1 files changed, 321 insertions, 0 deletions
diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c
new file mode 100644
index 000000000..5a00487ae
--- /dev/null
+++ b/drivers/clk/zynqmp/divider.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Zynq UltraScale+ MPSoC Divider support
+ *
+ *  Copyright (C) 2016-2019 Xilinx
+ *
+ * Adjustable divider clock implementation
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include "clk-zynqmp.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
+ */
+
+#define to_zynqmp_clk_divider(_hw)		\
+	container_of(_hw, struct zynqmp_clk_divider, hw)
+
+#define CLK_FRAC		BIT(13) /* has a fractional parent */
+#define CUSTOM_FLAG_CLK_FRAC	BIT(0) /* has a fractional parent in custom type flag */
+
+/**
+ * struct zynqmp_clk_divider - adjustable divider clock
+ * @hw:		handle between common and hardware-specific interfaces
+ * @flags:	Hardware specific flags
+ * @is_frac:	The divider is a fractional divider
+ * @clk_id:	Id of clock
+ * @div_type:	divisor type (TYPE_DIV1 or TYPE_DIV2)
+ * @max_div:	maximum supported divisor (fetched from firmware)
+ */
+struct zynqmp_clk_divider {
+	struct clk_hw hw;
+	u8 flags;
+	bool is_frac;
+	u32 clk_id;
+	u32 div_type;
+	u16 max_div;
+};
+
+static inline int zynqmp_divider_get_val(unsigned long parent_rate,
+					 unsigned long rate, u16 flags)
+{
+	int up, down;
+	unsigned long up_rate, down_rate;
+
+	if (flags & CLK_DIVIDER_POWER_OF_TWO) {
+		up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
+		down = DIV_ROUND_DOWN_ULL((u64)parent_rate, rate);
+
+		up = __roundup_pow_of_two(up);
+		down = __rounddown_pow_of_two(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;
+
+	} else {
+		return DIV_ROUND_CLOSEST(parent_rate, rate);
+	}
+}
+
+/**
+ * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock
+ * @hw:			handle between common and hardware-specific interfaces
+ * @parent_rate:	rate of parent clock
+ *
+ * Return: 0 on success else error+reason
+ */
+static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
+						    unsigned long parent_rate)
+{
+	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
+	const char *clk_name = clk_hw_get_name(hw);
+	u32 clk_id = divider->clk_id;
+	u32 div_type = divider->div_type;
+	u32 div, value;
+	int ret;
+
+	ret = zynqmp_pm_clock_getdivider(clk_id, &div);
+
+	if (ret)
+		pr_debug("%s() get divider failed for %s, ret = %d\n",
+			 __func__, clk_name, ret);
+
+	if (div_type == TYPE_DIV1)
+		value = div & 0xFFFF;
+	else
+		value = div >> 16;
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		value = 1 << value;
+
+	if (!value) {
+		WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
+		     "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+		     clk_name);
+		return parent_rate;
+	}
+
+	return DIV_ROUND_UP_ULL(parent_rate, value);
+}
+
+/**
+ * zynqmp_clk_divider_round_rate() - Round rate of divider clock
+ * @hw:			handle between common and hardware-specific interfaces
+ * @rate:		rate of clock to be set
+ * @prate:		rate of parent clock
+ *
+ * Return: 0 on success else error+reason
+ */
+static long zynqmp_clk_divider_round_rate(struct clk_hw *hw,
+					  unsigned long rate,
+					  unsigned long *prate)
+{
+	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
+	const char *clk_name = clk_hw_get_name(hw);
+	u32 clk_id = divider->clk_id;
+	u32 div_type = divider->div_type;
+	u32 bestdiv;
+	int ret;
+	u8 width;
+
+	/* if read only, just return current value */
+	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
+		ret = zynqmp_pm_clock_getdivider(clk_id, &bestdiv);
+
+		if (ret)
+			pr_debug("%s() get divider failed for %s, ret = %d\n",
+				 __func__, clk_name, ret);
+		if (div_type == TYPE_DIV1)
+			bestdiv = bestdiv & 0xFFFF;
+		else
+			bestdiv  = bestdiv >> 16;
+
+		if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+			bestdiv = 1 << bestdiv;
+
+		return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
+	}
+
+	width = fls(divider->max_div);
+
+	rate = divider_round_rate(hw, rate, prate, NULL, width, divider->flags);
+
+	if (divider->is_frac && (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && (rate % *prate))
+		*prate = rate;
+
+	return rate;
+}
+
+/**
+ * zynqmp_clk_divider_set_rate() - Set rate of divider clock
+ * @hw:			handle between common and hardware-specific interfaces
+ * @rate:		rate of clock to be set
+ * @parent_rate:	rate of parent clock
+ *
+ * Return: 0 on success else error+reason
+ */
+static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
+				       unsigned long parent_rate)
+{
+	struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw);
+	const char *clk_name = clk_hw_get_name(hw);
+	u32 clk_id = divider->clk_id;
+	u32 div_type = divider->div_type;
+	u32 value, div;
+	int ret;
+
+	value = zynqmp_divider_get_val(parent_rate, rate, divider->flags);
+	if (div_type == TYPE_DIV1) {
+		div = value & 0xFFFF;
+		div |= 0xffff << 16;
+	} else {
+		div = 0xffff;
+		div |= value << 16;
+	}
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		div = __ffs(div);
+
+	ret = zynqmp_pm_clock_setdivider(clk_id, div);
+
+	if (ret)
+		pr_debug("%s() set divider failed for %s, ret = %d\n",
+			 __func__, clk_name, ret);
+
+	return ret;
+}
+
+static const struct clk_ops zynqmp_clk_divider_ops = {
+	.recalc_rate = zynqmp_clk_divider_recalc_rate,
+	.round_rate = zynqmp_clk_divider_round_rate,
+	.set_rate = zynqmp_clk_divider_set_rate,
+};
+
+static const struct clk_ops zynqmp_clk_divider_ro_ops = {
+	.recalc_rate = zynqmp_clk_divider_recalc_rate,
+	.round_rate = zynqmp_clk_divider_round_rate,
+};
+
+/**
+ * zynqmp_clk_get_max_divisor() - Get maximum supported divisor from firmware.
+ * @clk_id:		Id of clock
+ * @type:		Divider type
+ *
+ * Return: Maximum divisor of a clock if query data is successful
+ *	   U16_MAX in case of query data is not success
+ */
+static u32 zynqmp_clk_get_max_divisor(u32 clk_id, u32 type)
+{
+	struct zynqmp_pm_query_data qdata = {0};
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+	int ret;
+
+	qdata.qid = PM_QID_CLOCK_GET_MAX_DIVISOR;
+	qdata.arg1 = clk_id;
+	qdata.arg2 = type;
+	ret = zynqmp_pm_query_data(qdata, ret_payload);
+	/*
+	 * To maintain backward compatibility return maximum possible value
+	 * (0xFFFF) if query for max divisor is not successful.
+	 */
+	if (ret)
+		return U16_MAX;
+
+	return ret_payload[1];
+}
+
+static inline unsigned long zynqmp_clk_map_divider_ccf_flags(
+					       const u32 zynqmp_type_flag)
+{
+	unsigned long ccf_flag = 0;
+
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ONE_BASED)
+		ccf_flag |= CLK_DIVIDER_ONE_BASED;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
+		ccf_flag |= CLK_DIVIDER_POWER_OF_TWO;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ALLOW_ZERO)
+		ccf_flag |= CLK_DIVIDER_ALLOW_ZERO;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_POWER_OF_TWO)
+		ccf_flag |= CLK_DIVIDER_HIWORD_MASK;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_ROUND_CLOSEST)
+		ccf_flag |= CLK_DIVIDER_ROUND_CLOSEST;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_READ_ONLY)
+		ccf_flag |= CLK_DIVIDER_READ_ONLY;
+	if (zynqmp_type_flag & ZYNQMP_CLK_DIVIDER_MAX_AT_ZERO)
+		ccf_flag |= CLK_DIVIDER_MAX_AT_ZERO;
+
+	return ccf_flag;
+}
+
+/**
+ * zynqmp_clk_register_divider() - Register a divider clock
+ * @name:		Name of this clock
+ * @clk_id:		Id of clock
+ * @parents:		Name of this clock's parents
+ * @num_parents:	Number of parents
+ * @nodes:		Clock topology node
+ *
+ * Return: clock hardware to registered clock divider
+ */
+struct clk_hw *zynqmp_clk_register_divider(const char *name,
+					   u32 clk_id,
+					   const char * const *parents,
+					   u8 num_parents,
+					   const struct clock_topology *nodes)
+{
+	struct zynqmp_clk_divider *div;
+	struct clk_hw *hw;
+	struct clk_init_data init;
+	int ret;
+
+	/* allocate the divider */
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	if (nodes->type_flag & CLK_DIVIDER_READ_ONLY)
+		init.ops = &zynqmp_clk_divider_ro_ops;
+	else
+		init.ops = &zynqmp_clk_divider_ops;
+
+	init.flags = zynqmp_clk_map_common_ccf_flags(nodes->flag);
+
+	init.parent_names = parents;
+	init.num_parents = 1;
+
+	/* struct clk_divider assignments */
+	div->is_frac = !!((nodes->flag & CLK_FRAC) |
+			  (nodes->custom_type_flag & CUSTOM_FLAG_CLK_FRAC));
+	div->flags = zynqmp_clk_map_divider_ccf_flags(nodes->type_flag);
+	div->hw.init = &init;
+	div->clk_id = clk_id;
+	div->div_type = nodes->type;
+
+	/*
+	 * To achieve best possible rate, maximum limit of divider is required
+	 * while computation.
+	 */
+	div->max_div = zynqmp_clk_get_max_divisor(clk_id, nodes->type);
+
+	hw = &div->hw;
+	ret = clk_hw_register(NULL, hw);
+	if (ret) {
+		kfree(div);
+		hw = ERR_PTR(ret);
+	}
+
+	return hw;
+}