[U-Boot-Users] I-cache and D-cache size problem on MPC859

Hello,
Now I have the U-Boot for MPC859, but I am not sure this line is correct
U-Boot 1.1.3 (Nov 11 2005 - 16:38:24)
CPU: MPC859TxxZPnnA at 133 MHz: 16 kB I-Cache 8 kB D-Cache FEC present
As far as I know, the I-Cache and the D-Cache of the MPC859 is 4 kB, as defined in the MPC866UM Appendix F.
Here is the chapter which describe the cache
F.3 Cache Control Registers The MPC859T bit fields and commands of the cache control and status registers (IC_CST and DC_CST) are implemented the same as for the MPC866P. However, the bit fields of the cache address registers (IC_ADR and DC_ADR) and the cache data port registers (IC_DAT and DC_DAT) must be used for the 4-Kbyte instruction and data caches. See Chapter 7, "Instruction and Data Caches."
We think that the MPC859 probably has phisically the same cache size as the MPC866, but only 4 kB must be used. Anyway, my question is, must I worry about the data printed on the screen or can I leave as they are? I mean, are these information used in other part of the U-Boot or the Kernel?
Thanks in advance.
Best Regards Agostino Sette

In message 69DF49BE936F4441980EC1D59F0ADC2F010ADC04@aqlby02a.siemens.it you wrote:
Now I have the U-Boot for MPC859, but I am not sure this line is correct
U-Boot 1.1.3 (Nov 11 2005 - 16:38:24)
CPU: MPC859TxxZPnnA at 133 MHz: 16 kB I-Cache 8 kB D-Cache FEC present
Looks good to me.
As far as I know, the I-Cache and the D-Cache of the MPC859 is 4 kB, as defined in the MPC866UM Appendix F.
Well, if you follow the Parametrics sheets on the freescale pages the size is not 4 KiB (= 4096 Bytes), but 4000 Bytes instead. Looks bogus to me.
We think that the MPC859 probably has phisically the same cache size as the MPC866, but only 4 kB must be used.
U-Boot uses the functions checkicache() and checkdcache() [see "cpu/mpc8xx/cpu.c"] to measure the size of the L1 instruction and data cache.
Anyway, my question is, must I worry about the data printed on the screen or can I leave as they are?
I don't see how you could change the sizes.
I mean, are these information used in other part of the U-Boot or the Kernel?
They are just informational messages.
Best regards,
Wolfgang Denk
participants (2)
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Sette Agostino
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Wolfgang Denk