[U-Boot] [RFC PATCH] am335x: Changes in DDR init procedure to Support Samsung K4B2G1646EBIH9 memory chip

[Maciej Zagrabski]

K4B2G1646EBIH9 Samsung memory chip used now on chiliSOM requires
refresh register REF CTRL to be initialized with large enough
value, faster than it is implemented in `config_sdram` in ddr.c
for am33xx, that mean before setting ZQ CTRL. Change should
not interferee with already supported DDR chips cause refresh rate value
is large enough to cover initialization, but it will finish during
`udelay` below anyway. If this is not acceptable I can `ifdef` this
line with config introduced in previous patch.

Signed-off-by: Maciej Zagrabski <maciej.zagrabski at grinn-global.com>
---
 arch/arm/mach-omap2/am33xx/ddr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/am33xx/ddr.c b/arch/arm/mach-omap2/am33xx/ddr.c
index be6f4d72ccd..3684508bb1c 100644
--- a/arch/arm/mach-omap2/am33xx/ddr.c
+++ b/arch/arm/mach-omap2/am33xx/ddr.c
@@ -171,12 +171,13 @@ void config_sdram(const struct emif_regs *regs, int nr)
 	writel(regs->ref_ctrl, &emif_reg[nr]->emif_sdram_ref_ctrl);
 #else
 	if (regs->zq_config) {
+		/* Trigger initialization */
+		writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl);
+
 		writel(regs->zq_config, &emif_reg[nr]->emif_zq_config);
 		writel(regs->sdram_config, &cstat->secure_emif_sdram_config);
 		writel(regs->sdram_config, &emif_reg[nr]->emif_sdram_config);
 
-		/* Trigger initialization */
-		writel(0x00003100, &emif_reg[nr]->emif_sdram_ref_ctrl);
 		/* Wait 1ms because of L3 timeout error */
 		udelay(1000);
 
-- 
2.11.0