2 * [origin: Linux kernel linux/arch/arm/mach-at91/clock.c]
4 * Copyright (C) 2011 Andreas Bießmann
5 * Copyright (C) 2005 David Brownell
6 * Copyright (C) 2005 Ivan Kokshaysky
7 * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
9 * SPDX-License-Identifier: GPL-2.0+
13 #include <asm/arch/hardware.h>
14 #include <asm/arch/at91_pmc.h>
15 #include <asm/arch/clk.h>
17 #if !defined(CONFIG_AT91FAMILY)
18 # error You need to define CONFIG_AT91FAMILY in your board config!
21 DECLARE_GLOBAL_DATA_PTR
;
23 static unsigned long at91_css_to_rate(unsigned long css
)
26 case AT91_PMC_MCKR_CSS_SLOW
:
27 return CONFIG_SYS_AT91_SLOW_CLOCK
;
28 case AT91_PMC_MCKR_CSS_MAIN
:
29 return gd
->arch
.main_clk_rate_hz
;
30 case AT91_PMC_MCKR_CSS_PLLA
:
31 return gd
->arch
.plla_rate_hz
;
32 case AT91_PMC_MCKR_CSS_PLLB
:
33 return gd
->arch
.pllb_rate_hz
;
39 #ifdef CONFIG_USB_ATMEL
40 static unsigned at91_pll_calc(unsigned main_freq
, unsigned out_freq
)
42 unsigned i
, div
= 0, mul
= 0, diff
= 1 << 30;
43 unsigned ret
= (out_freq
> 155000000) ? 0xbe00 : 0x3e00;
45 /* PLL output max 240 MHz (or 180 MHz per errata) */
46 if (out_freq
> 240000000)
49 for (i
= 1; i
< 256; i
++) {
54 * PLL input between 1MHz and 32MHz per spec, but lower
55 * frequences seem necessary in some cases so allow 100K.
56 * Warning: some newer products need 2MHz min.
58 input
= main_freq
/ i
;
64 mul1
= out_freq
/ input
;
70 diff1
= out_freq
- input
* mul1
;
81 if (i
== 256 && diff
> (out_freq
>> 5))
83 return ret
| ((mul
- 1) << 16) | div
;
89 static u32
at91_pll_rate(u32 freq
, u32 reg
)
94 mul
= (reg
>> 16) & 0x7ff;
104 int at91_clock_init(unsigned long main_clock
)
107 at91_pmc_t
*pmc
= (at91_pmc_t
*) ATMEL_BASE_PMC
;
108 #ifndef CONFIG_SYS_AT91_MAIN_CLOCK
111 * When the bootloader initialized the main oscillator correctly,
112 * there's no problem using the cycle counter. But if it didn't,
113 * or when using oscillator bypass mode, we must be told the speed
118 tmp
= readl(&pmc
->mcfr
);
119 } while (!(tmp
& AT91_PMC_MCFR_MAINRDY
));
120 tmp
&= AT91_PMC_MCFR_MAINF_MASK
;
121 main_clock
= tmp
* (CONFIG_SYS_AT91_SLOW_CLOCK
/ 16);
124 gd
->arch
.main_clk_rate_hz
= main_clock
;
126 /* report if PLLA is more than mildly overclocked */
127 gd
->arch
.plla_rate_hz
= at91_pll_rate(main_clock
, readl(&pmc
->pllar
));
129 #ifdef CONFIG_USB_ATMEL
131 * USB clock init: choose 48 MHz PLLB value,
132 * disable 48MHz clock during usb peripheral suspend.
134 * REVISIT: assumes MCK doesn't derive from PLLB!
136 gd
->arch
.at91_pllb_usb_init
= at91_pll_calc(main_clock
, 48000000 * 2) |
137 AT91_PMC_PLLBR_USBDIV_2
;
138 gd
->arch
.pllb_rate_hz
= at91_pll_rate(main_clock
,
139 gd
->arch
.at91_pllb_usb_init
);
143 * MCK and CPU derive from one of those primary clocks.
144 * For now, assume this parentage won't change.
146 mckr
= readl(&pmc
->mckr
);
147 gd
->arch
.mck_rate_hz
= at91_css_to_rate(mckr
& AT91_PMC_MCKR_CSS_MASK
);
148 freq
= gd
->arch
.mck_rate_hz
;
150 freq
/= (1 << ((mckr
& AT91_PMC_MCKR_PRES_MASK
) >> 2)); /* prescale */
152 gd
->arch
.mck_rate_hz
= freq
/
153 (1 + ((mckr
& AT91_PMC_MCKR_MDIV_MASK
) >> 8));
154 gd
->arch
.cpu_clk_rate_hz
= freq
;