On Sun, Dec 12, 2021 at 7:55 PM Anup Patel <anup@...> wrote:
Since, both OS-A platforms with M-mode and M platforms need ACLINT MTIMER so I suggest that OS-A platforms should say "If M-mode is implemented then ACLINT MTIMER should be supported ...".
I was thinking along the lines of how Greg was thinking here.
On Sun, Dec 12, 2021 at 08:43:30PM -0800, Greg Favor wrote: This separates out from the current OS-A platform specs the ACLINT MTIMER device as a standardized Machine-level implementation of the MTIME and MTIMECMP registers defined in the Priv spec.
Now, for systems that implement Priv 1.12 and the Sstc extension, and actually use the Sstc extension, then this can be the end of the story.
Agree.
But for today's systems and for future systems that don't implement Sstc (unless all OS-A 2022 platform specs were to mandate Sstc support and eliminate any possibility of existing systems complying with at least the Embedded (i.e. old "Base") OS-A platform spec), they also need the SBI API that provides Supervisor timer functionality to S/HS mode (with M-mode using MTIME and MTIMECMP to provide that functionality). While this is also an SEE interface, talking about this does start to sneak up on talking about MTIME. But then again one could still abstract MTIME as the system timebase, and MTIMECMP as a timebase compare value.
