[U-Boot] [PATCH 1/2] ARM: imx6: DHCOM i.MX6 PDK: use Kconfig for inclusion of DDR calibration

[Ludwig Zenz]

The four x16 DDR3 are wired in T-topology. From NXP AN4467:
'Although not required, T-Topologies may also benefit from performing
Write Leveling as there are package delays on both the processor and DDR
devices that can be de-skewed by performing Write Leveling. Therefore,
Freescale recommends determining Write Leveling calibration parameters
for all boards, regardless of topology used.'
That is why write level calibration is also done.

Signed-off-by: Ludwig Zenz <lzenz at dh-electronics.com>
---
 board/dhelectronics/dh_imx6/dh_imx6_spl.c | 32 +++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/board/dhelectronics/dh_imx6/dh_imx6_spl.c b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
index 04e9eab272a..bbd2dc26828 100644
--- a/board/dhelectronics/dh_imx6/dh_imx6_spl.c
+++ b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
@@ -482,6 +482,29 @@ static void setup_iomux_usb(void)
 	SETUP_IOMUX_PADS(usb_pads);
 }
 
+/* Perform DDR DRAM calibration */
+static int spl_dram_perform_cal(struct mx6_ddr_sysinfo const *sysinfo)
+{
+	int ret = 0;
+
+#ifdef CONFIG_MX6_DDRCAL
+	udelay(100);
+	ret = mmdc_do_write_level_calibration(sysinfo);
+	if (ret) {
+		printf("DDR3: Write level calibration error [%d]\n", ret);
+		return ret;
+	}
+
+	ret = mmdc_do_dqs_calibration(sysinfo);
+	if (ret) {
+		printf("DDR3: DQS calibration error [%d]\n", ret);
+		return ret;
+	}
+#endif /* CONFIG_MX6_DDRCAL */
+
+	return ret;
+}
+
 
 /* DRAM */
 static void dhcom_spl_dram_init(void)
@@ -509,8 +532,7 @@ static void dhcom_spl_dram_init(void)
 		}
 
 		/* Perform DDR DRAM calibration */
-		udelay(100);
-		mmdc_do_dqs_calibration(&dhcom_ddr_64bit);
+		spl_dram_perform_cal(&dhcom_ddr_64bit);
 
 	} else if (is_cpu_type(MXC_CPU_MX6DL)) {
 		mx6sdl_dram_iocfg(64, &dhcom6sdl_ddr_ioregs,
@@ -528,8 +550,7 @@ static void dhcom_spl_dram_init(void)
 		}
 
 		/* Perform DDR DRAM calibration */
-		udelay(100);
-		mmdc_do_dqs_calibration(&dhcom_ddr_64bit);
+		spl_dram_perform_cal(&dhcom_ddr_64bit);
 
 	} else if (is_cpu_type(MXC_CPU_MX6SOLO)) {
 		mx6sdl_dram_iocfg(32, &dhcom6sdl_ddr_ioregs,
@@ -552,8 +573,7 @@ static void dhcom_spl_dram_init(void)
 		}
 
 		/* Perform DDR DRAM calibration */
-		udelay(100);
-		mmdc_do_dqs_calibration(&dhcom_ddr_32bit);
+		spl_dram_perform_cal(&dhcom_ddr_32bit);
 	}
 }
 
-- 
2.11.0