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6#include <linux/kernel.h>
7#include <linux/io.h>
8#include <linux/err.h>
9#include <linux/slab.h>
10#include <linux/clk-provider.h>
11
12#include "clk.h"
13
14#define pll_out_override(p) (BIT((p->shift - 6)))
15#define div_mask(d) ((1 << (d->width)) - 1)
16#define get_mul(d) (1 << d->frac_width)
17#define get_max_div(d) div_mask(d)
18
19#define PERIPH_CLK_UART_DIV_ENB BIT(24)
20
21static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate,
22 unsigned long parent_rate)
23{
24 int div;
25
26 div = div_frac_get(rate, parent_rate, divider->width,
27 divider->frac_width, divider->flags);
28
29 if (div < 0)
30 return 0;
31
32 return div;
33}
34
35static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
36 unsigned long parent_rate)
37{
38 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
39 u32 reg;
40 int div, mul;
41 u64 rate = parent_rate;
42
43 reg = readl_relaxed(divider->reg);
44
45 if ((divider->flags & TEGRA_DIVIDER_UART) &&
46 !(reg & PERIPH_CLK_UART_DIV_ENB))
47 return rate;
48
49 div = (reg >> divider->shift) & div_mask(divider);
50
51 mul = get_mul(divider);
52 div += mul;
53
54 rate *= mul;
55 rate += div - 1;
56 do_div(rate, div);
57
58 return rate;
59}
60
61static long clk_frac_div_round_rate(struct clk_hw *hw, unsigned long rate,
62 unsigned long *prate)
63{
64 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
65 int div, mul;
66 unsigned long output_rate = *prate;
67
68 if (!rate)
69 return output_rate;
70
71 div = get_div(divider, rate, output_rate);
72 if (div < 0)
73 return *prate;
74
75 mul = get_mul(divider);
76
77 return DIV_ROUND_UP(output_rate * mul, div + mul);
78}
79
80static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
81 unsigned long parent_rate)
82{
83 struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
84 int div;
85 unsigned long flags = 0;
86 u32 val;
87
88 div = get_div(divider, rate, parent_rate);
89 if (div < 0)
90 return div;
91
92 if (divider->lock)
93 spin_lock_irqsave(divider->lock, flags);
94
95 val = readl_relaxed(divider->reg);
96 val &= ~(div_mask(divider) << divider->shift);
97 val |= div << divider->shift;
98
99 if (divider->flags & TEGRA_DIVIDER_UART) {
100 if (div)
101 val |= PERIPH_CLK_UART_DIV_ENB;
102 else
103 val &= ~PERIPH_CLK_UART_DIV_ENB;
104 }
105
106 if (divider->flags & TEGRA_DIVIDER_FIXED)
107 val |= pll_out_override(divider);
108
109 writel_relaxed(val, divider->reg);
110
111 if (divider->lock)
112 spin_unlock_irqrestore(divider->lock, flags);
113
114 return 0;
115}
116
117static void clk_divider_restore_context(struct clk_hw *hw)
118{
119 struct clk_hw *parent = clk_hw_get_parent(hw);
120 unsigned long parent_rate = clk_hw_get_rate(parent);
121 unsigned long rate = clk_hw_get_rate(hw);
122
123 if (clk_frac_div_set_rate(hw, rate, parent_rate) < 0)
124 WARN_ON(1);
125}
126
127const struct clk_ops tegra_clk_frac_div_ops = {
128 .recalc_rate = clk_frac_div_recalc_rate,
129 .set_rate = clk_frac_div_set_rate,
130 .round_rate = clk_frac_div_round_rate,
131 .restore_context = clk_divider_restore_context,
132};
133
134struct clk *tegra_clk_register_divider(const char *name,
135 const char *parent_name, void __iomem *reg,
136 unsigned long flags, u8 clk_divider_flags, u8 shift, u8 width,
137 u8 frac_width, spinlock_t *lock)
138{
139 struct tegra_clk_frac_div *divider;
140 struct clk *clk;
141 struct clk_init_data init;
142
143 divider = kzalloc(sizeof(*divider), GFP_KERNEL);
144 if (!divider) {
145 pr_err("%s: could not allocate fractional divider clk\n",
146 __func__);
147 return ERR_PTR(-ENOMEM);
148 }
149
150 init.name = name;
151 init.ops = &tegra_clk_frac_div_ops;
152 init.flags = flags;
153 init.parent_names = parent_name ? &parent_name : NULL;
154 init.num_parents = parent_name ? 1 : 0;
155
156 divider->reg = reg;
157 divider->shift = shift;
158 divider->width = width;
159 divider->frac_width = frac_width;
160 divider->lock = lock;
161 divider->flags = clk_divider_flags;
162
163
164 divider->hw.init = &init;
165
166 clk = clk_register(NULL, ÷r->hw);
167 if (IS_ERR(clk))
168 kfree(divider);
169
170 return clk;
171}
172
173static const struct clk_div_table mc_div_table[] = {
174 { .val = 0, .div = 2 },
175 { .val = 1, .div = 1 },
176 { .val = 0, .div = 0 },
177};
178
179struct clk *tegra_clk_register_mc(const char *name, const char *parent_name,
180 void __iomem *reg, spinlock_t *lock)
181{
182 return clk_register_divider_table(NULL, name, parent_name,
183 CLK_IS_CRITICAL,
184 reg, 16, 1, CLK_DIVIDER_READ_ONLY,
185 mc_div_table, lock);
186}
187
