[U-Boot-Users] U-Boot and MPC857T?

[Steven Scholz]

Hi Gunnar,

> ...
> I also thought to that, but it is not so easy, because of at least the
> following Macros showed below.
> 
> We have our board with a MPC855T 50 MHz and two prototypes with a MPC857T 100
> MHz. The CPU-Clock cannot be detected automatically. We need at
> least the following differences:
> 
> #elif defined(CONFIG_100MHz)   /* for 100 MHz  = "50 MHz" |= SCCR_EBDF01 */
> #define CFG_SCCR       (SCCR_TBS     | SCCR_EBDF01 | \
>                         SCCR_COM00   | SCCR_DFSYNC00 | SCCR_DFBRG00  | \
>                         SCCR_DFNL000 | SCCR_DFNH000  | SCCR_DFLCD000 | \
>                         SCCR_RTSEL   | SCCR_DFALCD00)
> #define CFG_PLPRCR ( (4-1)<<PLPRCR_MF_SHIFT | PLPRCR_TEXPS | PLPRCR_TMIST )
> #define CONFIG_8xx_GCLK_FREQ    100000000
> #else                  /* up to 50 MHz we use a 1:1 clock (CLKOUT=GCLK2) */
> #define CFG_SCCR       (SCCR_TBS     | \
>                         SCCR_COM00   | SCCR_DFSYNC00 | SCCR_DFBRG00  | \
>                         SCCR_DFNL000 | SCCR_DFNH000  | SCCR_DFLCD000 | \
>                         SCCR_RTSEL   | SCCR_DFALCD00)
> #define CFG_PLPRCR ( (2-1)<<PLPRCR_MF_SHIFT | PLPRCR_TEXPS | PLPRCR_TMIST )
> #define CONFIG_8xx_GCLK_FREQ     50000000
> #endif /* CONFIG_...MHz */

Ehm... I don't understand. The code above only depends on 
CONFIG_100MHz and not some CONFIG_MPC855T!
Of course you have to compile for a specific clock frequency. But it 
shouldn't matter if it's a 855T or a 857T!

That's why I thought the FW (compiled for one specific clock) should 
be able to detect the processor typ...

Steven