Good afternoon,
There appear to be a number of issues with the Rockchip rk3399 DDR RAM
initialisation sequence in Mainline. Specifically, I'm seeing
consistent failures on the Rock Pi 4+ during early boot. A typical
failure looks something like this:
U-Boot TPL 2022.07-rc3-00005-g1b04a961c6 (May 25 2022 - 11:09:19)
Channel 0: LPDDR4, 50MHz
BW=32 Col=10 Bk=8 CS0 Row=16/15 CS=1 Die BW=16 Size=2048MB
Channel 1: col error
Cap error!
256B stride
lpddr4_set_rate: change freq to 400000000 mhz 0, 1
lpddr4_set_rate: change freq to 800000000 mhz 1, 0
Trying to boot from BOOTROM
Returning to boot ROM...
Even when the system boots to a terminal, which happens very
infrequently, the LPDDR4 RAM chip at Channel 1 can have conflicting
discovery information printed during TPL. The following 3 lines were
printed during successive reboots using the same SD card with no
changes:
# Boot 1:
BW=32 Col=9 Bk=4 CS0 Row=16/15 CS=1 Die BW=16 Size=384MB
# Boot 2:
BW=32 Col=10 Bk=4 CS0 Row=16/15 CS=1 Die BW=16 Size=768MB
# Boot 3:
BW=32 Col=10 Bk=4 CS0 Row=15 CS=1 Die BW=16 Size=512MB
The story changes when I build the idbloader.img image with Rockchip's
TBL (?) binary blob [0]. With that built in, presumably in place of
the upstream TBL, both RAM chips are successfully enumerated and boot
succeeds with 100% success rate:
tools/mkimage -n rk3399 -T rksd -d \
rk3399_ddr_933MHz_v1.25.bin:spl/u-boot-spl.bin idbloader.img
Another thing that is very different between the 2 is the initial
frequency the LPDDR4 chips are clocked at. Using the upstream TBL
version, the default is 50Mhz, which seems very low. If using the
Rockchip supplied binary blob file, this is increased to a respectable
416MHz:
# Mainline
Channel 0: LPDDR4, 50MHz
# Rockchip TBL blob
Channel 0: LPDDR4,416MHz
One thing I did try was to load in the 400Mhz configuration settings
from drivers/ram/rockchip/sdram-rk3399-lpddr4-400.inc as the default
initial values, instead of the 50MHz default taken from
arch/arm/dts/rk3399-sdram-lpddr4-100.dtsi, but this failed in a number
of ways:
Setting clock: Freq: 400MHz (400000000)
Calling SDRAM init: 2 Channels
Starting SDRAM initialization...
mr5:0 mr12:0 mr14:0
Training failed for rank 2, ch 0 (ret: -22)
mr5:0 mr12:0 mr14:0
Training failed for rank 1, ch 0 (ret: -22)
mr5:0 mr12:0 mr14:0
Training failed for rank 2, ch 1 (ret: -22)
mr5:0 mr12:0 mr14:0
Training failed for rank 1, ch 1 (ret: -22)
Rank for Channel 1 is 0x0
Rank for Channel 0 is 0x0
Rank for Channel 1 is 0x0
sdram_init: LPDDR4 - 400MHz failed!
rk3399_dmc_init DRAM init failed -22
So my question is; does Rockchip, or anyone else for that matter, have
any plans on updating Mainline U-Boot with the upgraded/working LPDDR4
initialisation sequence?
As ever, any information / help would be gratefully received.
NB: If I have missed any critical people out from this discussion,
please feel free to loop as many of them in as you see fit.
Kind regards,
Lee
[0] https://github.com/rockchip-linux/rkbin/blob/master/bin/rk33/rk3399_ddr_933MHz_v1.25.bin
--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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