summaryrefslogtreecommitdiffstats
path: root/drivers/cpufreq/sparc-us2e-cpufreq.c
blob: cf5bc2ca16fa11f4155d757c6d5219b6691a6b81 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
/* us2e_cpufreq.c: UltraSPARC-IIe cpu frequency support
 *
 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
 *
 * Many thanks to Dominik Brodowski for fixing up the cpufreq
 * infrastructure in order to make this driver easier to implement.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/cpufreq.h>
#include <linux/threads.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <asm/asi.h>
#include <asm/timer.h>

static struct cpufreq_driver *cpufreq_us2e_driver;

struct us2e_freq_percpu_info {
	struct cpufreq_frequency_table table[6];
};

/* Indexed by cpu number. */
static struct us2e_freq_percpu_info *us2e_freq_table;

#define HBIRD_MEM_CNTL0_ADDR	0x1fe0000f010UL
#define HBIRD_ESTAR_MODE_ADDR	0x1fe0000f080UL

/* UltraSPARC-IIe has five dividers: 1, 2, 4, 6, and 8.  These are controlled
 * in the ESTAR mode control register.
 */
#define ESTAR_MODE_DIV_1	0x0000000000000000UL
#define ESTAR_MODE_DIV_2	0x0000000000000001UL
#define ESTAR_MODE_DIV_4	0x0000000000000003UL
#define ESTAR_MODE_DIV_6	0x0000000000000002UL
#define ESTAR_MODE_DIV_8	0x0000000000000004UL
#define ESTAR_MODE_DIV_MASK	0x0000000000000007UL

#define MCTRL0_SREFRESH_ENAB	0x0000000000010000UL
#define MCTRL0_REFR_COUNT_MASK	0x0000000000007f00UL
#define MCTRL0_REFR_COUNT_SHIFT	8
#define MCTRL0_REFR_INTERVAL	7800
#define MCTRL0_REFR_CLKS_P_CNT	64

static unsigned long read_hbreg(unsigned long addr)
{
	unsigned long ret;

	__asm__ __volatile__("ldxa	[%1] %2, %0"
			     : "=&r" (ret)
			     : "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E));
	return ret;
}

static void write_hbreg(unsigned long addr, unsigned long val)
{
	__asm__ __volatile__("stxa	%0, [%1] %2\n\t"
			     "membar	#Sync"
			     : /* no outputs */
			     : "r" (val), "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E)
			     : "memory");
	if (addr == HBIRD_ESTAR_MODE_ADDR) {
		/* Need to wait 16 clock cycles for the PLL to lock.  */
		udelay(1);
	}
}

static void self_refresh_ctl(int enable)
{
	unsigned long mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);

	if (enable)
		mctrl |= MCTRL0_SREFRESH_ENAB;
	else
		mctrl &= ~MCTRL0_SREFRESH_ENAB;
	write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
	(void) read_hbreg(HBIRD_MEM_CNTL0_ADDR);
}

static void frob_mem_refresh(int cpu_slowing_down,
			     unsigned long clock_tick,
			     unsigned long old_divisor, unsigned long divisor)
{
	unsigned long old_refr_count, refr_count, mctrl;

	refr_count  = (clock_tick * MCTRL0_REFR_INTERVAL);
	refr_count /= (MCTRL0_REFR_CLKS_P_CNT * divisor * 1000000000UL);

	mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
	old_refr_count = (mctrl & MCTRL0_REFR_COUNT_MASK)
		>> MCTRL0_REFR_COUNT_SHIFT;

	mctrl &= ~MCTRL0_REFR_COUNT_MASK;
	mctrl |= refr_count << MCTRL0_REFR_COUNT_SHIFT;
	write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
	mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);

	if (cpu_slowing_down && !(mctrl & MCTRL0_SREFRESH_ENAB)) {
		unsigned long usecs;

		/* We have to wait for both refresh counts (old
		 * and new) to go to zero.
		 */
		usecs = (MCTRL0_REFR_CLKS_P_CNT *
			 (refr_count + old_refr_count) *
			 1000000UL *
			 old_divisor) / clock_tick;
		udelay(usecs + 1UL);
	}
}

static void us2e_transition(unsigned long estar, unsigned long new_bits,
			    unsigned long clock_tick,
			    unsigned long old_divisor, unsigned long divisor)
{
	unsigned long flags;

	local_irq_save(flags);

	estar &= ~ESTAR_MODE_DIV_MASK;

	/* This is based upon the state transition diagram in the IIe manual.  */
	if (old_divisor == 2 && divisor == 1) {
		self_refresh_ctl(0);
		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
		frob_mem_refresh(0, clock_tick, old_divisor, divisor);
	} else if (old_divisor == 1 && divisor == 2) {
		frob_mem_refresh(1, clock_tick, old_divisor, divisor);
		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
		self_refresh_ctl(1);
	} else if (old_divisor == 1 && divisor > 2) {
		us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
				1, 2);
		us2e_transition(estar, new_bits, clock_tick,
				2, divisor);
	} else if (old_divisor > 2 && divisor == 1) {
		us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
				old_divisor, 2);
		us2e_transition(estar, new_bits, clock_tick,
				2, divisor);
	} else if (old_divisor < divisor) {
		frob_mem_refresh(0, clock_tick, old_divisor, divisor);
		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
	} else if (old_divisor > divisor) {
		write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
		frob_mem_refresh(1, clock_tick, old_divisor, divisor);
	} else {
		BUG();
	}

	local_irq_restore(flags);
}

static unsigned long index_to_estar_mode(unsigned int index)
{
	switch (index) {
	case 0:
		return ESTAR_MODE_DIV_1;

	case 1:
		return ESTAR_MODE_DIV_2;

	case 2:
		return ESTAR_MODE_DIV_4;

	case 3:
		return ESTAR_MODE_DIV_6;

	case 4:
		return ESTAR_MODE_DIV_8;

	default:
		BUG();
	}
}

static unsigned long index_to_divisor(unsigned int index)
{
	switch (index) {
	case 0:
		return 1;

	case 1:
		return 2;

	case 2:
		return 4;

	case 3:
		return 6;

	case 4:
		return 8;

	default:
		BUG();
	}
}

static unsigned long estar_to_divisor(unsigned long estar)
{
	unsigned long ret;

	switch (estar & ESTAR_MODE_DIV_MASK) {
	case ESTAR_MODE_DIV_1:
		ret = 1;
		break;
	case ESTAR_MODE_DIV_2:
		ret = 2;
		break;
	case ESTAR_MODE_DIV_4:
		ret = 4;
		break;
	case ESTAR_MODE_DIV_6:
		ret = 6;
		break;
	case ESTAR_MODE_DIV_8:
		ret = 8;
		break;
	default:
		BUG();
	}

	return ret;
}

static unsigned int us2e_freq_get(unsigned int cpu)
{
	cpumask_t cpus_allowed;
	unsigned long clock_tick, estar;

	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
	set_cpus_allowed_ptr(current, cpumask_of(cpu));

	clock_tick = sparc64_get_clock_tick(cpu) / 1000;
	estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);

	set_cpus_allowed_ptr(current, &cpus_allowed);

	return clock_tick / estar_to_divisor(estar);
}

static void us2e_set_cpu_divider_index(struct cpufreq_policy *policy,
		unsigned int index)
{
	unsigned int cpu = policy->cpu;
	unsigned long new_bits, new_freq;
	unsigned long clock_tick, divisor, old_divisor, estar;
	cpumask_t cpus_allowed;
	struct cpufreq_freqs freqs;

	cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
	set_cpus_allowed_ptr(current, cpumask_of(cpu));

	new_freq = clock_tick = sparc64_get_clock_tick(cpu) / 1000;
	new_bits = index_to_estar_mode(index);
	divisor = index_to_divisor(index);
	new_freq /= divisor;

	estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);

	old_divisor = estar_to_divisor(estar);

	freqs.old = clock_tick / old_divisor;
	freqs.new = new_freq;
	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	if (old_divisor != divisor)
		us2e_transition(estar, new_bits, clock_tick * 1000,
				old_divisor, divisor);

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

	set_cpus_allowed_ptr(current, &cpus_allowed);
}

static int us2e_freq_target(struct cpufreq_policy *policy,
			  unsigned int target_freq,
			  unsigned int relation)
{
	unsigned int new_index = 0;

	if (cpufreq_frequency_table_target(policy,
					   &us2e_freq_table[policy->cpu].table[0],
					   target_freq, relation, &new_index))
		return -EINVAL;

	us2e_set_cpu_divider_index(policy, new_index);

	return 0;
}

static int us2e_freq_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy,
					      &us2e_freq_table[policy->cpu].table[0]);
}

static int __init us2e_freq_cpu_init(struct cpufreq_policy *policy)
{
	unsigned int cpu = policy->cpu;
	unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
	struct cpufreq_frequency_table *table =
		&us2e_freq_table[cpu].table[0];

	table[0].driver_data = 0;
	table[0].frequency = clock_tick / 1;
	table[1].driver_data = 1;
	table[1].frequency = clock_tick / 2;
	table[2].driver_data = 2;
	table[2].frequency = clock_tick / 4;
	table[2].driver_data = 3;
	table[2].frequency = clock_tick / 6;
	table[2].driver_data = 4;
	table[2].frequency = clock_tick / 8;
	table[2].driver_data = 5;
	table[3].frequency = CPUFREQ_TABLE_END;

	policy->cpuinfo.transition_latency = 0;
	policy->cur = clock_tick;

	return cpufreq_frequency_table_cpuinfo(policy, table);
}

static int us2e_freq_cpu_exit(struct cpufreq_policy *policy)
{
	if (cpufreq_us2e_driver)
		us2e_set_cpu_divider_index(policy, 0);

	return 0;
}

static int __init us2e_freq_init(void)
{
	unsigned long manuf, impl, ver;
	int ret;

	if (tlb_type != spitfire)
		return -ENODEV;

	__asm__("rdpr %%ver, %0" : "=r" (ver));
	manuf = ((ver >> 48) & 0xffff);
	impl  = ((ver >> 32) & 0xffff);

	if (manuf == 0x17 && impl == 0x13) {
		struct cpufreq_driver *driver;

		ret = -ENOMEM;
		driver = kzalloc(sizeof(*driver), GFP_KERNEL);
		if (!driver)
			goto err_out;

		us2e_freq_table = kzalloc((NR_CPUS * sizeof(*us2e_freq_table)),
			GFP_KERNEL);
		if (!us2e_freq_table)
			goto err_out;

		driver->init = us2e_freq_cpu_init;
		driver->verify = us2e_freq_verify;
		driver->target = us2e_freq_target;
		driver->get = us2e_freq_get;
		driver->exit = us2e_freq_cpu_exit;
		strcpy(driver->name, "UltraSPARC-IIe");

		cpufreq_us2e_driver = driver;
		ret = cpufreq_register_driver(driver);
		if (ret)
			goto err_out;

		return 0;

err_out:
		if (driver) {
			kfree(driver);
			cpufreq_us2e_driver = NULL;
		}
		kfree(us2e_freq_table);
		us2e_freq_table = NULL;
		return ret;
	}

	return -ENODEV;
}

static void __exit us2e_freq_exit(void)
{
	if (cpufreq_us2e_driver) {
		cpufreq_unregister_driver(cpufreq_us2e_driver);
		kfree(cpufreq_us2e_driver);
		cpufreq_us2e_driver = NULL;
		kfree(us2e_freq_table);
		us2e_freq_table = NULL;
	}
}

MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-IIe");
MODULE_LICENSE("GPL");

module_init(us2e_freq_init);
module_exit(us2e_freq_exit);