[U-Boot] [PATCH V2 1/4] mx6: ddr: allow 32 cycles for DQS gating calibration

[Eric Nelson]

The DDR calibration code is only setting flag DG_CMP_CYC (DQS gating sample
cycle) for the first PHY.

Set the 32-cycle flag for both PHYs and clear when done so the MPDGCTRL0
output value isn't polluted with calibration artifacts.

Signed-off-by: Eric Nelson <eric at nelint.com>
Reviewed-by: Marek Vasut <marex at denx.de>
---
No change in V2.
 arch/arm/cpu/armv7/mx6/ddr.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm/cpu/armv7/mx6/ddr.c b/arch/arm/cpu/armv7/mx6/ddr.c
index 7beb7ea..b15f376 100644
--- a/arch/arm/cpu/armv7/mx6/ddr.c
+++ b/arch/arm/cpu/armv7/mx6/ddr.c
@@ -347,6 +347,8 @@ int mmdc_do_dqs_calibration(void)
 	 * 16 before comparing read data.
 	 */
 	setbits_le32(&mmdc0->mpdgctrl0, 1 << 30);
+	if (sysinfo->dsize == 2)
+		setbits_le32(&mmdc1->mpdgctrl0, 1 << 30);
 
 	/* Set bit 28 to start automatic read DQS gating calibration */
 	setbits_le32(&mmdc0->mpdgctrl0, 5 << 28);
@@ -365,6 +367,11 @@ int mmdc_do_dqs_calibration(void)
 	if ((bus_size == 0x2) && (readl(&mmdc1->mpdgctrl0) & 0x00001000))
 		errors |= 2;
 
+	/* now disable mpdgctrl0[DG_CMP_CYC] */
+	clrbits_le32(&mmdc0->mpdgctrl0, 1 << 30);
+	if (sysinfo->dsize == 2)
+		clrbits_le32(&mmdc1->mpdgctrl0, 1 << 30);
+
 	/*
 	 * DQS gating absolute offset should be modified from
 	 * reflecting (HW_DG_LOWx + HW_DG_UPx)/2 to
-- 
2.7.4