[yocto] TUNE_PKGARCH for Microblaze

[Sipke Vriend]

Hi all,

With help from Khem's email we have been able to perform 'some' sanity
checking against the microblaze architecture.

The TUNECONFLICTS assist us in ensuring conflicting features are flagged during
the bitbake sanity check, however because Microblaze's features are 
independently configurable, we would like to do some additional 'sanity 
checking'. 

Using a hierarchical method of features, like in arm, is not really viable for 
Microblaze, so if there are alternate existing ways we would like to use them 
rather than creating localised bb classes to do this for us.

1. Is there a way similar to TUNECONFLICTS for "paired" features, i.e. if one 
   feature exists another must also?
   (Certain microblaze versions must have a set of features if a particular 
   feature is enabled).
2. Is there a way to define that certain features must exist, other than 
   defining multiple machines   (e.g. in endian case we would like to ensure one 
   of them is picked)?
3. Additionally (or instead of 1 and 2) is there a way we can introduce/append a 
   'sanity check' into the bitbake layer model - i.e. inform bitbake to 
   run 'our complex sanity' check?

As a continuation from my last email, the following is a list of possible Microblaze 
architecture features, which can be supplied in the machine and/or local.conf 
file. Lack of  a hardware feature means the soft version is used.

big-endian/little-endian 
vXXX where XXX is a microblaze version (like v830) 
barrel-shift 
multiply-high multiply-low 
pattern-compare 
reorder 
divide-hard 
fpu-hard fpu-hard-extended 

Additionally we plan to modify the package name slightly, e.g.
microblazeel-v840-bs-ml-div-fe-cmp-re
microblazeel-v830-bs-mh
microblazeel-v830

Regards
Sipke

>On Mar 20, 2013, at 4:44 PM, Khem Raj <mailto:raj.khem at gmail.com> wrote:
>
>
>On Mar 19, 2013, at 9:08 PM, Sipke Vriend <sipke.vriend at xilinx.com> wrote:
>
>
>Hi all,
> 
>We are seeking some feedback regarding common practices for defining TUNE_PKGARCH within Yocto.
> 
>
>usually its dictated by architecture, ABI and other processor features. the current tune files have good ways to express the relationships 
>you would translate the below table into set of TUNE_FEATURES and define PACKAGE_EXTRA_ARCHS if you need to express compatibility between different tunes
>
>Look at arm tunes they are the best examples of complexity
>
>
>We need to define a unique TUNE_PKGARCH for the possible configuration of Microblaze architecture.
>Our proposal is short unique string for each HW feature which is enabled in Microblaze.
> 
>For 'extensive hardware usage' architecture, this would result in something like:
>mbebv730-bs-mh-div-fb-cmp
>mbebv840-bs-mh-div-fb-cmp-re
>mbelv840-bs-ml-div-fe-cmp-re
>and for architecture with no 'hardware usage':
>mbebv730
>mbebv840
>mbelv840
> 
>The table below details the unique strings and their relation to compiler and hardware flags, and a couple of versions of Microblaze architecture.
>(If this table does not show cleanly switch to fixed width font)
>-------------------
>String Compiler Flag        Hardware Flag         CPU versions
>       -mcpu=vX.YY.Z                              v7.30.a v8.40.a
> 
>mbel   -mlittle-endian      C_ENDIANNESS (LITTLE) -       o
>mbeb   -mbig-endian         C_ENDIANNESS (BIG)    x       o
> 
>bs     -mxl-barrel-shift    C_USE_BARREL          o       o
> 
>ml     -mnoxl-soft-mul      C_USE_HW_MUL (MUL32)  o       o
>mh     -mxl-multiply-high   C_USE_HW_MUL (MUL64)  o       o
> 
>div    -mnoxl-soft-div      C_USE_DIV             o       o
> 
>fb     -mhard-float         C_USE_FPU (BASIC)     o       o
>fe     -mxl-float-convert   C_USE_FPU (EXTENDED)  o       o
>fe     -mxl-float-sqrt      C_USE_FPU (EXTENDED)  o       o
> 
>cmp   -mxl-pattern-compare  C_USE_PCMP_INSTR      o       o
> 
>re    -mxl-reorder          C_USE_REORDER_INSTR   -       o
> 
>Where '-' means unavailable 'x' is only option and 'o' is optional.
>-------------------
> 
>
>
>you can express this with TUNECONFLICTS and TUNEVALID
>
>and may be create heirarchy of tune files which builds upon common tunings.
>
>
>Note the table rows have hardware feature 'groupings', which means only one of the strings should be present within the TUNE_PKGARCH. For example the Floating Point Unit hardware feature can be defined by either fb (for basic mode) or fe (for extended mode).
> 
>Regards
>Sipke
> 
> 
> 
>
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