[U-Boot] [PATCH] drivers: mtd: add Microchip PIC32 internal non-CFI flash driver.

[Purna Chandra Mandal]

On 03/15/2016 05:35 PM, Jagan Teki wrote:

> On 14 March 2016 at 19:37, Purna Chandra Mandal
> <purna.mandal at microchip.com> wrote:
>> Jagan.
>>
>> On 03/14/2016 07:16 PM, Jagan Teki wrote:
>>
>>> On Monday 14 March 2016 07:00 PM, Purna Chandra Mandal wrote:
>>>> On 03/14/2016 06:13 PM, Daniel Schwierzeck wrote:
>>>>> 2016-03-10 14:12 GMT+01:00 Purna Chandra Mandal <purna.mandal at microchip.com>:
>>>>>> PIC32 embedded flash banks are memory mapped, directly read by CPU,
>>>>>> and programming (erase followed by write) operation on them are
>>>>>> handled by on-chip NVM controller.
>>>>>> Signed-off-by: Purna Chandra Mandal <purna.mandal at microchip.com>
>>>>>> ---
>>>>>>   drivers/mtd/Kconfig       |   6 +
>>>>>>   drivers/mtd/Makefile      |   1 +
>>>>>>   drivers/mtd/pic32_flash.c | 377 ++++++++++++++++++++++++++++++++++++++++++++++
>>> BTW: this driver need to be write in mtd driver mode, see for existing
>>> drivers and let me know for any help.
>> Will take up this activity [of supporting MTD] later on. For the time-being we are
>> not using mtd on embedded flash, mainly using for environment and bootcode which
>> are at well-known offset, size defined in include/configs/<board.h>.
> I understand your concern, but It look very hard to maintain the new
> drivers with non-dm model.

If issue is only non-dm model I can add DM support with exception that it will not
implement MTD functionality.

> My suggestions are better to add this on existing mtd(cfi or
> something) I guess ie "not possible"  or move this driver to your soc
> or board code for time being till mtd uclass addition or write a fresh
> mtd dm driver.

PIC32 flash devices are non CFI/JEDEC compliant so no way we can separate one flash
chip from other. Even though flash devices are parallel erase and program on these
flash chips are performed through NVM controller (serial interface). So we can't
directly port the functionality on CFI driver.

I like the idea of adding this driver under arch/soc/ or board/. But that is where it was
initially added, but based on review comment it is moved to drivers/mtd/.

Please suggest me a way!

> thanks!