With the T-HEAD C9XX cores being designed before or during ratification
of the SSCOFPMF extension, they implement a PMU extension that behaves
very similar but not equal to it by providing overflow interrupts though
in a slightly different registers format.
The sun20i-d1 is using this core. So implement the necessary overrides
to allow its pmu to be used via the standard sbi-pmu extension.
For now it's also the only soc using this core, so keep the additional
code in the d1-space for now.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Allwinner D1 contains a "PPU" power domain controller which can
automatically power down/up the CPU power domain. This power domain
includes the C906 core along with its CLINT and PLIC.
This HSM implementation supports non-retentive hart suspend by:
1) Saving/restoring state that is lost during hart suspend,
2) Performing cache maintenance before/after hart suspend,
3) Configuring wakeup sources before hart suspend, and
4) Asking the PPU to power down the hart when it enters WFI.
Since this HSM implementation is for a single-core SoC, it does not need
to worry about concurrency or saving multiple instances of state.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
