[PATCH V2 4/9] sunxi: H616: DRAM: Adjust size scan procedure

[Chris Morgan]

From: Jernej Skrabec <jernej.skrabec at gmail.com>

It's safer to start scanning for columns first and then rows. Columns
reside on LSB address pins, which means that second configuration will
already have all needed row pins active.

This is also preparation for introducing DDR4 support, which need scan
for banks and bank groups too.

Signed-off-by: Jernej Skrabec <jernej.skrabec at gmail.com>
Tested-by: Chris Morgan <macromorgan at hotmail.com>
---
 arch/arm/mach-sunxi/dram_sun50i_h616.c | 31 +++++++++++++++-----------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/arch/arm/mach-sunxi/dram_sun50i_h616.c b/arch/arm/mach-sunxi/dram_sun50i_h616.c
index 72194fffc2..2f2776ce35 100644
--- a/arch/arm/mach-sunxi/dram_sun50i_h616.c
+++ b/arch/arm/mach-sunxi/dram_sun50i_h616.c
@@ -1371,28 +1371,33 @@ static void mctl_auto_detect_rank_width(const struct dram_para *para,
 static void mctl_auto_detect_dram_size(const struct dram_para *para,
 				       struct dram_config *config)
 {
-	/* detect row address bits */
-	config->cols = 8;
-	config->rows = 18;
+	unsigned int shift;
+
+	/* max. config for columns, but not rows */
+	config->cols = 11;
+	config->rows = 13;
 	mctl_core_init(para, config);
 
-	for (config->rows = 13; config->rows < 18; config->rows++) {
-		/* 8 banks, 8 bit per byte and 16/32 bit width */
-		if (mctl_mem_matches((1 << (config->rows + config->cols +
-					    4 + config->bus_full_width))))
+	shift = config->bus_full_width + 1;
+
+	/* detect column address bits */
+	for (config->cols = 8; config->cols < 11; config->cols++) {
+		if (mctl_mem_matches(1ULL << (config->cols + shift)))
 			break;
 	}
+	debug("detected %u columns\n", config->cols);
 
-	/* detect column address bits */
-	config->cols = 11;
+	/* reconfigure to make sure that all active rows are accessible */
+	config->rows = 18;
 	mctl_core_init(para, config);
 
-	for (config->cols = 8; config->cols < 11; config->cols++) {
-		/* 8 bits per byte and 16/32 bit width */
-		if (mctl_mem_matches(1 << (config->cols + 1 +
-					   config->bus_full_width)))
+	/* detect row address bits */
+	shift = config->bus_full_width + 4 + config->cols;
+	for (config->rows = 13; config->rows < 18; config->rows++) {
+		if (mctl_mem_matches(1ULL << (config->rows + shift)))
 			break;
 	}
+	debug("detected %u rows\n", config->rows);
 }
 
 static unsigned long mctl_calc_size(const struct dram_config *config)
-- 
2.34.1