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d5ed4c2e MD |
1 | /* |
2 | * SuperH Timer Support - MTU2 | |
3 | * | |
4 | * Copyright (C) 2009 Magnus Damm | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | ||
20 | #include <linux/init.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/interrupt.h> | |
24 | #include <linux/ioport.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/io.h> | |
27 | #include <linux/clk.h> | |
28 | #include <linux/irq.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/clockchips.h> | |
46a12f74 | 31 | #include <linux/sh_timer.h> |
d5ed4c2e MD |
32 | |
33 | struct sh_mtu2_priv { | |
34 | void __iomem *mapbase; | |
35 | struct clk *clk; | |
36 | struct irqaction irqaction; | |
37 | struct platform_device *pdev; | |
38 | unsigned long rate; | |
39 | unsigned long periodic; | |
40 | struct clock_event_device ced; | |
41 | }; | |
42 | ||
43 | static DEFINE_SPINLOCK(sh_mtu2_lock); | |
44 | ||
45 | #define TSTR -1 /* shared register */ | |
46 | #define TCR 0 /* channel register */ | |
47 | #define TMDR 1 /* channel register */ | |
48 | #define TIOR 2 /* channel register */ | |
49 | #define TIER 3 /* channel register */ | |
50 | #define TSR 4 /* channel register */ | |
51 | #define TCNT 5 /* channel register */ | |
52 | #define TGR 6 /* channel register */ | |
53 | ||
54 | static unsigned long mtu2_reg_offs[] = { | |
55 | [TCR] = 0, | |
56 | [TMDR] = 1, | |
57 | [TIOR] = 2, | |
58 | [TIER] = 4, | |
59 | [TSR] = 5, | |
60 | [TCNT] = 6, | |
61 | [TGR] = 8, | |
62 | }; | |
63 | ||
64 | static inline unsigned long sh_mtu2_read(struct sh_mtu2_priv *p, int reg_nr) | |
65 | { | |
46a12f74 | 66 | struct sh_timer_config *cfg = p->pdev->dev.platform_data; |
d5ed4c2e MD |
67 | void __iomem *base = p->mapbase; |
68 | unsigned long offs; | |
69 | ||
70 | if (reg_nr == TSTR) | |
71 | return ioread8(base + cfg->channel_offset); | |
72 | ||
73 | offs = mtu2_reg_offs[reg_nr]; | |
74 | ||
75 | if ((reg_nr == TCNT) || (reg_nr == TGR)) | |
76 | return ioread16(base + offs); | |
77 | else | |
78 | return ioread8(base + offs); | |
79 | } | |
80 | ||
81 | static inline void sh_mtu2_write(struct sh_mtu2_priv *p, int reg_nr, | |
82 | unsigned long value) | |
83 | { | |
46a12f74 | 84 | struct sh_timer_config *cfg = p->pdev->dev.platform_data; |
d5ed4c2e MD |
85 | void __iomem *base = p->mapbase; |
86 | unsigned long offs; | |
87 | ||
88 | if (reg_nr == TSTR) { | |
89 | iowrite8(value, base + cfg->channel_offset); | |
90 | return; | |
91 | } | |
92 | ||
93 | offs = mtu2_reg_offs[reg_nr]; | |
94 | ||
95 | if ((reg_nr == TCNT) || (reg_nr == TGR)) | |
96 | iowrite16(value, base + offs); | |
97 | else | |
98 | iowrite8(value, base + offs); | |
99 | } | |
100 | ||
101 | static void sh_mtu2_start_stop_ch(struct sh_mtu2_priv *p, int start) | |
102 | { | |
46a12f74 | 103 | struct sh_timer_config *cfg = p->pdev->dev.platform_data; |
d5ed4c2e MD |
104 | unsigned long flags, value; |
105 | ||
106 | /* start stop register shared by multiple timer channels */ | |
107 | spin_lock_irqsave(&sh_mtu2_lock, flags); | |
108 | value = sh_mtu2_read(p, TSTR); | |
109 | ||
110 | if (start) | |
111 | value |= 1 << cfg->timer_bit; | |
112 | else | |
113 | value &= ~(1 << cfg->timer_bit); | |
114 | ||
115 | sh_mtu2_write(p, TSTR, value); | |
116 | spin_unlock_irqrestore(&sh_mtu2_lock, flags); | |
117 | } | |
118 | ||
119 | static int sh_mtu2_enable(struct sh_mtu2_priv *p) | |
120 | { | |
46a12f74 | 121 | struct sh_timer_config *cfg = p->pdev->dev.platform_data; |
d5ed4c2e MD |
122 | int ret; |
123 | ||
124 | /* enable clock */ | |
125 | ret = clk_enable(p->clk); | |
126 | if (ret) { | |
127 | pr_err("sh_mtu2: cannot enable clock \"%s\"\n", cfg->clk); | |
128 | return ret; | |
129 | } | |
130 | ||
131 | /* make sure channel is disabled */ | |
132 | sh_mtu2_start_stop_ch(p, 0); | |
133 | ||
134 | p->rate = clk_get_rate(p->clk) / 64; | |
135 | p->periodic = (p->rate + HZ/2) / HZ; | |
136 | ||
137 | /* "Periodic Counter Operation" */ | |
138 | sh_mtu2_write(p, TCR, 0x23); /* TGRA clear, divide clock by 64 */ | |
139 | sh_mtu2_write(p, TIOR, 0); | |
140 | sh_mtu2_write(p, TGR, p->periodic); | |
141 | sh_mtu2_write(p, TCNT, 0); | |
142 | sh_mtu2_write(p, TMDR, 0); | |
143 | sh_mtu2_write(p, TIER, 0x01); | |
144 | ||
145 | /* enable channel */ | |
146 | sh_mtu2_start_stop_ch(p, 1); | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | static void sh_mtu2_disable(struct sh_mtu2_priv *p) | |
152 | { | |
153 | /* disable channel */ | |
154 | sh_mtu2_start_stop_ch(p, 0); | |
155 | ||
156 | /* stop clock */ | |
157 | clk_disable(p->clk); | |
158 | } | |
159 | ||
160 | static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id) | |
161 | { | |
162 | struct sh_mtu2_priv *p = dev_id; | |
163 | ||
164 | /* acknowledge interrupt */ | |
165 | sh_mtu2_read(p, TSR); | |
166 | sh_mtu2_write(p, TSR, 0xfe); | |
167 | ||
168 | /* notify clockevent layer */ | |
169 | p->ced.event_handler(&p->ced); | |
170 | return IRQ_HANDLED; | |
171 | } | |
172 | ||
173 | static struct sh_mtu2_priv *ced_to_sh_mtu2(struct clock_event_device *ced) | |
174 | { | |
175 | return container_of(ced, struct sh_mtu2_priv, ced); | |
176 | } | |
177 | ||
178 | static void sh_mtu2_clock_event_mode(enum clock_event_mode mode, | |
179 | struct clock_event_device *ced) | |
180 | { | |
181 | struct sh_mtu2_priv *p = ced_to_sh_mtu2(ced); | |
182 | int disabled = 0; | |
183 | ||
184 | /* deal with old setting first */ | |
185 | switch (ced->mode) { | |
186 | case CLOCK_EVT_MODE_PERIODIC: | |
187 | sh_mtu2_disable(p); | |
188 | disabled = 1; | |
189 | break; | |
190 | default: | |
191 | break; | |
192 | } | |
193 | ||
194 | switch (mode) { | |
195 | case CLOCK_EVT_MODE_PERIODIC: | |
196 | pr_info("sh_mtu2: %s used for periodic clock events\n", | |
197 | ced->name); | |
198 | sh_mtu2_enable(p); | |
199 | break; | |
200 | case CLOCK_EVT_MODE_UNUSED: | |
201 | if (!disabled) | |
202 | sh_mtu2_disable(p); | |
203 | break; | |
204 | case CLOCK_EVT_MODE_SHUTDOWN: | |
205 | default: | |
206 | break; | |
207 | } | |
208 | } | |
209 | ||
210 | static void sh_mtu2_register_clockevent(struct sh_mtu2_priv *p, | |
211 | char *name, unsigned long rating) | |
212 | { | |
213 | struct clock_event_device *ced = &p->ced; | |
214 | int ret; | |
215 | ||
216 | memset(ced, 0, sizeof(*ced)); | |
217 | ||
218 | ced->name = name; | |
219 | ced->features = CLOCK_EVT_FEAT_PERIODIC; | |
220 | ced->rating = rating; | |
221 | ced->cpumask = cpumask_of(0); | |
222 | ced->set_mode = sh_mtu2_clock_event_mode; | |
223 | ||
224 | ret = setup_irq(p->irqaction.irq, &p->irqaction); | |
225 | if (ret) { | |
226 | pr_err("sh_mtu2: failed to request irq %d\n", | |
227 | p->irqaction.irq); | |
228 | return; | |
229 | } | |
230 | ||
231 | pr_info("sh_mtu2: %s used for clock events\n", ced->name); | |
232 | clockevents_register_device(ced); | |
233 | } | |
234 | ||
d1fcc0a8 PM |
235 | static int sh_mtu2_register(struct sh_mtu2_priv *p, char *name, |
236 | unsigned long clockevent_rating) | |
d5ed4c2e MD |
237 | { |
238 | if (clockevent_rating) | |
239 | sh_mtu2_register_clockevent(p, name, clockevent_rating); | |
240 | ||
241 | return 0; | |
242 | } | |
243 | ||
244 | static int sh_mtu2_setup(struct sh_mtu2_priv *p, struct platform_device *pdev) | |
245 | { | |
46a12f74 | 246 | struct sh_timer_config *cfg = pdev->dev.platform_data; |
d5ed4c2e MD |
247 | struct resource *res; |
248 | int irq, ret; | |
249 | ret = -ENXIO; | |
250 | ||
251 | memset(p, 0, sizeof(*p)); | |
252 | p->pdev = pdev; | |
253 | ||
254 | if (!cfg) { | |
255 | dev_err(&p->pdev->dev, "missing platform data\n"); | |
256 | goto err0; | |
257 | } | |
258 | ||
259 | platform_set_drvdata(pdev, p); | |
260 | ||
261 | res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0); | |
262 | if (!res) { | |
263 | dev_err(&p->pdev->dev, "failed to get I/O memory\n"); | |
264 | goto err0; | |
265 | } | |
266 | ||
267 | irq = platform_get_irq(p->pdev, 0); | |
268 | if (irq < 0) { | |
269 | dev_err(&p->pdev->dev, "failed to get irq\n"); | |
270 | goto err0; | |
271 | } | |
272 | ||
273 | /* map memory, let mapbase point to our channel */ | |
274 | p->mapbase = ioremap_nocache(res->start, resource_size(res)); | |
275 | if (p->mapbase == NULL) { | |
276 | pr_err("sh_mtu2: failed to remap I/O memory\n"); | |
277 | goto err0; | |
278 | } | |
279 | ||
280 | /* setup data for setup_irq() (too early for request_irq()) */ | |
281 | p->irqaction.name = cfg->name; | |
282 | p->irqaction.handler = sh_mtu2_interrupt; | |
283 | p->irqaction.dev_id = p; | |
284 | p->irqaction.irq = irq; | |
285 | p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL; | |
d5ed4c2e MD |
286 | |
287 | /* get hold of clock */ | |
288 | p->clk = clk_get(&p->pdev->dev, cfg->clk); | |
289 | if (IS_ERR(p->clk)) { | |
290 | pr_err("sh_mtu2: cannot get clock \"%s\"\n", cfg->clk); | |
291 | ret = PTR_ERR(p->clk); | |
292 | goto err1; | |
293 | } | |
294 | ||
295 | return sh_mtu2_register(p, cfg->name, cfg->clockevent_rating); | |
296 | err1: | |
297 | iounmap(p->mapbase); | |
298 | err0: | |
299 | return ret; | |
300 | } | |
301 | ||
302 | static int __devinit sh_mtu2_probe(struct platform_device *pdev) | |
303 | { | |
304 | struct sh_mtu2_priv *p = platform_get_drvdata(pdev); | |
46a12f74 | 305 | struct sh_timer_config *cfg = pdev->dev.platform_data; |
d5ed4c2e MD |
306 | int ret; |
307 | ||
308 | if (p) { | |
309 | pr_info("sh_mtu2: %s kept as earlytimer\n", cfg->name); | |
310 | return 0; | |
311 | } | |
312 | ||
313 | p = kmalloc(sizeof(*p), GFP_KERNEL); | |
314 | if (p == NULL) { | |
315 | dev_err(&pdev->dev, "failed to allocate driver data\n"); | |
316 | return -ENOMEM; | |
317 | } | |
318 | ||
319 | ret = sh_mtu2_setup(p, pdev); | |
320 | if (ret) { | |
321 | kfree(p); | |
322 | platform_set_drvdata(pdev, NULL); | |
323 | } | |
324 | return ret; | |
325 | } | |
326 | ||
327 | static int __devexit sh_mtu2_remove(struct platform_device *pdev) | |
328 | { | |
329 | return -EBUSY; /* cannot unregister clockevent */ | |
330 | } | |
331 | ||
332 | static struct platform_driver sh_mtu2_device_driver = { | |
333 | .probe = sh_mtu2_probe, | |
334 | .remove = __devexit_p(sh_mtu2_remove), | |
335 | .driver = { | |
336 | .name = "sh_mtu2", | |
337 | } | |
338 | }; | |
339 | ||
340 | static int __init sh_mtu2_init(void) | |
341 | { | |
342 | return platform_driver_register(&sh_mtu2_device_driver); | |
343 | } | |
344 | ||
345 | static void __exit sh_mtu2_exit(void) | |
346 | { | |
347 | platform_driver_unregister(&sh_mtu2_device_driver); | |
348 | } | |
349 | ||
350 | early_platform_init("earlytimer", &sh_mtu2_device_driver); | |
351 | module_init(sh_mtu2_init); | |
352 | module_exit(sh_mtu2_exit); | |
353 | ||
354 | MODULE_AUTHOR("Magnus Damm"); | |
355 | MODULE_DESCRIPTION("SuperH MTU2 Timer Driver"); | |
356 | MODULE_LICENSE("GPL v2"); |