1 /*
2 * Copyright (C) 2014 Broadcom Corporation
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation version 2.
7 *
8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9 * kind, whether express or implied; without even the implied warranty
10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/err.h>
16 #include <linux/clk-provider.h>
17 #include <linux/io.h>
18 #include <linux/of.h>
19 #include <linux/clkdev.h>
20 #include <linux/of_address.h>
21 #include <linux/delay.h>
22
23 #include "clk-iproc.h"
24
25 struct iproc_asiu;
26
27 struct iproc_asiu_clk {
28 struct clk_hw hw;
29 const char *name;
30 struct iproc_asiu *asiu;
31 unsigned long rate;
32 struct iproc_asiu_div div;
33 struct iproc_asiu_gate gate;
34 };
35
36 struct iproc_asiu {
37 void __iomem *div_base;
38 void __iomem *gate_base;
39
40 struct clk_hw_onecell_data *clk_data;
41 struct iproc_asiu_clk *clks;
42 };
43
44 #define to_asiu_clk(hw) container_of(hw, struct iproc_asiu_clk, hw)
45
iproc_asiu_clk_enable(struct clk_hw * hw)46 static int iproc_asiu_clk_enable(struct clk_hw *hw)
47 {
48 struct iproc_asiu_clk *clk = to_asiu_clk(hw);
49 struct iproc_asiu *asiu = clk->asiu;
50 u32 val;
51
52 /* some clocks at the ASIU level are always enabled */
53 if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
54 return 0;
55
56 val = readl(asiu->gate_base + clk->gate.offset);
57 val |= (1 << clk->gate.en_shift);
58 writel(val, asiu->gate_base + clk->gate.offset);
59
60 return 0;
61 }
62
iproc_asiu_clk_disable(struct clk_hw * hw)63 static void iproc_asiu_clk_disable(struct clk_hw *hw)
64 {
65 struct iproc_asiu_clk *clk = to_asiu_clk(hw);
66 struct iproc_asiu *asiu = clk->asiu;
67 u32 val;
68
69 /* some clocks at the ASIU level are always enabled */
70 if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
71 return;
72
73 val = readl(asiu->gate_base + clk->gate.offset);
74 val &= ~(1 << clk->gate.en_shift);
75 writel(val, asiu->gate_base + clk->gate.offset);
76 }
77
iproc_asiu_clk_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)78 static unsigned long iproc_asiu_clk_recalc_rate(struct clk_hw *hw,
79 unsigned long parent_rate)
80 {
81 struct iproc_asiu_clk *clk = to_asiu_clk(hw);
82 struct iproc_asiu *asiu = clk->asiu;
83 u32 val;
84 unsigned int div_h, div_l;
85
86 if (parent_rate == 0) {
87 clk->rate = 0;
88 return 0;
89 }
90
91 /* if clock divisor is not enabled, simply return parent rate */
92 val = readl(asiu->div_base + clk->div.offset);
93 if ((val & (1 << clk->div.en_shift)) == 0) {
94 clk->rate = parent_rate;
95 return parent_rate;
96 }
97
98 /* clock rate = parent rate / (high_div + 1) + (low_div + 1) */
99 div_h = (val >> clk->div.high_shift) & bit_mask(clk->div.high_width);
100 div_h++;
101 div_l = (val >> clk->div.low_shift) & bit_mask(clk->div.low_width);
102 div_l++;
103
104 clk->rate = parent_rate / (div_h + div_l);
105 pr_debug("%s: rate: %lu. parent rate: %lu div_h: %u div_l: %u\n",
106 __func__, clk->rate, parent_rate, div_h, div_l);
107
108 return clk->rate;
109 }
110
iproc_asiu_clk_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)111 static long iproc_asiu_clk_round_rate(struct clk_hw *hw, unsigned long rate,
112 unsigned long *parent_rate)
113 {
114 unsigned int div;
115
116 if (rate == 0 || *parent_rate == 0)
117 return -EINVAL;
118
119 if (rate == *parent_rate)
120 return *parent_rate;
121
122 div = DIV_ROUND_CLOSEST(*parent_rate, rate);
123 if (div < 2)
124 return *parent_rate;
125
126 return *parent_rate / div;
127 }
128
iproc_asiu_clk_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)129 static int iproc_asiu_clk_set_rate(struct clk_hw *hw, unsigned long rate,
130 unsigned long parent_rate)
131 {
132 struct iproc_asiu_clk *clk = to_asiu_clk(hw);
133 struct iproc_asiu *asiu = clk->asiu;
134 unsigned int div, div_h, div_l;
135 u32 val;
136
137 if (rate == 0 || parent_rate == 0)
138 return -EINVAL;
139
140 /* simply disable the divisor if one wants the same rate as parent */
141 if (rate == parent_rate) {
142 val = readl(asiu->div_base + clk->div.offset);
143 val &= ~(1 << clk->div.en_shift);
144 writel(val, asiu->div_base + clk->div.offset);
145 return 0;
146 }
147
148 div = DIV_ROUND_CLOSEST(parent_rate, rate);
149 if (div < 2)
150 return -EINVAL;
151
152 div_h = div_l = div >> 1;
153 div_h--;
154 div_l--;
155
156 val = readl(asiu->div_base + clk->div.offset);
157 val |= 1 << clk->div.en_shift;
158 if (div_h) {
159 val &= ~(bit_mask(clk->div.high_width)
160 << clk->div.high_shift);
161 val |= div_h << clk->div.high_shift;
162 } else {
163 val &= ~(bit_mask(clk->div.high_width)
164 << clk->div.high_shift);
165 }
166 if (div_l) {
167 val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
168 val |= div_l << clk->div.low_shift;
169 } else {
170 val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
171 }
172 writel(val, asiu->div_base + clk->div.offset);
173
174 return 0;
175 }
176
177 static const struct clk_ops iproc_asiu_ops = {
178 .enable = iproc_asiu_clk_enable,
179 .disable = iproc_asiu_clk_disable,
180 .recalc_rate = iproc_asiu_clk_recalc_rate,
181 .round_rate = iproc_asiu_clk_round_rate,
182 .set_rate = iproc_asiu_clk_set_rate,
183 };
184
iproc_asiu_setup(struct device_node * node,const struct iproc_asiu_div * div,const struct iproc_asiu_gate * gate,unsigned int num_clks)185 void __init iproc_asiu_setup(struct device_node *node,
186 const struct iproc_asiu_div *div,
187 const struct iproc_asiu_gate *gate,
188 unsigned int num_clks)
189 {
190 int i, ret;
191 struct iproc_asiu *asiu;
192
193 if (WARN_ON(!gate || !div))
194 return;
195
196 asiu = kzalloc(sizeof(*asiu), GFP_KERNEL);
197 if (WARN_ON(!asiu))
198 return;
199
200 asiu->clk_data = kzalloc(struct_size(asiu->clk_data, hws, num_clks),
201 GFP_KERNEL);
202 if (WARN_ON(!asiu->clk_data))
203 goto err_clks;
204 asiu->clk_data->num = num_clks;
205
206 asiu->clks = kcalloc(num_clks, sizeof(*asiu->clks), GFP_KERNEL);
207 if (WARN_ON(!asiu->clks))
208 goto err_asiu_clks;
209
210 asiu->div_base = of_iomap(node, 0);
211 if (WARN_ON(!asiu->div_base))
212 goto err_iomap_div;
213
214 asiu->gate_base = of_iomap(node, 1);
215 if (WARN_ON(!asiu->gate_base))
216 goto err_iomap_gate;
217
218 for (i = 0; i < num_clks; i++) {
219 struct clk_init_data init;
220 const char *parent_name;
221 struct iproc_asiu_clk *asiu_clk;
222 const char *clk_name;
223
224 ret = of_property_read_string_index(node, "clock-output-names",
225 i, &clk_name);
226 if (WARN_ON(ret))
227 goto err_clk_register;
228
229 asiu_clk = &asiu->clks[i];
230 asiu_clk->name = clk_name;
231 asiu_clk->asiu = asiu;
232 asiu_clk->div = div[i];
233 asiu_clk->gate = gate[i];
234 init.name = clk_name;
235 init.ops = &iproc_asiu_ops;
236 init.flags = 0;
237 parent_name = of_clk_get_parent_name(node, 0);
238 init.parent_names = (parent_name ? &parent_name : NULL);
239 init.num_parents = (parent_name ? 1 : 0);
240 asiu_clk->hw.init = &init;
241
242 ret = clk_hw_register(NULL, &asiu_clk->hw);
243 if (WARN_ON(ret))
244 goto err_clk_register;
245 asiu->clk_data->hws[i] = &asiu_clk->hw;
246 }
247
248 ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
249 asiu->clk_data);
250 if (WARN_ON(ret))
251 goto err_clk_register;
252
253 return;
254
255 err_clk_register:
256 while (--i >= 0)
257 clk_hw_unregister(asiu->clk_data->hws[i]);
258 iounmap(asiu->gate_base);
259
260 err_iomap_gate:
261 iounmap(asiu->div_base);
262
263 err_iomap_div:
264 kfree(asiu->clks);
265
266 err_asiu_clks:
267 kfree(asiu->clk_data);
268
269 err_clks:
270 kfree(asiu);
271 }
272