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| author | Andre Przywara <andre.przywara@arm.com> | 2020-03-11 15:18:03 +0000 |
|---|---|---|
| committer | Andre Przywara <andre.przywara@arm.com> | 2020-03-17 13:44:55 +0000 |
| commit | 9cc3fa1b8ae31c18fd3a6070b782b3384590523e (patch) | |
| tree | 48cee2fee944d1c2bd262b4785258eb7630c4187 /docs | |
| parent | 29e8c460664c88dc3834813d94785fbf6e27b8d1 (diff) | |
| download | platform_external_arm-trusted-firmware-9cc3fa1b8ae31c18fd3a6070b782b3384590523e.tar.gz platform_external_arm-trusted-firmware-9cc3fa1b8ae31c18fd3a6070b782b3384590523e.tar.bz2 platform_external_arm-trusted-firmware-9cc3fa1b8ae31c18fd3a6070b782b3384590523e.zip | |
rpi: console: Autodetect Mini-UART vs. PL011 configuration
The Raspberry Pi has two different UART devices pin-muxed to GPIO 14&15:
One ARM PL011 one and the 8250 compatible "Mini-UART".
A dtoverlay parameter in config.txt will tell the firmware to switch
between the two: it will setup the right clocks and will configure the
pinmuxes accordingly.
To autodetect the user's choice, we read the pinmux register and check
its setting: ALT5 (0x2) means the Mini-UART is used, ALT0 (0x4) points
to the PL011.
Based on that we select the UART driver to initialise.
This will allow console output in any case.
Change-Id: I620d3ce68de6c6576599f2a405636020e1fd1376
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Diffstat (limited to 'docs')
0 files changed, 0 insertions, 0 deletions