drivers/clk/zynqmp/divider.c - kernel/common - Git at Google

 // 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)
  */
 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_warn_once("%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_warn_once("%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_warn_once("%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,
 };

 /**
  * 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];
 }

 /**
  * 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;
 	init.ops = &zynqmp_clk_divider_ops;
 	/* CLK_FRAC is not defined in the common clk framework */
 	init.flags = nodes->flag & ~CLK_FRAC;
 	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 = 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;
 }
	// 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)
	*/
	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_warn_once("%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_warn_once("%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_warn_once("%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,
	};

	/**
	* 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];
	}

	/**
	* 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;
	init.ops = &zynqmp_clk_divider_ops;
	/* CLK_FRAC is not defined in the common clk framework */
	init.flags = nodes->flag & ~CLK_FRAC;
	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 = 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;
	}