Hi Graeme,
On Wed, Mar 14, 2012 at 8:02 PM, Graeme Russ graeme.russ@gmail.com wrote:
Hi Simon,
On Thu, Mar 15, 2012 at 1:50 PM, Simon Glass sjg@chromium.org wrote:
Hi Graeme,
On Wed, Mar 14, 2012 at 7:35 PM, Graeme Russ graeme.russ@gmail.com wrote:
Hi Simon,
[snip]
IMHO, global data should contain only globally common members and an arch- specific struct and ditch (most of) the #ifdefs
My thinking here was to try to bring everything into a single file. It then should be clearer when things are common between different architectures. Patches to the generic file can be made without also having to patch the non-generic files, etc.
A fair number of the #ifdefs are not needed, or are there because some archs don't implement all the features of U-Boot.
You have an example right there: cpu_clk_rate_hz is similar to cpu_clk and core_clk.
That said it is a bit of a daunting task to amalgamate them.
Also there is the purely practical consideration that if we continue to have an asm/global_data.h then we end up with two global datas. One is for CONFIG_SYS_GENERIC_BOARD and contains just the non-common fields. The other is for non-CONFIG_SYS_GENERIC_BOARD and contains all fields. Ick.
So what do you think?
Do you really need to unify global data to achieve what the title of the patch series suggests (i.e. to unify the init processing loop)? Maybe you could leave global data as is (or slightly tweak the odd arch) and leave the resolution of just how bad global data is becoming for another day
It's not that easy, because in board_f.c and board_r.c and other files there are certain fields required. It doesn't make a huge amount of sense to have generic code which accesses a different global structure depending on what architecture it is built for. Then there are fields are are only used when certain options are defined. Ick.
If I am going to pull this off I need a bit of flexibility. I've looked into this quite a bit and mapped a path through this which I think will work. It requires doing things in stages, or it will never happen.
I only say this because this is turning into "let's do a dirty hack now to partially fix it and leave the rest for later (it'll get done, really, honestly, I promise)" ;)
It was always like that. Although I wouldn't characterise it as a dirty hack. If there was a requirement to do all of this in one big bang then I wouldn't have even started. It is just too hard :-(
There will always be arch specific global data members - I see a few options:
- Move them into bd
I recall talk of getting rid of this (Mike?)
- Move them into an arch_global_data struct inside gd
This was Mike's idea. It is probably the easiest thing to do.
- Move them into an arch_global_data struct totally seperate from gd
I sort-of like this except it would slow down access and maybe increase code size. Then again perhaps that's a good thing if it provides an incentive to reduce the number of arch-specific fields.
- Question how many are really required to be in gd (remember, gd is only there to cart around writable global variable before .bss and .data are available after relocation)
Well yes, I feel there are far more at present than are needed. Having them all there in the open feels like a nice way to draw attention to the mess.
Regards, Simon
Regards,
Graeme