[U-Boot] [linux-sunxi] Re: [RFC 02/11] mtd/nand: add ONFI timing mode to nand_timings converter

[Roy Spliet]

Hello Michal,

Op 08-06-15 om 10:34 schreef Michal Suchanek:
> On 8 June 2015 at 10:11, Roy Spliet <r.spliet at ultimaker.com> wrote:
>> Hello Scott et al.,
>>
>> Op 06-06-15 om 00:02 schreef Scott Wood:
>>
>> On Fri, 2015-06-05 at 13:52 +0200, Roy Spliet wrote:
>>
>> From: yassin <yassinjaffer at gmail.com>
>>
>> Signed-off-by: Roy Spliet <r.spliet at ultimaker.com>
>> ---
>>   drivers/mtd/nand/Makefile       |   2 +-
>>   drivers/mtd/nand/nand_timings.c | 252
>> ++++++++++++++++++++++++++++++++++++++++
>>   include/linux/mtd/nand.h        |   3 +
>>   3 files changed, 256 insertions(+), 1 deletion(-)
>>   create mode 100644 drivers/mtd/nand/nand_timings.c
>>
>> This code comes from Linux and yet I see no acknowledgement of that,
>> much less a statement of which version of Linux this was pulled from.
>>
>> Correct, my apologies as I should have clarified that "work by Boris
>> Brezillon" does not
>> mean "upsteam work". The code comes from Boris' github tree[1] and contains
>> work
>> that was not yet brought upstream, yet is required for NAND on sunxi to
>> work.
>>
>> It would probably be better to handle this as part of a general sync
>> with the Linux mtd code.
>>
>> Ideally yes, but. In upstream Linux MTD we have a few issues to address as
>> shown
>> by Boris' patch-set, most importantly:
>> - NAND chip timings (patch 1 to 3)
>> - Randomisation support (patch 6)
>> - Per-partition settings for ECC and randomisation (left out of my RFC,
>> highly desirable
>> but not strictly required for U-boot booting)
> Hello,
>
> as I understand it the ECC and randomisation settings for the
> bootloader part of the nand are suboptimal or unusable for ubifs so if
> u-boot SPL is to read the u-boot binary and later u-boot the kernel
> from an ubifs volume it has to support non-uniform settings.
> Alternatively the bootloader part can be extended to contain
> partitions for u-boot binary and kernel image written to raw partition
> without filesystem much like what Andriod usually does.
SPL does not read U-boot from UBI. The SPL driver is separate, much 
smaller and
only reads in the same way BROM does. U-boot itself is not bound by the 
limitations
imposed by BROM, which means proper randomisation and ECC settings can 
be used
for "the UBI partition".
Yours,

Roy
>
> Thanks
>
> Michal


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