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Re: [PATCH 28/39] mtd: nand: denali: move multi NAND fixup code to a helper function

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On Wed, 30 Nov 2016 15:09:27 +0900
Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> Hi Boris,
> 
> 
> 2016-11-28 1:24 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
> > On Sun, 27 Nov 2016 03:06:14 +0900
> > Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> >  
> >> Collect multi NAND fixups into a helper function instead of
> >> scattering them in denali_init().  
> >
> > Can you tell me more about this multi-NAND feature?
> > The core is already able to detect multi-die NAND chips in a generic
> > way,  
> 
> This is not the case.
> 
> > but I fear this is something else, like "put two 8-bits chips on a
> > 16bits bus to emulate a single 16bits chip".  
> 
> Yes, it is.
> 
> (I have never used this controller like that.
> But, I am pretty sure it is
> from the code and the
> Denali's User Guide mentions such usage.)
> 
> 
> Just in case, I will clearly rephrase the comment block like follows in v2:
> 
>         /*
>          * Support for multi device:
>          * When the IP configuration is x16 capable and two x8 chips are
>          * connected in parallel, DEVICES_CONNECTED should be set to 2.
>          * In this case, the core framework knows nothing about this fact,
>          * so we should tell it the _logical_ pagesize and anything necessary.
>          */
> 

BTW, you should also set the NAND_BUSWIDTH_16 flag in this case.

> 
> 
> 
> > If that's a case, and this feature is actually used, then it's a bad
> > idea IMHO.
> > For example, how do you handle the case where one block is bad on a
> > chip but not on the other? And I fear this is not the only problem
> > with this approach :-/.  
> 
> As you expect, if one block is bad,
> the correspond block on the other chip can not be used.
> 

Hm, last time I thought about this usage I found others things that
could cause problems, but I can't remember exactly what.

Anyway, if this feature is already used, let's keep it.

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[PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 09/39] mtd: nand: denali: fix erased page check code Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 09/39] mtd: nand: denali: fix erased page check code Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 16:30 +0100
      Re: [PATCH 09/39] mtd: nand: denali: fix erased page check code Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-02 05:40 +0100
        Re: [PATCH 09/39] mtd: nand: denali: fix erased page check code Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-12-02 09:00 +0100
  [PATCH 22/39] mtd: nand: denali_dt: remove dma-mask DT property Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 22/39] mtd: nand: denali_dt: remove dma-mask DT property Rob Herring <robh@kernel.org> - 2016-12-01 17:00 +0100
  [PATCH 29/39] mtd: nand: denali: refactor multi NAND fixup code in more generic way Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 28/39] mtd: nand: denali: move multi NAND fixup code to a helper function Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 28/39] mtd: nand: denali: move multi NAND fixup code to  a helper function Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 17:30 +0100
      Re: [PATCH 28/39] mtd: nand: denali: move multi NAND fixup code to a  helper function Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-30 07:10 +0100
        Re: [PATCH 28/39] mtd: nand: denali: move multi NAND fixup code to  a helper function Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-30 09:10 +0100
  [PATCH 15/39] mtd: nand: denali: improve readability of handle_ecc() Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 15/39] mtd: nand: denali: improve readability of  handle_ecc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 16:40 +0100
    Re: [PATCH 15/39] mtd: nand: denali: improve readability of  handle_ecc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 16:50 +0100
      Re: [PATCH 15/39] mtd: nand: denali: improve readability of handle_ecc() Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-02 05:30 +0100
        Re: [PATCH 15/39] mtd: nand: denali: improve readability of  handle_ecc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-12-02 09:00 +0100
  [PATCH 18/39] mtd: nand: denali: move denali_read_page_raw() above denali_read_page() Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 18/39] mtd: nand: denali: move denali_read_page_raw()  above denali_read_page() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 17:20 +0100
      Re: [PATCH 18/39] mtd: nand: denali: move denali_read_page_raw()  above denali_read_page() Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-30 07:20 +0100
  [PATCH 37/39] mtd: nand: denali: support "nand-ecc-strength" DT property Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 37/39] mtd: nand: denali: support "nand-ecc-strength" DT  property Rob Herring <robh@kernel.org> - 2016-12-01 17:20 +0100
  [PATCH 23/39] mtd: nand: denali_dt: use pdev instead of ofdev for platform_device Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 36/39] mtd: nand: denali: allow to use SoC-specific ECC strength Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 02/39] mtd: nand: denali: remove unused CONFIG option and macros Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 30/39] mtd: nand: denali: set DEVICES_CONNECTED 1 if not set Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 27/39] mtd: nand: denali: do not set mtd->name Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 35/39] mtd: nand: denali: calculate ecc.strength and ecc.bytes generically Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Rob Herring <robh@kernel.org> - 2016-12-01 17:10 +0100
      Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-02 04:00 +0100
        Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Rob Herring <robh@kernel.org> - 2016-12-02 17:30 +0100
          Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-03 03:50 +0100
            Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Marek Vasut <marek.vasut@gmail.com> - 2016-12-03 04:00 +0100
              Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Dinh Nguyen <dinh.linux@gmail.com> - 2016-12-03 23:10 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-05 04:40 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Marek Vasut <marek.vasut@gmail.com> - 2016-12-05 04:50 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-05 05:20 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Marek Vasut <marek.vasut@gmail.com> - 2016-12-05 05:30 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Dinh Nguyen <dinh.linux@gmail.com> - 2016-12-05 22:00 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Marek Vasut <marek.vasut@gmail.com> - 2016-12-05 22:50 +0100
                Re: [PATCH 39/39] mtd: nand: denali_dt: add compatible strings for  UniPhier SoC variants Dinh Nguyen <dinguyen@kernel.org> - 2016-12-05 23:40 +0100
  [PATCH 12/39] mtd: nand: denali: return 0 for uncorrectable ECC error Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 31/39] mtd: nand: denali: remove meaningless writes to read-only registers Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 32/39] mtd: nand: denali: remove unnecessary writes to ECC_CORRECTION Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 01/39] mtd: nand: allow to set only one of ECC size and ECC strength from DT Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 01/39] mtd: nand: allow to set only one of ECC size and  ECC strength from DT Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 15:00 +0100
  [PATCH 06/39] mtd: nand: denali: fix write_oob_data() function Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 03/39] mtd: nand: denali: remove redundant define of BANK(x) Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 05/39] mtd: nand: denali: fix comment of denali_nand_info::flash_mem Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 14/39] mtd: nand: denali: replace uint{8/16/32}_t with u{8/16/32} Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 24/39] mtd: nand: denali: add NEW_N_BANKS_FORMAT capability Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 26/39] mtd: nand: denali: call nand_set_flash_node() to set DT node Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 33/39] mtd: nand: denali: support 1024 byte ECC step size Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 33/39] mtd: nand: denali: support 1024 byte ECC step size Rob Herring <robh@kernel.org> - 2016-12-01 17:00 +0100
  [PATCH 10/39] mtd: nand: denali: remove redundant if conditional of erased_check Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
  [PATCH 38/39] mtd: nand: denali: remove Toshiba, Hynix specific fixup code Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-26 19:20 +0100
    Re: [PATCH 38/39] mtd: nand: denali: remove Toshiba, Hynix specific  fixup code Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 17:30 +0100
  Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 16:10 +0100
    Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-30 09:10 +0100
      Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-30 09:20 +0100
        Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-01 10:20 +0100
    Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-11-30 09:20 +0100
  Re: [PATCH 00/39] mtd: nand: denali: 2nd round of Denali NAND IP  patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-11-27 17:40 +0100

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