Re: [PATCH] sh: cache: Fill in invalidate_icache_all()

Good morning Geert,

On Wed, 2024-09-11 at 09:19 +0200, Geert Uytterhoeven wrote:
> Hi Marek,
> 
> On Tue, Sep 10, 2024 at 7:55 PM Marek Vasut <[email protected]> wrote:
> > On 9/10/24 7:21 PM, Tom Rini wrote:
> > > On Tue, Sep 10, 2024 at 02:15:58AM +0200, Marek Vasut wrote:
> > > 
> > > > Implement invalidate_icache_all() by clearing all V bits in
> > > > IC and OC. This is done by setting CCR cache control register
> > > > ICI and OCI bits.
> > > > 
> > > > Signed-off-by: Marek Vasut <[email protected]>
> > > > ---
> > > > Cc: Ilias Apalodimas <[email protected]>
> > > > Cc: Nobuhiro Iwamatsu <[email protected]>
> > > > Cc: Tom Rini <[email protected]>
> > > > Cc: [email protected]
> > > > ---
> > > >   arch/sh/cpu/sh4/cache.c | 11 +++++++----
> > > >   1 file changed, 7 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/arch/sh/cpu/sh4/cache.c b/arch/sh/cpu/sh4/cache.c
> > > > index d3c480e79ed..99acc599965 100644
> > > > --- a/arch/sh/cpu/sh4/cache.c
> > > > +++ b/arch/sh/cpu/sh4/cache.c
> > > > @@ -33,8 +33,9 @@ static inline void cache_wback_all(void)
> > > >      }
> > > >   }
> > > > 
> > > > -#define CACHE_ENABLE      0
> > > > -#define CACHE_DISABLE     1
> > > > +#define CACHE_ENABLE                0
> > > > +#define CACHE_DISABLE               1
> > > > +#define CACHE_INVALIDATE    2
> > > > 
> > > >   static int cache_control(unsigned int cmd)
> > > >   {
> > > > @@ -46,7 +47,9 @@ static int cache_control(unsigned int cmd)
> > > >      if (ccr & CCR_CACHE_ENABLE)
> > > >              cache_wback_all();
> > > > 
> > > > -    if (cmd == CACHE_DISABLE)
> > > > +    if (cmd == CACHE_INVALIDATE)
> > > > +            outl(CCR_CACHE_ICI | ccr, CCR);
> > > > +    else if (cmd == CACHE_DISABLE)
> > > >              outl(CCR_CACHE_STOP, CCR);
> > > >      else
> > > >              outl(CCR_CACHE_INIT, CCR);
> > > > @@ -103,7 +106,7 @@ void icache_disable(void)
> > > > 
> > > >   void invalidate_icache_all(void)
> > > >   {
> > > > -    puts("No arch specific invalidate_icache_all available!\n");
> > > > +    cache_control(CACHE_INVALIDATE);
> > > >   }
> > > > 
> > > >   int icache_status(void)
> > > 
> > > Thanks for filling this in, I wasn't sure how the implementation would
> > > look from a quick skim of the linux kernel code.
> > I believe it should look like the above, but lemme CC Geert to be on the
> > safe side.
> 
> I have no idea.  I removed the corresponding (but incomplete) code
> from Linux in commit 25c7d77d695a4104 ("sh: boot: Remove sh5 cache
> handling"), as it was a relic of sh5 cache handling.
> 
> SH4 cache handling seems to be buried deeper. At least the above
> matches for invalidation:
> 
> arch/sh/mm/cache-sh4.c- /* Flush I-cache */
> arch/sh/mm/cache-sh4.c: ccr = __raw_readl(SH_CCR);
> arch/sh/mm/cache-sh4.c- ccr |= CCR_CACHE_ICI;
> arch/sh/mm/cache-sh4.c: __raw_writel(ccr, SH_CCR);

Odd, I haven't received the original mail.

@Marek: Could you resent your patch CC'ing the current maintainers of arch/sh?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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