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bd74931d79
The old scheme doesn't allow sending hart0 self-IPI as the
corresponding bit on pending register is hardwired to 0, this
could lead to unhandle IPIs on SMP systems, esp. on single-core.
Furthermore, the limitation of old scheme is 8-core, instead of
reserving source hart information, we assign bit (x + 1) as the
enable and pending bit of hartx, this also expands the bootable
hart number.
The following diagram shows the enable bits of the new scheme
on 32-core Andes platform.
Pending regs: 0x1000 x---0---0---0---0------0---0
Pending hart ID: 0 1 2 3 ... 30 31
Interrupt ID: 0 1 2 3 4 ... 31 32
| | | | | | |
Enable regs: 0x2000 x---1---0---0---0-...--0---0---> hart0
| | | | | | |
0x2080 x---0---1---0---0-...--0---0---> hart1
| | | | | | |
0x2100 x---0---0---1---0-...--0---0---> hart2
| | | | | | |
0x2180 x---0---0---0---1-...--0---0---> hart3
. . . . . . .
. . . . . . .
. . . . . . .
0x2f00 x---0---0---0---0-...--1---0---> hart30
| | | | | | |
0x2f80 x---0---0---0---0-...--0---1---> hart31
<-------- word 0 -------><--- word 1 --->
To send IPI to hart0, for example, another hart (including hart0
itself) will set bit 1 of first word on the pending register.
We also fix indentation in andes_plicsw.h along with this patch.
Fixes: ce7c490719ed ("lib: utils/ipi: Add Andes fdt ipi driver support")
Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Randolph <randolph@andestech.com>
Reported-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lists.infradead.org/pipermail/opensbi/2023-October/005665.html
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Anup Patel <anup@brainfault.org>