Hang up when write MMDC->MDSCR in write leveling function.

[takayuki_ishii]

Hello community,

I try to do write leveling in Plugin Image of u-boot for imx6qp Android BSP N7.1.2_2.0.0-ga.

So make assembler macro "mx6_write_level_calibration" based on the "int mmdc_do_write_level_calibration()"

in the arch/arm/cpu/armv7/mx6.

And call it from arch/arm/include/asm/arch-mx6/mx6_plugin.S

plugin_loop:
      nop
      b plugin_loop    /* to connect debug session */
      nop
      imx6_ddr_setting
      imx6_clock_gating
      imx6_qos_setting
      mx6_write_level_calibration

In Write leveling sequence, after write mmcd0->mdscr register to configure the external DDR device to enter

write-leveling mode through Load Mode Register command.

/* writel(0x00808231, &mmdc0->mdscr); */

i.MX6QP will hang-up and JTAG debug session is stopping.

To send Load Mode Register command, do I need some other setting?

Best regards,

Ishii.

[gusarambula]

Hello Takayuki Ishii,

If you are calibrating your board I would recommend using the DDR Stress Tool:

https://community.nxp.com/docs/DOC-105652

I hope this helps!

Regards,