[PATCH v1] reset: npcm: Add support for Nuvoton NPCM BMC family

[Jim Liu]

Add reset controller driver for Nuvoton BMCs.
The npcm reset driver not only supports reset each module reset
but setting initial value of reset Control Registers.

And The driver support each module reset.

Signed-off-by: Jim Liu <JJLIU0 at nuvoton.com>
---
 drivers/reset/Kconfig      |   7 ++
 drivers/reset/Makefile     |   1 +
 drivers/reset/reset-npcm.c | 133 +++++++++++++++++++++++++++++++++++++
 3 files changed, 141 insertions(+)
 create mode 100644 drivers/reset/reset-npcm.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 73bbd30692..ccd4182682 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -114,6 +114,13 @@ config RESET_MESON
 	help
 	  Support for reset controller on Amlogic Meson SoC.
 
+config RESET_NPCM
+	bool "Reset controller driver for Nuvoton BMCs"
+	depends on DM_RESET && ARCH_NPCM
+	default y
+	help
+	  Support for reset controller on Nuvotom BMCs.
+
 config RESET_SOCFPGA
 	bool "Reset controller driver for SoCFPGA"
 	depends on DM_RESET && ARCH_SOCFPGA
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index e2239a250a..8cc947fc34 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_RESET_AST2500) += reset-ast2500.o
 obj-$(CONFIG_RESET_AST2600) += reset-ast2600.o
 obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o rst-rk3588.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
+obj-$(CONFIG_RESET_NPCM) += reset-npcm.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_MEDIATEK) += reset-mediatek.o
 obj-$(CONFIG_RESET_MTMIPS) += reset-mtmips.o
diff --git a/drivers/reset/reset-npcm.c b/drivers/reset/reset-npcm.c
new file mode 100644
index 0000000000..d8d629b28e
--- /dev/null
+++ b/drivers/reset/reset-npcm.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Nuvoton Technology Corp.
+ */
+
+#include <dm.h>
+#include <reset-uclass.h>
+#include <asm/io.h>
+#include <dm/device_compat.h>
+
+struct npcm_reset_priv {
+	void __iomem *base;
+};
+
+static int npcm_reset_request(struct reset_ctl *rst)
+{
+	return 0;
+}
+
+static int npcm_reset_free(struct reset_ctl *rst)
+{
+	return 0;
+}
+
+static int npcm_reset_assert(struct reset_ctl *rst)
+{
+	struct npcm_reset_priv *priv = dev_get_priv(rst->dev);
+	u32 val;
+
+	debug("%s: id 0x%lx, data %ld\n", __func__, rst->id, rst->data);
+	val = readl(priv->base + rst->id);
+	val |= BIT(rst->data);
+	writel(val, priv->base + rst->id);
+
+	return 0;
+}
+
+static int npcm_reset_deassert(struct reset_ctl *rst)
+{
+	struct npcm_reset_priv *priv = dev_get_priv(rst->dev);
+	u32 val;
+
+	debug("%s: id 0x%lx, data %ld\n", __func__, rst->id, rst->data);
+	val = readl(priv->base + rst->id);
+	val &= ~BIT(rst->data);
+	writel(val, priv->base + rst->id);
+
+	return 0;
+}
+
+static int npcm_reset_xlate(struct reset_ctl *rst,
+			    struct ofnode_phandle_args *args)
+{
+	if (args->args_count != 2) {
+		dev_err(rst->dev, "Invalid args_count: %d\n", args->args_count);
+		return -EINVAL;
+	}
+
+	/* Use id field as register offset and data field as reset bit positiion */
+	rst->id = args->args[0];
+	rst->data = args->args[1];
+
+	return 0;
+}
+
+static int npcm_reset_bind(struct udevice *dev)
+{
+	struct npcm_reset_priv *priv = dev_get_priv(dev);
+	u32 *rcr_values;
+	int num_fields;
+	u32 reg, val;
+	int ret, i;
+
+	priv->base = dev_remap_addr(dev);
+	if (!priv->base)
+		return -EINVAL;
+
+	/*
+	 * Set RCR initial value
+	 * The rcr-initial-values cell is <reg_offset val>
+	 */
+	num_fields = dev_read_size(dev, "rcr-initial-values");
+	if (num_fields < 2)
+		return 0;
+
+	num_fields /= sizeof(u32);
+	if (num_fields % 2)
+		return -EINVAL;
+
+	num_fields = num_fields / 2;
+	rcr_values = malloc(num_fields * 2 * sizeof(u32));
+	if (!rcr_values)
+		return -ENOMEM;
+
+	ret = dev_read_u32_array(dev, "rcr-initial-values", rcr_values,
+				 num_fields * 2);
+	if (ret < 0) {
+		free(rcr_values);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num_fields; i++) {
+		reg = rcr_values[2 * i];
+		val = rcr_values[2 * i + 1];
+		writel(val, priv->base + reg);
+	}
+	free(rcr_values);
+
+	return 0;
+}
+
+static const struct udevice_id npcm_reset_ids[] = {
+	{ .compatible = "nuvoton,npcm845-reset" },
+	{ .compatible = "nuvoton,npcm750-reset" },
+	{ }
+};
+
+struct reset_ops npcm_reset_ops = {
+	.request = npcm_reset_request,
+	.rfree = npcm_reset_free,
+	.rst_assert = npcm_reset_assert,
+	.rst_deassert = npcm_reset_deassert,
+	.of_xlate = npcm_reset_xlate,
+};
+
+U_BOOT_DRIVER(npcm_reset) = {
+	.name = "npcm_reset",
+	.id = UCLASS_RESET,
+	.of_match = npcm_reset_ids,
+	.bind = npcm_reset_bind,
+	.ops = &npcm_reset_ops,
+	.priv_auto = sizeof(struct npcm_reset_priv),
+};
-- 
2.25.1