In order to improve the main frequency of CPU, the clock path of CPU is
simplified as follows:
|--\
| \ |--\
--apll--|\ | \ | \
| |--apll_core--| \ | \
--24M---|/ |mux1 |--[gate]--|mux2|---clk_core
| / | /
--gpll--|\ | / |------| /
| |--gpll_core--| / | |--/
--24M---|/ |--/ |
|
-------apll_directly--------------|
When the CPU requests high frequency, we want to use MUX2 select the
"apll_directly".
At low frequencies use MUX1 to select “apll_core" and then MUX2 to
select "apll_core_gate".
However, in this way, the CPU frequency conversion needs to be
in the following order:
1. MUX2 select to "apll_core_gate", MUX1 select "gpll_core"
2. Apll sets slow_mode, sets APLL parameters, locks APLL, and then APLL
sets normal_mode
3. MUX1 select "apll_core", MUX2 select "apll_directly"
So add pre_muxs and post_muxs to cover this special requirements.
Change-Id: I944c22f774f5f9c4edaf28099b6c2926076d4749
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
a8657b15fa