[U-Boot] [PATCH v2 1/2] ARM: imx6: DHCOM i.MX6 PDK: use Kconfig for inclusion of DDR calibration

Ludwig Zenz
2019-04-15T09:13:08Z

From: Ludwig Zenz <lzenz@dh-electronics.de>

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@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