On Fri, Mar 17, 2017 at 09:15:22PM -0700, Bjorn Andersson wrote: > In order to aid post-mortem debugging the Qualcomm platforms provides a > "memory download mode", where the boot loader will provide an interface > for custom tools to "download" the content of RAM to a host machine. > > The mode is triggered by writing a magic value somehwere in RAM, that is > read in the boot code path after a warm-restart. Two mechanism for > setting this magic value are supported in modern platforms; a direct SCM > call to enable the mode or through a secure io write of a magic value. > > In order for a normal reboot not to trigger "download mode" the magic > must be cleared during a clean reboot. > > Download mode has to be enabled by including qcom_scm.download_mode=1 on > the command line. > > Signed-off-by: Bjorn Andersson <bjorn.anders...@linaro.org> > --- > .../devicetree/bindings/firmware/qcom,scm.txt | 1 + > drivers/firmware/qcom_scm-32.c | 6 ++++ > drivers/firmware/qcom_scm-64.c | 16 +++++++++ > drivers/firmware/qcom_scm.c | 42 > ++++++++++++++++++++++ > drivers/firmware/qcom_scm.h | 2 ++ > 5 files changed, 67 insertions(+) > > diff --git a/Documentation/devicetree/bindings/firmware/qcom,scm.txt > b/Documentation/devicetree/bindings/firmware/qcom,scm.txt > index 20f26fbce875..8467a181f22c 100644 > --- a/Documentation/devicetree/bindings/firmware/qcom,scm.txt > +++ b/Documentation/devicetree/bindings/firmware/qcom,scm.txt > @@ -18,6 +18,7 @@ Required properties: > * Core, iface, and bus clocks required for "qcom,scm" > - clock-names: Must contain "core" for the core clock, "iface" for the > interface > clock and "bus" for the bus clock per the requirements of the compatible. > +- qcom,dload-mode-addr: Specifies the address for the download mode magic > (optional)
Size? 1 cell, 2 cell(, red cell, blue cell) or follows #addr-cells? Rob
