1 files changed, 689 insertions, 0 deletions

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
new file mode 100644
index 000000000..a2c2b5203
--- /dev/null
+++ b/drivers/clk/clk-divider.c
@@ -0,0 +1,689 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * Adjustable divider clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/log2.h>
+
+/*
+ * DOC: basic adjustable divider clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable.  clk->rate = ceiling(parent->rate / divisor)
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+static inline u32 clk_div_readl(struct clk_divider *divider)
+{
+	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+		return ioread32be(divider->reg);
+
+	return readl(divider->reg);
+}
+
+static inline void clk_div_writel(struct clk_divider *divider, u32 val)
+{
+	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+		iowrite32be(val, divider->reg);
+	else
+		writel(val, divider->reg);
+}
+
+static unsigned int _get_table_maxdiv(const struct clk_div_table *table,
+				      u8 width)
+{
+	unsigned int maxdiv = 0, mask = clk_div_mask(width);
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div > maxdiv && clkt->val <= mask)
+			maxdiv = clkt->div;
+	return maxdiv;
+}
+
+static unsigned int _get_table_mindiv(const struct clk_div_table *table)
+{
+	unsigned int mindiv = UINT_MAX;
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div < mindiv)
+			mindiv = clkt->div;
+	return mindiv;
+}
+
+static unsigned int _get_maxdiv(const struct clk_div_table *table, u8 width,
+				unsigned long flags)
+{
+	if (flags & CLK_DIVIDER_ONE_BASED)
+		return clk_div_mask(width);
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return 1 << clk_div_mask(width);
+	if (table)
+		return _get_table_maxdiv(table, width);
+	return clk_div_mask(width) + 1;
+}
+
+static unsigned int _get_table_div(const struct clk_div_table *table,
+							unsigned int val)
+{
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->val == val)
+			return clkt->div;
+	return 0;
+}
+
+static unsigned int _get_div(const struct clk_div_table *table,
+			     unsigned int val, unsigned long flags, u8 width)
+{
+	if (flags & CLK_DIVIDER_ONE_BASED)
+		return val;
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return 1 << val;
+	if (flags & CLK_DIVIDER_MAX_AT_ZERO)
+		return val ? val : clk_div_mask(width) + 1;
+	if (table)
+		return _get_table_div(table, val);
+	return val + 1;
+}
+
+static unsigned int _get_table_val(const struct clk_div_table *table,
+							unsigned int div)
+{
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div == div)
+			return clkt->val;
+	return 0;
+}
+
+static unsigned int _get_val(const struct clk_div_table *table,
+			     unsigned int div, unsigned long flags, u8 width)
+{
+	if (flags & CLK_DIVIDER_ONE_BASED)
+		return div;
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return __ffs(div);
+	if (flags & CLK_DIVIDER_MAX_AT_ZERO)
+		return (div == clk_div_mask(width) + 1) ? 0 : div;
+	if (table)
+		return  _get_table_val(table, div);
+	return div - 1;
+}
+
+unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
+				  unsigned int val,
+				  const struct clk_div_table *table,
+				  unsigned long flags, unsigned long width)
+{
+	unsigned int div;
+
+	div = _get_div(table, val, flags, width);
+	if (!div) {
+		WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
+			"%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+			clk_hw_get_name(hw));
+		return parent_rate;
+	}
+
+	return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+}
+EXPORT_SYMBOL_GPL(divider_recalc_rate);
+
+static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	unsigned int val;
+
+	val = clk_div_readl(divider) >> divider->shift;
+	val &= clk_div_mask(divider->width);
+
+	return divider_recalc_rate(hw, parent_rate, val, divider->table,
+				   divider->flags, divider->width);
+}
+
+static bool _is_valid_table_div(const struct clk_div_table *table,
+							 unsigned int div)
+{
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div == div)
+			return true;
+	return false;
+}
+
+static bool _is_valid_div(const struct clk_div_table *table, unsigned int div,
+			  unsigned long flags)
+{
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return is_power_of_2(div);
+	if (table)
+		return _is_valid_table_div(table, div);
+	return true;
+}
+
+static int _round_up_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int up = INT_MAX;
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div < div)
+			continue;
+
+		if ((clkt->div - div) < (up - div))
+			up = clkt->div;
+	}
+
+	return up;
+}
+
+static int _round_down_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int down = _get_table_mindiv(table);
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div > div)
+			continue;
+
+		if ((div - clkt->div) < (div - down))
+			down = clkt->div;
+	}
+
+	return down;
+}
+
+static int _div_round_up(const struct clk_div_table *table,
+			 unsigned long parent_rate, unsigned long rate,
+			 unsigned long flags)
+{
+	int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
+
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		div = __roundup_pow_of_two(div);
+	if (table)
+		div = _round_up_table(table, div);
+
+	return div;
+}
+
+static int _div_round_closest(const struct clk_div_table *table,
+			      unsigned long parent_rate, unsigned long rate,
+			      unsigned long flags)
+{
+	int up, down;
+	unsigned long up_rate, down_rate;
+
+	up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
+	down = parent_rate / rate;
+
+	if (flags & CLK_DIVIDER_POWER_OF_TWO) {
+		up = __roundup_pow_of_two(up);
+		down = __rounddown_pow_of_two(down);
+	} else if (table) {
+		up = _round_up_table(table, up);
+		down = _round_down_table(table, down);
+	}
+
+	up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
+	down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
+
+	return (rate - up_rate) <= (down_rate - rate) ? up : down;
+}
+
+static int _div_round(const struct clk_div_table *table,
+		      unsigned long parent_rate, unsigned long rate,
+		      unsigned long flags)
+{
+	if (flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return _div_round_closest(table, parent_rate, rate, flags);
+
+	return _div_round_up(table, parent_rate, rate, flags);
+}
+
+static bool _is_best_div(unsigned long rate, unsigned long now,
+			 unsigned long best, unsigned long flags)
+{
+	if (flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return abs(rate - now) < abs(rate - best);
+
+	return now <= rate && now > best;
+}
+
+static int _next_div(const struct clk_div_table *table, int div,
+		     unsigned long flags)
+{
+	div++;
+
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
+		return __roundup_pow_of_two(div);
+	if (table)
+		return _round_up_table(table, div);
+
+	return div;
+}
+
+static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent,
+			       unsigned long rate,
+			       unsigned long *best_parent_rate,
+			       const struct clk_div_table *table, u8 width,
+			       unsigned long flags)
+{
+	int i, bestdiv = 0;
+	unsigned long parent_rate, best = 0, now, maxdiv;
+	unsigned long parent_rate_saved = *best_parent_rate;
+
+	if (!rate)
+		rate = 1;
+
+	maxdiv = _get_maxdiv(table, width, flags);
+
+	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
+		parent_rate = *best_parent_rate;
+		bestdiv = _div_round(table, parent_rate, rate, flags);
+		bestdiv = bestdiv == 0 ? 1 : bestdiv;
+		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
+		return bestdiv;
+	}
+
+	/*
+	 * The maximum divider we can use without overflowing
+	 * unsigned long in rate * i below
+	 */
+	maxdiv = min(ULONG_MAX / rate, maxdiv);
+
+	for (i = _next_div(table, 0, flags); i <= maxdiv;
+					     i = _next_div(table, i, flags)) {
+		if (rate * i == parent_rate_saved) {
+			/*
+			 * It's the most ideal case if the requested rate can be
+			 * divided from parent clock without needing to change
+			 * parent rate, so return the divider immediately.
+			 */
+			*best_parent_rate = parent_rate_saved;
+			return i;
+		}
+		parent_rate = clk_hw_round_rate(parent, rate * i);
+		now = DIV_ROUND_UP_ULL((u64)parent_rate, i);
+		if (_is_best_div(rate, now, best, flags)) {
+			bestdiv = i;
+			best = now;
+			*best_parent_rate = parent_rate;
+		}
+	}
+
+	if (!bestdiv) {
+		bestdiv = _get_maxdiv(table, width, flags);
+		*best_parent_rate = clk_hw_round_rate(parent, 1);
+	}
+
+	return bestdiv;
+}
+
+int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+			   const struct clk_div_table *table, u8 width,
+			   unsigned long flags)
+{
+	int div;
+
+	div = clk_divider_bestdiv(hw, req->best_parent_hw, req->rate,
+				  &req->best_parent_rate, table, width, flags);
+
+	req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(divider_determine_rate);
+
+int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
+			      const struct clk_div_table *table, u8 width,
+			      unsigned long flags, unsigned int val)
+{
+	int div;
+
+	div = _get_div(table, val, flags, width);
+
+	/* Even a read-only clock can propagate a rate change */
+	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
+		if (!req->best_parent_hw)
+			return -EINVAL;
+
+		req->best_parent_rate = clk_hw_round_rate(req->best_parent_hw,
+							  req->rate * div);
+	}
+
+	req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(divider_ro_determine_rate);
+
+long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
+			       unsigned long rate, unsigned long *prate,
+			       const struct clk_div_table *table,
+			       u8 width, unsigned long flags)
+{
+	struct clk_rate_request req;
+	int ret;
+
+	clk_hw_init_rate_request(hw, &req, rate);
+	req.best_parent_rate = *prate;
+	req.best_parent_hw = parent;
+
+	ret = divider_determine_rate(hw, &req, table, width, flags);
+	if (ret)
+		return ret;
+
+	*prate = req.best_parent_rate;
+
+	return req.rate;
+}
+EXPORT_SYMBOL_GPL(divider_round_rate_parent);
+
+long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
+				  unsigned long rate, unsigned long *prate,
+				  const struct clk_div_table *table, u8 width,
+				  unsigned long flags, unsigned int val)
+{
+	struct clk_rate_request req;
+	int ret;
+
+	clk_hw_init_rate_request(hw, &req, rate);
+	req.best_parent_rate = *prate;
+	req.best_parent_hw = parent;
+
+	ret = divider_ro_determine_rate(hw, &req, table, width, flags, val);
+	if (ret)
+		return ret;
+
+	*prate = req.best_parent_rate;
+
+	return req.rate;
+}
+EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
+
+static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *prate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+
+	/* if read only, just return current value */
+	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
+		u32 val;
+
+		val = clk_div_readl(divider) >> divider->shift;
+		val &= clk_div_mask(divider->width);
+
+		return divider_ro_round_rate(hw, rate, prate, divider->table,
+					     divider->width, divider->flags,
+					     val);
+	}
+
+	return divider_round_rate(hw, rate, prate, divider->table,
+				  divider->width, divider->flags);
+}
+
+static int clk_divider_determine_rate(struct clk_hw *hw,
+				      struct clk_rate_request *req)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+
+	/* if read only, just return current value */
+	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
+		u32 val;
+
+		val = clk_div_readl(divider) >> divider->shift;
+		val &= clk_div_mask(divider->width);
+
+		return divider_ro_determine_rate(hw, req, divider->table,
+						 divider->width,
+						 divider->flags, val);
+	}
+
+	return divider_determine_rate(hw, req, divider->table, divider->width,
+				      divider->flags);
+}
+
+int divider_get_val(unsigned long rate, unsigned long parent_rate,
+		    const struct clk_div_table *table, u8 width,
+		    unsigned long flags)
+{
+	unsigned int div, value;
+
+	div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
+
+	if (!_is_valid_div(table, div, flags))
+		return -EINVAL;
+
+	value = _get_val(table, div, flags, width);
+
+	return min_t(unsigned int, value, clk_div_mask(width));
+}
+EXPORT_SYMBOL_GPL(divider_get_val);
+
+static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	int value;
+	unsigned long flags = 0;
+	u32 val;
+
+	value = divider_get_val(rate, parent_rate, divider->table,
+				divider->width, divider->flags);
+	if (value < 0)
+		return value;
+
+	if (divider->lock)
+		spin_lock_irqsave(divider->lock, flags);
+	else
+		__acquire(divider->lock);
+
+	if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
+		val = clk_div_mask(divider->width) << (divider->shift + 16);
+	} else {
+		val = clk_div_readl(divider);
+		val &= ~(clk_div_mask(divider->width) << divider->shift);
+	}
+	val |= (u32)value << divider->shift;
+	clk_div_writel(divider, val);
+
+	if (divider->lock)
+		spin_unlock_irqrestore(divider->lock, flags);
+	else
+		__release(divider->lock);
+
+	return 0;
+}
+
+const struct clk_ops clk_divider_ops = {
+	.recalc_rate = clk_divider_recalc_rate,
+	.round_rate = clk_divider_round_rate,
+	.determine_rate = clk_divider_determine_rate,
+	.set_rate = clk_divider_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_divider_ops);
+
+const struct clk_ops clk_divider_ro_ops = {
+	.recalc_rate = clk_divider_recalc_rate,
+	.round_rate = clk_divider_round_rate,
+	.determine_rate = clk_divider_determine_rate,
+};
+EXPORT_SYMBOL_GPL(clk_divider_ro_ops);
+
+struct clk_hw *__clk_hw_register_divider(struct device *dev,
+		struct device_node *np, const char *name,
+		const char *parent_name, const struct clk_hw *parent_hw,
+		const struct clk_parent_data *parent_data, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		const struct clk_div_table *table, spinlock_t *lock)
+{
+	struct clk_divider *div;
+	struct clk_hw *hw;
+	struct clk_init_data init = {};
+	int ret;
+
+	if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+		if (width + shift > 16) {
+			pr_warn("divider value exceeds LOWORD field\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* allocate the divider */
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	if (clk_divider_flags & CLK_DIVIDER_READ_ONLY)
+		init.ops = &clk_divider_ro_ops;
+	else
+		init.ops = &clk_divider_ops;
+	init.flags = flags;
+	init.parent_names = parent_name ? &parent_name : NULL;
+	init.parent_hws = parent_hw ? &parent_hw : NULL;
+	init.parent_data = parent_data;
+	if (parent_name || parent_hw || parent_data)
+		init.num_parents = 1;
+	else
+		init.num_parents = 0;
+
+	/* struct clk_divider assignments */
+	div->reg = reg;
+	div->shift = shift;
+	div->width = width;
+	div->flags = clk_divider_flags;
+	div->lock = lock;
+	div->hw.init = &init;
+	div->table = table;
+
+	/* register the clock */
+	hw = &div->hw;
+	ret = clk_hw_register(dev, hw);
+	if (ret) {
+		kfree(div);
+		hw = ERR_PTR(ret);
+	}
+
+	return hw;
+}
+EXPORT_SYMBOL_GPL(__clk_hw_register_divider);
+
+/**
+ * clk_register_divider_table - register a table based divider clock with
+ * the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust divider
+ * @shift: number of bits to shift the bitfield
+ * @width: width of the bitfield
+ * @clk_divider_flags: divider-specific flags for this clock
+ * @table: array of divider/value pairs ending with a div set to 0
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_divider_table(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags, const struct clk_div_table *table,
+		spinlock_t *lock)
+{
+	struct clk_hw *hw;
+
+	hw =  __clk_hw_register_divider(dev, NULL, name, parent_name, NULL,
+			NULL, flags, reg, shift, width, clk_divider_flags,
+			table, lock);
+	if (IS_ERR(hw))
+		return ERR_CAST(hw);
+	return hw->clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_divider_table);
+
+void clk_unregister_divider(struct clk *clk)
+{
+	struct clk_divider *div;
+	struct clk_hw *hw;
+
+	hw = __clk_get_hw(clk);
+	if (!hw)
+		return;
+
+	div = to_clk_divider(hw);
+
+	clk_unregister(clk);
+	kfree(div);
+}
+EXPORT_SYMBOL_GPL(clk_unregister_divider);
+
+/**
+ * clk_hw_unregister_divider - unregister a clk divider
+ * @hw: hardware-specific clock data to unregister
+ */
+void clk_hw_unregister_divider(struct clk_hw *hw)
+{
+	struct clk_divider *div;
+
+	div = to_clk_divider(hw);
+
+	clk_hw_unregister(hw);
+	kfree(div);
+}
+EXPORT_SYMBOL_GPL(clk_hw_unregister_divider);
+
+static void devm_clk_hw_release_divider(struct device *dev, void *res)
+{
+	clk_hw_unregister_divider(*(struct clk_hw **)res);
+}
+
+struct clk_hw *__devm_clk_hw_register_divider(struct device *dev,
+		struct device_node *np, const char *name,
+		const char *parent_name, const struct clk_hw *parent_hw,
+		const struct clk_parent_data *parent_data, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		const struct clk_div_table *table, spinlock_t *lock)
+{
+	struct clk_hw **ptr, *hw;
+
+	ptr = devres_alloc(devm_clk_hw_release_divider, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	hw = __clk_hw_register_divider(dev, np, name, parent_name, parent_hw,
+				       parent_data, flags, reg, shift, width,
+				       clk_divider_flags, table, lock);
+
+	if (!IS_ERR(hw)) {
+		*ptr = hw;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return hw;
+}
+EXPORT_SYMBOL_GPL(__devm_clk_hw_register_divider);