Hang issue when firmware load into M7 via remoteproc in Linux (i.MX8M Plus)

[Jimmychea]

Experienced hang issue when firmware loading into M7 via remoteproc in Linux.

Initial setup in uboot

$ setenv fdtfile imx8mp-evk-rpmsg.dtb

$ saveenv

Issue reproduce steps :

$ echo -n /lib/firmware/ > /sys/module/firmware_class/parameters/path

$ echo -n imx8mp_m7_TCM_hello_world.elf > /sys/class/remoteproc/remoteproc0/firmware

$ echo start > /sys/class/remoteproc/remoteproc0/state

Issue happened... can refer to picture attached.

[Jimmychea]

it's working. But wondering why required to run the command "run prepare_mcore", i can't find this in any documents. Can you explain on this ? And also how to make it to auto run when booting ? Thanks

[Sanket_Parekh · Accepted solution]

Hi @Jimmychea 

I hope you are doing well.

Please refer to the below note in  AN5317.

For i.MX 8M platforms, the root clock for M7/M4 must be kept always enabled by Linux to load the firmware code and start Cortex M7/M4. By default, NXP Linux BSP keeps the root clock enabled for the M core when it is started from U-Boot. 

Otherwise, if you need to first start the M core from the Linux booting phase, the clock driver (drivers/clk/imx/clk-composite-8m.c) must be updated to always skip the gate registration to keep the root clock always enabled for the M core.

prepare_mcore is used to indicate to linux that the m4 core is booted.

One can edit bsp_bootcmd to run prepare_mcore in /include/configs/imx8mp_evk.h

Thanks & Regards,

Sanket Parekh

[Sanket_Parekh]

Hi @Jimmychea 

I hope you are doing well.

Please make sure that you have referred to 9.1 i.MX Linux RPROC support in AN5317.

and reserved TCM in dts as below.

m7_itcm: m4@0x7E0000 {
       no-map;
       reg = <0 0x7E0000 0 0x20000>;
 };

m7_dtcm: m4@0x800000 {
        no-map;
        reg = <0 0x800000 0 0x20000>;
};

Please add the above nodes in dts as shown in 9.1 i.MX Linux RPROC support in AN5317.

Please make sure that you have followed the below steps in u-boot cmd.

=> setenv fdtfile imx8mp-evk-rpmsg.dtb
=> saveenv

=> run prepare_mcore

Please mention the BSP version for further debugging.

Thanks & Regards,

Sanket Parekh

[maryellenmclaug]

Hi @Sanket_Parekh 

Do we also need the code changes described in AN12225

Section 5.2.  My M7 just uses ECSPI-1.  So I tried that code change but with the following in /drivers/clk/imx/clk-imx8mp.c

  clk_prepare_enable(clks[IMX8MP_CLK_M4_CG]->clk);
  clk_prepare_enable(clks[IMX8MP_CLK_M7_CORE]->clk);
  clk_prepare_enable(clks[IMX8MP_CLK_ECSPI1]->clk);

And the kernel hung.   Do I not need the IMX8MP_CLK_M7_CORE?