add docs

docs/index.md

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+# Rockchip bare metal reference
+This is a resource for bare-metal bringup on RK3399 and RK3588-based devices.
+
+I learned all this and make all this documentation during my time working for FUTO doing bringup for our unreleased FUBS project.
+
+For RK3399 bringup, I initially wrote everything in C before porting it to our own language, as I was still learning and figuring things out.
+For RK3588 bringup, our system was robust enough to to bringup without a separate C implementation.

docs/ref.md

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+# RK3588
+- edk2 uefi monorepo: https://gitlab.com/rk3588_linux/rk/uefi-monorepo
+Lots of early bare-metal rk3588 code written by rockchip employees, good reference for when the TRM is missing info
+- rkdocs: https://github.com/axlrose/rkdocs
+- TRM/Datasheet: https://github.com/FanX-Tek/rk3588-TRM-and-Datasheet
+- RK3588 Base: https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3588-base.dtsi pinctrl https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3588-base-pinctrl.dtsi
+
+## RK3399
+- RK3399 TRM v1.4: https://opensource.rock-chips.com/images/e/ee/Rockchip_RK3399TRM_V1.4_Part1-20170408.pdf
+- RK3399 TRM V1.3 Part2: https://rockchip.fr/Rockchip%20RK3399%20TRM%20V1.3%20Part2.pdf
+- 2022 Pinebook Pro main board schematic: https://files.pine64.org/doc/PinebookPro/pinebookpro_schematic_v21a_20220419.pdf
+- Tool to decode exception syndrome register: https://esr.arm64.dev/
+- Intro to eDP: https://www.vesa.org/wp-content/uploads/2010/12/DisplayPort-DevCon-Presentation-eDP-Dec-2010-v3.pdf
+- eDP technical overview: https://www.vesa.org/wp-content/uploads/2011/01/ICCE-Presentation-on-VESA-DisplayPort.pdf
+- DisplayPort Specification (covers DPCD): https://glenwing.github.io/docs/DP-1.1.pdf
+- rk3399 bootrom analysis: https://github.com/trebisky/Rockchip/blob/4c4623e3df37f01d1d1ae0131fec5bc75f9e8463/bootrom/bootrom.txt
+- arm-trusted-firmware: https://github.com/ARM-software/arm-trusted-firmware
+- Dynamic Memory Controller: https://www.kernel.org/doc/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
+- ARM GIC architecture specification: https://developer.arm.com/documentation/ihi0069/latest/

docs/rk3399-disp.md

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+# VOP
+- 6 layers supported
+- Background color
+- 4 Window Layers
+- Hardware Cursor Layer
+- Hardware alpha blending
+
+## VOP Setup process
+- Select reference clock
+- Set VOP to L or B (`grf.edp_lcdc_sel`)
+- Setup and lock PLL
+- Set to standby mode
+- Enable desired interface (such as eDP) and disable unneeded interfaces
+- Configure display settings
+- Configure window layers settings
+  - Width, height
+  - Porch offsets
+  - Enable the window(s)
+  - Set format (eg, ARGB888)
+  - Set framebuffer address (win0_yrgb_mst)
+- Set reg_cfg_done to `0b1`.
+- The framebuffer is fetched over AXI from DDR.
+
+## eDP TX Setup process
+- Setup reference clock
+- Wait for HDP
+- Set SW_FUNC_EN_N to normal operation
+- dp_pd = 0
+- Reset PLL
+- Wait until PLL is locked
+- Setup AUX channel
+  - Enable AUX AUX_FUNC_EN_N
+  - Clear AUX interrupts
+  - Disable AUX, set aux defer setting, enable AUX
+  - Set AUX channel module to normal func_en_2
+- Enable all function and video modes (func_en_1)
+- Perform a AUX DPCD transfer to get display info (`aux_` registers)
+  - Get the display resolution
+  - Get the lane count and link rate
+  - Set `link_bw_set` and `lane_count_set`
+  - You can hardcode these values rather than implementing AUX DPCD transfers
+- Link training
+  - Link rates, clock recovery, etc
+  - This can be skipped
+- Make sure eDP clock is on
+- Disable video mute
+- Enable video output