gpoulios commented on code in PR #16729: URL: https://github.com/apache/nuttx/pull/16729#discussion_r2208318032
########## drivers/misc/optee.c: ########## @@ -345,6 +346,10 @@ optee_shm_to_page_list(FAR struct optee_shm *shm, FAR uintptr_t *list_pa) *list_pa = optee_va_to_pa(list) | pgoff; } +#ifndef CONFIG_ARCH_USE_MMU Review Comment: If you’re asking why the MMU has this behaviour, I believe it is because the DRAM regions are typically configured as `MT_NORMAL` ([eg1](https://github.com/apache/nuttx/blob/master/arch/arm64/src/qemu/qemu_boot.c#L65), [eg2](https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L201), [eg3](https://github.com/apache/nuttx/blob/master/arch/arm64/src/imx9/imx9_boot.c#L65)) which translates in page tables [marked as inner-shareable](https://github.com/apache/nuttx/blob/def76c90d5648f64b2ef51175fb3327e2d8d9352/arch/arm64/src/imx9/imx9_boot.c#L65). According to A-profile ref. manual, B2.10.1.1.1: > Each Inner Shareability domain contains a set of observers that are data coherent for each member of that set for data accesses with the Inner Shareable attribute made by any member of that set. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org