breakpoint not working in do_mmc_read (using qemu)

Chan Kim ckim at
Fri Oct 22 10:19:18 CEST 2021

Hello, u-boot experts,


I need to modify a proprietary SD card host controller driver to be used in u-boot and I wanted to see the driver interface with the u-boot using qemu.

Trying to run u-boot on qemu with SD card, I found this nice question :

So I followed it and saw ‘mmc rescan’, ‘mmc read’ command works.

Using debugger (arm-none-eabi-gdb), I can follow the code from _start and can set breakpoint at board_init_f and etc. 

But even if I set breakpoint at do_mmc_read or do_mmc_rescan, the breakpoint for those functions are not working.

Could anyone tell me what I’m doing wrong? (Are there things I should set in the config?)

The qemu command is this :

qemu-system-arm -machine vexpress-a9 -cpu cortex-a9 -m 128M -dtb ~/prj/abdsn/ab21sim/ab21tsim/LinuxDevDrv/linux-5.4.21/arch/arm/boot/dts/vexpress-v2p-ca9.dtb -kernel u-boot -sd sd.img -nographic -s -S

and the u-boot (ELF file) contains debug_info.

Any help will be deeply appreciated.


Chan Kim

p.s. BTW, this email list contains mostly PATCH emails between u-boot developers, so I feel a little sorry to ask questions here. 😊


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