In current design, if any peripheral was assigned to both A7 and M4,
it will receive ipg_stop or ipg_wait when any of the 2 platforms
enter low power mode. We will have a risk that, if A7 enter wait,
M4 enter stop, peripheral will have chance to get ipg_stop and ipg_wait
asserted same time. Also if M4 enters stop mode, A7 will have no
chance to access the peripheral.
There are 26 peripherals affected by this IC issue:
SIM2(sim2/emvsim2)
SIM1(sim1/emvsim1)
UART1/UART2/UART3/UART4/UART5/UART6/UART7
SAI1/SAI2/SAI3
WDOG1/WDOG2/WDOG3/WDOG4
GPT1/GPT2/GPT3/GPT4
PWM1/PWM2/PWM3/PWM4
ENET1/ENET2
Software Workaround:
The solution is to set the peripherals to Domain0 by A core, since A core
in Domain0. The peripherals which will be used by M4, will be set to Domain1
by M4.
For example, A core set WDOG4 to domain0, but when M4 boots up, M4 will
set WDOG4 to domain1, because M4 will use WDOG4.
So the peripherals are not shared by them. This way requires
the uboot implemented the RDC driver and set the 26 IPs above
to domain 0 only. M4 image will set the M4 to domain 1 and
set peripheral which it will use to domain 1.
This patch enables the CONFIG_IMX_RDC and CONFIG_IMX_BOOTAUX for
i.MX7D SABRESD board, and setup the 26 IP resources to domain 0.
Signed-off-by: Ye.Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
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