ARM: OMAP4+: dmm: Take care of overlapping dmm and trap sections.

The DMM sections can be overlapping with each other, with
sections 3 to 0 having the highest to lowest priority in that
order. There could also be a section that is used trap the
unmapped Tiler entries and this trap section could be
overlapping with the actual sdram area.

So take care of the above scenarios while calculating the
size of the actual ram.

Signed-off-by: R Sricharan <r.sricharan@ti.com>

arch/arm/cpu/armv7/omap-common/hwinit-common.c

@@ -162,11 +162,16 @@ void watchdog_init(void)
  */
 u32 omap_sdram_size(void)
 {
-	u32 section, i, total_size = 0, size, addr;
+	u32 section, i, valid;
+	u64 sdram_start = 0, sdram_end = 0, addr,
+	    size, total_size = 0, trap_size = 0;
 
 	for (i = 0; i < 4; i++) {
 		section	= __raw_readl(DMM_BASE + i*4);
+		valid = (section & EMIF_SDRC_ADDRSPC_MASK) >>
+			(EMIF_SDRC_ADDRSPC_SHIFT);
 		addr = section & EMIF_SYS_ADDR_MASK;
+
 		/* See if the address is valid */
 		if ((addr >= DRAM_ADDR_SPACE_START) &&
 		    (addr < DRAM_ADDR_SPACE_END)) {
@@ -174,9 +179,20 @@ u32 omap_sdram_size(void)
 				   EMIF_SYS_SIZE_SHIFT);
 			size = 1 << size;
 			size *= SZ_16M;
-			total_size += size;
+
+			if (valid != DMM_SDRC_ADDR_SPC_INVALID) {
+				if (!sdram_start || (addr < sdram_start))
+					sdram_start = addr;
+				if (!sdram_end || ((addr + size) > sdram_end))
+					sdram_end = addr + size;
+			} else {
+				trap_size = size;
+			}
+
 		}
+
 	}
+	total_size = (sdram_end - sdram_start) - (trap_size);
 
 	return total_size;
 }