On Mon, Jan 26, 2015 at 08:32:41PM +0100, Hans de Goede wrote: > Hi, > > On 26-01-15 16:18, Tom Rini wrote: > >On Fri, Jan 23, 2015 at 09:54:12AM +0100, Hans de Goede wrote: > >>Hi, > >> > >>On 22-01-15 22:03, Tom Rini wrote: > >>>On Thu, Jan 22, 2015 at 08:10:06PM +0100, Hans de Goede wrote: > >>>>Hi, > >>>> > >>>>On 22-01-15 17:20, Tom Rini wrote: > >>>>>On Wed, Jan 21, 2015 at 09:03:25PM +0100, Hans de Goede wrote: > >>>>> > >>>>>>On some SoCs / ARMv7 CPU cores we need to do some setup before enabling > >>>>>>the > >>>>>>icache, etc. Add a soc_init hook with a weak default which just calls > >>>>>>cpu_init_cp15. > >>>>>> > >>>>>>This way different implementations can be provided to do some extra work > >>>>>>before or after cpu_init_cp15, or completely replacing cpu_init_cp15. > >>>>>> > >>>>>>Signed-off-by: Hans de Goede <hdego...@redhat.com> > >>>>>>--- > >>>>>> arch/arm/cpu/armv7/start.S | 18 +++++++++++++++++- > >>>>>> 1 file changed, 17 insertions(+), 1 deletion(-) > >>>>>> > >>>>>>diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S > >>>>>>index fdc05b9..9882b20 100644 > >>>>>>--- a/arch/arm/cpu/armv7/start.S > >>>>>>+++ b/arch/arm/cpu/armv7/start.S > >>>>>>@@ -64,7 +64,7 @@ reset: > >>>>>> > >>>>>> /* the mask ROM code should have PLL and others stable */ > >>>>>> #ifndef CONFIG_SKIP_LOWLEVEL_INIT > >>>>>>- bl cpu_init_cp15 > >>>>>>+ bl soc_init > >>>>>> bl cpu_init_crit > >>>>>> #endif > >>>>> > >>>>>I like the direction here. And I want to make sure I get the sunxi > >>>>>direction right here too (as I agree with the need / desire for boot0 + > >>>>>U-Boot to be a valid combination). I think we can take this a step > >>>>>farther. cpu_init_crit (on armv7) is basically a call to s_init(). > >>>>> > >>>>>For am33xx (and I bet but need to do and test omap3+) we can, with > >>>>>Simon's patch to let us move stack to DDR a tiny bit later, in the SPL > >>>>>case make s_init empty, which just leaves us with (with your patch) > >>>>>soc_init. Is there some way we can put all of this together in a > >>>>>function? > >>>> > >>>>You mean essentially call s_init here and have s_init call cpu_init_cp15 > >>>>I guess we could do that, but it would require auditing all existing armv7 > >>>>users of s_init. This may require me to rethink how / when I do timer & > >>>>gpio init etc. for u-boot.bin on sunxi, but that should not be a (big) > >>>>problem. > >>> > >>>Basically. From my first pass audit of s_init, it's either empty > >>>(Kona), sunxi, or omap/etc so I get to deal with it. And the default > >>>soc_init would just be the call to cpu_init_cp15 as you have it and we > >>>drop the lowlevel_init hurdles. > >> > >>Ok, so what you're suggesting is a patch which: > >> > >>1) Changes: > >> > >>#ifndef CONFIG_SKIP_LOWLEVEL_INIT > >> bl cpu_init_cp15 > >> bl cpu_init_crit > >>#endif > >> > >>Into: > >> > >>#ifndef CONFIG_SKIP_LOWLEVEL_INIT > >> bl lowlevel_init > >>#endif > >> > >>Which will setup the stack and then call the s_init C function > >> > >>2) Adds a weak default s_init which calls cpu_init_cp15 > >> > >>3) Patch all existing s_init functions to call cpu_init_cp15 > >>before doing anything else. > > > >Pretty close. Simon's SPL DM series and related clean-ups got me > >thinking that yes, seemingly too much got shoved into "s_init" that > >really could have been done using an existing hook done slightly later. > > > >>And then in follow up patches we can: > >> > >>4) Drop cpu_init_crit > >> > >>5) Cleanup some s_init functions (this will be left to the individual > >>SoC maintainers) > >> > >>I think that is a good idea, Albert what do you think about this ? > > > >So I'd like to see 5 done "soon" afterwards as it's me (omap*) and > >sunxi. I think we can simplfy the call sequence too, to roughly: > >#ifndef CONFIG_SKIP_LOWLEVEL_INIT > > ... Set up stack for C, it's just a few instrs > > bl lowlevel_init > >#endif > > bl _main > > > >__weak asm > >lowlevel_init: > > bl cpu_init_cp15 > > return to caller > > > >And comment that anything called via lowlevel_init must be C-callable. > >I hope that once #5 is done no one actually has a lowlevel_init that's > >done in C but we've kept the door open should it be needed down the > >road (as I _think_ we can shuffle both the omap* and sunxi stuff to do > >their inits as needed in both SPL and full U-Boot from an early hook in > >board_init_r, top of my head is board_init calls some_other_func() in > >full U-Boot to ensure GPIOs, etc, on sunxi and spl_board_init() calls > >same func in SPL, and we can consolidate again further down the road as > >we get SPL and full U-Boot more in sync on the call chain). > > Sounds good to me, and I'm fine with working the sunxi side of things. > > Since you seem to have this all in your head can you do a patch for this > replacing my patchset ?
I suppose that's what happens when you have a detailed plan, will do ;) -- Tom
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