
> 
> Yes, I know, but forcing nand_bch to a be a boolean is not the right
> solution either, hence my suggestion to use 'imply'.

Got it, Thanks, will send v2 as your suggestion.

> 
> .
>