Merge branch 'master'
[linux-2.6] / arch / sh / kernel / cpu / clock.c
1 /*
2  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
3  *
4  *  Copyright (C) 2005  Paul Mundt
5  *
6  * This clock framework is derived from the OMAP version by:
7  *
8  *      Copyright (C) 2004 Nokia Corporation
9  *      Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
10  *
11  * This file is subject to the terms and conditions of the GNU General Public
12  * License.  See the file "COPYING" in the main directory of this archive
13  * for more details.
14  */
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/list.h>
19 #include <linux/kref.h>
20 #include <linux/seq_file.h>
21 #include <linux/err.h>
22 #include <asm/clock.h>
23 #include <asm/timer.h>
24
25 static LIST_HEAD(clock_list);
26 static DEFINE_SPINLOCK(clock_lock);
27 static DECLARE_MUTEX(clock_list_sem);
28
29 /*
30  * Each subtype is expected to define the init routines for these clocks,
31  * as each subtype (or processor family) will have these clocks at the
32  * very least. These are all provided through the CPG, which even some of
33  * the more quirky parts (such as ST40, SH4-202, etc.) still have.
34  *
35  * The processor-specific code is expected to register any additional
36  * clock sources that are of interest.
37  */
38 static struct clk master_clk = {
39         .name           = "master_clk",
40         .flags          = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
41         .rate           = CONFIG_SH_PCLK_FREQ,
42 };
43
44 static struct clk module_clk = {
45         .name           = "module_clk",
46         .parent         = &master_clk,
47         .flags          = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
48 };
49
50 static struct clk bus_clk = {
51         .name           = "bus_clk",
52         .parent         = &master_clk,
53         .flags          = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
54 };
55
56 static struct clk cpu_clk = {
57         .name           = "cpu_clk",
58         .parent         = &master_clk,
59         .flags          = CLK_ALWAYS_ENABLED,
60 };
61
62 /*
63  * The ordering of these clocks matters, do not change it.
64  */
65 static struct clk *onchip_clocks[] = {
66         &master_clk,
67         &module_clk,
68         &bus_clk,
69         &cpu_clk,
70 };
71
72 static void propagate_rate(struct clk *clk)
73 {
74         struct clk *clkp;
75
76         list_for_each_entry(clkp, &clock_list, node) {
77                 if (likely(clkp->parent != clk))
78                         continue;
79                 if (likely(clkp->ops && clkp->ops->recalc))
80                         clkp->ops->recalc(clkp);
81         }
82 }
83
84 int __clk_enable(struct clk *clk)
85 {
86         /*
87          * See if this is the first time we're enabling the clock, some
88          * clocks that are always enabled still require "special"
89          * initialization. This is especially true if the clock mode
90          * changes and the clock needs to hunt for the proper set of
91          * divisors to use before it can effectively recalc.
92          */
93         if (unlikely(atomic_read(&clk->kref.refcount) == 1))
94                 if (clk->ops && clk->ops->init)
95                         clk->ops->init(clk);
96
97         if (clk->flags & CLK_ALWAYS_ENABLED)
98                 return 0;
99
100         if (likely(clk->ops && clk->ops->enable))
101                 clk->ops->enable(clk);
102
103         kref_get(&clk->kref);
104         return 0;
105 }
106
107 int clk_enable(struct clk *clk)
108 {
109         unsigned long flags;
110         int ret;
111
112         spin_lock_irqsave(&clock_lock, flags);
113         ret = __clk_enable(clk);
114         spin_unlock_irqrestore(&clock_lock, flags);
115
116         return ret;
117 }
118
119 static void clk_kref_release(struct kref *kref)
120 {
121         /* Nothing to do */
122 }
123
124 void __clk_disable(struct clk *clk)
125 {
126         if (clk->flags & CLK_ALWAYS_ENABLED)
127                 return;
128
129         kref_put(&clk->kref, clk_kref_release);
130 }
131
132 void clk_disable(struct clk *clk)
133 {
134         unsigned long flags;
135
136         spin_lock_irqsave(&clock_lock, flags);
137         __clk_disable(clk);
138         spin_unlock_irqrestore(&clock_lock, flags);
139 }
140
141 int clk_register(struct clk *clk)
142 {
143         down(&clock_list_sem);
144
145         list_add(&clk->node, &clock_list);
146         kref_init(&clk->kref);
147
148         up(&clock_list_sem);
149
150         return 0;
151 }
152
153 void clk_unregister(struct clk *clk)
154 {
155         down(&clock_list_sem);
156         list_del(&clk->node);
157         up(&clock_list_sem);
158 }
159
160 inline unsigned long clk_get_rate(struct clk *clk)
161 {
162         return clk->rate;
163 }
164
165 int clk_set_rate(struct clk *clk, unsigned long rate)
166 {
167         int ret = -EOPNOTSUPP;
168
169         if (likely(clk->ops && clk->ops->set_rate)) {
170                 unsigned long flags;
171
172                 spin_lock_irqsave(&clock_lock, flags);
173                 ret = clk->ops->set_rate(clk, rate);
174                 spin_unlock_irqrestore(&clock_lock, flags);
175         }
176
177         if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
178                 propagate_rate(clk);
179
180         return ret;
181 }
182
183 void clk_recalc_rate(struct clk *clk)
184 {
185         if (likely(clk->ops && clk->ops->recalc)) {
186                 unsigned long flags;
187
188                 spin_lock_irqsave(&clock_lock, flags);
189                 clk->ops->recalc(clk);
190                 spin_unlock_irqrestore(&clock_lock, flags);
191         }
192
193         if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
194                 propagate_rate(clk);
195 }
196
197 struct clk *clk_get(const char *id)
198 {
199         struct clk *p, *clk = ERR_PTR(-ENOENT);
200
201         down(&clock_list_sem);
202         list_for_each_entry(p, &clock_list, node) {
203                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
204                         clk = p;
205                         break;
206                 }
207         }
208         up(&clock_list_sem);
209
210         return clk;
211 }
212
213 void clk_put(struct clk *clk)
214 {
215         if (clk && !IS_ERR(clk))
216                 module_put(clk->owner);
217 }
218
219 void __init __attribute__ ((weak))
220 arch_init_clk_ops(struct clk_ops **ops, int type)
221 {
222 }
223
224 int __init clk_init(void)
225 {
226         int i, ret = 0;
227
228         BUG_ON(unlikely(!master_clk.rate));
229
230         for (i = 0; i < ARRAY_SIZE(onchip_clocks); i++) {
231                 struct clk *clk = onchip_clocks[i];
232
233                 arch_init_clk_ops(&clk->ops, i);
234                 ret |= clk_register(clk);
235                 clk_enable(clk);
236         }
237
238         /* Kick the child clocks.. */
239         propagate_rate(&master_clk);
240         propagate_rate(&bus_clk);
241
242         return ret;
243 }
244
245 int show_clocks(struct seq_file *m)
246 {
247         struct clk *clk;
248
249         list_for_each_entry_reverse(clk, &clock_list, node) {
250                 unsigned long rate = clk_get_rate(clk);
251
252                 /*
253                  * Don't bother listing dummy clocks with no ancestry
254                  * that only support enable and disable ops.
255                  */
256                 if (unlikely(!rate && !clk->parent))
257                         continue;
258
259                 seq_printf(m, "%-12s\t: %ld.%02ldMHz\n", clk->name,
260                            rate / 1000000, (rate % 1000000) / 10000);
261         }
262
263         return 0;
264 }
265
266 EXPORT_SYMBOL_GPL(clk_register);
267 EXPORT_SYMBOL_GPL(clk_unregister);
268 EXPORT_SYMBOL_GPL(clk_get);
269 EXPORT_SYMBOL_GPL(clk_put);
270 EXPORT_SYMBOL_GPL(clk_enable);
271 EXPORT_SYMBOL_GPL(clk_disable);
272 EXPORT_SYMBOL_GPL(__clk_enable);
273 EXPORT_SYMBOL_GPL(__clk_disable);
274 EXPORT_SYMBOL_GPL(clk_get_rate);
275 EXPORT_SYMBOL_GPL(clk_set_rate);
276 EXPORT_SYMBOL_GPL(clk_recalc_rate);