[U-Boot] [PATCH v4 10/14] OMAP3 SPL: Add identify_nand_chip function

Wed Nov 23 08:39:11 CET 2011

On 11/22/11 17:39, Tom Rini wrote:
> On 11/22/2011 07:51 AM, Tom Rini wrote:
>> On 11/22/2011 07:33 AM, Igor Grinberg wrote:
>>> On 11/21/11 17:33, Tom Rini wrote:
>>>> On 11/21/2011 07:41 AM, Igor Grinberg wrote:
>>>>> On 11/21/11 16:12, Tom Rini wrote:
>>>>>> On Mon, Nov 21, 2011 at 12:04 AM, Igor Grinberg <grinberg at compulab.co.il> wrote:
>>>>>>> On 11/20/11 16:26, Tom Rini wrote:
>>>>>>>> On Sun, Nov 20, 2011 at 12:36 AM, Igor Grinberg <grinberg at compulab.co.il> wrote:
>>>>>>>>> Hi Tom,
>>>>>>>>>
>>>>>>>>> On 11/19/11 00:48, Tom Rini wrote:
>>>>>>>>>> A number of boards are populated with a PoP chip for both DDR and NAND
>>>>>>>>>> memory.  Other boards may simply use this as an easy way to identify
>>>>>>>>>> board revs.  So we provide a function that can be called early to reset
>>>>>>>>>> the NAND chip and return the result of NAND_CMD_READID.  All of this
>>>>>>>>>> code is put into spl_id_nand.c and controlled via CONFIG_SPL_OMAP3_ID_NAND.
>>>>>>>>>>
>>>>>>>>>> Signed-off-by: Tom Rini <trini at ti.com>
>>>>>>>>>> ---
>>>>>>>>>>  arch/arm/cpu/armv7/omap3/Makefile           |    3 +
>>>>>>>>>>  arch/arm/cpu/armv7/omap3/spl_id_nand.c      |   87 +++++++++++++++++++++++++++
>>>>>>>>>>  arch/arm/include/asm/arch-omap3/sys_proto.h |    1 +
>>>>>>>>>>  3 files changed, 91 insertions(+), 0 deletions(-)
>>>>>>>>>>  create mode 100644 arch/arm/cpu/armv7/omap3/spl_id_nand.c
>>>>>>>>>>
>>>>>>>>>> diff --git a/arch/arm/cpu/armv7/omap3/Makefile b/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>> index 8e85891..4b38e45 100644
>>>>>>>>>> --- a/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>> +++ b/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>> @@ -31,6 +31,9 @@ COBJS       += board.o
>>>>>>>>>>  COBJS        += clock.o
>>>>>>>>>>  COBJS        += mem.o
>>>>>>>>>>  COBJS        += sys_info.o
>>>>>>>>>> +ifdef CONFIG_SPL_BUILD
>>>>>>>>>> +COBJS-$(CONFIG_SPL_OMAP3_ID_NAND)    += spl_id_nand.o
>>>>>>>>>> +endif
>>>>>>>>>
>>>>>>>>> You haven't responded to my question on the above stuff.
>>>>>>>>> Otherwise all the series look good to me.
>>>>>>>>
>>>>>>>> Missed that, sorry!
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Original version available at:
>>>>>>>>> http://www.mail-archive.com/u-boot@lists.denx.de/msg68828.html
>>>>>>>>>
>>>>>>>>> Here is the relevant part:
>>>>>>>>>
>>>>>>>>>>>> diff --git a/arch/arm/cpu/armv7/omap3/Makefile b/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>>>>>>> index 8e85891..772f3d4 100644
>>>>>>>>>>>>>>> --- a/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>>>>>>> +++ b/arch/arm/cpu/armv7/omap3/Makefile
>>>>>>>>>>>>>>> @@ -31,6 +31,9 @@ COBJS += board.o
>>>>>>>>>>>>>>>  COBJS  += clock.o
>>>>>>>>>>>>>>>  COBJS  += mem.o
>>>>>>>>>>>>>>>  COBJS  += sys_info.o
>>>>>>>>>>>>>>> +ifdef CONFIG_SPL_BUILD
>>>>>>>>>>>>>>> +COBJS-$(CONFIG_SPL_OMAP3_POP_PROBE)    += spl_pop_probe.o
>>>>>>>>>>>>>>> +endif
>>>>>>>>>>>>>
>>>>>>>>>>>>> Can't CONFIG_SPL_OMAP3_..._PROBE symbol default to "no"
>>>>>>>>>>>>> and depend on CONFIG_SPL_BUILD, so you don't need to enclose
>>>>>>>>>>>>> it in #ifdef?
>>>>>>>>>>>
>>>>>>>>>>> But then it would build for both SPL and non-SPL cases.
>>>>>>>>>
>>>>>>>>> No, it should not.
>>>>>>>>> What do you think of the following:
>>>>>>>>> In the Makefile have only:
>>>>>>>>> COBJS-$(CONFIG_SPL_OMAP3_POP_PROBE)     += spl_pop_probe.o
>>>>>>>>>
>>>>>>>>> Then in the spl_pop_probe.c have this type of check:
>>>>>>>>> #ifndef CONFIG_SPL_BUILD
>>>>>>>>> # error CONFIG_SPL_OMAP3_POP_PROBE requires CONFIG_SPL_BUILD
>>>>>>>>> #endif
>>>>>>>>>
>>>>>>>>> This way, you require the CONFIG_SPL_OMAP3_POP_PROBE symbol
>>>>>>>>> be a part of the CONFIG_SPL_BUILD symbols group.
>>>>>>>>
>>>>>>>> Well, if we always link this, but then #error, U-Boot won't build :)
>>>>>>>
>>>>>>> No you do not always link this... please, read more carefully...
>>>>>>> Only when CONFIG_SPL_OMAP3_POP_PROBE symbol is defined, the file will
>>>>>>> be compiled, but if CONFIG_SPL_OMAP3_POP_PROBE defined without
>>>>>>> CONFIG_SPL_BUILD being defined, then it will emit an error.
>>>>>>
>>>>>> So make the config file do:
>>>>>> #ifdef CONFIG_SPL_BUILD
>>>>>> #define CONFIG_SPL_OMAP3_POP_PROBE
>>>>>> #endif
>>>>>> ?  That's now how the rest of the SPL code works.
>>>>>
>>>>> Well, yes I think it makes sense for all SPL related config options
>>>>> to do something like:
>>>>> #ifdef CONFIG_SPL_BUILD
>>>>> #define CONFIG_SPL_OMAP3_POP_PROBE
>>>>> #define CONFIG_SPL_...
>>>>> #define CONFIG_SPL_...
>>>>> #endif
>>>>>
>>>>> And the error message, I have proposed above, will prevent
>>>>> people from doing stupid things, like defining
>>>>> CONFIG_SPL_OMAP3_POP_PROBE without the CONFIG_SPL_BUILD.
>>>>> At least for now, until we have Kbuild with dependencies and stuff...
>>>>
>>>> Well, I guess the point I'd try and make is that it's not how SPL is
>>>> done today.  Really following the existing format would be (in the
>>>> Makefile):
>>>> ifdef CONFIG_SPL_BUILD
>>>> ifdef CONFIG_SPL_OMAP3_ID_NAND
>>>> COBJS-y += spl_id_nand.o
>>>> endif
>>>> endif
>>>
>>> This is bad!
>>> We don't want the code to look like the above crap, do we?
>>> Because next thing will be even worth:
>>> ifdef CONFIG_SPL_BUILD
>>> ifdef CONFIG_SPL_OMAP3_ID_NAND 
>>> ifdef CONFIG_SPL_OMAP3_ID_NAND_SHIT...
>>> COBJS-y += spl_id_nand_shit...o
>>> endif
>>> endif
>>> endif
>>>
>>>>
>>>> I can see the point you're making but I'm asking if we need to change
>>>> everyone around to your suggested way of building before we can merge
>>>> these changes in?  Thanks!
>>>
>>> Ok. I understand your point. No, I don't think we should.
>>> The real question is, do we want it look like the above crap?
>>> If not, then please, do it right in this patch and all the rest
>>> can be changed later.
>>> Also would be nice to make all future patches do the right thing.
>>
>> OK, will do.  Thanks!
> 
> Well, there's a problem.  spl/Makefile both sets CONFIG_SPL_BUILD and
> then says "here's a bunch of core stuff" we need.  So... we can't hide
> most CONFIG choices under a CONFIG_SPL_BUILD check.

Why? What's the problem?
Is a board config file gets included before the CONFIG_SPL_BUILD
gets exported? And then the "sub" symbol does not get defined?
Is that what's going on? or am I missing something?

> We can in the
> Makefiles however do more:
> ifdef CONFIG_SPL_BUILD
> COBJS-$(CONFIG_SPL_...) += spl_foo.o
> endif
> than we do today.

And it will turn into a crap... and spread over all the U-Boot code...
This is a problem!

What I propose here is to use the same model as
Linux uses - one independent config option per feature,
which can be selected by a board config file.
Is it impossible right now?

-- 
Regards,
Igor.