| |
| DMA API trace BASIC USAGE |
| =========================== |
| |
| |
| Enable CONFIG_DMA_API_DEBUG |
| ---------------------------- |
| $TOP/kernel/scripts/config \ |
| --file $OUT/obj/KERNEL/.config \ |
| -e DMA_API_DEBUG |
| make -C$TOP/kernel ARCH=arm O=$OUT/obj/KERNEL oldconfig |
| grep DMA_API_DEBUG $OUT/obj/KERNEL/.config |
| |
| |
| |
| Via debugfs |
| ----------- |
| adb shell cat /d/dma-api/dump_{mappings,allocs,allocs_detail} |
| |
| |
| Via Ftrace |
| ---------- |
| # All ftraces from boot, add "trace_event=dmadebug:*" to kernel command line |
| sed -i '/strlcpy(cmd_line, boot_command_line, /i \ |
| \tstrcat(boot_command_line, " trace_event=dmadebug:*");' \ |
| $TOP/kernel/arch/arm/kernel/setup.c |
| |
| Or |
| |
| adb shell "echo 'dmadebug:*' >> /d/tracing/set_event" |
| |
| adb shell <your_test_here> |
| adb shell "echo '\!dmadebug:*' >> /d/tracing/set_event" |
| adb pull /d/tracing/trace |
| |
| python $TOP/kernel/scripts/tracing/dma-api/trace.py trace |
