[U-Boot] [PATCH 11/14] sunxi: Fill memory before comparing it when doing dram init on sun6i

[Hans de Goede]

The sun8i boot0 code fills the DRAM with a "random" pattern before comparing
it at different offsets to do columns, etc. detection. The sun6i boot0 code
does not do it, but it seems like a good idea to do this regardless.

The new mctl_mem_fill function this introduces is added as an inline helper
in dram.h, so that it can be shared with the sun8i dram code.

While at it move mctl_mem_matches to dram.h for re-use in sun8i too.

Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 arch/arm/cpu/armv7/sunxi/dram_sun6i.c  | 15 +--------------
 arch/arm/include/asm/arch-sunxi/dram.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/arch/arm/cpu/armv7/sunxi/dram_sun6i.c b/arch/arm/cpu/armv7/sunxi/dram_sun6i.c
index e1670e5..4675c48 100644
--- a/arch/arm/cpu/armv7/sunxi/dram_sun6i.c
+++ b/arch/arm/cpu/armv7/sunxi/dram_sun6i.c
@@ -326,20 +326,6 @@ static void mctl_port_cfg(void)
 	writel(0x00000307, &mctl_com->mbagcr[5]);
 }
 
-static bool mctl_mem_matches(u32 offset)
-{
-	const int match_count = 64;
-	int i, matches = 0;
-
-	for (i = 0; i < match_count; i++) {
-		if (readl(CONFIG_SYS_SDRAM_BASE + i * 4) ==
-		    readl(CONFIG_SYS_SDRAM_BASE + offset + i * 4))
-			matches++;
-	}
-
-	return matches == match_count;
-}
-
 unsigned long sunxi_dram_init(void)
 {
 	struct sunxi_mctl_com_reg * const mctl_com =
@@ -391,6 +377,7 @@ unsigned long sunxi_dram_init(void)
 		    MCTL_CR_BANK(1) | MCTL_CR_RANK(1));
 
 	/* Detect and set page size */
+	mctl_mem_fill();
 	for (columns = 7; columns < 20; columns++) {
 		if (mctl_mem_matches(1 << columns))
 			break;
diff --git a/arch/arm/include/asm/arch-sunxi/dram.h b/arch/arm/include/asm/arch-sunxi/dram.h
index 18924f5..0bf718c 100644
--- a/arch/arm/include/asm/arch-sunxi/dram.h
+++ b/arch/arm/include/asm/arch-sunxi/dram.h
@@ -22,6 +22,8 @@
 #include <asm/arch/dram_sun4i.h>
 #endif
 
+#define MCTL_MEM_FILL_MATCH_COUNT 64
+
 unsigned long sunxi_dram_init(void);
 
 /*
@@ -37,4 +39,31 @@ static inline void mctl_await_completion(u32 *reg, u32 mask, u32 val)
 	}
 }
 
+/*
+ * Fill beginning of DRAM with "random" data for mctl_mem_matches()
+ */
+static inline void mctl_mem_fill(void)
+{
+	int i;
+
+	for (i = 0; i < MCTL_MEM_FILL_MATCH_COUNT; i++)
+		writel(0xaa55aa55 + i, CONFIG_SYS_SDRAM_BASE + i * 4);
+}
+
+/*
+ * Test if memory at offset offset matches memory at begin of DRAM
+ */
+static inline bool mctl_mem_matches(u32 offset)
+{
+	int i, matches = 0;
+
+	for (i = 0; i < MCTL_MEM_FILL_MATCH_COUNT; i++) {
+		if (readl(CONFIG_SYS_SDRAM_BASE + i * 4) ==
+		    readl(CONFIG_SYS_SDRAM_BASE + offset + i * 4))
+			matches++;
+	}
+
+	return matches == MCTL_MEM_FILL_MATCH_COUNT;
+}
+
 #endif /* _SUNXI_DRAM_H */
-- 
2.1.0