[U-Boot] PATCH: bugfix for reading maximum TLB size on mpc85xx

[Fredrik Arnerup]

The MAXSIZE field in the TLB1CFG register is 4 bits, not 8 bits.
This made setup_ddr_tlbs() try to set up a TLB larger than the e500 maximum
(256 MB)
which made u-boot hang in board_init_f() when trying to create a new stack
in RAM.
I have an mpc8540 with one 1GB dimm.

Signed-off-by: Fredrik Arnerup <fredrik.arnerup at edgeware.tv>

--- ../tmp/u-boot-2009.03/cpu/mpc85xx/tlb.c     2009-03-21
22:04:41.000000000 +0100
+++ cpu/mpc85xx/tlb.c   2009-05-14 19:26:17.000000000 +0200
@@ -134,7 +134,7 @@
        unsigned int tlb_size;
        unsigned int ram_tlb_index = CONFIG_SYS_DDR_TLB_START;
        unsigned int ram_tlb_address = (unsigned
int)CONFIG_SYS_DDR_SDRAM_BASE;
-       unsigned int max_cam = (mfspr(SPRN_TLB1CFG) >> 16) & 0xff;
+       unsigned int max_cam = (mfspr(SPRN_TLB1CFG) >> 16) & 0xf;
        u64 size, memsize = (u64)memsize_in_meg << 20;

        size = min(memsize, CONFIG_MAX_MEM_MAPPED);