[U-Boot] [PATCH 3/3] board/tqm85xx: Create and tear down TLB for get_ram_size()

[Becky Bruce]

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 at kernel.crashing.org>
---
 board/tqc/tqm85xx/sdram.c |    7 +++++++
 include/configs/TQM85xx.h |    2 ++
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/board/tqc/tqm85xx/sdram.c b/board/tqc/tqm85xx/sdram.c
index 39a9e21..baf073e 100644
--- a/board/tqc/tqm85xx/sdram.c
+++ b/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) {
diff --git a/include/configs/TQM85xx.h b/include/configs/TQM85xx.h
index b4eef28..0eadcd2 100644
--- a/include/configs/TQM85xx.h
+++ b/include/configs/TQM85xx.h
@@ -152,8 +152,10 @@
 	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
-- 
1.5.6.5