xref: /linux/arch/powerpc/boot/pq2.c (revision 9e56ff53b4115875667760445b028357848b4748)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * PowerQUICC II support functions
4  *
5  * Author: Scott Wood <scottwood@freescale.com>
6  *
7  * Copyright (c) 2007 Freescale Semiconductor, Inc.
8  */
9 
10 #include "ops.h"
11 #include "types.h"
12 #include "fsl-soc.h"
13 #include "pq2.h"
14 #include "stdio.h"
15 #include "io.h"
16 
17 #define PQ2_SCCR (0x10c80/4) /* System Clock Configuration Register */
18 #define PQ2_SCMR (0x10c88/4) /* System Clock Mode Register */
19 
20 static int pq2_corecnf_map[] = {
21 	3, 2, 2, 2, 4, 4, 5, 9, 6, 11, 8, 10, 3, 12, 7, -1,
22 	6, 5, 13, 2, 14, 4, 15, 9, 0, 11, 8, 10, 16, 12, 7, -1
23 };
24 
25 /* Get various clocks from crystal frequency.
26  * Returns zero on failure and non-zero on success.
27  */
28 int pq2_get_clocks(u32 crystal, u32 *sysfreq, u32 *corefreq,
29                    u32 *timebase, u32 *brgfreq)
30 {
31 	u32 *immr;
32 	u32 sccr, scmr, mainclk, busclk;
33 	int corecnf, busdf, plldf, pllmf, dfbrg;
34 
35 	immr = fsl_get_immr();
36 	if (!immr) {
37 		printf("pq2_get_clocks: Couldn't get IMMR base.\r\n");
38 		return 0;
39 	}
40 
41 	sccr = in_be32(&immr[PQ2_SCCR]);
42 	scmr = in_be32(&immr[PQ2_SCMR]);
43 
44 	dfbrg = sccr & 3;
45 	corecnf = (scmr >> 24) & 0x1f;
46 	busdf = (scmr >> 20) & 0xf;
47 	plldf = (scmr >> 12) & 1;
48 	pllmf = scmr & 0xfff;
49 
50 	mainclk = crystal * (pllmf + 1) / (plldf + 1);
51 	busclk = mainclk / (busdf + 1);
52 
53 	if (sysfreq)
54 		*sysfreq = mainclk / 2;
55 	if (timebase)
56 		*timebase = busclk / 4;
57 	if (brgfreq)
58 		*brgfreq = mainclk / (1 << ((dfbrg + 1) * 2));
59 
60 	if (corefreq) {
61 		int coremult = pq2_corecnf_map[corecnf];
62 
63 		if (coremult < 0)
64 			*corefreq = mainclk / 2;
65 		else if (coremult == 0)
66 			return 0;
67 		else
68 			*corefreq = busclk * coremult / 2;
69 	}
70 
71 	return 1;
72 }
73 
74 /* Set common device tree fields based on the given clock frequencies. */
75 void pq2_set_clocks(u32 sysfreq, u32 corefreq, u32 timebase, u32 brgfreq)
76 {
77 	void *node;
78 
79 	dt_fixup_cpu_clocks(corefreq, timebase, sysfreq);
80 
81 	node = finddevice("/soc/cpm");
82 	if (node)
83 		setprop(node, "clock-frequency", &sysfreq, 4);
84 
85 	node = finddevice("/soc/cpm/brg");
86 	if (node)
87 		setprop(node, "clock-frequency", &brgfreq, 4);
88 }
89 
90 int pq2_fixup_clocks(u32 crystal)
91 {
92 	u32 sysfreq, corefreq, timebase, brgfreq;
93 
94 	if (!pq2_get_clocks(crystal, &sysfreq, &corefreq, &timebase, &brgfreq))
95 		return 0;
96 
97 	pq2_set_clocks(sysfreq, corefreq, timebase, brgfreq);
98 	return 1;
99 }
100