[U-Boot] [RFC PATCH 17/20] cmd: mtd: add 'mtd' command

[Stefan Roese]

Hi Miquel,

On 06.07.2018 14:26, Miquel Raynal wrote:
> Jagan Teki <jagannadh.teki at gmail.com> wrote on Fri, 6 Jul 2018 17:08:57
> +0530:
> 
>> On Wed, Jun 6, 2018 at 9:00 PM, Miquel Raynal <miquel.raynal at bootlin.com> wrote:
>>> There should not be a 'nand' command, a 'sf' command and certainly not
>>> another 'spi-nand'. Write a 'mtd' command instead to manage all MTD
>>> devices at once. This should be the preferred way to access any MTD
>>> device.
>>
>> So are you planning to integrate sf, nand command in future, adding
>> them dm conversion of many stuff. I would like to reommend to go with
>> spinand command. I have been through this and finally added spinor
>> command, which I will going to in soon. once all are converted to dm,
>> it would be easy and meaningfull to have common command.
> 
> I'm not sure we are in sync about this. The whole point of the previous
> discussion was to decide whether or not we should make full use of
> the MTD stack or not. I think it was pretty clear on the fact that
> people prefer to be close to Linux's architecture on this regard.
> 
> MTD being an abstraction of the type of memory, I don't get the
> point in creating yet another command each time a new type of
> device is supported. The fact that all the drivers of these devices
> register to the MTD layer makes it trivial to interact with. So why
> should we wait?

Yes, please don't add new commands for each subsystem / device-type.
I like the idea of adding one new command-set (your mtd command) and
extending this one to all other device-types over the time.

BTW: I'm testing your SPI NAND patches right now (still struggling
with some Gigadevice SPI NAND) and found that the "mtd" command is
not really in-line with the usual U-Boot commands. Here some
comments:

- Use hex values per default (addresses, sizes and soffset)
- "mtd read" just prints the read values. It makes more sense
   to read into memory instead (similar to the "mtd write")

I have some patches to address these issues in the queue (still
need some massaging), which you can fold into your patchset, once
we agree on this.

Thanks,
Stefan