>>> 2. Why does the cache to be cleared at all? L2-SRAM is usually
>>> just used to copy in the second part of the u-boot image, so
>>> the 0s will be overwritten again anyway.
>
>This needs to be done because we enable ECC.
I'm still trying to get my head around this. From looking at the code
this doesn't seem to be necessary. The ECC errors are disabled
before L2 is configured as SRAM:
cpu_init_f (NAND)
/* set MBECCDIS=1, SBECCDIS=1 */
out_be32(&l2cache->l2errdis,
(MPC85xx_L2ERRDIS_MBECC | MPC85xx_L2ERRDIS_SBECC));
/* set L2E=1 & L2SRAM=001 */
out_be32(&l2cache->l2ctl,
(MPC85xx_L2CTL_L2E | MPC85xx_L2CTL_L2SRAM_ENTIRE));
And these ECC disable bits are only cleared once the u-boot has
already been copied to RAM and L2 is really used as cache:
cpu_init_r
/* set MBECCDIS=0, SBECCDIS=0 */
clrbits_be32(&l2cache->l2errdis,
(MPC85xx_L2ERRDIS_MBECC |
MPC85xx_L2ERRDIS_SBECC));
So am I getting something wrong?
Thanks
bye Fabi
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