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Lee Lup Yuen 2022-08-26 08:26:26 +08:00
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@ -898,6 +898,42 @@ Starting kernel ...
According to the U-Boot Log, the Start of RAM `kernel_addr_r` is 0x4008 0000.
We need to set this in the NuttX Linker Script and the NuttX Header...
# NuttX Boots On PinePhone
In the previous section, U-Boot says that the Start of RAM `kernel_addr_r` is 0x4008 0000.
Let's set this in the NuttX Linker Script and the NuttX Header...
- Change Image Load Offset in NuttX Header to 0x0 (from 0x48000)
[(See the changes)](https://github.com/lupyuen/incubator-nuttx/commit/9916b52f9dba17944a35aafd4c21fb9eabb17c0e#diff-a830678a9f1b0773c404196c86ad45d1ef7d7e51a52b935cd08df35f5949aaf8)
- Change NuttX Linker Script to set the Start Address `_start` to 0x4008 0000 (from 0x4028 0000)
[(See the changes)](https://github.com/lupyuen/incubator-nuttx/commit/9916b52f9dba17944a35aafd4c21fb9eabb17c0e#diff-d8d987cb5ba644b5f79987e42663217799e03e384552b2e8dbb041f145fa8ad1)
For PinePhone Allwinner A64 UART: We reused the previous code for transmitting output to UART...
https://github.com/lupyuen/incubator-nuttx/blob/9916b52f9dba17944a35aafd4c21fb9eabb17c0e/arch/arm64/src/qemu/qemu_lowputc.S#L87-L94
But we updated the UART Register Address for Allwinner A64 UART...
https://github.com/lupyuen/incubator-nuttx/blob/9916b52f9dba17944a35aafd4c21fb9eabb17c0e/arch/arm64/src/qemu/qemu_lowputc.S#L40-L45
Right now we don't check if UART is ready to transmit, so our UART output will have missing characters. This needs to be fixed...
https://github.com/lupyuen/incubator-nuttx/blob/9916b52f9dba17944a35aafd4c21fb9eabb17c0e/arch/arm64/src/qemu/qemu_lowputc.S#L74-L85
We don't init the UART Port because U-Boot has kindly done it for us. This needs to be fixed...
https://github.com/lupyuen/incubator-nuttx/blob/9916b52f9dba17944a35aafd4c21fb9eabb17c0e/arch/arm64/src/qemu/qemu_lowputc.S#L55-L72
With the above changes, NuttX boots on PinePhone yay!
![NuttX Boots On PinePhone](https://lupyuen.github.io/images/Screenshot_2022-08-26_08-04-34_080626.png)
# TODO
TODO: Allwinner A64 UART