xref: /freebsd/sys/dev/qcom_clk/qcom_clk_ro_div.c (revision 02e9120893770924227138ba49df1edb3896112a)
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_ro_div.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 a read-only divisor table node.
51  * It represents some divisor that is setup by the boot environment
52  * and we don't have any need for the driver to go and fiddle with.
53  *
54  * It likely should just live in the extres/clk code.
55  */
56 
57 struct qcom_clk_ro_div_sc {
58 	struct clknode	*clknode;
59 	uint32_t offset;
60 	uint32_t shift;
61 	uint32_t width;
62 	struct qcom_clk_ro_div_tbl *div_tbl;
63 };
64 
65 static int
66 qcom_clk_ro_div_recalc(struct clknode *clk, uint64_t *freq)
67 {
68 	struct qcom_clk_ro_div_sc *sc;
69 	uint32_t reg, idx, div = 1;
70 	int i;
71 
72 	sc = clknode_get_softc(clk);
73 
74 	if (freq == NULL || *freq == 0) {
75 		printf("%s: called; NULL or 0 frequency\n", __func__);
76 		return (ENXIO);
77 	}
78 
79 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
80 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->offset, &reg);
81 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
82 
83 	idx = (reg >> sc->shift) & ((1U << sc->width) - 1);
84 
85 	for (i = 0; (sc->div_tbl[i].div != 0); i++) {
86 		if (idx == sc->div_tbl[i].val) {
87 			div = sc->div_tbl[i].div;
88 			break;
89 		}
90 	}
91 
92 	DPRINTF(clknode_get_device(sc->clknode),
93 	    "%s: freq=%llu, idx=%u, div=%u, out_freq=%llu\n",
94 	    __func__,
95 	    *freq,
96 	    idx,
97 	    div,
98 	    *freq / div);
99 
100 	*freq = *freq / div;
101 	return (0);
102 }
103 
104 static int
105 qcom_clk_ro_div_init(struct clknode *clk, device_t dev)
106 {
107 
108 	/*
109 	 * There's only a single parent here for this divisor,
110 	 * so just set it 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_ro_div_methods[] = {
118 	/* Device interface */
119 	CLKNODEMETHOD(clknode_init,		qcom_clk_ro_div_init),
120 	CLKNODEMETHOD(clknode_recalc_freq,	qcom_clk_ro_div_recalc),
121 	CLKNODEMETHOD_END
122 };
123 
124 DEFINE_CLASS_1(qcom_clk_fepll, qcom_clk_ro_div_class,
125    qcom_clk_ro_div_methods, sizeof(struct qcom_clk_ro_div_sc),
126    clknode_class);
127 
128 int
129 qcom_clk_ro_div_register(struct clkdom *clkdom,
130     struct qcom_clk_ro_div_def *clkdef)
131 {
132 	struct clknode *clk;
133 	struct qcom_clk_ro_div_sc *sc;
134 
135 	clk = clknode_create(clkdom, &qcom_clk_ro_div_class,
136 	    &clkdef->clkdef);
137 	if (clk == NULL)
138 		return (1);
139 
140 	sc = clknode_get_softc(clk);
141 	sc->clknode = clk;
142 	sc->offset = clkdef->offset;
143 	sc->shift = clkdef->shift;
144 	sc->width = clkdef->width;
145 	sc->div_tbl = clkdef->div_tbl;
146 
147 	clknode_register(clkdom, clk);
148 
149 	return (0);
150 }
151