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SubjectRe: [PATCH 2/3] firmware: qcom: scm: Expose download-mode control
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.andersson@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

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