The reserved-memory regions are mostly undocumented by QCA and are named
very unspecific in the QSDK device trees. It was tried to clean them up by
commit 71ed9f10a3 ("ipq40xx: Use detailed reserved memory for A42") and
similar changes.
The features which require these regions were mostly unknown but
Senthilkumar N L <snlakshm@qti.qualcomm.com> and Sricharan Ramabadhran
<srichara@qti.qualcomm.com> provided some more insight in some of them:
* crash dump feature
- a couple of regions used when 'qca,scm_restart_reason' dt node has the
value 'dload_status' not set to 1
+ apps_bl <0x87000000 0x400000>
+ sbl <0x87400000 0x100000>
+ cnss_debug <0x87400000 0x100000>
+ cpu_context_dump <0x87b00000 0x080000>
- required driver not available in Linux
- safe to remove
* QSEE app execution
- region tz_apps <0x87b80000 0x280000>
- required driver not available in Linux
- safe to remove
* communication with TZ/QSEE
- region smem <0x87b80000 0x280000>
- driver changes not yet upstreamed
- must not be removed because any access can crash kernel/program
* trustzone (QSEE) private memory
- region tz <0x87e80000 0x180000>
- must not be removed because any access can crash kernel/program
Removing the unnecessary regions saves some kilobyte of reserved-memory and
cleans up the device tree:
* 2560 KiB
- 8devices Jalapeno
- AVM FRITZ!Box 4040
- Compex WPJ428
- Meraki MR33 Access Point
- OpenMesh A42
* 14336 KiB
- GL.iNet GL-B1300
- Qualcomm Technologies, Inc. IPQ40xx/AP-DK01.1-C1
Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
