Re: Raspberry Pi 4 support on 32 bit earmv7hf GENERIC kernel

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

mlelstv@ wrote:

> >On Raspberry Pi 4, it looks the firmware (start4.elf) dynamically
> >populates /chosen node, puts "simple-framebuffer" under it, and
> >then gives /chosen the non-standard compatible string "simple_bus".
> >(see quoted "strings(1)" output above)
> 
> 
> The firmware looks for a 'display0' alias and for a '/soc/fb'
> entry in 'okay' state. If neither exists, it adds the
> 'simple-framebuffer'. The state of '/soc/fb' is normally
> controlled by a device tree overlay.
> 
> So the most simple way to get a display is to restore /soc/fb.
> Our platform code is then talking to the RPI firmware to get
> data about the framebuffer.

I'm not familiar FDT or Raspberry Pi firmware, but ofctl says:

---
arm64-% ofctl -p /aliases
[Caching 272 nodes and 1562 properties]
blconfig                2f726573 65727665 642d6d65 6d6f7279   /reserved-memory
            0010:       2f6e7672 616d4030 00...... ........   /nvram@0.
display0                2f63686f 73656e2f 6672616d 65627566   /chosen/framebuf
            0010:       66657240 33653430 32303030 00......   fer@3e402000.
emmc2bus                2f656d6d 63326275 7300.... ........   /emmc2bus.
ethernet0               2f736362 2f657468 65726e65 74403764   /scb/ethernet@7d
            0010:       35383030 303000.. ........ ........   580000.
name                    616c6961 73657300 ........ ........   "aliases"
pcie0                   2f736362 2f706369 65403764 35303030   /scb/pcie@7d5000
            0010:       303000.. ........ ........ ........   00.
serial0                 2f736f63 2f736572 69616c40 37653230   /soc/serial@7e20
            0010:       31303030 00...... ........ ........   1000.
serial1                 2f736f63 2f736572 69616c40 37653231   /soc/serial@7e21
            0010:       35303430 00...... ........ ........   5040.
arm64-% ofctl -p /soc
[Caching 272 nodes and 1562 properties]
#address-cells          00000001 ........ ........ ........     1
#size-cells             00000001 ........ ........ ........     1
compatible              73696d70 6c652d62 757300.. ........   "simple-bus"
dma-ranges              c0000000 00000000 00000000 40000000   ............@...
name                    736f6300 ........ ........ ........   "soc"
ranges                  7e000000 00000000 fe000000 01800000   ~...............
            0010:       7c000000 00000000 fc000000 02000000   |...............
            0020:       40000000 00000000 ff800000 00800000   @...............
arm64-%  ofctl -l /soc/fb
[Caching 272 nodes and 1562 properties]
ofctl: OF node '/soc/fb' not found: No such file or directory
arm64-% 

---
Izumi Tsutsui