[RESEND 0/3] rockchip: Fix RAM training on RK3399 based platforms (Rock Pi 4)

[Lee Jones]

On Thu, 11 Aug 2022, Lee Jones wrote:

> This set fixes several issues found on the Rock Pi 4.
> 
> For full context, please see this initial bug report:
> 
>  "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?"
> 
> Lee Jones (3):
>   ram: rk3399: Fix .set_rate_index() error handling
>   ram: rk3399: Fix faulty frequency change reports
>   ram: rk3399: Conduct memory training at 400MHz
> 
>  drivers/ram/rockchip/sdram_rk3399.c | 38 +++++++++++++++++------------
>  1 file changed, 23 insertions(+), 15 deletions(-)

Looks as though we have all the Reviews we need.

Would someone be kind enough to merge these patches please?

They solve some pretty serious user reported issues.

Thank you.

-- 
Lee Jones [李琼斯]