2 * linux/arch/arm/mach-at91/clock.c
4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2005 Ivan Kokshaysky
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.
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/init.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>
27 #include <mach/hardware.h>
28 #include <mach/at91_pmc.h>
31 #include <asm/proc-fns.h>
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.
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)
50 * Chips have some kind of clocks : group them by functionality
52 #define cpu_has_utmi() ( cpu_is_at91sam9rl() \
53 || cpu_is_at91sam9g45() \
54 || cpu_is_at91sam9x5())
56 #define cpu_has_800M_plla() ( cpu_is_at91sam9g20() \
57 || cpu_is_at91sam9g45() \
58 || cpu_is_at91sam9x5())
60 #define cpu_has_300M_plla() (cpu_is_at91sam9g10())
62 #define cpu_has_pllb() (!(cpu_is_at91sam9rl() \
63 || cpu_is_at91sam9g45() \
64 || cpu_is_at91sam9x5()))
66 #define cpu_has_upll() (cpu_is_at91sam9g45() \
67 || cpu_is_at91sam9x5())
69 /* USB host HS & FS */
70 #define cpu_has_uhp() (!cpu_is_at91sam9rl())
72 /* USB device FS only */
73 #define cpu_has_udpfs() (!(cpu_is_at91sam9rl() \
74 || cpu_is_at91sam9g45() \
75 || cpu_is_at91sam9x5()))
77 #define cpu_has_plladiv2() (cpu_is_at91sam9g45() \
78 || cpu_is_at91sam9x5())
80 #define cpu_has_mdiv3() (cpu_is_at91sam9g45() \
81 || cpu_is_at91sam9x5())
83 #define cpu_has_alt_prescaler() (cpu_is_at91sam9x5())
85 static LIST_HEAD(clocks);
86 static DEFINE_SPINLOCK(clk_lock);
88 static u32 at91_pllb_usb_init;
91 * Four primary clock sources: two crystal oscillators (32K, main), and
92 * two PLLs. PLLA usually runs the master clock; and PLLB must run at
93 * 48 MHz (unless no USB function clocks are needed). The main clock and
94 * both PLLs are turned off to run in "slow clock mode" (system suspend).
96 static struct clk clk32k = {
98 .rate_hz = AT91_SLOW_CLOCK,
99 .users = 1, /* always on */
101 .type = CLK_TYPE_PRIMARY,
103 static struct clk main_clk = {
105 .pmc_mask = AT91_PMC_MOSCS, /* in PMC_SR */
107 .type = CLK_TYPE_PRIMARY,
109 static struct clk plla = {
112 .pmc_mask = AT91_PMC_LOCKA, /* in PMC_SR */
114 .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL,
117 static void pllb_mode(struct clk *clk, int is_on)
122 is_on = AT91_PMC_LOCKB;
123 value = at91_pllb_usb_init;
127 // REVISIT: Add work-around for AT91RM9200 Errata #26 ?
128 at91_sys_write(AT91_CKGR_PLLBR, value);
132 } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKB) != is_on);
135 static struct clk pllb = {
138 .pmc_mask = AT91_PMC_LOCKB, /* in PMC_SR */
141 .type = CLK_TYPE_PRIMARY | CLK_TYPE_PLL,
144 static void pmc_sys_mode(struct clk *clk, int is_on)
147 at91_sys_write(AT91_PMC_SCER, clk->pmc_mask);
149 at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
152 static void pmc_uckr_mode(struct clk *clk, int is_on)
154 unsigned int uckr = at91_sys_read(AT91_CKGR_UCKR);
157 is_on = AT91_PMC_LOCKU;
158 at91_sys_write(AT91_CKGR_UCKR, uckr | clk->pmc_mask);
160 at91_sys_write(AT91_CKGR_UCKR, uckr & ~(clk->pmc_mask));
164 } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKU) != is_on);
167 /* USB function clocks (PLLB must be 48 MHz) */
168 static struct clk udpck = {
171 .mode = pmc_sys_mode,
173 struct clk utmi_clk = {
176 .pmc_mask = AT91_PMC_UPLLEN, /* in CKGR_UCKR */
177 .mode = pmc_uckr_mode,
178 .type = CLK_TYPE_PLL,
180 static struct clk uhpck = {
182 /*.parent = ... we choose parent at runtime */
183 .mode = pmc_sys_mode,
188 * The master clock is divided from the CPU clock (by 1-4). It's used for
189 * memory, interfaces to on-chip peripherals, the AIC, and sometimes more
190 * (e.g baud rate generation). It's sourced from one of the primary clocks.
194 .pmc_mask = AT91_PMC_MCKRDY, /* in PMC_SR */
197 static void pmc_periph_mode(struct clk *clk, int is_on)
200 at91_sys_write(AT91_PMC_PCER, clk->pmc_mask);
202 at91_sys_write(AT91_PMC_PCDR, clk->pmc_mask);
205 static struct clk __init *at91_css_to_clk(unsigned long css)
208 case AT91_PMC_CSS_SLOW:
210 case AT91_PMC_CSS_MAIN:
212 case AT91_PMC_CSS_PLLA:
214 case AT91_PMC_CSS_PLLB:
216 /* CSS_PLLB == CSS_UPLL */
218 else if (cpu_has_pllb())
221 /* alternate PMC: can use master clock */
222 case AT91_PMC_CSS_MASTER:
229 static int pmc_prescaler_divider(u32 reg)
231 if (cpu_has_alt_prescaler()) {
232 return 1 << ((reg & AT91_PMC_ALT_PRES) >> PMC_ALT_PRES_OFFSET);
234 return 1 << ((reg & AT91_PMC_PRES) >> PMC_PRES_OFFSET);
238 static void __clk_enable(struct clk *clk)
241 __clk_enable(clk->parent);
242 if (clk->users++ == 0 && clk->mode)
246 int clk_enable(struct clk *clk)
250 spin_lock_irqsave(&clk_lock, flags);
252 spin_unlock_irqrestore(&clk_lock, flags);
255 EXPORT_SYMBOL(clk_enable);
257 static void __clk_disable(struct clk *clk)
259 BUG_ON(clk->users == 0);
260 if (--clk->users == 0 && clk->mode)
263 __clk_disable(clk->parent);
266 void clk_disable(struct clk *clk)
270 spin_lock_irqsave(&clk_lock, flags);
272 spin_unlock_irqrestore(&clk_lock, flags);
274 EXPORT_SYMBOL(clk_disable);
276 unsigned long clk_get_rate(struct clk *clk)
281 spin_lock_irqsave(&clk_lock, flags);
284 if (rate || !clk->parent)
288 spin_unlock_irqrestore(&clk_lock, flags);
291 EXPORT_SYMBOL(clk_get_rate);
293 /*------------------------------------------------------------------------*/
295 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
298 * For now, only the programmable clocks support reparenting (MCK could
299 * do this too, with care) or rate changing (the PLLs could do this too,
300 * ditto MCK but that's more for cpufreq). Drivers may reparent to get
301 * a better rate match; we don't.
304 long clk_round_rate(struct clk *clk, unsigned long rate)
308 unsigned long actual;
309 unsigned long prev = ULONG_MAX;
311 if (!clk_is_programmable(clk))
313 spin_lock_irqsave(&clk_lock, flags);
315 actual = clk->parent->rate_hz;
316 for (prescale = 0; prescale < 7; prescale++) {
320 if (actual && actual <= rate) {
321 if ((prev - rate) < (rate - actual)) {
330 spin_unlock_irqrestore(&clk_lock, flags);
331 return (prescale < 7) ? actual : -ENOENT;
333 EXPORT_SYMBOL(clk_round_rate);
335 int clk_set_rate(struct clk *clk, unsigned long rate)
339 unsigned long prescale_offset, css_mask;
340 unsigned long actual;
342 if (!clk_is_programmable(clk))
347 if (cpu_has_alt_prescaler()) {
348 prescale_offset = PMC_ALT_PRES_OFFSET;
349 css_mask = AT91_PMC_ALT_PCKR_CSS;
351 prescale_offset = PMC_PRES_OFFSET;
352 css_mask = AT91_PMC_CSS;
355 spin_lock_irqsave(&clk_lock, flags);
357 actual = clk->parent->rate_hz;
358 for (prescale = 0; prescale < 7; prescale++) {
359 if (actual && actual <= rate) {
362 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
363 pckr &= css_mask; /* keep clock selection */
364 pckr |= prescale << prescale_offset;
365 at91_sys_write(AT91_PMC_PCKR(clk->id), pckr);
366 clk->rate_hz = actual;
372 spin_unlock_irqrestore(&clk_lock, flags);
373 return (prescale < 7) ? actual : -ENOENT;
375 EXPORT_SYMBOL(clk_set_rate);
377 struct clk *clk_get_parent(struct clk *clk)
381 EXPORT_SYMBOL(clk_get_parent);
383 int clk_set_parent(struct clk *clk, struct clk *parent)
389 if (!clk_is_primary(parent) || !clk_is_programmable(clk))
392 if (cpu_is_at91sam9rl() && parent->id == AT91_PMC_CSS_PLLB)
395 spin_lock_irqsave(&clk_lock, flags);
397 clk->rate_hz = parent->rate_hz;
398 clk->parent = parent;
399 at91_sys_write(AT91_PMC_PCKR(clk->id), parent->id);
401 spin_unlock_irqrestore(&clk_lock, flags);
404 EXPORT_SYMBOL(clk_set_parent);
406 /* establish PCK0..PCKN parentage and rate */
407 static void __init init_programmable_clock(struct clk *clk)
411 unsigned int css_mask;
413 if (cpu_has_alt_prescaler())
414 css_mask = AT91_PMC_ALT_PCKR_CSS;
416 css_mask = AT91_PMC_CSS;
418 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
419 parent = at91_css_to_clk(pckr & css_mask);
420 clk->parent = parent;
421 clk->rate_hz = parent->rate_hz / pmc_prescaler_divider(pckr);
424 #endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
426 /*------------------------------------------------------------------------*/
428 #ifdef CONFIG_DEBUG_FS
430 static int at91_clk_show(struct seq_file *s, void *unused)
432 u32 scsr, pcsr, uckr = 0, sr;
435 seq_printf(s, "SCSR = %8x\n", scsr = at91_sys_read(AT91_PMC_SCSR));
436 seq_printf(s, "PCSR = %8x\n", pcsr = at91_sys_read(AT91_PMC_PCSR));
437 seq_printf(s, "MOR = %8x\n", at91_sys_read(AT91_CKGR_MOR));
438 seq_printf(s, "MCFR = %8x\n", at91_sys_read(AT91_CKGR_MCFR));
439 seq_printf(s, "PLLA = %8x\n", at91_sys_read(AT91_CKGR_PLLAR));
441 seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR));
443 seq_printf(s, "UCKR = %8x\n", uckr = at91_sys_read(AT91_CKGR_UCKR));
444 seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR));
446 seq_printf(s, "USB = %8x\n", at91_sys_read(AT91_PMC_USB));
447 seq_printf(s, "SR = %8x\n", sr = at91_sys_read(AT91_PMC_SR));
451 list_for_each_entry(clk, &clocks, node) {
454 if (clk->mode == pmc_sys_mode)
455 state = (scsr & clk->pmc_mask) ? "on" : "off";
456 else if (clk->mode == pmc_periph_mode)
457 state = (pcsr & clk->pmc_mask) ? "on" : "off";
458 else if (clk->mode == pmc_uckr_mode)
459 state = (uckr & clk->pmc_mask) ? "on" : "off";
460 else if (clk->pmc_mask)
461 state = (sr & clk->pmc_mask) ? "on" : "off";
462 else if (clk == &clk32k || clk == &main_clk)
467 seq_printf(s, "%-10s users=%2d %-3s %9ld Hz %s\n",
468 clk->name, clk->users, state, clk_get_rate(clk),
469 clk->parent ? clk->parent->name : "");
474 static int at91_clk_open(struct inode *inode, struct file *file)
476 return single_open(file, at91_clk_show, NULL);
479 static const struct file_operations at91_clk_operations = {
480 .open = at91_clk_open,
483 .release = single_release,
486 static int __init at91_clk_debugfs_init(void)
488 /* /sys/kernel/debug/at91_clk */
489 (void) debugfs_create_file("at91_clk", S_IFREG | S_IRUGO, NULL, NULL, &at91_clk_operations);
493 postcore_initcall(at91_clk_debugfs_init);
497 /*------------------------------------------------------------------------*/
499 /* Register a new clock */
500 static void __init at91_clk_add(struct clk *clk)
502 list_add_tail(&clk->node, &clocks);
504 clk->cl.con_id = clk->name;
506 clkdev_add(&clk->cl);
509 int __init clk_register(struct clk *clk)
511 if (clk_is_peripheral(clk)) {
514 clk->mode = pmc_periph_mode;
516 else if (clk_is_sys(clk)) {
518 clk->mode = pmc_sys_mode;
520 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
521 else if (clk_is_programmable(clk)) {
522 clk->mode = pmc_sys_mode;
523 init_programmable_clock(clk);
532 /*------------------------------------------------------------------------*/
534 static u32 __init at91_pll_rate(struct clk *pll, u32 freq, u32 reg)
539 mul = (reg >> 16) & 0x7ff;
549 static u32 __init at91_usb_rate(struct clk *pll, u32 freq, u32 reg)
551 if (pll == &pllb && (reg & AT91_PMC_USB96M))
557 static unsigned __init at91_pll_calc(unsigned main_freq, unsigned out_freq)
559 unsigned i, div = 0, mul = 0, diff = 1 << 30;
560 unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
562 /* PLL output max 240 MHz (or 180 MHz per errata) */
563 if (out_freq > 240000000)
566 for (i = 1; i < 256; i++) {
568 unsigned input, mul1;
571 * PLL input between 1MHz and 32MHz per spec, but lower
572 * frequences seem necessary in some cases so allow 100K.
573 * Warning: some newer products need 2MHz min.
575 input = main_freq / i;
576 if (cpu_is_at91sam9g20() && input < 2000000)
580 if (input > 32000000)
583 mul1 = out_freq / input;
584 if (cpu_is_at91sam9g20() && mul > 63)
591 diff1 = out_freq - input * mul1;
602 if (i == 256 && diff > (out_freq >> 5))
604 return ret | ((mul - 1) << 16) | div;
609 static struct clk *const standard_pmc_clocks[] __initdata = {
610 /* four primary clocks */
619 /* PLLB generated USB full speed clock init */
620 static void __init at91_pllb_usbfs_clock_init(unsigned long main_clock)
623 * USB clock init: choose 48 MHz PLLB value,
624 * disable 48MHz clock during usb peripheral suspend.
626 * REVISIT: assumes MCK doesn't derive from PLLB!
628 uhpck.parent = &pllb;
630 at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | AT91_PMC_USB96M;
631 pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);
632 if (cpu_is_at91rm9200()) {
633 uhpck.pmc_mask = AT91RM9200_PMC_UHP;
634 udpck.pmc_mask = AT91RM9200_PMC_UDP;
635 at91_sys_write(AT91_PMC_SCER, AT91RM9200_PMC_MCKUDP);
636 } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() ||
637 cpu_is_at91sam9263() || cpu_is_at91sam9g20() ||
638 cpu_is_at91sam9g10()) {
639 uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
640 udpck.pmc_mask = AT91SAM926x_PMC_UDP;
642 at91_sys_write(AT91_CKGR_PLLBR, 0);
644 udpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
645 uhpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
648 /* UPLL generated USB full speed clock init */
649 static void __init at91_upll_usbfs_clock_init(unsigned long main_clock)
652 * USB clock init: choose 480 MHz from UPLL,
654 unsigned int usbr = AT91_PMC_USBS_UPLL;
656 /* Setup divider by 10 to reach 48 MHz */
657 usbr |= ((10 - 1) << 8) & AT91_PMC_OHCIUSBDIV;
659 at91_sys_write(AT91_PMC_USB, usbr);
661 /* Now set uhpck values */
662 uhpck.parent = &utmi_clk;
663 uhpck.pmc_mask = AT91SAM926x_PMC_UHP;
664 uhpck.rate_hz = utmi_clk.rate_hz;
665 uhpck.rate_hz /= 1 + ((at91_sys_read(AT91_PMC_USB) & AT91_PMC_OHCIUSBDIV) >> 8);
668 int __init at91_clock_init(unsigned long main_clock)
670 unsigned tmp, freq, mckr;
672 int pll_overclock = false;
675 * When the bootloader initialized the main oscillator correctly,
676 * there's no problem using the cycle counter. But if it didn't,
677 * or when using oscillator bypass mode, we must be told the speed
682 tmp = at91_sys_read(AT91_CKGR_MCFR);
683 } while (!(tmp & AT91_PMC_MAINRDY));
684 main_clock = (tmp & AT91_PMC_MAINF) * (AT91_SLOW_CLOCK / 16);
686 main_clk.rate_hz = main_clock;
688 /* report if PLLA is more than mildly overclocked */
689 plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR));
690 if (cpu_has_300M_plla()) {
691 if (plla.rate_hz > 300000000)
692 pll_overclock = true;
693 } else if (cpu_has_800M_plla()) {
694 if (plla.rate_hz > 800000000)
695 pll_overclock = true;
697 if (plla.rate_hz > 209000000)
698 pll_overclock = true;
701 pr_info("Clocks: PLLA overclocked, %ld MHz\n", plla.rate_hz / 1000000);
703 if (cpu_has_plladiv2()) {
704 mckr = at91_sys_read(AT91_PMC_MCKR);
705 plla.rate_hz /= (1 << ((mckr & AT91_PMC_PLLADIV2) >> 12)); /* plla divisor by 2 */
708 if (!cpu_has_pllb() && cpu_has_upll()) {
709 /* setup UTMI clock as the fourth primary clock
710 * (instead of pllb) */
711 utmi_clk.type |= CLK_TYPE_PRIMARY;
719 if (cpu_has_utmi()) {
721 * multiplier is hard-wired to 40
722 * (obtain the USB High Speed 480 MHz when input is 12 MHz)
724 utmi_clk.rate_hz = 40 * utmi_clk.parent->rate_hz;
726 /* UTMI bias and PLL are managed at the same time */
728 utmi_clk.pmc_mask |= AT91_PMC_BIASEN;
735 at91_pllb_usbfs_clock_init(main_clock);
737 /* assumes that we choose UPLL for USB and not PLLA */
738 at91_upll_usbfs_clock_init(main_clock);
741 * MCK and CPU derive from one of those primary clocks.
742 * For now, assume this parentage won't change.
744 mckr = at91_sys_read(AT91_PMC_MCKR);
745 mck.parent = at91_css_to_clk(mckr & AT91_PMC_CSS);
746 freq = mck.parent->rate_hz;
747 freq /= pmc_prescaler_divider(mckr); /* prescale */
748 if (cpu_is_at91rm9200()) {
749 mck.rate_hz = freq / (1 + ((mckr & AT91_PMC_MDIV) >> 8)); /* mdiv */
750 } else if (cpu_is_at91sam9g20()) {
751 mck.rate_hz = (mckr & AT91_PMC_MDIV) ?
752 freq / ((mckr & AT91_PMC_MDIV) >> 7) : freq; /* mdiv ; (x >> 7) = ((x >> 8) * 2) */
753 if (mckr & AT91_PMC_PDIV)
754 freq /= 2; /* processor clock division */
755 } else if (cpu_has_mdiv3()) {
756 mck.rate_hz = (mckr & AT91_PMC_MDIV) == AT91SAM9_PMC_MDIV_3 ?
757 freq / 3 : freq / (1 << ((mckr & AT91_PMC_MDIV) >> 8)); /* mdiv */
759 mck.rate_hz = freq / (1 << ((mckr & AT91_PMC_MDIV) >> 8)); /* mdiv */
762 if (cpu_has_alt_prescaler()) {
763 /* Programmable clocks can use MCK */
764 mck.type |= CLK_TYPE_PRIMARY;
768 /* Register the PMC's standard clocks */
769 for (i = 0; i < ARRAY_SIZE(standard_pmc_clocks); i++)
770 at91_clk_add(standard_pmc_clocks[i]);
776 at91_clk_add(&uhpck);
779 at91_clk_add(&udpck);
782 at91_clk_add(&utmi_clk);
784 /* MCK and CPU clock are "always on" */
787 printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",
788 freq / 1000000, (unsigned) mck.rate_hz / 1000000,
789 (unsigned) main_clock / 1000000,
790 ((unsigned) main_clock % 1000000) / 1000);
796 * Several unused clocks may be active. Turn them off.
798 static int __init at91_clock_reset(void)
800 unsigned long pcdr = 0;
801 unsigned long scdr = 0;
804 list_for_each_entry(clk, &clocks, node) {
808 if (clk->mode == pmc_periph_mode)
809 pcdr |= clk->pmc_mask;
811 if (clk->mode == pmc_sys_mode)
812 scdr |= clk->pmc_mask;
814 pr_debug("Clocks: disable unused %s\n", clk->name);
817 at91_sys_write(AT91_PMC_PCDR, pcdr);
818 at91_sys_write(AT91_PMC_SCDR, scdr);
822 late_initcall(at91_clock_reset);
824 void at91sam9_idle(void)
826 at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK);