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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2018 Fuzhou Rockchip Electronics Co., Ltd
*/
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/slab.h>
#include "clk.h"
#define div_mask(width) ((1 << (width)) - 1)
static bool _is_best_half_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 unsigned long clk_half_divider_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
unsigned int val;
val = readl(divider->reg) >> divider->shift;
val &= div_mask(divider->width);
val = val * 2 + 3;
return DIV_ROUND_UP_ULL(((u64)parent_rate * 2), val);
}
static int clk_half_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate, u8 width,
unsigned long flags)
{
unsigned 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 = div_mask(width);
if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
parent_rate = *best_parent_rate;
bestdiv = DIV_ROUND_UP_ULL(((u64)parent_rate * 2), rate);
if (bestdiv < 3)
bestdiv = 0;
else
bestdiv = (bestdiv - 3) / 2;
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 = 0; i <= maxdiv; i++) {
if (((u64)rate * (i * 2 + 3)) == ((u64)parent_rate_saved * 2)) {
/*
* 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(clk_hw_get_parent(hw),
((u64)rate * (i * 2 + 3)) / 2);
now = DIV_ROUND_UP_ULL(((u64)parent_rate * 2),
(i * 2 + 3));
if (_is_best_half_div(rate, now, best, flags)) {
bestdiv = i;
best = now;
*best_parent_rate = parent_rate;
}
}
if (!bestdiv) {
bestdiv = div_mask(width);
*best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), 1);
}
return bestdiv;
}
static long clk_half_divider_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_divider *divider = to_clk_divider(hw);
int div;
div = clk_half_divider_bestdiv(hw, rate, prate,
divider->width,
divider->flags);
return DIV_ROUND_UP_ULL(((u64)*prate * 2), div * 2 + 3);
}
static int clk_half_divider_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_divider *divider = to_clk_divider(hw);
unsigned int value;
unsigned long flags = 0;
u32 val;
value = DIV_ROUND_UP_ULL(((u64)parent_rate * 2), rate);
value = (value - 3) / 2;
value = min_t(unsigned int, value, div_mask(divider->width));
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
else
__acquire(divider->lock);
if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
val = div_mask(divider->width) << (divider->shift + 16);
} else {
val = readl(divider->reg);
val &= ~(div_mask(divider->width) << divider->shift);
}
val |= value << divider->shift;
writel(val, divider->reg);
if (divider->lock)
spin_unlock_irqrestore(divider->lock, flags);
else
__release(divider->lock);
return 0;
}
const struct clk_ops clk_half_divider_ops = {
.recalc_rate = clk_half_divider_recalc_rate,
.round_rate = clk_half_divider_round_rate,
.set_rate = clk_half_divider_set_rate,
};
EXPORT_SYMBOL_GPL(clk_half_divider_ops);
/**
* Register a clock branch.
* Most clock branches have a form like
*
* src1 --|--\
* |M |--[GATE]-[DIV]-
* src2 --|--/
*
* sometimes without one of those components.
*/
struct clk *rockchip_clk_register_halfdiv(const char *name,
const char *const *parent_names,
u8 num_parents, void __iomem *base,
int muxdiv_offset, u8 mux_shift,
u8 mux_width, u8 mux_flags,
u8 div_shift, u8 div_width,
u8 div_flags, int gate_offset,
u8 gate_shift, u8 gate_flags,
unsigned long flags,
spinlock_t *lock)
{
struct clk *clk;
struct clk_mux *mux = NULL;
struct clk_gate *gate = NULL;
struct clk_divider *div = NULL;
const struct clk_ops *mux_ops = NULL, *div_ops = NULL,
*gate_ops = NULL;
if (num_parents > 1) {
mux = kzalloc(sizeof(*mux), GFP_KERNEL);
if (!mux)
return ERR_PTR(-ENOMEM);
mux->reg = base + muxdiv_offset;
mux->shift = mux_shift;
mux->mask = BIT(mux_width) - 1;
mux->flags = mux_flags;
mux->lock = lock;
mux_ops = (mux_flags & CLK_MUX_READ_ONLY) ? &clk_mux_ro_ops
: &clk_mux_ops;
}
if (gate_offset >= 0) {
gate = kzalloc(sizeof(*gate), GFP_KERNEL);
if (!gate)
goto err_gate;
gate->flags = gate_flags;
gate->reg = base + gate_offset;
gate->bit_idx = gate_shift;
gate->lock = lock;
gate_ops = &clk_gate_ops;
}
if (div_width > 0) {
div = kzalloc(sizeof(*div), GFP_KERNEL);
if (!div)
goto err_div;
div->flags = div_flags;
div->reg = base + muxdiv_offset;
div->shift = div_shift;
div->width = div_width;
div->lock = lock;
div_ops = &clk_half_divider_ops;
}
clk = clk_register_composite(NULL, name, parent_names, num_parents,
mux ? &mux->hw : NULL, mux_ops,
div ? &div->hw : NULL, div_ops,
gate ? &gate->hw : NULL, gate_ops,
flags);
return clk;
err_div:
kfree(gate);
err_gate:
kfree(mux);
return ERR_PTR(-ENOMEM);
}