ARM: uniphier: move NAND reset assertion to U-Boot proper from SPL

The comment /* deassert reset */ is wrong. It asserts the reset.

It no longer needs to stay in SPL. The NAND controller reset is
handled  in the driver. So, this assert can be moved to the
board_init() of U-Boot proper.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/mach-uniphier/Makefile

@@ -22,6 +22,7 @@ endif
 obj-$(CONFIG_MICRO_SUPPORT_CARD) += micro-support-card.o
 obj-y += pinctrl-glue.o
 obj-$(CONFIG_MMC) += mmc-first-dev.o
+obj-$(CONFIG_NAND_DENALI) += nand-reset.o
 obj-y += fdt-fixup.o
 
 endif

arch/arm/mach-uniphier/board_init.c

@@ -141,6 +141,10 @@ int board_init(void)
 
 	support_card_late_init();
 
+	led_puts("U4");
+
+	uniphier_nand_reset_assert();
+
 	led_puts("Uboo");
 
 	return 0;

arch/arm/mach-uniphier/clk/clk-early-ld4.c

@@ -15,13 +15,6 @@ void uniphier_ld4_early_clk_init(void)
 {
 	u32 tmp;
 
-	/* deassert reset */
-	if (spl_boot_device() != BOOT_DEVICE_NAND) {
-		tmp = readl(sc_base + SC_RSTCTRL);
-		tmp &= ~SC_RSTCTRL_NRST_NAND;
-		writel(tmp, sc_base + SC_RSTCTRL);
-	};
-
 	/* provide clocks */
 	tmp = readl(sc_base + SC_CLKCTRL);
 	tmp |= SC_CLKCTRL_CEN_SBC | SC_CLKCTRL_CEN_PERI;

arch/arm/mach-uniphier/init.h

@@ -101,6 +101,14 @@ unsigned int uniphier_boot_device_raw(void);
 int uniphier_have_internal_stm(void);
 int uniphier_boot_from_backend(void);
 int uniphier_pin_init(const char *pinconfig_name);
+
+#ifdef CONFIG_NAND_DENALI
+void uniphier_nand_reset_assert(void);
+#else
+static inline void uniphier_nand_reset_assert(void)
+{
+}
+#endif
 #ifdef CONFIG_ARM64
 void uniphier_mem_map_init(unsigned long dram_base, unsigned long dram_size);
 #else

arch/arm/mach-uniphier/nand-reset.c

+// SPDX-License-Identifier: GPL-2.0 or later
+/*
+ * Copyright (C) 2020 Socionext Inc.
+ *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
+ */
+
+#include <linux/errno.h>
+#include <dm.h>
+#include <dm/uclass-internal.h>
+#include <reset.h>
+
+#include "init.h"
+
+/*
+ * Assert the Denali NAND controller reset if found.
+ *
+ * On LD4, the bootstrap process starts running after power-on reset regardless
+ * of the boot mode, here the pin-mux is not necessarily set up for NAND, then
+ * the controller is stuck. Assert the controller reset here, and should be
+ * deasserted in the driver after the pin-mux is correctly handled. For other
+ * SoCs, the bootstrap runs only when the boot mode selects ONFi, but it is yet
+ * effective when the boot swap is on. So, the reset should be asserted anyway.
+ */
+void uniphier_nand_reset_assert(void)
+{
+	struct udevice *dev;
+	struct reset_ctl_bulk resets;
+	int ret;
+
+	ret = uclass_find_first_device(UCLASS_MTD, &dev);
+	if (ret || !dev)
+		return;
+
+	/* make sure this is the Denali NAND controller */
+	if (strcmp(dev->driver->name, "denali-nand-dt"))
+		return;
+
+	ret = reset_get_bulk(dev, &resets);
+	if (ret)
+		return;
+
+	reset_assert_bulk(&resets);
+}