When I try to set priorities in certain programs, such as init_priority(HIGH_PRIORITY), I've noticed that during linking, there's no guarantee that the programs will be compiled in the sequence I've specified based on priority. This has led to some runtime errors in my program.
I realized that in the ld file, when initializing dynamic arrays, there's no assurance of initializing init_array.* before init_array. This has resulted in runtime errors in the program. Consequently, I've rearranged the init_array.* in the ld file of NuttX to be placed before init_array and added a SORT operation to init_array.* to ensure accurate initialization based on priorities during linking.
Currently the IHC (Inter Hart Communication) depends on OpenAMP and
rptun. However, the bootloader portion of the IHC doesn't need
either of them. Now they are wasting a lot of bootloader space.
Reorganize the bootloader portion into a separate file 'mpfs_ihc_sbi.c'.
This file contains the OpenSBI vendor extensions, or the only required
functionalities for the bootloader. On the other hand, 'mpfs_ihc.c'
contains the non-bootloader code.
This patch also makes it possible to utilize 2 RPMSG channels. This
has been tested so that 2 separate NuttXs on harts 1 and 2 communicate
with Linux kernel that runs on harts 3 and 4.
New configuration files are added as well:
- rpmsg-ch1: sample config for RPMSG
- rpmsg-ch2: sample config for another RPMSG channel
- rpmsg-sbi: sample bootloader config for RPMSG/OpenSBI
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
This provides an example of Asymmetric Multiprocessing (AMP). The
master from Linux sends pings that this NuttX echoes back. The system
uses RPMsg from OpenAMP.
The Inter-Hart Communication module is present in the vendor's software
stack with the tag "2021.11". The software is present on github at the
polarfire-soc project. The following conditions must be met:
1. FPGA programmed with 2021.11 software
2. HSS (Vendor bootloader) with 2021.11 software
3. U-boot and Linux kernel from 2011.11 software
Currently the IHC works as a slave only on the hart number 4.
On the NuttX side, this patch uses rptun that incorporates rpmsg and
virtio. If it used only rpmsg and virtio, the future maintenance would
likely be much heavier. Using rptun also simplifies many things.
Upon success, the master side from Linux may issue an example test:
root@icicle-kit-es-amp:/opt/microchip/amp/rpmsg-pingpong# ./rpmsg-pingpong
However, the rpmsg-pingpong.c (compiled on target with gcc), may need to
be modified as seen below to match the device id:
- char *rpmsg_dev="virtio0.rpmsg-amp-demo-channel.-1.0";
+ char *rpmsg_dev="virtio0.rpmsg-amp-demo-channel.-1.1024";
This work uses a separate linker script. Due to a bug yet unknown to date,
a small NuttX, when loaded by the vendor HSS bootloader, will cause the
Linux kernel to hang at boot. Thus, the binary size is increased with
a section 'filler_area' whose only purpose is to increase the image size
so that the Linux kernel will boot up.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
