Hi, I'm working on a iMX8M Mini EVK (official NXP Android bsp) and I want to use the UART4 , formally used as debug
port for M4 microcontroller .
Changed the DTS file to include the UART:
/*pin muxing */
pinctrl_uart4: uart4grp {
fsl,pins = <
MX8MM_IOMUXC_UART4_RXD_UART4_DCE_RX 0x140 /* GPIO5.28 */
MX8MM_IOMUXC_UART4_TXD_UART4_DCE_TX 0x140 /* GPIO5.29 */
>;
};
&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4>;
assigned-clocks = <&clk IMX8MM_CLK_UART4_SRC>;
assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>;
/* status = "disabled"; */
status = "okay";
};
But system will go in crash when accesing the first UART4 register.
Problem is that the RDC register @ 303d0518 is set to 0xFC, so UART is assigned to M4 core:
A workaround is to set a macro in UBOOT to set register to 0xFF:
setenv ena_uart4 mw.l 0x303D0518 0xFF
setenv bootcmd 'run ena_uart4; boota mmc0'
Problem is that in UBOOT code I was not able to detect where the register is initially set to 0xfc:
a patch placed into board_early_init_f() do not works as expected, and it was impossible to
assign the UART4 to UBOOT console ...
Any idea where to find this setting?
M. Sangalli
Thank You Diego, but such directory do not exist in my distro(it was based on imx-p9.0.9_1-0.0-beta) :
the only arm-trusted-firmware is under linaro and I've not found any reference to IMX_RDC_BASE anyway
but UART4 is evidently locked to M4.
I do not want to upgrade now the sources to latest bsp because I've to do a lot of works to allign...
Any other suggestion where to find this setting?
Thanks mario
Hello,
Unfortunately, the BSP that you are using is not an official BSP from us. What I suggest you is to use our Android BSP. Otherwise, we cannot guarantee anything. I apologize for the inconvenience this could give you.
Best regards,
Diego.
Hi Mario: I do not have a imx-atf directory in my Android' s tree: I've search in the whole sources
for IMX_RDC_BASE but with no results
I've found android_build\device\linaro\bootloader\arm-trusted-firmware directory, but in plat directory
I'v found only a generic arm, none specific of imx8 , no RDC_BASE in any sources..
Maybe the setting is in some other point ?
Thank You
Mario