1 files changed, 43 insertions, 0 deletions
diff --git a/arch/arm/mach-uniphier/nand-reset.c b/arch/arm/mach-uniphier/nand-reset.c
new file mode 100644
index 0000000000..11cadaabd8
--- /dev/null
+++ b/arch/arm/mach-uniphier/nand-reset.c
@@ -0,0 +1,43 @@
+// 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);
+}