<div dir="ltr"><div><div><div><div>Hi All,<br><br></div>I have to implement the cache coherency support for Cortex A7. But for A7 MPCore, unlike for A9, I am not able to find any register description for the Snoop Control Unit from the TRM.<br></div>I need help here on how to proceed. <br><br></div>Additionally for A9 there is a single bit for A9 in the Auxiliary Control Register which enables cache broadcast operations. The register format is different for A7 and again I am unable to find how to achieve the same for A7.<br><br></div>Thanks!<br><div><br><div><br><br><div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, May 5, 2015 at 10:42 PM, Joel Sherrill <span dir="ltr"><<a href="mailto:joel.sherrill@oarcorp.com" target="_blank">joel.sherrill@oarcorp.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"><span>
<br>
<br>
<div>On 5/5/2015 11:11 AM, Rohini Kulkarni
wrote:<br>
</div>
<blockquote type="cite">
<p dir="ltr">Hi,</p>
<p dir="ltr">I am working with the code for bsp hooks. I am
referring to existing ARM multicore bsp codes, zync mainly. </p>
<p dir="ltr">1. There are existing hooks for the raspberry pi.
Where should the code for the Pi2 hooks be added?</p>
</blockquote></span>
The Pi and Pi2 are remarkably similar so Pi2 should be placed inside
the Pi BSP directory.<br>
There is already a Pi2 variant of that code built. But we know
specific places where there<br>
are variances. Depending on the scope of what is different, it can
be as simple as<br>
a cpp conditional in a .h to select a value or two implementations
of a single method<br>
and the Makefile.am picking the right file to build based on the
board variant.<br>
<br>
The big question to always ask is: Is this specific to the Pi2 and
incompatible with the Pi?<br>
<br>
Since the Pi BSP is still missing capabilities, it is likely code
common to both will<br>
be added this summer. For example, did the mailbox interface change?
I don't know<br>
but would guess that it didn't. Each new capability added needs
that added.<br>
<br>
And any differences need to be analyzed to pick the least intrusive
way to provide<br>
alternate implementations. Or enable special code like the Pi2 SMP
support which<br>
is dependent on --enable-smp and being a Pi2.<span><br>
<blockquote type="cite">
<p dir="ltr">2. Am I right in understanding that I will have to
implement A7 specific functions as have been for A9? I am
referring specifically to the arm-a9mpcore-start.h</p>
</blockquote></span>
Yes.<br>
<br>
If the code is very similar between the a7 and a9, then a discussion<br>
on devel@ should occur to decide the best way to minimize
duplication.<br>
<br>
If you end up with a7 specific code, you should follow the location
and <br>
naming patterns already established. That places it in
libbsp/arm/shared/... <br>
so it can be used by any BSP with the right SMP core.<span><br>
<br>
<br>
<blockquote type="cite">
<p dir="ltr">I am referring to existing codes to locate and get
hold of what needs to be done in the hooks. However, being new
to such implementations, I am taking longer to understand the
details. Any suggestions that might help here are welcome</p>
</blockquote></span>
The answer will depend on the factors listed above. When code can<br>
be shared, we want to share it across as many BSPs as makes sense.<br>
When it is unique to a specific BSP **variant** (e.g. Pi vs Pi2),
then<br>
you want to find the way to account for the variation in the least<br>
intrusive code way possible.<span><br>
<blockquote type="cite">
<p dir="ltr">Thanks!</p>
<div class="gmail_quote">On 1 May 2015 12:45, "Rohini Kulkarni"
<<a href="mailto:krohini1593@gmail.com" target="_blank">krohini1593@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div><br clear="all">
</div>
Hi,<br>
<br>
</div>
<div>Excited to be a part of this edition of GSoC! Thanks
to everybody for helping me get here and congratulations
to all the participating students!<br>
<br>
</div>
So, now getting to work, firstly I wish to know,
specifically from my mentors, any changes that must be made
to my proposed project or schedule. <br>
<br>
Secondly, are there any specifics for the development blog
that we need to create for the project? Over time what is
the blog expected to convey. <br>
<br>
Also, I have to create a new wiki page for my project as
none exists. I want to know how to add one.<br>
<br>
<div>
<div>-- <br>
<div>
<div dir="ltr">Rohini Kulkarni</div>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</blockquote>
<br>
</span><span><font color="#888888"><pre cols="72">--
Joel Sherrill, Ph.D. Director of Research & Development
<a href="mailto:joel.sherrill@OARcorp.com" target="_blank">joel.sherrill@OARcorp.com</a> On-Line Applications Research
Ask me about RTEMS: a free RTOS Huntsville AL 35805
Support Available (256) 722-9985</pre>
</font></span></div>
</blockquote></div><br><br clear="all"><br>-- <br><div><div dir="ltr">Rohini Kulkarni</div></div>
</div></div></div></div></div>