This patch series is to enable coresight debug module. With debug module we can check CPU state and PC value, etc. So this is helpful for CPU lockup bugs, e.g. if one CPU has run into infinite loop with IRQ disabled. The hang CPU cannot switch context and handle any interrupt, so it cannot handle SMP call for stack dump, etc. Furthermore, now ARMv8 introduces some runtime firmwares like ARM trusted firmware BL31, so sometime CPU lockup may happen in the firmware and cannot return back to kernel. This initial patch series enable debug module and registers call back notifier for PCSR register dumping when panic happens, so we can see below dumping info for panic: [ 13.751777] Coresight debug module: [ 13.755275] CPU[0]: PSCR=0xffff000008090cbc [ 13.759469] CPU[1]: PSCR=0xffff0000088bf9e4 [ 13.763662] CPU[2]: PSCR=0xffff000008090cc0 [ 13.767856] CPU[3]: PSCR=0xffff000008090cb8 [ 13.772049] CPU[4]: PSCR=0xffff000008090cc0 [ 13.776243] CPU[5]: PSCR=0xffff000008090cbc [ 13.780436] CPU[6]: PSCR=0xffff000008090cc0 [ 13.784630] CPU[7]: PSCR=0xffff000008090cbc This patch series has been verified on 96boards Hikey. Leo Yan (3): coresight: binding for coresight debug driver coresight: add support for debug module arm64: dts: register Hi6220's coresight debug module .../devicetree/bindings/arm/coresight.txt | 9 +- .../boot/dts/hisilicon/hikey_6220_coresight.dtsi | 73 +++++++++ drivers/hwtracing/coresight/Kconfig | 8 + drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-debug.c | 169 +++++++++++++++++++++ 5 files changed, 258 insertions(+), 2 deletions(-) create mode 100644 drivers/hwtracing/coresight/coresight-debug.c -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
