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authorAndrew Victor <andrew@sanpeople.com>2007-02-05 05:42:07 -0500
committerRussell King <rmk+kernel@arm.linux.org.uk>2007-02-08 09:50:56 -0500
commit9d0412680e6c7b685ee466842047bcfb924d6dc5 (patch)
treec79300964ef1aca5d24571696f95e76b37c14679 /arch/arm/mach-at91/clock.c
parenta93d48cc6019f84394b31d10c0d830a3b71696be (diff)
[ARM] 4124/1: Rename mach-at91rm9200 and arch-at91rm9200 directories
Now that Linux includes support for the Atmel AT91SAM9260 and AT91SAM9261 processors in addition to the original Atmel AT91RM9200 (with support for more AT91 processors pending), the "mach-at91rm9200" and "arch-at91rm9200" directories should be renamed to indicate their more generic nature. The following git commands should be run BEFORE applying this patch: git-mv arch/arm/mach-at91rm9200 arch/arm/mach-at91 git-mv include/asm-arm/arch-at91rm9200 include/asm-arm/arch-at91 Signed-off-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-at91/clock.c')
-rw-r--r--arch/arm/mach-at91/clock.c644
1 files changed, 644 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/clock.c b/arch/arm/mach-at91/clock.c
new file mode 100644
index 000000000000..baab095f6e32
--- /dev/null
+++ b/arch/arm/mach-at91/clock.c
@@ -0,0 +1,644 @@
1/*
2 * linux/arch/arm/mach-at91/clock.c
3 *
4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2005 Ivan Kokshaysky
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 */
12
13#include <linux/module.h>
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/fs.h>
17#include <linux/debugfs.h>
18#include <linux/seq_file.h>
19#include <linux/list.h>
20#include <linux/errno.h>
21#include <linux/err.h>
22#include <linux/spinlock.h>
23#include <linux/delay.h>
24#include <linux/clk.h>
25
26#include <asm/semaphore.h>
27#include <asm/io.h>
28#include <asm/mach-types.h>
29
30#include <asm/hardware.h>
31#include <asm/arch/at91_pmc.h>
32#include <asm/arch/cpu.h>
33
34#include "clock.h"
35
36
37/*
38 * There's a lot more which can be done with clocks, including cpufreq
39 * integration, slow clock mode support (for system suspend), letting
40 * PLLB be used at other rates (on boards that don't need USB), etc.
41 */
42
43#define clk_is_primary(x) ((x)->type & CLK_TYPE_PRIMARY)
44#define clk_is_programmable(x) ((x)->type & CLK_TYPE_PROGRAMMABLE)
45#define clk_is_peripheral(x) ((x)->type & CLK_TYPE_PERIPHERAL)
46#define clk_is_sys(x) ((x)->type & CLK_TYPE_SYSTEM)
47
48
49static LIST_HEAD(clocks);
50static DEFINE_SPINLOCK(clk_lock);
51
52static u32 at91_pllb_usb_init;
53
54/*
55 * Four primary clock sources: two crystal oscillators (32K, main), and
56 * two PLLs. PLLA usually runs the master clock; and PLLB must run at
57 * 48 MHz (unless no USB function clocks are needed). The main clock and
58 * both PLLs are turned off to run in "slow clock mode" (system suspend).
59 */
60static struct clk clk32k = {
61 .name = "clk32k",
62 .rate_hz = AT91_SLOW_CLOCK,
63 .users = 1, /* always on */
64 .id = 0,
65 .type = CLK_TYPE_PRIMARY,
66};
67static struct clk main_clk = {
68 .name = "main",
69 .pmc_mask = AT91_PMC_MOSCS, /* in PMC_SR */
70 .id = 1,
71 .type = CLK_TYPE_PRIMARY,
72};
73static struct clk plla = {
74 .name = "plla",
75 .parent = &main_clk,
76 .pmc_mask = AT91_PMC_LOCKA, /* in PMC_SR */
77 .id = 2,
78 .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL,
79};
80
81static void pllb_mode(struct clk *clk, int is_on)
82{
83 u32 value;
84
85 if (is_on) {
86 is_on = AT91_PMC_LOCKB;
87 value = at91_pllb_usb_init;
88 } else
89 value = 0;
90
91 // REVISIT: Add work-around for AT91RM9200 Errata #26 ?
92 at91_sys_write(AT91_CKGR_PLLBR, value);
93
94 do {
95 cpu_relax();
96 } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKB) != is_on);
97}
98
99static struct clk pllb = {
100 .name = "pllb",
101 .parent = &main_clk,
102 .pmc_mask = AT91_PMC_LOCKB, /* in PMC_SR */
103 .mode = pllb_mode,
104 .id = 3,
105 .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL,
106};
107
108static void pmc_sys_mode(struct clk *clk, int is_on)
109{
110 if (is_on)
111 at91_sys_write(AT91_PMC_SCER, clk->pmc_mask);
112 else
113 at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
114}
115
116/* USB function clocks (PLLB must be 48 MHz) */
117static struct clk udpck = {
118 .name = "udpck",
119 .parent = &pllb,
120 .mode = pmc_sys_mode,
121};
122static struct clk uhpck = {
123 .name = "uhpck",
124 .parent = &pllb,
125 .mode = pmc_sys_mode,
126};
127
128
129/*
130 * The master clock is divided from the CPU clock (by 1-4). It's used for
131 * memory, interfaces to on-chip peripherals, the AIC, and sometimes more
132 * (e.g baud rate generation). It's sourced from one of the primary clocks.
133 */
134static struct clk mck = {
135 .name = "mck",
136 .pmc_mask = AT91_PMC_MCKRDY, /* in PMC_SR */
137};
138
139static void pmc_periph_mode(struct clk *clk, int is_on)
140{
141 if (is_on)
142 at91_sys_write(AT91_PMC_PCER, clk->pmc_mask);
143 else
144 at91_sys_write(AT91_PMC_PCDR, clk->pmc_mask);
145}
146
147static struct clk __init *at91_css_to_clk(unsigned long css)
148{
149 switch (css) {
150 case AT91_PMC_CSS_SLOW:
151 return &clk32k;
152 case AT91_PMC_CSS_MAIN:
153 return &main_clk;
154 case AT91_PMC_CSS_PLLA:
155 return &plla;
156 case AT91_PMC_CSS_PLLB:
157 return &pllb;
158 }
159
160 return NULL;
161}
162
163/*
164 * Associate a particular clock with a function (eg, "uart") and device.
165 * The drivers can then request the same 'function' with several different
166 * devices and not care about which clock name to use.
167 */
168void __init at91_clock_associate(const char *id, struct device *dev, const char *func)
169{
170 struct clk *clk = clk_get(NULL, id);
171
172 if (!dev || !clk || !IS_ERR(clk_get(dev, func)))
173 return;
174
175 clk->function = func;
176 clk->dev = dev;
177}
178
179/* clocks cannot be de-registered no refcounting necessary */
180struct clk *clk_get(struct device *dev, const char *id)
181{
182 struct clk *clk;
183
184 list_for_each_entry(clk, &clocks, node) {
185 if (strcmp(id, clk->name) == 0)
186 return clk;
187 if (clk->function && (dev == clk->dev) && strcmp(id, clk->function) == 0)
188 return clk;
189 }
190
191 return ERR_PTR(-ENOENT);
192}
193EXPORT_SYMBOL(clk_get);
194
195void clk_put(struct clk *clk)
196{
197}
198EXPORT_SYMBOL(clk_put);
199
200static void __clk_enable(struct clk *clk)
201{
202 if (clk->parent)
203 __clk_enable(clk->parent);
204 if (clk->users++ == 0 && clk->mode)
205 clk->mode(clk, 1);
206}
207
208int clk_enable(struct clk *clk)
209{
210 unsigned long flags;
211
212 spin_lock_irqsave(&clk_lock, flags);
213 __clk_enable(clk);
214 spin_unlock_irqrestore(&clk_lock, flags);
215 return 0;
216}
217EXPORT_SYMBOL(clk_enable);
218
219static void __clk_disable(struct clk *clk)
220{
221 BUG_ON(clk->users == 0);
222 if (--clk->users == 0 && clk->mode)
223 clk->mode(clk, 0);
224 if (clk->parent)
225 __clk_disable(clk->parent);
226}
227
228void clk_disable(struct clk *clk)
229{
230 unsigned long flags;
231
232 spin_lock_irqsave(&clk_lock, flags);
233 __clk_disable(clk);
234 spin_unlock_irqrestore(&clk_lock, flags);
235}
236EXPORT_SYMBOL(clk_disable);
237
238unsigned long clk_get_rate(struct clk *clk)
239{
240 unsigned long flags;
241 unsigned long rate;
242
243 spin_lock_irqsave(&clk_lock, flags);
244 for (;;) {
245 rate = clk->rate_hz;
246 if (rate || !clk->parent)
247 break;
248 clk = clk->parent;
249 }
250 spin_unlock_irqrestore(&clk_lock, flags);
251 return rate;
252}
253EXPORT_SYMBOL(clk_get_rate);
254
255/*------------------------------------------------------------------------*/
256
257#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
258
259/*
260 * For now, only the programmable clocks support reparenting (MCK could
261 * do this too, with care) or rate changing (the PLLs could do this too,
262 * ditto MCK but that's more for cpufreq). Drivers may reparent to get
263 * a better rate match; we don't.
264 */
265
266long clk_round_rate(struct clk *clk, unsigned long rate)
267{
268 unsigned long flags;
269 unsigned prescale;
270 unsigned long actual;
271
272 if (!clk_is_programmable(clk))
273 return -EINVAL;
274 spin_lock_irqsave(&clk_lock, flags);
275
276 actual = clk->parent->rate_hz;
277 for (prescale = 0; prescale < 7; prescale++) {
278 if (actual && actual <= rate)
279 break;
280 actual >>= 1;
281 }
282
283 spin_unlock_irqrestore(&clk_lock, flags);
284 return (prescale < 7) ? actual : -ENOENT;
285}
286EXPORT_SYMBOL(clk_round_rate);
287
288int clk_set_rate(struct clk *clk, unsigned long rate)
289{
290 unsigned long flags;
291 unsigned prescale;
292 unsigned long actual;
293
294 if (!clk_is_programmable(clk))
295 return -EINVAL;
296 if (clk->users)
297 return -EBUSY;
298 spin_lock_irqsave(&clk_lock, flags);
299
300 actual = clk->parent->rate_hz;
301 for (prescale = 0; prescale < 7; prescale++) {
302 if (actual && actual <= rate) {
303 u32 pckr;
304
305 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
306 pckr &= AT91_PMC_CSS_PLLB; /* clock selection */
307 pckr |= prescale << 2;
308 at91_sys_write(AT91_PMC_PCKR(clk->id), pckr);
309 clk->rate_hz = actual;
310 break;
311 }
312 actual >>= 1;
313 }
314
315 spin_unlock_irqrestore(&clk_lock, flags);
316 return (prescale < 7) ? actual : -ENOENT;
317}
318EXPORT_SYMBOL(clk_set_rate);
319
320struct clk *clk_get_parent(struct clk *clk)
321{
322 return clk->parent;
323}
324EXPORT_SYMBOL(clk_get_parent);
325
326int clk_set_parent(struct clk *clk, struct clk *parent)
327{
328 unsigned long flags;
329
330 if (clk->users)
331 return -EBUSY;
332 if (!clk_is_primary(parent) || !clk_is_programmable(clk))
333 return -EINVAL;
334 spin_lock_irqsave(&clk_lock, flags);
335
336 clk->rate_hz = parent->rate_hz;
337 clk->parent = parent;
338 at91_sys_write(AT91_PMC_PCKR(clk->id), parent->id);
339
340 spin_unlock_irqrestore(&clk_lock, flags);
341 return 0;
342}
343EXPORT_SYMBOL(clk_set_parent);
344
345/* establish PCK0..PCK3 parentage and rate */
346static void init_programmable_clock(struct clk *clk)
347{
348 struct clk *parent;
349 u32 pckr;
350
351 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
352 parent = at91_css_to_clk(pckr & AT91_PMC_CSS);
353 clk->parent = parent;
354 clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));
355}
356
357#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
358
359/*------------------------------------------------------------------------*/
360
361#ifdef CONFIG_DEBUG_FS
362
363static int at91_clk_show(struct seq_file *s, void *unused)
364{
365 u32 scsr, pcsr, sr;
366 struct clk *clk;
367 unsigned i;
368
369 seq_printf(s, "SCSR = %8x\n", scsr = at91_sys_read(AT91_PMC_SCSR));
370 seq_printf(s, "PCSR = %8x\n", pcsr = at91_sys_read(AT91_PMC_PCSR));
371
372 seq_printf(s, "MOR = %8x\n", at91_sys_read(AT91_CKGR_MOR));
373 seq_printf(s, "MCFR = %8x\n", at91_sys_read(AT91_CKGR_MCFR));
374 seq_printf(s, "PLLA = %8x\n", at91_sys_read(AT91_CKGR_PLLAR));
375 seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR));
376
377 seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR));
378 for (i = 0; i < 4; i++)
379 seq_printf(s, "PCK%d = %8x\n", i, at91_sys_read(AT91_PMC_PCKR(i)));
380 seq_printf(s, "SR = %8x\n", sr = at91_sys_read(AT91_PMC_SR));
381
382 seq_printf(s, "\n");
383
384 list_for_each_entry(clk, &clocks, node) {
385 char *state;
386
387 if (clk->mode == pmc_sys_mode)
388 state = (scsr & clk->pmc_mask) ? "on" : "off";
389 else if (clk->mode == pmc_periph_mode)
390 state = (pcsr & clk->pmc_mask) ? "on" : "off";
391 else if (clk->pmc_mask)
392 state = (sr & clk->pmc_mask) ? "on" : "off";
393 else if (clk == &clk32k || clk == &main_clk)
394 state = "on";
395 else
396 state = "";
397
398 seq_printf(s, "%-10s users=%2d %-3s %9ld Hz %s\n",
399 clk->name, clk->users, state, clk_get_rate(clk),
400 clk->parent ? clk->parent->name : "");
401 }
402 return 0;
403}
404
405static int at91_clk_open(struct inode *inode, struct file *file)
406{
407 return single_open(file, at91_clk_show, NULL);
408}
409
410static struct file_operations at91_clk_operations = {
411 .open = at91_clk_open,
412 .read = seq_read,
413 .llseek = seq_lseek,
414 .release = single_release,
415};
416
417static int __init at91_clk_debugfs_init(void)
418{
419 /* /sys/kernel/debug/at91_clk */
420 (void) debugfs_create_file("at91_clk", S_IFREG | S_IRUGO, NULL, NULL, &at91_clk_operations);
421
422 return 0;
423}
424postcore_initcall(at91_clk_debugfs_init);
425
426#endif
427
428/*------------------------------------------------------------------------*/
429
430/* Register a new clock */
431int __init clk_register(struct clk *clk)
432{
433 if (clk_is_peripheral(clk)) {
434 clk->parent = &mck;
435 clk->mode = pmc_periph_mode;
436 list_add_tail(&clk->node, &clocks);
437 }
438 else if (clk_is_sys(clk)) {
439 clk->parent = &mck;
440 clk->mode = pmc_sys_mode;
441
442 list_add_tail(&clk->node, &clocks);
443 }
444#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
445 else if (clk_is_programmable(clk)) {
446 clk->mode = pmc_sys_mode;
447 init_programmable_clock(clk);
448 list_add_tail(&clk->node, &clocks);
449 }
450#endif
451
452 return 0;
453}
454
455
456/*------------------------------------------------------------------------*/
457
458static u32 __init at91_pll_rate(struct clk *pll, u32 freq, u32 reg)
459{
460 unsigned mul, div;
461
462 div = reg & 0xff;
463 mul = (reg >> 16) & 0x7ff;
464 if (div && mul) {
465 freq /= div;
466 freq *= mul + 1;
467 } else
468 freq = 0;
469
470 return freq;
471}
472
473static u32 __init at91_usb_rate(struct clk *pll, u32 freq, u32 reg)
474{
475 if (pll == &pllb && (reg & AT91_PMC_USB96M))
476 return freq / 2;
477 else
478 return freq;
479}
480
481static unsigned __init at91_pll_calc(unsigned main_freq, unsigned out_freq)
482{
483 unsigned i, div = 0, mul = 0, diff = 1 << 30;
484 unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
485
486 /* PLL output max 240 MHz (or 180 MHz per errata) */
487 if (out_freq > 240000000)
488 goto fail;
489
490 for (i = 1; i < 256; i++) {
491 int diff1;
492 unsigned input, mul1;
493
494 /*
495 * PLL input between 1MHz and 32MHz per spec, but lower
496 * frequences seem necessary in some cases so allow 100K.
497 */
498 input = main_freq / i;
499 if (input < 100000)
500 continue;
501 if (input > 32000000)
502 continue;
503
504 mul1 = out_freq / input;
505 if (mul1 > 2048)
506 continue;
507 if (mul1 < 2)
508 goto fail;
509
510 diff1 = out_freq - input * mul1;
511 if (diff1 < 0)
512 diff1 = -diff1;
513 if (diff > diff1) {
514 diff = diff1;
515 div = i;
516 mul = mul1;
517 if (diff == 0)
518 break;
519 }
520 }
521 if (i == 256 && diff > (out_freq >> 5))
522 goto fail;
523 return ret | ((mul - 1) << 16) | div;
524fail:
525 return 0;
526}
527
528/*
529 * Several unused clocks may be active. Turn them off.
530 */
531static void __init at91_periphclk_reset(void)
532{
533 unsigned long reg;
534 struct clk *clk;
535
536 reg = at91_sys_read(AT91_PMC_PCSR);
537
538 list_for_each_entry(clk, &clocks, node) {
539 if (clk->mode != pmc_periph_mode)
540 continue;
541
542 if (clk->users > 0)
543 reg &= ~clk->pmc_mask;
544 }
545
546 at91_sys_write(AT91_PMC_PCDR, reg);
547}
548
549static struct clk *const standard_pmc_clocks[] __initdata = {
550 /* four primary clocks */
551 &clk32k,
552 &main_clk,
553 &plla,
554 &pllb,
555
556 /* PLLB children (USB) */
557 &udpck,
558 &uhpck,
559
560 /* MCK */
561 &mck
562};
563
564int __init at91_clock_init(unsigned long main_clock)
565{
566 unsigned tmp, freq, mckr;
567 int i;
568
569 /*
570 * When the bootloader initialized the main oscillator correctly,
571 * there's no problem using the cycle counter. But if it didn't,
572 * or when using oscillator bypass mode, we must be told the speed
573 * of the main clock.
574 */
575 if (!main_clock) {
576 do {
577 tmp = at91_sys_read(AT91_CKGR_MCFR);
578 } while (!(tmp & AT91_PMC_MAINRDY));
579 main_clock = (tmp & AT91_PMC_MAINF) * (AT91_SLOW_CLOCK / 16);
580 }
581 main_clk.rate_hz = main_clock;
582
583 /* report if PLLA is more than mildly overclocked */
584 plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR));
585 if (plla.rate_hz > 209000000)
586 pr_info("Clocks: PLLA overclocked, %ld MHz\n", plla.rate_hz / 1000000);
587
588 /*
589 * USB clock init: choose 48 MHz PLLB value, turn all clocks off,
590 * disable 48MHz clock during usb peripheral suspend.
591 *
592 * REVISIT: assumes MCK doesn't derive from PLLB!
593 */
594 at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | AT91_PMC_USB96M;
595 pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);
596 if (cpu_is_at91rm9200()) {
597 uhpck.pmc_mask = AT91RM9200_PMC_UHP;
598 udpck.pmc_mask = AT91RM9200_PMC_UDP;
599 at91_sys_write(AT91_PMC_SCDR, AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP);
600 at91_sys_write(AT91_PMC_SCER, AT91RM9200_PMC_MCKUDP);
601 } else if (cpu_is_at91sam9260()) {
602 uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
603 udpck.pmc_mask = AT91SAM926x_PMC_UDP;
604 at91_sys_write(AT91_PMC_SCDR, AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP);
605 } else if (cpu_is_at91sam9261()) {
606 uhpck.pmc_mask = (AT91SAM926x_PMC_UHP | AT91_PMC_HCK0);
607 udpck.pmc_mask = AT91SAM926x_PMC_UDP;
608 at91_sys_write(AT91_PMC_SCDR, AT91SAM926x_PMC_UHP | AT91_PMC_HCK0 | AT91SAM926x_PMC_UDP);
609 }
610 at91_sys_write(AT91_CKGR_PLLBR, 0);
611
612 udpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
613 uhpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
614
615 /*
616 * MCK and CPU derive from one of those primary clocks.
617 * For now, assume this parentage won't change.
618 */
619 mckr = at91_sys_read(AT91_PMC_MCKR);
620 mck.parent = at91_css_to_clk(mckr & AT91_PMC_CSS);
621 freq = mck.parent->rate_hz;
622 freq /= (1 << ((mckr >> 2) & 3)); /* prescale */
623 mck.rate_hz = freq / (1 + ((mckr >> 8) & 3)); /* mdiv */
624
625 /* Register the PMC's standard clocks */
626 for (i = 0; i < ARRAY_SIZE(standard_pmc_clocks); i++)
627 list_add_tail(&standard_pmc_clocks[i]->node, &clocks);
628
629 /* MCK and CPU clock are "always on" */
630 clk_enable(&mck);
631
632 printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",
633 freq / 1000000, (unsigned) mck.rate_hz / 1000000,
634 (unsigned) main_clock / 1000000,
635 ((unsigned) main_clock % 1000000) / 1000);
636
637 /* disable all programmable clocks */
638 at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);
639
640 /* disable all other unused peripheral clocks */
641 at91_periphclk_reset();
642
643 return 0;
644}