Implement a system-wide suspend driver for the Andes AE350 platform.
This driver supports Andes-specific deep sleep (suspend to RAM) and
light sleep (suspend to standby) functionalities via the ATCSMU.
The major differences between deep sleep and light sleep are:
- Power Domain and Resume Path: Deep sleep powers down the core domain.
Consequently, harts waking from deep sleep resume from the reset
vector. Light sleep utilizes clock gating to the core domain; harts
maintain state and resume execution at the instruction immediately
following the WFI instruction.
- Primary Hart Wakeup: In both modes, the primary hart is woken by
UART or RTC alarm interrupts. In deep sleep, the primary hart is
additionally responsible for re-enabling the Last Level Cache (LLC)
and restoring Andes-specific CSRs.
- Secondary Hart Wakeup: In light sleep, secondary harts are woken
by an IPI sent from the primary hart. In deep sleep, they are
woken by an ATCSMU hardware wake-up command. Furthermore,
secondary harts must restore Andes-specific CSRs when returning
from deep sleep.
Signed-off-by: Ben Zong-You Xie <ben717@andestech.com>
Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Link: https://lore.kernel.org/r/20251229071914.1451587-6-ben717@andestech.com
Signed-off-by: Anup Patel <anup@brainfault.org>
The SiFive SMC0 controls the clock and power domain of the core complex
on the SiFive platform. The core complex enters the low power state
after the secondary cores enter the tile power gating and last core
execute the `CEASE` instruction with the corresponding SMC0
configurations. The devices that inside both tile power domain and core
complex power domain will be off, including caches and timer. Therefore
we need to flush the last level cache before entering the core complex
power gating and update the timer after waking up.
Reviewed-by: Cyan Yang <cyan.yang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Nick Hu <nick.hu@sifive.com>
Link: https://lore.kernel.org/r/20251020-cache-upstream-v7-12-69a132447d8a@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Add RPMI based system suspend driver.
To test this, execute the follwoing in Linux:
$ echo mem > /sys/power/state
To wake up, execute the following command on qemu monitor terminal:
(qemu) system_wakeup
Signed-off-by: Subrahmanya Lingappa <slingappa@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
The generic platform can have multiple system suspend drivers so add a
simple FDT based system suspend driver framework.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
