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| author | Ahmad Fatoum <a.fatoum@pengutronix.de> | 2021-08-03 18:59:37 +0200 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2021-08-09 20:17:47 +0200 |
| commit | bdde03ece9ba29e381aa2f9dcd1bf7b6e62ebb37 (patch) | |
| tree | 8db8aa6f2d723362834c49cad79b79965703c5b5 /Documentation/boards | |
| parent | 47caa7d3676dac07d9807834827127db179cff7d (diff) | |
| download | barebox-bdde03ece9ba29e381aa2f9dcd1bf7b6e62ebb37.tar.gz barebox-bdde03ece9ba29e381aa2f9dcd1bf7b6e62ebb37.tar.xz | |
ARM: i.MX8MM: add reboot to serial download mode
The i.MX8MM reference manual follows long established tradition in not
documenting BootROM magic reboot codes. For older i.MX variants, the
values can be seen in the bmode tables of Freescale's U-Boot patches.
There are no such patches for the i.MX8M, but testing shows that
mw 0x30390094 0x10 ; mw 0x30390098 0x40000000
is one of the configurations that trigger serial download on next warm
reset on an i.MX8MM. Describe this in the device tree, so
gpr.reboot_mode.next=serial reset -r imxwd-warm
does the right thing for that SoC.
This all might work for other i.MX8M variants as well, but the dtsi
can be genericized later on when tested.
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20210803165937.31608-2-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'Documentation/boards')
| -rw-r--r-- | Documentation/boards/imx.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Documentation/boards/imx.rst b/Documentation/boards/imx.rst index 887b45c708..4ce9d9808c 100644 --- a/Documentation/boards/imx.rst +++ b/Documentation/boards/imx.rst @@ -83,6 +83,35 @@ The images can also always be started as second stage on the target: barebox@Board Name:/ bootm /mnt/tftp/barebox-freescale-imx51-babbage.img +BootROM Reboot mode codes (bmode) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For select SoCs, barebox supports communicating an alternative boot medium +that BootROM should select after a warm reset:: + + barebox@FSL i.MX8MM EVK board:/ devinfo gpr.reboot_mode + Driver: syscon-reboot-mode + Bus: platform + Parent: 30390000.reset-controller@30390000.of + Parameters: + next: normal (type: enum) (values: "normal", "serial") + prev: normal (type: enum) (values: "normal", "serial") + Device node: /soc@0/bus@30000000/reset-controller@30390000/reboot-mode + reboot-mode { + compatible = "barebox,syscon-reboot-mode"; + offset = <0x94 0x98>; + mask = <0xffffffff 0x40000000>; + mode-normal = <0x0 0x0>; + mode-serial = <0x10 0x40000000>; + }; + + barebox@FSL i.MX8MM EVK board:/ gpr.reboot_mode.next=serial reset -r imxwd-warm + +This will cause barebox to fall into serial download mode on an i.MX8MM. + +Different SoCs may have more possible reboot modes available. +See the section on :ref:`Reboot modes<reboot_mode>` for more information. + High Assurance Boot ^^^^^^^^^^^^^^^^^^^ |