swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: f40ddce88593482919761f74910f42f4b84c004b authored by Linus Torvalds on 14 February 2021, 22:32:24 UTC
Linux 5.11
Linux 5.11
Tip revision: f40ddce
divider.c
// 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);
}
static void zynqmp_get_divider2_val(struct clk_hw *hw,
unsigned long rate,
struct zynqmp_clk_divider *divider,
int *bestdiv)
{
int div1;
int div2;
long error = LONG_MAX;
unsigned long div1_prate;
struct clk_hw *div1_parent_hw;
struct clk_hw *div2_parent_hw = clk_hw_get_parent(hw);
struct zynqmp_clk_divider *pdivider =
to_zynqmp_clk_divider(div2_parent_hw);
if (!pdivider)
return;
div1_parent_hw = clk_hw_get_parent(div2_parent_hw);
if (!div1_parent_hw)
return;
div1_prate = clk_hw_get_rate(div1_parent_hw);
*bestdiv = 1;
for (div1 = 1; div1 <= pdivider->max_div;) {
for (div2 = 1; div2 <= divider->max_div;) {
long new_error = ((div1_prate / div1) / div2) - rate;
if (abs(new_error) < abs(error)) {
*bestdiv = div2;
error = new_error;
}
if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
div2 = div2 << 1;
else
div2++;
}
if (pdivider->flags & CLK_DIVIDER_POWER_OF_TWO)
div1 = div1 << 1;
else
div1++;
}
}
/**
* 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;
/* 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);
}
bestdiv = zynqmp_divider_get_val(*prate, rate, divider->flags);
/*
* In case of two divisors, compute best divider values and return
* divider2 value based on compute value. div1 will be automatically
* set to optimum based on required total divider value.
*/
if (div_type == TYPE_DIV2 &&
(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
zynqmp_get_divider2_val(hw, rate, divider, &bestdiv);
}
if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && divider->is_frac)
bestdiv = rate % *prate ? 1 : bestdiv;
bestdiv = min_t(u32, bestdiv, divider->max_div);
*prate = rate * bestdiv;
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;
}