reset: hisilicon: add reset controller driver for hisilicon SOCs

In most of hisilicon SOCs, reset controller and clock provider are
combined together as a block named CRG (Clock and Reset Generator).
This patch mainly implements the reset function.

Signed-off-by: Jiancheng Xue <xuejiancheng@hisilicon.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/drivers/clk/hisilicon/reset.c b/drivers/clk/hisilicon/reset.c
new file mode 100644
index 000000000000..6aa49c2204d0
--- /dev/null
+++ b/drivers/clk/hisilicon/reset.c
@@ -0,0 +1,134 @@
+/*
+ * Hisilicon Reset Controller Driver
+ *
+ * Copyright (c) 2015-2016 HiSilicon Technologies Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include "reset.h"
+
+#define	HISI_RESET_BIT_MASK	0x1f
+#define	HISI_RESET_OFFSET_SHIFT	8
+#define	HISI_RESET_OFFSET_MASK	0xffff00
+
+struct hisi_reset_controller {
+	spinlock_t	lock;
+	void __iomem	*membase;
+	struct reset_controller_dev	rcdev;
+};
+
+
+#define to_hisi_reset_controller(rcdev)  \
+	container_of(rcdev, struct hisi_reset_controller, rcdev)
+
+static int hisi_reset_of_xlate(struct reset_controller_dev *rcdev,
+			const struct of_phandle_args *reset_spec)
+{
+	u32 offset;
+	u8 bit;
+
+	offset = (reset_spec->args[0] << HISI_RESET_OFFSET_SHIFT)
+		& HISI_RESET_OFFSET_MASK;
+	bit = reset_spec->args[1] & HISI_RESET_BIT_MASK;
+
+	return (offset | bit);
+}
+
+static int hisi_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
+	unsigned long flags;
+	u32 offset, reg;
+	u8 bit;
+
+	offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
+	bit = id & HISI_RESET_BIT_MASK;
+
+	spin_lock_irqsave(&rstc->lock, flags);
+
+	reg = readl(rstc->membase + offset);
+	writel(reg | BIT(bit), rstc->membase + offset);
+
+	spin_unlock_irqrestore(&rstc->lock, flags);
+
+	return 0;
+}
+
+static int hisi_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	struct hisi_reset_controller *rstc = to_hisi_reset_controller(rcdev);
+	unsigned long flags;
+	u32 offset, reg;
+	u8 bit;
+
+	offset = (id & HISI_RESET_OFFSET_MASK) >> HISI_RESET_OFFSET_SHIFT;
+	bit = id & HISI_RESET_BIT_MASK;
+
+	spin_lock_irqsave(&rstc->lock, flags);
+
+	reg = readl(rstc->membase + offset);
+	writel(reg & ~BIT(bit), rstc->membase + offset);
+
+	spin_unlock_irqrestore(&rstc->lock, flags);
+
+	return 0;
+}
+
+static const struct reset_control_ops hisi_reset_ops = {
+	.assert		= hisi_reset_assert,
+	.deassert	= hisi_reset_deassert,
+};
+
+struct hisi_reset_controller *hisi_reset_init(struct device_node *np)
+{
+	struct hisi_reset_controller *rstc;
+
+	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
+	if (!rstc)
+		return NULL;
+
+	rstc->membase = of_iomap(np, 0);
+	if (!rstc->membase) {
+		kfree(rstc);
+		return NULL;
+	}
+
+	spin_lock_init(&rstc->lock);
+
+	rstc->rcdev.owner = THIS_MODULE;
+	rstc->rcdev.ops = &hisi_reset_ops;
+	rstc->rcdev.of_node = np;
+	rstc->rcdev.of_reset_n_cells = 2;
+	rstc->rcdev.of_xlate = hisi_reset_of_xlate;
+	reset_controller_register(&rstc->rcdev);
+
+	return rstc;
+}
+EXPORT_SYMBOL_GPL(hisi_reset_init);
+
+void hisi_reset_exit(struct hisi_reset_controller *rstc)
+{
+	reset_controller_unregister(&rstc->rcdev);
+	iounmap(rstc->membase);
+	kfree(rstc);
+}
+EXPORT_SYMBOL_GPL(hisi_reset_exit);