Specifying specific CPU models in powerpc/qoriq BSPs

Travis Wheatley travis.wheatley at emergentspace.com
Tue Mar 15 18:28:28 UTC 2016

I am using a T1040.  More specifically, I am attempting to get RTEMs running on a T1040RDB development system. The 4.12 tree has code for a T2080RDB, which is very similar. However, the T2080 uses an mpc6500 core whereas the T1040 uses an mpc5500 core. I see that the 4.12 tree has some mpc55xx code in libcpu. So, step 1 in the porting process is to tweak the qoriq_t2080rdb bsp to build for an mpc5500 rather than an mpc6500 core. 

On Mar 15, 2016, at 1:16 PM, Sebastian Huber wrote:

> Hello Travis,
> which processor do you want to use? For which peripherals do you need drivers?
> ----- Am 15. Mrz 2016 um 18:32 schrieb Travis Wheatley travis.wheatley at emergentspace.com:
>> I am working with a powerpc development board. RTEMS 4.12 has an existing BSP
>> configuration that is very similar to what I am looking for. However, my
>> development board uses a different processor/core, and therefore I presume will
>> need a different a different set of libcpu files. I have read several documents
>> including Chapter 3 of the RTEMS On-Line library files and understand that the
>> Makefile.am, Makefile.in, and configure.ac files are used by bootstrap to
>> generate the bsp configuration. Additionally, I understand that there is a .cfg
>> file found in the make/custom directory associated with the BSP in which one
>> specifies items like RTEMS_CPU_MODEL. In the case of this BSP here is what I
>> find in the existing .cfg file:
>> --- Begin included text ---
>> include $(RTEMS_ROOT)/make/custom/default.cfg
>> RTEMS_CPU = powerpc
>> RTEMS_CPU_MODEL = qoriq
>> CPU_CFLAGS = -mcpu=e6500 -m32 -msdata=sysv -fno-common \
>>     -D__ppc_generic
>> CFLAGS_OPTIMIZE_V += -ffunction-sections -fdata-sections
>> LDFLAGS = -Wl,--gc-sections
>> --- end included text ---
>> Where I am confused is that the RTEMS_CPU_MODEL is listed as "qoriq". However,
>> under the lib/cpu/powerpc directory I see processor specific code for multiple
>> powerpc processors including both mpc5xx and mpc6xx specific items So my
>> question is this...
>> While I see that the CPU_CFLAGS variable in the above .cfg file contains a flag
>> that tells the compiler to build code for the e6500, I do not see any flag that
>> tells bootstrap or the resulting build files produced to use the mpc6xx libcpu
>> items. So, if I want to build a similar BSP configuration but for a development
>> board using an mpc5xx processor, exactly where do I specify that in the various
>> make and configuration files?
>> -- Travis Wheatley
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