[U-Boot] [PATCH v3 07/20] ARM: UniPhier: reset NAND core in SPL for non-NAND boot mode

[Masahiro Yamada]

For all the UniPhier SoCs so far, the reset signal of the NAND core
is automatically deasserted after the PLL gets stabled.
(The bit 2 of SC_RSTCTRL is default to one.)

This causes a fatal problem on the NAND controller of PH1-LD4.
For that SoC, the NAND I/O pins are not set up yet at the power-on
reset except the NAND boot mode.  As a result, the NAND controller
begins automatic device scanning with wrong I/O pins and finally
hangs up.

Actually, U-Boot dies after printing "NAND:" on the console unless
the boot mode latch detected the NAND boot mode.

To work around this problem, reset the NAND core in SPL for non-NAND
boot modes.  If CONFIG_NAND_DENALI is enabled, the reset signal is
deasserted again in U-Boot proper.  At this time, I/O pins have been
correctly set up, the device scanning should succeed.

Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
---

Changes in v3: None
Changes in v2:
  - Added

 arch/arm/mach-uniphier/ph1-pro4/early_clkrst_init.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/mach-uniphier/ph1-pro4/early_clkrst_init.c b/arch/arm/mach-uniphier/ph1-pro4/early_clkrst_init.c
index 6c006f3..e18bf9c 100644
--- a/arch/arm/mach-uniphier/ph1-pro4/early_clkrst_init.c
+++ b/arch/arm/mach-uniphier/ph1-pro4/early_clkrst_init.c
@@ -5,6 +5,8 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#include <common.h>
+#include <spl.h>
 #include <asm/io.h>
 #include <mach/sc-regs.h>
 
@@ -14,7 +16,10 @@ void early_clkrst_init(void)
 
 	/* deassert reset */
 	tmp = readl(SC_RSTCTRL);
+
 	tmp |= SC_RSTCTRL_NRST_UMC1 | SC_RSTCTRL_NRST_UMC0;
+	if (spl_boot_device() != BOOT_DEVICE_NAND)
+		tmp &= ~SC_RSTCTRL_NRST_NAND;
 	writel(tmp, SC_RSTCTRL);
 	readl(SC_RSTCTRL); /* dummy read */
 
-- 
1.9.1