[U-Boot] [PATCH] arch/arm: Add individual TLB size support.

[Albert ARIBAUD]

Hi Li.Xiubo at freescale.com,

On Wed, 10 Sep 2014 03:10:27 +0000, "Li.Xiubo at freescale.com"
<Li.Xiubo at freescale.com> wrote:

> Hi Albert,
> 
> > Subject: Re: [PATCH] arch/arm: Add individual TLB size support.
> > 
> > Hi Xiubo,
> > 
> > On Mon, 7 Jul 2014 13:19:11 +0800, Xiubo Li <Li.Xiubo at freescale.com>
> > wrote:
> > 
> > > This adds CONFIG_TLB_SIZE for individual board, whose TLB size maybe
> > > larger than PGTABLE_SIZE.
> > >
> > > Signed-off-by: Xiubo Li <Li.Xiubo at freescale.com>
> > > ---
> > >  arch/arm/lib/board.c | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > >
> > > diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> > > index dc34190..b7327ce 100644
> > > --- a/arch/arm/lib/board.c
> > > +++ b/arch/arm/lib/board.c
> > > @@ -353,7 +353,11 @@ void board_init_f(ulong bootflag)
> > >
> > >  #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
> > >  	/* reserve TLB table */
> > > +#ifdef CONFIG_TLB_SIZE
> > > +	gd->arch.tlb_size = CONFIG_TLB_SIZE;
> > > +#else
> > >  	gd->arch.tlb_size = PGTABLE_SIZE;
> > > +#endif
> > >  	addr -= gd->arch.tlb_size;
> > >
> > >  	/* round down to next 64 kB limit */
> > 
> > There is no code in current mainline which defines CONFIG_TLB_SIZE;
> > that makes the patch a dead code addition.
> >
> 
> Yes, this will be used by our LS1 SoC first, and it is still doing
> The upstream.

Then please sumbit this patch as part of the LS1 SoC support series,
where the code it creates will actually be used.
 
> > Besides, what's the point of this as opposed to, e.g., just defining the
> > right PGTABLE_SIZE, or renaming PGTABLE_SIZE as CONFIG_TLB_SIZE?
> > 
> 
> We'll add the LPAE support in uboot and need more space for tlb.

I still don't get it. Is gd->arch.tlb_size the size of a page table or
of a translation lookahead buffer?

> Thanks very much,
> 
> BRs
> Xiubo

Amicalement,
-- 
Albert.