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Date:   Fri, 12 Apr 2019 17:04:50 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     YueHaibing <yuehaibing@huawei.com>
Cc:     Miquel Raynal <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>
Subject: Re: [PATCH] mtd: nand: Fix build error while
 CONFIG_MTD_NAND_ECC_SW_BCH is set to module
Message-ID: <20190412170450.4d215ad4@collabora.com>
In-Reply-To: <79bce66d-6bb5-39f9-6f36-0667dede52fd@huawei.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>
        <41165c39-da0c-0f15-87f9-4fb588b77dcc@huawei.com>
        <20190410181843.489a4e33@xps13>
        <20190410190328.433a954f@collabora.com>
        <79bce66d-6bb5-39f9-6f36-0667dede52fd@huawei.com>
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On Fri, 12 Apr 2019 22:28:57 +0800
YueHaibing <yuehaibing@huawei.com> wrote:

> On 2019/4/11 1:03, Boris Brezillon wrote:
> > On Wed, 10 Apr 2019 18:18:43 +0200
> > Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >   
> >> Hi YueHaibing,
> >>
> >> YueHaibing <yuehaibing@huawei.com> wrote on Wed, 10 Apr 2019 23:03:24
> >> +0800:
> >>  
> >>> 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'.      
> >>
> >> Why exactly? SW BCH is going to be converted to the generic ECC engine
> >> abstraction and IIRC you told me that it would not be problematic to
> >> turn it into a boolean?  
> > 
> > Yes, I told you we should turn it into a boolean and embed the code in
> > the nandcore.o object which can itself be linked as a module or embedded
> > in the kernel image (see above for a version adapted for nand.o). That's
> > not exactly what Yue proposed.  
> 
> So is there anothor fix or just to pick my v2 ?
> 
> https://patchwork.ozlabs.org/patch/1083480/


Looks like someone posted it already:

https://patchwork.ozlabs.org/patch/1083603/