reset: npcm: Add support for Nuvoton NPCM BMC family

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@nuvoton.com>

drivers/reset/Kconfig

@@ -135,6 +135,13 @@ config RESET_MTMIPS
 	help
 	  Support for reset controller on MediaTek MIPS platform.
 
+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_SUNXI
 	bool "RESET support for Allwinner SoCs"
 	depends on DM_RESET && ARCH_SUNXI

drivers/reset/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_MEDIATEK) += reset-mediatek.o
 obj-$(CONFIG_RESET_MTMIPS) += reset-mtmips.o
+obj-$(CONFIG_RESET_NPCM) += reset-npcm.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_RESET_HISILICON) += reset-hisilicon.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o

drivers/reset/reset-npcm.c

@@ -0,0 +1,145 @@
+// 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_probe(struct udevice *dev)
+{
+	struct npcm_reset_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_remap_addr(dev);
+	if (!priv->base)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int npcm_reset_bind(struct udevice *dev)
+{
+	void __iomem *reg_base;
+	u32 *rcr_values;
+	int num_fields;
+	u32 reg, val;
+	int ret, i;
+
+	reg_base = dev_remap_addr(dev);
+	if (!reg_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, reg_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,
+	.probe = npcm_reset_probe,
+	.ops = &npcm_reset_ops,
+	.priv_auto = sizeof(struct npcm_reset_priv),
+};