FreeRTOS running on both ARM cores

XAPP 1078 was just published yesterday.  It details how one cpu may run linux, and the other gets used for another purpose (in this case a simple 'bare metal' task).

pretty painless. .dts and app_cpu1 .ld changes reflect only 512 MB DDR. app_cpu1 load address start of upper 128 MB as well.
cheated on creating the hardware platform from scratch. added IP's, but then used a windiff of .mhs to update my zedboard .mhs.
without a hitch from there.

hello James,

I am a newby in the Xilinx and FPGAs world, and I am interested by porting Linux and freertos to Zeboard. however I didn't fully understand what you proposed as modifications to the XAPP1078. Could you please provide me with more details on the needed modifications to the original project.

Best regards,
Chafic

The linkerscript (pg 18 of xapp1078) should place the baremetal app to, for example, 0x10000000 instead of 0x30000000 (since there is only 512 MB available for Zedboard).

Further the dts file should be modified to select the memory range visible for linux. and modify zedboard specific nodes (remove i2c and adjust ethernet) when running the rwmem.elf from linux on page 25 of xapp1078 you have to use, for example, "rwmem.elf 0xfffffff0 0x10000000" instead of "rwmem.elf 0xfffffff0 0x30000000" 

good explanation. thanks for helping our colleague to understand.

i also moved ahead to linux/freertos.

http://zedboard.org/comment/1973#comment-1973

i'm not sure if this is what is in question.

i should have mentioned that the linux including dts that i used was from the speedway course. the mod's i made were as described, but to the .dts as already made for the zedboard.

tmemory {
ttdevice_type = "memory";
ttreg = <0x0 0x18000000>;
   t};

tchosen {
ttbootargs = "console=ttyPS0,115200 root=/dev/ram rw initrd=0x2000000,32M earlyprintk maxcpus=1 debug ip=192.168.1.10";
ttlinux,stdout-path = "/amba@0/uart@E0001000";
t};

i chose the upper quarter of DDR for the second core so 0x18000000.

the APP mentioned the maxcpus = 1 mod to bootargs.

There are no other mods because the edited .dts was already created for the zedboard. then just conver to binary over in linux:

./scripts/dtc/dtc -O dtb -I dts -o devicetree.dtb
devicetree.dts

as for the linkerscript:

MEMORY
{
   ps7_ddr_0_S_AXI_BASEADDR : ORIGIN = 0x18000000, LENGTH = 0x8000000
   ps7_ram_0_S_AXI_BASEADDR : ORIGIN = 0x00000000, LENGTH = 0x00030000
   ps7_ram_1_S_AXI_BASEADDR : ORIGIN = 0xFFFF0000, LENGTH = 0x0000FE00
}

i again chose the upper 128 MB, viz. 0x18000000 for 0x8000000.

to run from zedboard core0 under linux:

"rwmem.elf 0xfffffff0 0x18000000.

I'm sorry. I should explain abou what I did to get the ports defined the easy way.
After I used PlanAhead and XPS to instantiate the approprate cores in the design, I use WinDiff to compare the 2 file, viz. the .mhs from the XAPP 1078 downloaded files and the one I created for the Zedboard as just mentioned. This allowed me to easily make the appropriate changes to the Chipscope cores and the custom irq_gen. Just a quick way to get the port assignments to match -- you do need to understand what is going on though. I am still learning myself.
thanks for your patience.

Hello James and rvincke,

Thanks for your help. I proceeded as you have suggested.

uboot booted correctly however the boot process got blocked when trying to copy the ramdisk as showed below.

Do you think it's related to the ramdisk size that the zedboard can support?

U-Boot 2012.04.01-00304-g7639205 (Oct 29 2012 - 16:46:09)

DRAM:  1 GiB
WARNING: Caches not enabled
MMC:   SDHCI: 0
Using default environment

In:    serial
Out:   serial
Err:   serial
Net:   zynq_gem
Hit any key to stop autoboot:  0
Copying Linux from SD to RAM...
Device: SDHCI
Manufacturer ID: 12
OEM: 3456
Name: SMI
Tran Speed: 25000000
Rd Block Len: 512
SD version 2.0
High Capacity: Yes
Capacity: 3.7 GiB
Bus Width: 4-bit
reading uImage

2752728 bytes read
reading devicetree.dtb

6828 bytes read
reading uramdisk.image.gz

5273846 bytes read
## Booting kernel from Legacy Image at 03000000 ...
   Image Name:   Linux-3.6.0-xilinx
   Created:      2013-03-04  10:30:06 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2752664 Bytes = 2.6 MiB
   Load Address: 00008000
   Entry Point:  00008000
   Verifying Checksum ... OK
## Loading init Ramdisk from Legacy Image at 02000000 ...
   Image Name:
   Created:      2012-10-29  20:19:40 UTC
   Image Type:   ARM Linux RAMDisk Image (gzip compressed)
   Data Size:    5273782 Bytes = 5 MiB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 02a00000
   Booting using the fdt blob at 0x02a00000
   Loading Kernel Image ... OK
OK
   Loading Ramdisk to 1faf8000, end 1ffff8b6 ...

Did you tried the prebuild ramdisk or build one yourself ?

I used the pre-build ramdisk