MLK-10361 imx: mx7d arm2: Change to use WDOG_B reset

The default u-boot reset is a internal WDOG reset (warm reset on i.MX6) which
does not have power and DDR reset. So the peripherals and DDR may meet problem.
When using the internal WDOG reset on i.MX7D ARM2 boards,
we meets two DDR issues:

1. On 12x12 ARM2, sometimes the system may hang in DCD because the DDRC Operating Mode
does not become to normal.

2. On 19x19 ARM2, the reset always brings system to USB download because the
DDR3 turns to unstable.

On the i.MX7D ARM2 board, the WDOG_B signal connects to POR_B or PMIC_PWRON. This gives
a chance to use a stronger reset. So in this patch, we set the IOMUX for WDOG_B pin and
enable WDOG_B signal output in WDOG WCR register.

Signed-off-by: Ye.Li <B37916@freescale.com>
(cherry picked from commit 1192501c1fcf3b266eb22639a6bc93ac7c03b367)
Signed-off-by: Peng Fan <Peng.Fan@freescale.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/mx7/soc.c b/arch/arm/cpu/armv7/mx7/soc.c
index f150569..829e30c 100644
--- a/arch/arm/cpu/armv7/mx7/soc.c
+++ b/arch/arm/cpu/armv7/mx7/soc.c
@@ -356,6 +356,24 @@ void boot_mode_apply(uint32_t cfg_val)
 	writel(reg, &src_reg->gpr10);
 }
 
+void set_wdog_reset(struct wdog_regs *wdog)
+{
+	u32 reg = readw(&wdog->wcr);
+	/*
+	 * Output WDOG_B signal to reset external pmic or POR_B decided by
+	 * the board desgin. Without external reset, the peripherals/DDR/
+	 * PMIC are not reset, that may cause system working abnormal.
+	 */
+	reg = readw(&wdog->wcr);
+	reg |= 1 << 3;
+	/*
+	 * WDZST bit is write-once only bit. Align this bit in kernel,
+	 * otherwise kernel code will have no chance to set this bit.
+	 */
+	reg |= 1 << 0;
+	writew(reg, &wdog->wcr);
+}
+
 /*
  * cfg_val will be used for
  * Boot_cfg4[7:0]:Boot_cfg3[7:0]:Boot_cfg2[7:0]:Boot_cfg1[7:0]