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| author | Bjorn Andersson <bjorn.andersson@linaro.org> | 2017-08-14 15:46:18 -0700 |
|---|---|---|
| committer | Andy Gross <andy.gross@linaro.org> | 2017-10-11 23:48:27 -0500 |
| commit | 8c1b7dc9ba2294c6dbd1870a3d2e534bfda3047a (patch) | |
| tree | 8d9823b880adb03cdf422d6773c720b79c6233e5 /drivers/firmware/Kconfig | |
| parent | 4e659dbe2d02a56ca0df25c77e099760252a329c (diff) | |
| download | lwn-8c1b7dc9ba2294c6dbd1870a3d2e534bfda3047a.tar.gz lwn-8c1b7dc9ba2294c6dbd1870a3d2e534bfda3047a.zip | |
firmware: qcom: scm: Expose download-mode control
In order to aid post-mortem debugging the Qualcomm platforms provide 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 somewhere 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.
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Diffstat (limited to 'drivers/firmware/Kconfig')
| -rw-r--r-- | drivers/firmware/Kconfig | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 6e4ed5a9c6fd..fa87a055905e 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -215,6 +215,17 @@ config QCOM_SCM_64 def_bool y depends on QCOM_SCM && ARM64 +config QCOM_SCM_DOWNLOAD_MODE_DEFAULT + bool "Qualcomm download mode enabled by default" + depends on QCOM_SCM + help + A device with "download mode" enabled will upon an unexpected + warm-restart enter a special debug mode that allows the user to + "download" memory content over USB for offline postmortem analysis. + The feature can be enabled/disabled on the kernel command line. + + Say Y here to enable "download mode" by default. + config TI_SCI_PROTOCOL tristate "TI System Control Interface (TISCI) Message Protocol" depends on TI_MESSAGE_MANAGER |