[U-Boot] [PATCH] arm: re-implement proper ISB instruction for ARMv7-A

[Tom Rini]

On Thu, Jul 28, 2016 at 07:03:17PM +0800, Chen-Yu Tsai wrote:
> Hi,
> 
> On Thu, Jul 28, 2016 at 6:13 PM, Ziyuan Xu <xzy.xu at rock-chips.com> wrote:
> > For ARMv7-A architecture, the valid ISB instruction is asm volatile("isb").
> >
> > This patch fixes the U-Boot was stuck in invalidate_dcache_all() before
> > booting linux kernel, which occurred on rk3288-base development board
> > such as evb-rk3288, rock2-rk3288. And something output via console like:
> >
> > => bootz 0x2000000
> > 0x02000000
> >    ramdisk start = 0x00000000, ramdisk end = 0x00000000
> >    Continuing to boot without FDT
> >    Initial value for argc=3
> >    Final value for argc=3
> >    using: ATAGS
> >
> >    Starting kernel ...
> >
> > Linux kernel exactly the same way(see arch/arm/include/asm/barrier.h).
> >
> > Signed-off-by: Ziyuan Xu <xzy.xu at rock-chips.com>
> > ---
> >
> >  arch/arm/include/asm/system.h | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
> > index 2bdc0be..12d4ba0 100644
> > --- a/arch/arm/include/asm/system.h
> > +++ b/arch/arm/include/asm/system.h
> > @@ -227,13 +227,15 @@ void __noreturn psci_system_reset(bool smc);
> >   */
> >  void save_boot_params_ret(void);
> >
> > -#define isb() __asm__ __volatile__ ("" : : : "memory")
> > -
> >  #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
> >
> >  #ifdef __ARM_ARCH_7A__
> > +#define isb() __asm__ __volatile__ ("isb" : : : "memory")
> > +
> >  #define wfi() __asm__ __volatile__ ("wfi" : : : "memory")
> >  #else
> > +#define isb() __asm__ __volatile__ ("" : : : "memory")
> > +
> >  #define wfi()
> >  #endif
> >
> 
> arch/arm/include/asm/barriers.h already has a proper set of
> ISB/DSB macros. Please consider using those instead.

Please fix arch/arm/include/asm/system.h to use the macros found in
barriers.h rather than have their own versions.  Thanks!

-- 
Tom
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