[PATCH-V2 7/7] bsp/sparc: Flush only instruction cache

[Gedare Bloom]

On Wed, Jul 9, 2014 at 3:02 AM, Daniel Cederman <cederman at gaisler.com> wrote:
> The flush instruction on LEON flushes both the data and the instruction
> cache. Flushing of just the instruction cache can be done by setting
> the "flush instruction cache" bit in the cache control register.
> ---
>  c/src/lib/libbsp/sparc/leon3/include/cache_.h |    5 ++++-
>  c/src/lib/libbsp/sparc/leon3/include/leon.h   |    1 +
>  2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/c/src/lib/libbsp/sparc/leon3/include/cache_.h b/c/src/lib/libbsp/sparc/leon3/include/cache_.h
> index 63790c1..ced5b6d 100644
> --- a/c/src/lib/libbsp/sparc/leon3/include/cache_.h
> +++ b/c/src/lib/libbsp/sparc/leon3/include/cache_.h
> @@ -136,7 +136,10 @@ static inline void _CPU_cache_unfreeze_data(void)
>
>  static inline void _CPU_cache_invalidate_entire_instruction(void)
>  {
> -  __asm__ volatile ("flush");
> +  uint32_t cache_reg = leon3_get_cache_control_register();
> +
> +  cache_reg |= LEON3_REG_CACHE_CTRL_FI;
> +  leon3_set_cache_control_register(cache_reg);
>  }
Now you should also flush the d-cache explicitly for the case of
updating the trap table, as I mentioned in my previous email the store
to tbr[] can get cached in d-cache, so if we don't flush d-cache to
memory and it is write-back cache, there could be a problem. (I don't
know whether sparc32 cache are write-back or write-thru.)

-Gedare

>
>  static inline void _CPU_cache_invalidate_instruction_range(
> diff --git a/c/src/lib/libbsp/sparc/leon3/include/leon.h b/c/src/lib/libbsp/sparc/leon3/include/leon.h
> index a62ad29..bc3cdde 100644
> --- a/c/src/lib/libbsp/sparc/leon3/include/leon.h
> +++ b/c/src/lib/libbsp/sparc/leon3/include/leon.h
> @@ -90,6 +90,7 @@ extern "C" {
>   *  The following defines the bits in the LEON Cache Control Register.
>   */
>  #define LEON3_REG_CACHE_CTRL_DS      0x00800000 /* Data cache snooping */
> +#define LEON3_REG_CACHE_CTRL_FI      0x00200000 /* Flush instruction cache */
>
>  /* LEON3 Interrupt Controller */
>  extern volatile struct irqmp_regs *LEON3_IrqCtrl_Regs;
> --
> 1.7.9.5
>
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