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* [PATCH v2] m68k: fix ColdFire clear cache operation
@ 2012-07-11  0:37 gerg
  2012-07-11 15:51 ` Philippe De Muyter
  2012-07-16 19:13 ` Geert Uytterhoeven
  0 siblings, 2 replies; 5+ messages in thread
From: gerg @ 2012-07-11  0:37 UTC (permalink / raw)
  To: linux-m68k; +Cc: Greg Ungerer

From: Greg Ungerer <gerg@uclinux.org>

The code for clearing (invalidating) the ColdFire cache is actually performing
a push operation. Add functions to clear the cache, and fix cache_clear() to
call the appropriate clear cache function.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/m68k/include/asm/cacheflush_mm.h |   35 +++++++++++++++++++++++++++++++++
 arch/m68k/mm/memory.c                 |    2 +-
 2 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/arch/m68k/include/asm/cacheflush_mm.h b/arch/m68k/include/asm/cacheflush_mm.h
index 8104bd8..b05990e 100644
--- a/arch/m68k/include/asm/cacheflush_mm.h
+++ b/arch/m68k/include/asm/cacheflush_mm.h
@@ -17,6 +17,41 @@
 #define DCACHE_SETMASK	0
 #endif
 
+/*
+ * ColdFire architecture has no way to clear individual cache lines, so we
+ * are stuck invalidating all the cache entries when we want a clear operation.
+ */
+static inline void clear_cf_icache(unsigned long start, unsigned long end)
+{
+	__asm__ __volatile__ (
+		"movec	%0,%%cacr\n\t"
+		"nop\n\t"
+		:
+		: "r" (CACHE_MODE | CACR_ICINVA | CACR_BCINVA));
+}
+
+static inline void clear_cf_dcache(unsigned long start, unsigned long end)
+{
+	__asm__ __volatile__ (
+		"movec	%0,%%cacr\n\t"
+		"nop\n\t"
+		:
+		: "r" (CACHE_MODE | CACR_DCINVA));
+}
+
+static inline void clear_cf_bcache(unsigned long start, unsigned long end)
+{
+	__asm__ __volatile__ (
+		"movec	%0,%%cacr\n\t"
+		"nop\n\t"
+		:
+		: "r" (CACHE_MODE | CACR_ICINVA | CACR_BCINVA | CACR_DCINVA));
+}
+
+/*
+ * Use the ColdFire cpushl instruction to push (and invalidate) cache lines.
+ * The start and end addresses are cache line numbers not memory addresses.
+ */
 static inline void flush_cf_icache(unsigned long start, unsigned long end)
 {
 	unsigned long set;
diff --git a/arch/m68k/mm/memory.c b/arch/m68k/mm/memory.c
index 250b8b7..51bc9d2 100644
--- a/arch/m68k/mm/memory.c
+++ b/arch/m68k/mm/memory.c
@@ -203,7 +203,7 @@ static inline void pushcl040(unsigned long paddr)
 void cache_clear (unsigned long paddr, int len)
 {
     if (CPU_IS_COLDFIRE) {
-	flush_cf_bcache(0, DCACHE_MAX_ADDR);
+	clear_cf_bcache(0, DCACHE_MAX_ADDR);
     } else if (CPU_IS_040_OR_060) {
 	int tmp;
 
-- 
1.7.0.4

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] m68k: fix ColdFire clear cache operation
  2012-07-11  0:37 [PATCH v2] m68k: fix ColdFire clear cache operation gerg
@ 2012-07-11 15:51 ` Philippe De Muyter
  2012-07-12  1:50   ` Greg Ungerer
  2012-07-16 19:13 ` Geert Uytterhoeven
  1 sibling, 1 reply; 5+ messages in thread
From: Philippe De Muyter @ 2012-07-11 15:51 UTC (permalink / raw)
  To: gerg; +Cc: linux-m68k, Greg Ungerer

On Wed, Jul 11, 2012 at 10:37:16AM +1000, gerg@snapgear.com wrote:

> +	__asm__ __volatile__ (
> +		"movec	%0,%%cacr\n\t"
> +		"nop\n\t"

This could be written as

		"movec %0,%%cacr; nop"

i.e. :
	final "\n\t" is useless
	other "\n\t" may be replaced by ";"

Philippe

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] m68k: fix ColdFire clear cache operation
  2012-07-11 15:51 ` Philippe De Muyter
@ 2012-07-12  1:50   ` Greg Ungerer
  0 siblings, 0 replies; 5+ messages in thread
From: Greg Ungerer @ 2012-07-12  1:50 UTC (permalink / raw)
  To: Philippe De Muyter; +Cc: linux-m68k, Greg Ungerer

Hi Philippe,

On 12/07/12 01:51, Philippe De Muyter wrote:
> On Wed, Jul 11, 2012 at 10:37:16AM +1000, gerg@snapgear.com wrote:
>
>> +	__asm__ __volatile__ (
>> +		"movec	%0,%%cacr\n\t"
>> +		"nop\n\t"
>
> This could be written as
>
> 		"movec %0,%%cacr; nop"

It could, but IMHO that is not as clear. One instruction per line
is easier to read.


> i.e. :
> 	final "\n\t" is useless

Yep, I will remove that.

Thanks
Greg


------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
8 Gardner Close                             FAX:         +61 7 3217 5323
Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] m68k: fix ColdFire clear cache operation
  2012-07-11  0:37 [PATCH v2] m68k: fix ColdFire clear cache operation gerg
  2012-07-11 15:51 ` Philippe De Muyter
@ 2012-07-16 19:13 ` Geert Uytterhoeven
  2012-07-17  6:03   ` Greg Ungerer
  1 sibling, 1 reply; 5+ messages in thread
From: Geert Uytterhoeven @ 2012-07-16 19:13 UTC (permalink / raw)
  To: gerg; +Cc: linux-m68k, Greg Ungerer

On Wed, Jul 11, 2012 at 2:37 AM,  <gerg@snapgear.com> wrote:
> --- a/arch/m68k/include/asm/cacheflush_mm.h
> +++ b/arch/m68k/include/asm/cacheflush_mm.h
> @@ -17,6 +17,41 @@
>  #define DCACHE_SETMASK 0
>  #endif
>
> +/*
> + * ColdFire architecture has no way to clear individual cache lines, so we
> + * are stuck invalidating all the cache entries when we want a clear operation.
> + */
> +static inline void clear_cf_icache(unsigned long start, unsigned long end)
> +{
> +       __asm__ __volatile__ (
> +               "movec  %0,%%cacr\n\t"
> +               "nop\n\t"
> +               :
> +               : "r" (CACHE_MODE | CACR_ICINVA | CACR_BCINVA));

These new functions should be moved inside the #ifdef CONFIG_COLDFIRE
at the top of the file:

arch/m68k/include/asm/cacheflush_mm.h:30:10: error: 'CACHE_MODE'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:30:23: error: 'CACR_ICINVA'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:30:37: error: 'CACR_BCINVA'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:39:10: error: 'CACHE_MODE'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:39:23: error: 'CACR_DCINVA'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:48:10: error: 'CACHE_MODE'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:48:23: error: 'CACR_ICINVA'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:48:37: error: 'CACR_BCINVA'
undeclared (first use in this function)
arch/m68k/include/asm/cacheflush_mm.h:48:51: error: 'CACR_DCINVA'
undeclared (first use in this function)

http://kisskb.ellerman.id.au/kisskb/buildresult/6720541/

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] m68k: fix ColdFire clear cache operation
  2012-07-16 19:13 ` Geert Uytterhoeven
@ 2012-07-17  6:03   ` Greg Ungerer
  0 siblings, 0 replies; 5+ messages in thread
From: Greg Ungerer @ 2012-07-17  6:03 UTC (permalink / raw)
  To: Geert Uytterhoeven; +Cc: linux-m68k, Greg Ungerer

Hi Geert,

On 17/07/12 05:13, Geert Uytterhoeven wrote:
> On Wed, Jul 11, 2012 at 2:37 AM,  <gerg@snapgear.com> wrote:
>> --- a/arch/m68k/include/asm/cacheflush_mm.h
>> +++ b/arch/m68k/include/asm/cacheflush_mm.h
>> @@ -17,6 +17,41 @@
>>   #define DCACHE_SETMASK 0
>>   #endif
>>
>> +/*
>> + * ColdFire architecture has no way to clear individual cache lines, so we
>> + * are stuck invalidating all the cache entries when we want a clear operation.
>> + */
>> +static inline void clear_cf_icache(unsigned long start, unsigned long end)
>> +{
>> +       __asm__ __volatile__ (
>> +               "movec  %0,%%cacr\n\t"
>> +               "nop\n\t"
>> +               :
>> +               : "r" (CACHE_MODE | CACR_ICINVA | CACR_BCINVA));
>
> These new functions should be moved inside the #ifdef CONFIG_COLDFIRE
> at the top of the file:
>
> arch/m68k/include/asm/cacheflush_mm.h:30:10: error: 'CACHE_MODE'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:30:23: error: 'CACR_ICINVA'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:30:37: error: 'CACR_BCINVA'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:39:10: error: 'CACHE_MODE'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:39:23: error: 'CACR_DCINVA'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:48:10: error: 'CACHE_MODE'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:48:23: error: 'CACR_ICINVA'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:48:37: error: 'CACR_BCINVA'
> undeclared (first use in this function)
> arch/m68k/include/asm/cacheflush_mm.h:48:51: error: 'CACR_DCINVA'
> undeclared (first use in this function)
>
> http://kisskb.ellerman.id.au/kisskb/buildresult/6720541/

Ah yes. Just moving those functions into a CONFIG_COLDFIRE region
is not enough though. That will fail with:

   CC      arch/m68k/mm/memory.o
arch/m68k/mm/memory.c: In function ‘cache_clear’:
arch/m68k/mm/memory.c:206:2: error: implicit declaration of function ‘clear_cf_bcache’

I hit the same problem with the other ColdFire flush functions too.
To fix those I locally defined the required definitions if they are
not set. I can do the same here with:

   #ifndef CACHE_MODE
   #define CACHE_MODE      0
   #define CACR_ICINVA     0
   #define CACR_DCINVA     0
   #define CACR_BCINVA     0
   #endif

This pollutes the code less than littering the code with #ifdefs on
the use COFIG_COLDFIRE, and doesn't seem any worse than defining
empty cache clear and push functions when not CONFIG_COLDFIRE.

Regards
Greg


------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
8 Gardner Close                             FAX:         +61 7 3217 5323
Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com

^ permalink raw reply	[flat|nested] 5+ messages in thread

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2012-07-11  0:37 [PATCH v2] m68k: fix ColdFire clear cache operation gerg
2012-07-11 15:51 ` Philippe De Muyter
2012-07-12  1:50   ` Greg Ungerer
2012-07-16 19:13 ` Geert Uytterhoeven
2012-07-17  6:03   ` Greg Ungerer

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