[U-Boot] [PATCH] arm: socfpga: gen5: Enabling cache and TLB maintenance broadcast

[See, Chin Liang]

On Thu, 2018-03-01 at 17:17 +0100, Marek Vasut wrote:
> On 02/28/2018 06:12 AM, chin.liang.see at intel.com wrote:
> > 
> > From: Chin Liang See <chin.liang.see at intel.com>
> > 
> > Enabling cache and TLB maintenance broadcast through ACTLR as
> > required
> > by Linux.
> This needs far more clarification. What is the problem you're fixing
> here ? How does it fix the problem ?

Sure. When the 2 processors is enabled with SMP, popen operation would
fail as content are different after the copy. This issue goes away when
we force Linux to run with 1 core only. Checked with ARM, this bit is
required by Linux when running SMP.

Chin Liang

> 
> > 
> > Signed-off-by: Chin Liang See <chin.liang.see at intel.com>
> > ---
> >  arch/arm/mach-socfpga/misc_gen5.c | 11 ++++++++++-
> >  1 file changed, 10 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/mach-socfpga/misc_gen5.c b/arch/arm/mach-
> > socfpga/misc_gen5.c
> > index a7dcacc..7c7a708 100644
> > --- a/arch/arm/mach-socfpga/misc_gen5.c
> > +++ b/arch/arm/mach-socfpga/misc_gen5.c
> > @@ -239,7 +239,7 @@ static u32 iswgrp_handoff[8];
> >  
> >  int arch_early_init_r(void)
> >  {
> > -	int i;
> > +	int i, val;
> >  
> >  	/*
> >  	 * Write magic value into magic register to unlock support
> > for
> > @@ -285,6 +285,15 @@ int arch_early_init_r(void)
> >  	socfpga_per_reset(SOCFPGA_RESET(NAND), 0);
> >  #endif
> >  
> > +	/* Enable cache and TLB maintainance broadcast as required
> > by Linux */
> > +	/* Read auxiliary control register */
> > +	asm volatile ("mrc     p15, 0, %0, c1, c0, 1\n\t" :
> > "=r"(val));
> > +	val |= (1 << 0);
> > +	/* Write auxiliary control register */
> > +	asm volatile ("mcr     p15, 0, %0, c1, c0, 1\n\t" : :
> > "r"(val));
> > +	CP15DSB;
> > +	CP15ISB;
> > +
> >  	return 0;
> >  }
> >  
> > 
>