ppc4xx: Remove superfluous dram_init() call or replace it by initdram()

Historically the 405 U-Boot port had a dram_init() call in early init
stage. This function was still called from start.S and most of the time
coded in assembler. This is not needed anymore (since a long time) and
boards should implement the common initdram() function in C instead.

This patch now removed the dram_init() call from start.S and removes the
empty implementations that are scattered through most of the 405 board
ports. Some older board ports really implement this dram_init() though.
These are:

csb272
csb472
ERIC
EXBITGEN
W7OLMC
W7OLMG

I changed those boards to call this assembler dram_init() function now
from their board specific initdram() instead. This *should* work, but please
test again on those platforms. And it is perhaps a good idea that those
boards use some common 405 SDRAM initialization code from cpu/ppc4xx at
some time. So further patches welcome here.

Signed-off-by: Stefan Roese <sr@denx.de>

cpu/ppc4xx/sdram.c

@@ -164,7 +164,7 @@ static ulong compute_rtr(ulong speed, ulong rows, ulong refresh)
 /*
  * Autodetect onboard SDRAM on 405 platforms
  */
-void sdram_init(void)
+long int initdram(int board_type)
 {
 	ulong speed;
 	ulong sdtr1;
@@ -232,9 +232,15 @@ void sdram_init(void)
 				mtsdram(mem_mcopt1, 0);
 			}
 #endif
-			return;
+
+			/*
+			 * OK, size detected -> all done
+			 */
+			return mb0cf[i].size;
 		}
 	}
+
+	return 0;
 }
 
 #else /* CONFIG_440 */

cpu/ppc4xx/start.S

@@ -217,7 +217,6 @@
 
 
 	.extern ext_bus_cntlr_init
-	.extern sdram_init
 #ifdef CONFIG_NAND_U_BOOT
 	.extern reconfig_tlb0
 #endif
@@ -1119,11 +1118,6 @@ _start:
 	stw	r0, +12(r1)		/* Save return addr (underflow vect) */
 #endif /* CFG_INIT_DCACHE_CS */
 
-	/*----------------------------------------------------------------------- */
-	/* Initialize SDRAM Controller	*/
-	/*----------------------------------------------------------------------- */
-	bl	sdram_init
-
 #ifdef CONFIG_NAND_SPL
 	bl	nand_boot_common	/* will not return */
 #else