xref: /freebsd/sys/dev/qcom_clk/qcom_clk_fepll.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * Copyright (c) 2021 Adrian Chadd <adrian@FreeBSD.org>.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  */
25 
26 #include <sys/param.h>
27 #include <sys/systm.h>
28 #include <sys/bus.h>
29 #include <sys/lock.h>
30 #include <sys/mutex.h>
31 #include <sys/rman.h>
32 #include <machine/bus.h>
33 
34 #include <dev/extres/clk/clk.h>
35 #include <dev/extres/clk/clk_div.h>
36 #include <dev/extres/clk/clk_fixed.h>
37 #include <dev/extres/clk/clk_mux.h>
38 
39 #include "qcom_clk_fepll.h"
40 
41 #include "clkdev_if.h"
42 
43 #if 0
44 #define DPRINTF(dev, msg...) device_printf(dev, "cpufreq_dt: " msg);
45 #else
46 #define DPRINTF(dev, msg...)
47 #endif
48 
49 /*
50  * This is the top-level PLL clock on the IPQ4018/IPQ4019.
51  * It's a fixed PLL clock that feeds a bunch of divisors into
52  * downstrem FEPLL* and DDR clocks.
53  *
54  * Now, on Linux the clock code creates multiple instances of this
55  * with an inbuilt divisor.  Here instead there'll be a single
56  * instance of the FEPLL, and then normal divisors will feed into
57  * the multiple PLL nodes.
58  */
59 
60 struct qcom_clk_fepll_sc {
61 	struct clknode	*clknode;
62 	uint32_t offset;
63 	uint32_t fdbkdiv_shift; /* FDBKDIV base */
64 	uint32_t fdbkdiv_width; /* FDBKDIV width */
65 	uint32_t refclkdiv_shift; /* REFCLKDIV base */
66 	uint32_t refclkdiv_width; /* REFCLKDIV width */
67 };
68 
69 static int
70 qcom_clk_fepll_recalc(struct clknode *clk, uint64_t *freq)
71 {
72 	struct qcom_clk_fepll_sc *sc;
73 	uint64_t vco, parent_rate;
74 	uint32_t reg, fdbkdiv, refclkdiv;
75 
76 	sc = clknode_get_softc(clk);
77 
78 	if (freq == NULL || *freq == 0) {
79 		device_printf(clknode_get_device(sc->clknode),
80 		    "%s: called; NULL or 0 frequency\n",
81 		    __func__);
82 		return (ENXIO);
83 	}
84 
85 	parent_rate = *freq;
86 
87 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
88 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->offset, &reg);
89 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
90 
91 	fdbkdiv = (reg >> sc->fdbkdiv_shift) &
92 	    ((1U << sc->fdbkdiv_width) - 1);
93 	refclkdiv = (reg >> sc->refclkdiv_shift) &
94 	    ((1U << sc->refclkdiv_width) - 1);
95 
96 	vco = parent_rate / refclkdiv;
97 	vco = vco * 2;
98 	vco = vco * fdbkdiv;
99 
100 	*freq = vco;
101 	return (0);
102 }
103 
104 static int
105 qcom_clk_fepll_init(struct clknode *clk, device_t dev)
106 {
107 
108 	/*
109 	 * There's only a single parent here for an FEPLL, so just set it
110 	 * to 0; the caller doesn't need to supply it.
111 	 */
112 	clknode_init_parent_idx(clk, 0);
113 
114 	return (0);
115 }
116 
117 static clknode_method_t qcom_clk_fepll_methods[] = {
118 	/* Device interface */
119 	CLKNODEMETHOD(clknode_init,		qcom_clk_fepll_init),
120 	CLKNODEMETHOD(clknode_recalc_freq,	qcom_clk_fepll_recalc),
121 	CLKNODEMETHOD_END
122 };
123 
124 DEFINE_CLASS_1(qcom_clk_fepll, qcom_clk_fepll_class, qcom_clk_fepll_methods,
125    sizeof(struct qcom_clk_fepll_sc), clknode_class);
126 
127 int
128 qcom_clk_fepll_register(struct clkdom *clkdom,
129     struct qcom_clk_fepll_def *clkdef)
130 {
131 	struct clknode *clk;
132 	struct qcom_clk_fepll_sc *sc;
133 
134 	clk = clknode_create(clkdom, &qcom_clk_fepll_class, &clkdef->clkdef);
135 	if (clk == NULL)
136 		return (1);
137 
138 	sc = clknode_get_softc(clk);
139 	sc->clknode = clk;
140 
141 	sc->offset = clkdef->offset;
142 	sc->fdbkdiv_shift = clkdef->fdbkdiv_shift;
143 	sc->fdbkdiv_width = clkdef->fdbkdiv_width;
144 	sc->refclkdiv_shift = clkdef->refclkdiv_shift;
145 	sc->refclkdiv_width = clkdef->refclkdiv_width;
146 
147 	clknode_register(clkdom, clk);
148 
149 	return (0);
150 }
151