While the PowerPC 405EX(r) shares in common the AMCC/IBM DDR2 SDRAM
controller core also used in the 440SP, 440SPe, 460EX, and 460GT, in
the 405EX(r), SDRAM_MCSTAT has a different DCR value.
Its present value on the 405EX(r) causes a read back of 0xFFFFFFFF
which causes SDRAM initialization to periodically fail since it can
prematurely indicate SDRAM ready status.
Signed-off-by: Grant Erickson <gerickson@nuovations.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Newer PPC's like 440SPe, 460EX/GT can be equipped with more than 2GB of SDRAM.
To support such configurations, we "only" map the first 2GB via the TLB's. We
need some free virtual address space for the remaining peripherals like, SoC
devices, FLASH etc.
Note that ECC is currently not supported on configurations with more than 2GB
SDRAM. This is because we only map the first 2GB on such systems, and therefore
the ECC parity byte of the remaining area can't be written.
Signed-off-by: Stefan Roese <sr@denx.de>
This patch now adds a new header file (asm-ppc/ppc4xx-sdram.h) for all
ppc4xx related SDRAM/DDR/DDR2 controller defines.
Signed-off-by: Stefan Roese <sr@denx.de>
