[PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[gerg]

From: Greg Ungerer <gerg@uclinux.org>

All current ColdFire CPUs are able to support unaligned memory accesses.
So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.

It seems that the current restriction was inherrited from the early non-MMU
support for the basic 68000 proecssors - which do not support unaligned
accesses.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/m68k/Kconfig.cpu |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index d4f3a98..06fa0c3 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -27,7 +27,6 @@ config COLDFIRE
 	select ARCH_HAVE_CUSTOM_GPIO_H
 	select CPU_HAS_NO_BITFIELDS
 	select CPU_HAS_NO_MULDIV64
-	select CPU_HAS_NO_UNALIGNED
 	select GENERIC_CSUM
 
 endchoice
-- 
1.7.0.4

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Geert Uytterhoeven]

On Fri, Jun 8, 2012 at 7:43 AM,  <gerg@snapgear.com> wrote:
> From: Greg Ungerer <gerg@uclinux.org>
>
> All current ColdFire CPUs are able to support unaligned memory accesses.
> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
>
> It seems that the current restriction was inherrited from the early non-MMU
> support for the basic 68000 proecssors - which do not support unaligned
> accesses.
>
> Signed-off-by: Greg Ungerer <gerg@uclinux.org>

I'll add this to my tree, as it depends on the other
CPU_HAS_NO_UNALIGNED patches.

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

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Greg Ungerer]

On 06/08/2012 05:19 PM, Geert Uytterhoeven wrote:
> On Fri, Jun 8, 2012 at 7:43 AM,<gerg@snapgear.com>  wrote:
>> From: Greg Ungerer<gerg@uclinux.org>
>>
>> All current ColdFire CPUs are able to support unaligned memory accesses.
>> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
>>
>> It seems that the current restriction was inherrited from the early non-MMU
>> support for the basic 68000 proecssors - which do not support unaligned
>> accesses.
>>
>> Signed-off-by: Greg Ungerer<gerg@uclinux.org>
>
> I'll add this to my tree, as it depends on the other
> CPU_HAS_NO_UNALIGNED patches.

Thanks Geert!

Regards
Greg



> --
> 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
> --
> To unsubscribe from this list: send the line "unsubscribe linux-m68k" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Philippe De Muyter]

On Fri, Jun 08, 2012 at 03:43:00PM +1000, gerg@snapgear.com wrote:
> From: Greg Ungerer <gerg@uclinux.org>
> 
> All current ColdFire CPUs are able to support unaligned memory accesses.
> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
> 
> It seems that the current restriction was inherrited from the early non-MMU
> support for the basic 68000 proecssors - which do not support unaligned
> accesses.

It seems that the first ColdFires needed the restriction :

I read in the "MCF5200 ColdFire Family Programmer’s Reference Manual" :

The ColdFire processor default configuration supports word- and
longword-sized operand references on 0-modulo-2 and 0-modulo-4
addresses, respectively. All other references are defined as
misaligned accesses. Any attempt to access a misaligned operand
generates an address-error exception, unless the optional hardware
module for handling misalignment is present. This misalignment
module converts any misaligned operand references into a series
of aligned bus cycles to access the data. The existence of the
misalignment module is implementation-dependent and is documented
in the appropriate ColdFire user’s manual.

Philippe

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Greg Ungerer]

Hi Philippe,

On 06/08/2012 08:39 PM, Philippe De Muyter wrote:
> On Fri, Jun 08, 2012 at 03:43:00PM +1000, gerg@snapgear.com wrote:
>> From: Greg Ungerer<gerg@uclinux.org>
>>
>> All current ColdFire CPUs are able to support unaligned memory accesses.
>> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
>>
>> It seems that the current restriction was inherrited from the early non-MMU
>> support for the basic 68000 proecssors - which do not support unaligned
>> accesses.
>
> It seems that the first ColdFires needed the restriction :
>
> I read in the "MCF5200 ColdFire Family ProgrammerÆs Reference Manual" :
>
> The ColdFire processor default configuration supports word- and
> longword-sized operand references on 0-modulo-2 and 0-modulo-4
> addresses, respectively. All other references are defined as
> misaligned accesses. Any attempt to access a misaligned operand
> generates an address-error exception, unless the optional hardware
> module for handling misalignment is present. This misalignment
> module converts any misaligned operand references into a series
> of aligned bus cycles to access the data. The existence of the
> misalignment module is implementation-dependent and is documented
> in the appropriate ColdFire userÆs manual.

I wish Freescale really did make that clear within the doco for each
part!

The oldest (and I assume simplest) part we support is the 5206, and it
does explicitly state in the MCF5206UM that it supports unaligned
accesses (Section 6.6). It is not as clear as this in some of the
other CPU/SoC User Manuals that I looked through.

I am pretty confident that all the parts we currently support in Linux
do unaligned accesses.

Regards
Greg


------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
8 Gardner Close,                            FAX:         +61 7 3891 3630
Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Philippe De Muyter]

Hi Greg,

On Fri, Jun 08, 2012 at 10:19:43PM +1000, Greg Ungerer wrote:
> Hi Philippe,
>
> On 06/08/2012 08:39 PM, Philippe De Muyter wrote:
>> On Fri, Jun 08, 2012 at 03:43:00PM +1000, gerg@snapgear.com wrote:
>>> From: Greg Ungerer<gerg@uclinux.org>
>>>
>>> All current ColdFire CPUs are able to support unaligned memory accesses.
>>> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
>>>
>>> It seems that the current restriction was inherrited from the early 
>>> non-MMU
>>> support for the basic 68000 proecssors - which do not support unaligned
>>> accesses.
>>
>> It seems that the first ColdFires needed the restriction :
>>
>> I read in the "MCF5200 ColdFire Family ProgrammerÆs Reference Manual" 
>> :
>>
>> The ColdFire processor default configuration supports word- and
>> longword-sized operand references on 0-modulo-2 and 0-modulo-4
>> addresses, respectively. All other references are defined as
>> misaligned accesses. Any attempt to access a misaligned operand
>> generates an address-error exception, unless the optional hardware
>> module for handling misalignment is present. This misalignment
>> module converts any misaligned operand references into a series
>> of aligned bus cycles to access the data. The existence of the
>> misalignment module is implementation-dependent and is documented
>> in the appropriate ColdFire userÆs manual.

I mentionned that only to make you able to soften the commit comment :)

>
> I wish Freescale really did make that clear within the doco for each
> part!
>
> The oldest (and I assume simplest) part we support is the 5206, and it
> does explicitly state in the MCF5206UM that it supports unaligned
> accesses (Section 6.6). It is not as clear as this in some of the
> other CPU/SoC User Manuals that I looked through.
>
> I am pretty confident that all the parts we currently support in Linux
> do unaligned accesses.

I agree.  And if some parts did not implement it, we'd see it quickly.

Regards

Philippe

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Greg Ungerer]

Hi Philippe,

On 08/06/12 23:35, Philippe De Muyter wrote:
> On Fri, Jun 08, 2012 at 10:19:43PM +1000, Greg Ungerer wrote:
>> Hi Philippe,
>>
>> On 06/08/2012 08:39 PM, Philippe De Muyter wrote:
>>> On Fri, Jun 08, 2012 at 03:43:00PM +1000, gerg@snapgear.com wrote:
>>>> From: Greg Ungerer<gerg@uclinux.org>
>>>>
>>>> All current ColdFire CPUs are able to support unaligned memory accesses.
>>>> So remove the CONFIG_CPU_HAS_NO_UNALIGNED option selection for ColdFire.
>>>>
>>>> It seems that the current restriction was inherrited from the early
>>>> non-MMU
>>>> support for the basic 68000 proecssors - which do not support unaligned
>>>> accesses.
>>>
>>> It seems that the first ColdFires needed the restriction :
>>>
>>> I read in the "MCF5200 ColdFire Family ProgrammerÆs Reference Manual"
>>> :
>>>
>>> The ColdFire processor default configuration supports word- and
>>> longword-sized operand references on 0-modulo-2 and 0-modulo-4
>>> addresses, respectively. All other references are defined as
>>> misaligned accesses. Any attempt to access a misaligned operand
>>> generates an address-error exception, unless the optional hardware
>>> module for handling misalignment is present. This misalignment
>>> module converts any misaligned operand references into a series
>>> of aligned bus cycles to access the data. The existence of the
>>> misalignment module is implementation-dependent and is documented
>>> in the appropriate ColdFire userÆs manual.
>
> I mentionned that only to make you able to soften the commit comment :)

Ok, makes sense. I should probably have mentioned that this means
the ColdFire processors currently support by Linux :-)

Something like:

   All of the current Linux supported ColdFire CPUs handle unaligned
   memory accesses. So remove the CONFIG_CPU_HAS_NO_UNALIGNED option
   selection for ColdFire. If we ever support a specific ColdFire CPU
   that does not support unaligned accesses then we can insert the
   CONFIG_CPU_HAS_NO_UNALIGNED for that specific CPU type.


>> I wish Freescale really did make that clear within the doco for each
>> part!
>>
>> The oldest (and I assume simplest) part we support is the 5206, and it
>> does explicitly state in the MCF5206UM that it supports unaligned
>> accesses (Section 6.6). It is not as clear as this in some of the
>> other CPU/SoC User Manuals that I looked through.
>>
>> I am pretty confident that all the parts we currently support in Linux
>> do unaligned accesses.
>
> I agree.  And if some parts did not implement it, we'd see it quickly.

Yep.

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

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Philippe De Muyter]

Hi Greg,

On Tue, Jun 12, 2012 at 12:25:44PM +1000, Greg Ungerer wrote:
> Hi Philippe,
>
> On 08/06/12 23:35, Philippe De Muyter wrote:
...
>>
>> I mentionned that only to make you able to soften the commit comment :)
>
> Ok, makes sense. I should probably have mentioned that this means
> the ColdFire processors currently support by Linux :-)
>
> Something like:
>
>   All of the current Linux supported ColdFire CPUs handle unaligned
>   memory accesses. So remove the CONFIG_CPU_HAS_NO_UNALIGNED option
>   selection for ColdFire. If we ever support a specific ColdFire CPU
>   that does not support unaligned accesses then we can insert the
>   CONFIG_CPU_HAS_NO_UNALIGNED for that specific CPU type.

That's perfect.  The line about dumb copying of the m68knommu settings
was too much self-flagellation for you to my eyes :)

Philippe

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Geert Uytterhoeven]

On Tue, Jun 12, 2012 at 9:26 AM, Philippe De Muyter <phdm@macqel.be> wrote:
> On Tue, Jun 12, 2012 at 12:25:44PM +1000, Greg Ungerer wrote:
>> On 08/06/12 23:35, Philippe De Muyter wrote:
> ...
>>>
>>> I mentionned that only to make you able to soften the commit comment :)
>>
>> Ok, makes sense. I should probably have mentioned that this means
>> the ColdFire processors currently support by Linux :-)
>>
>> Something like:
>>
>>   All of the current Linux supported ColdFire CPUs handle unaligned
>>   memory accesses. So remove the CONFIG_CPU_HAS_NO_UNALIGNED option
>>   selection for ColdFire. If we ever support a specific ColdFire CPU
>>   that does not support unaligned accesses then we can insert the
>>   CONFIG_CPU_HAS_NO_UNALIGNED for that specific CPU type.
>
> That's perfect.  The line about dumb copying of the m68knommu settings
> was too much self-flagellation for you to my eyes :)

So I rewrote history on my for-3.6 branch...

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

Re: [PATCH] m68knommu: allow ColdFire CPUs to use unaligned accesses

[Greg Ungerer]

On 13/06/12 06:27, Geert Uytterhoeven wrote:
> On Tue, Jun 12, 2012 at 9:26 AM, Philippe De Muyter<phdm@macqel.be>  wrote:
>> On Tue, Jun 12, 2012 at 12:25:44PM +1000, Greg Ungerer wrote:
>>> On 08/06/12 23:35, Philippe De Muyter wrote:
>> ...
>>>>
>>>> I mentionned that only to make you able to soften the commit comment :)
>>>
>>> Ok, makes sense. I should probably have mentioned that this means
>>> the ColdFire processors currently support by Linux :-)
>>>
>>> Something like:
>>>
>>> á All of the current Linux supported ColdFire CPUs handle unaligned
>>> á memory accesses. So remove the CONFIG_CPU_HAS_NO_UNALIGNED option
>>> á selection for ColdFire. If we ever support a specific ColdFire CPU
>>> á that does not support unaligned accesses then we can insert the
>>> á CONFIG_CPU_HAS_NO_UNALIGNED for that specific CPU type.
>>
>> That's perfect. áThe line about dumb copying of the m68knommu settings
>> was too much self-flagellation for you to my eyes :)
>
> So I rewrote history on my for-3.6 branch...

Thanks Geert!

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