board/tqm85xx: Create and tear down TLB for get_ram_size()

We need a TLB entry to call get_ram_size(); the common code doesn't create
one until *after* fixed_sdram() has determined the size.  So we set up tlbs
for the max possible size and tear them down once we're done with
get_ram_size(); the common 85xx code will then set up a final set of tlb
entries for the *actual* detected size of ddr.

This prevents us from having TLB entries that are larger than DDR sitting
around for very long, which is not a recommended scenario.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

board/tqc/tqm85xx/sdram.c

@@ -363,6 +363,12 @@ static phys_size_t sdram_setup(int casl)
 	udelay (1000);
 #endif /* CONFIG_TQM8548 */
 
+	/*
+	 * get_ram_size() depends on having tlbs for the DDR, but they are
+	 * not yet setup because we don't know the size.  Set up a temp
+	 * mapping and delete it when done.
+	 */
+	setup_ddr_tlbs(CONFIG_SYS_DDR_EARLY_SIZE_MB);
 	for (i = 0; i < N_DDR_CS_CONF; i++) {
 		ddr->cs0_config = ddr_cs_conf[i].reg;
 
@@ -376,6 +382,7 @@ static phys_size_t sdram_setup(int casl)
 			break;
 		}
 	}
+	clear_ddr_tlbs(CONFIG_SYS_DDR_EARLY_SIZE_MB);
 
 #ifdef CONFIG_TQM8548
 	if (i < N_DDR_CS_CONF) {

include/configs/TQM85xx.h

@@ -147,10 +147,16 @@
  * DDR Setup
  */
 #define CONFIG_SYS_DDR_SDRAM_BASE	0x00000000	/* DDR is system memory	*/
+
 #if defined(CONFIG_TQM_BIGFLASH) || \
 	(!defined(CONFIG_TQM8548_AG) && !defined(CONFIG_TQM8548_BE))
 #define CONFIG_SYS_PPC_DDR_WIMGE (MAS2_I | MAS2_G)
+#define CONFIG_SYS_DDR_EARLY_SIZE_MB	(512)
+#else
+#define CONFIG_SYS_PPC_DDR_WIMGE (0)
+#define CONFIG_SYS_DDR_EARLY_SIZE_MB	(2 * 1024)
 #endif
+
 #define CONFIG_SYS_SDRAM_BASE		CONFIG_SYS_DDR_SDRAM_BASE
 #ifdef CONFIG_TQM8548_AG
 #define CONFIG_VERY_BIG_RAM