reset: add reset driver for HiSilicon platform

It adds a Driver Model compatible reset driver for HiSlicon platform.
The driver implements a custom .of_xlate function, and uses .data field
as reset register offset and .id field as bit shift.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

drivers/reset/Kconfig

@@ -121,4 +121,10 @@ config RESET_SUNXI
 	  This enables support for common reset driver for
 	  Allwinner SoCs.
 
+config RESET_HISILICON
+	bool "Reset controller driver for HiSilicon SoCs"
+	depends on DM_RESET
+	help
+	  Support for reset controller on HiSilicon SoCs.
+
 endmenu

drivers/reset/Makefile

@@ -19,3 +19,4 @@ obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_MEDIATEK) += reset-mediatek.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
+obj-$(CONFIG_RESET_HISILICON) += reset-hisilicon.o

drivers/reset/reset-hisilicon.c

@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#include <asm/io.h>
+#include <common.h>
+#include <dm.h>
+#include <dt-bindings/reset/ti-syscon.h>
+#include <reset-uclass.h>
+
+struct hisi_reset_priv {
+	void __iomem *base;
+};
+
+static int hisi_reset_deassert(struct reset_ctl *rst)
+{
+	struct hisi_reset_priv *priv = dev_get_priv(rst->dev);
+	u32 val;
+
+	val = readl(priv->base + rst->data);
+	if (rst->polarity & DEASSERT_SET)
+		val |= BIT(rst->id);
+	else
+		val &= ~BIT(rst->id);
+	writel(val, priv->base + rst->data);
+
+	return 0;
+}
+
+static int hisi_reset_assert(struct reset_ctl *rst)
+{
+	struct hisi_reset_priv *priv = dev_get_priv(rst->dev);
+	u32 val;
+
+	val = readl(priv->base + rst->data);
+	if (rst->polarity & ASSERT_SET)
+		val |= BIT(rst->id);
+	else
+		val &= ~BIT(rst->id);
+	writel(val, priv->base + rst->data);
+
+	return 0;
+}
+
+static int hisi_reset_free(struct reset_ctl *rst)
+{
+	return 0;
+}
+
+static int hisi_reset_request(struct reset_ctl *rst)
+{
+	return 0;
+}
+
+static int hisi_reset_of_xlate(struct reset_ctl *rst,
+			       struct ofnode_phandle_args *args)
+{
+	if (args->args_count != 3) {
+		debug("Invalid args_count: %d\n", args->args_count);
+		return -EINVAL;
+	}
+
+	/* Use .data field as register offset and .id field as bit shift */
+	rst->data = args->args[0];
+	rst->id = args->args[1];
+	rst->polarity = args->args[2];
+
+	return 0;
+}
+
+static const struct reset_ops hisi_reset_reset_ops = {
+	.of_xlate = hisi_reset_of_xlate,
+	.request = hisi_reset_request,
+	.free = hisi_reset_free,
+	.rst_assert = hisi_reset_assert,
+	.rst_deassert = hisi_reset_deassert,
+};
+
+static const struct udevice_id hisi_reset_ids[] = {
+	{ .compatible = "hisilicon,hi3798cv200-reset" },
+	{ }
+};
+
+static int hisi_reset_probe(struct udevice *dev)
+{
+	struct hisi_reset_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_remap_addr(dev);
+	if (!priv->base)
+		return -ENOMEM;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(hisi_reset) = {
+	.name = "hisilicon_reset",
+	.id = UCLASS_RESET,
+	.of_match = hisi_reset_ids,
+	.ops = &hisi_reset_reset_ops,
+	.probe = hisi_reset_probe,
+	.priv_auto_alloc_size = sizeof(struct hisi_reset_priv),
+};