xref: /openbmc/u-boot/arch/m68k/cpu/mcf5227x/speed.c (revision ae485b54)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *
4  * Copyright (C) 2004-2007, 2012 Freescale Semiconductor, Inc.
5  * TsiChung Liew (Tsi-Chung.Liew@freescale.com)
6  */
7 
8 #include <common.h>
9 #include <asm/processor.h>
10 
11 #include <asm/immap.h>
12 #include <asm/io.h>
13 
14 DECLARE_GLOBAL_DATA_PTR;
15 
16 /*
17  * Low Power Divider specifications
18  */
19 #define CLOCK_LPD_MIN		(1 << 0)	/* Divider (decoded) */
20 #define CLOCK_LPD_MAX		(1 << 15)	/* Divider (decoded) */
21 
22 #define CLOCK_PLL_FVCO_MAX	540000000
23 #define CLOCK_PLL_FVCO_MIN	300000000
24 
25 #define CLOCK_PLL_FSYS_MAX	266666666
26 #define CLOCK_PLL_FSYS_MIN	100000000
27 #define MHZ			1000000
28 
29 void clock_enter_limp(int lpdiv)
30 {
31 	ccm_t *ccm = (ccm_t *)MMAP_CCM;
32 	int i, j;
33 
34 	/* Check bounds of divider */
35 	if (lpdiv < CLOCK_LPD_MIN)
36 		lpdiv = CLOCK_LPD_MIN;
37 	if (lpdiv > CLOCK_LPD_MAX)
38 		lpdiv = CLOCK_LPD_MAX;
39 
40 	/* Round divider down to nearest power of two */
41 	for (i = 0, j = lpdiv; j != 1; j >>= 1, i++) ;
42 
43 	/* Apply the divider to the system clock */
44 	clrsetbits_be16(&ccm->cdr, 0x0f00, CCM_CDR_LPDIV(i));
45 
46 	/* Enable Limp Mode */
47 	setbits_be16(&ccm->misccr, CCM_MISCCR_LIMP);
48 }
49 
50 /*
51  * brief   Exit Limp mode
52  * warning The PLL should be set and locked prior to exiting Limp mode
53  */
54 void clock_exit_limp(void)
55 {
56 	ccm_t *ccm = (ccm_t *)MMAP_CCM;
57 	pll_t *pll = (pll_t *)MMAP_PLL;
58 
59 	/* Exit Limp mode */
60 	clrbits_be16(&ccm->misccr, CCM_MISCCR_LIMP);
61 
62 	/* Wait for the PLL to lock */
63 	while (!(in_be32(&pll->psr) & PLL_PSR_LOCK))
64 		;
65 }
66 
67 /*
68  * get_clocks() fills in gd->cpu_clock and gd->bus_clk
69  */
70 int get_clocks(void)
71 {
72 
73 	ccm_t *ccm = (ccm_t *)MMAP_CCM;
74 	pll_t *pll = (pll_t *)MMAP_PLL;
75 	int vco, temp, pcrvalue, pfdr;
76 	u8 bootmode;
77 
78 	pcrvalue = in_be32(&pll->pcr) & 0xFF0F0FFF;
79 	pfdr = pcrvalue >> 24;
80 
81 	if (pfdr == 0x1E)
82 		bootmode = 0;	/* Normal Mode */
83 
84 #ifdef CONFIG_CF_SBF
85 	bootmode = 3;		/* Serial Mode */
86 #endif
87 
88 	if (bootmode == 0) {
89 		/* Normal mode */
90 		vco = ((in_be32(&pll->pcr) & 0xFF000000) >> 24) * CONFIG_SYS_INPUT_CLKSRC;
91 		if ((vco < CLOCK_PLL_FVCO_MIN) || (vco > CLOCK_PLL_FVCO_MAX)) {
92 			/* Default value */
93 			pcrvalue = (in_be32(&pll->pcr) & 0x00FFFFFF);
94 			pcrvalue |= 0x1E << 24;
95 			out_be32(&pll->pcr, pcrvalue);
96 			vco =
97 			    ((in_be32(&pll->pcr) & 0xFF000000) >> 24) *
98 			    CONFIG_SYS_INPUT_CLKSRC;
99 		}
100 		gd->arch.vco_clk = vco;	/* Vco clock */
101 	} else if (bootmode == 3) {
102 		/* serial mode */
103 		vco = ((in_be32(&pll->pcr) & 0xFF000000) >> 24) * CONFIG_SYS_INPUT_CLKSRC;
104 		gd->arch.vco_clk = vco;	/* Vco clock */
105 	}
106 
107 	if ((in_be16(&ccm->ccr) & CCM_MISCCR_LIMP) == CCM_MISCCR_LIMP) {
108 		/* Limp mode */
109 	} else {
110 		gd->arch.inp_clk = CONFIG_SYS_INPUT_CLKSRC; /* Input clock */
111 
112 		temp = (in_be32(&pll->pcr) & PLL_PCR_OUTDIV1_MASK) + 1;
113 		gd->cpu_clk = vco / temp;	/* cpu clock */
114 
115 		temp = ((in_be32(&pll->pcr) & PLL_PCR_OUTDIV2_MASK) >> 4) + 1;
116 		gd->arch.flb_clk = vco / temp;	/* flexbus clock */
117 		gd->bus_clk = gd->arch.flb_clk;
118 	}
119 
120 #ifdef CONFIG_SYS_I2C_FSL
121 	gd->arch.i2c1_clk = gd->bus_clk;
122 #endif
123 
124 	return (0);
125 }
126