There are two states in i.MX6Q cpuidle driver.
state[1]: ARM WFI mode
state[2]: i.MX6Q WAIT mode
Take i.MX6DL as example, think out such a case:
1. CPU0/1 both run at normal mode
2. On CPU0, `sleep 1` is executed. And there are no workload on CPU1.
3. CPU0 first runs into state[2] and 'wfi' instruction. Switched to use
GPT broadcast.
4. CPU1 runs into state[2] and configure CCM to WAIT MODE,
then 'wfi' instruction. Now arm_clk and local timer clock are
shutdown. Switched to use GPT broadcast
5. GPT broadcast timer interrupt comes to GPC/GIC, then CPU0 wakes up.
CPU0 switched to use arm local timer. CPU1 is still sleeping.
6. No workload on CPU0, CPU0 runs into state[1]. But CCM register
is still not restored to Normal RUN mode. 'wfi' + CCM WAIT will
cause arm_clk and arm core clk.
Now CPU0 stops, which is not correct.
So, need to make sure CCM configured to RUN mode when any cpu exit
state[2].
In this patch,
When CPU exits state[2], it configures CCM to RUN mode.
When all CPUs enters state[2], the last CPU needs to check
whether it's ok to configure CCM to WAIT mode or not.
In imx6q_set_lpm, we only need to unmask GINT when not WAIT_CLOCKED,
so add a check condition.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
0d980646ee