I use LSDK2004, and dma api functions.
i use dma_alloc_coherent to alloc dma memory, and i check physical address of /proc/iomap which is 32bit address.
when i access to dma physical address at user space, there is access limit of dma memory.
But in case of kernel access such as ioctl, there is no problem.
May i have the reason?
Solved! Go to Solution.
I solved the issue.
In case of LSDK2004, there is access limit from user space to kernel memory when arch is ppc, x86, arm64.
So I changed the Kconfig of kernel.
How are you using this physical address when you see this limitation ?
Does this limitation also happen while accessing mmap'ed memory ?
I usually use devmem tool. and
i found there was access limit when i use mmap memory on kernel
I solved the issue.
In case of LSDK2004, there is access limit from user space to kernel memory when arch is ppc, x86, arm64.
So I changed the Kconfig of kernel.