[Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Florian Fainelli]

MIPS IV is an older ISA than R1 but is still useful to support older
MIPS-based systems (e.g.: Cobalt Qube).

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 arch/Config.in.mips | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/Config.in.mips b/arch/Config.in.mips
index 7f44f06c9df6..29b4180d21ab 100644
--- a/arch/Config.in.mips
+++ b/arch/Config.in.mips
@@ -40,8 +40,8 @@ choice
 	help
 	  Specific CPU variant to use
 
-	  64bit capable: 64, 64r2, 64r3, 64r5, 64r6
-	  non-64bit capable: 32, 32r2, 32r3, 32r5, 32r6
+	  64bit capable: mips4, 64, 64r2, 64r3, 64r5, 64r6
+	  non-64bit capable: mips4, 32, 32r2, 32r3, 32r5, 32r6
 
 config BR2_mips_32
 	bool "Generic MIPS32"
@@ -97,6 +97,8 @@ config BR2_mips_xburst
 	  to be used in order to prevent emitting these instructions.
 
 	  See http://www.ingenic.com/en/?xburst.html
+config BR2_mips4
+	bool "MIPS IV"
 config BR2_mips_64
 	bool "Generic MIPS64"
 	depends on BR2_ARCH_IS_64
@@ -262,6 +264,7 @@ config BR2_GCC_TARGET_ARCH
 	default "octeon2"	if BR2_mips_octeon2
 	default "octeon3"	if BR2_mips_octeon3
 	default "p6600"		if BR2_mips_p6600
+	default "mips4"		if BR2_mips4
 
 config BR2_MIPS_OABI32
 	bool
-- 
2.34.1

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Re: [Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Thomas Petazzoni via buildroot]

Hello Florian,

On Tue,  8 Aug 2023 14:41:53 -0700
Florian Fainelli <f.fainelli@gmail.com> wrote:

> MIPS IV is an older ISA than R1 but is still useful to support older
> MIPS-based systems (e.g.: Cobalt Qube).
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

Thanks for this patch. Support for MIPS IV was initially in Buildroot,
and got removed in 2014, as part of:

commit dd45fe0efb678a8a674330ad46b7641a3284dff9
Author: Gustavo Zacarias <gustavo@zacarias.com.ar>
Date:   Mon Dec 1 11:16:59 2014 -0300

    arch/mips: remove deprecated mips1/2/3/4 support
    
    Remove the support for generating mips1/2/3/4 code since it has been
    deprecated for more than a year now.
    Also remove the unnecessary kludges in packages for it.
    
    Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
    Acked-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
    Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

> -	  64bit capable: 64, 64r2, 64r3, 64r5, 64r6
> -	  non-64bit capable: 32, 32r2, 32r3, 32r5, 32r6
> +	  64bit capable: mips4, 64, 64r2, 64r3, 64r5, 64r6
> +	  non-64bit capable: mips4, 32, 32r2, 32r3, 32r5, 32r6

This list is quite odd, because it's not even an exhaustive list of the
MIPS cores that we support.

Is mips4 supported by glibc, uclibc-ng and musl?

Since IMG kind of gave up on MIPS, we have difficulties in getting some
help in Buildroot to maintain MIPS support and address issues, so I'm a
bit cautious about adding more MIPS stuff.

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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Re: [Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Florian Fainelli]

On 8/8/23 14:54, Thomas Petazzoni wrote:
> Hello Florian,
> 
> On Tue,  8 Aug 2023 14:41:53 -0700
> Florian Fainelli <f.fainelli@gmail.com> wrote:
> 
>> MIPS IV is an older ISA than R1 but is still useful to support older
>> MIPS-based systems (e.g.: Cobalt Qube).
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> 
> Thanks for this patch. Support for MIPS IV was initially in Buildroot,
> and got removed in 2014, as part of:
> 
> commit dd45fe0efb678a8a674330ad46b7641a3284dff9
> Author: Gustavo Zacarias <gustavo@zacarias.com.ar>
> Date:   Mon Dec 1 11:16:59 2014 -0300
> 
>      arch/mips: remove deprecated mips1/2/3/4 support
>      
>      Remove the support for generating mips1/2/3/4 code since it has been
>      deprecated for more than a year now.
>      Also remove the unnecessary kludges in packages for it.
>      
>      Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
>      Acked-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
>      Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
> 
>> -	  64bit capable: 64, 64r2, 64r3, 64r5, 64r6
>> -	  non-64bit capable: 32, 32r2, 32r3, 32r5, 32r6
>> +	  64bit capable: mips4, 64, 64r2, 64r3, 64r5, 64r6
>> +	  non-64bit capable: mips4, 32, 32r2, 32r3, 32r5, 32r6
> 
> This list is quite odd, because it's not even an exhaustive list of the
> MIPS cores that we support.

Good point, I suppose that should be addressed in a separate patch.

> 
> Is mips4 supported by glibc, uclibc-ng and musl?

Yes, all 3 C libraries still support mips4.

> 
> Since IMG kind of gave up on MIPS, we have difficulties in getting some
> help in Buildroot to maintain MIPS support and address issues, so I'm a
> bit cautious about adding more MIPS stuff.

If there are not too many issues, I suppose you can CC me when you 
encounter them and I could try to take a look.
-- 
Florian

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Re: [Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Thomas Petazzoni via buildroot]

On Tue, 8 Aug 2023 14:56:56 -0700
Florian Fainelli <f.fainelli@gmail.com> wrote:

> > This list is quite odd, because it's not even an exhaustive list of the
> > MIPS cores that we support.  
> 
> Good point, I suppose that should be addressed in a separate patch.

Sure thing.

> > Is mips4 supported by glibc, uclibc-ng and musl?  
> 
> Yes, all 3 C libraries still support mips4.

OK.

> > Since IMG kind of gave up on MIPS, we have difficulties in getting some
> > help in Buildroot to maintain MIPS support and address issues, so I'm a
> > bit cautious about adding more MIPS stuff.  
> 
> If there are not too many issues, I suppose you can CC me when you 
> encounter them and I could try to take a look.

OK, sounds good. Sometimes it's not an issue, but simply trying to
understand what all those MIPS cores are, what they support, etc. We'll
definitely reach out to you when such questions arise.

Example of a MIPS-specific build failure:
http://autobuild.buildroot.net/results/4b4/4b488cc62c3c1496109528eb78020c64001d4300/build-end.log
(I haven't investigated, maybe it's trivial).

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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Re: [Buildroot] [PATCH] arch/mips: Allow building for MIPS IV

[Thomas Petazzoni via buildroot]

On Tue,  8 Aug 2023 14:41:53 -0700
Florian Fainelli <f.fainelli@gmail.com> wrote:

> MIPS IV is an older ISA than R1 but is still useful to support older
> MIPS-based systems (e.g.: Cobalt Qube).
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  arch/Config.in.mips | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)

Applied to next with a slightly tweaked commit log, thanks.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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