xref: /freebsd/sys/dev/qcom_clk/qcom_clk_ro_div.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
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/cdefs.h>
27 #include <sys/param.h>
28 #include <sys/systm.h>
29 #include <sys/bus.h>
30 #include <sys/lock.h>
31 #include <sys/mutex.h>
32 #include <sys/rman.h>
33 #include <machine/bus.h>
34 
35 #include <dev/extres/clk/clk.h>
36 #include <dev/extres/clk/clk_div.h>
37 #include <dev/extres/clk/clk_fixed.h>
38 #include <dev/extres/clk/clk_mux.h>
39 
40 #include "qcom_clk_ro_div.h"
41 
42 #include "clkdev_if.h"
43 
44 #if 0
45 #define DPRINTF(dev, msg...) device_printf(dev, "cpufreq_dt: " msg);
46 #else
47 #define DPRINTF(dev, msg...)
48 #endif
49 
50 /*
51  * This is a read-only divisor table node.
52  * It represents some divisor that is setup by the boot environment
53  * and we don't have any need for the driver to go and fiddle with.
54  *
55  * It likely should just live in the extres/clk code.
56  */
57 
58 struct qcom_clk_ro_div_sc {
59 	struct clknode	*clknode;
60 	uint32_t offset;
61 	uint32_t shift;
62 	uint32_t width;
63 	struct qcom_clk_ro_div_tbl *div_tbl;
64 };
65 
66 static int
67 qcom_clk_ro_div_recalc(struct clknode *clk, uint64_t *freq)
68 {
69 	struct qcom_clk_ro_div_sc *sc;
70 	uint32_t reg, idx, div = 1;
71 	int i;
72 
73 	sc = clknode_get_softc(clk);
74 
75 	if (freq == NULL || *freq == 0) {
76 		printf("%s: called; NULL or 0 frequency\n", __func__);
77 		return (ENXIO);
78 	}
79 
80 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
81 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->offset, &reg);
82 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
83 
84 	idx = (reg >> sc->shift) & ((1U << sc->width) - 1);
85 
86 	for (i = 0; (sc->div_tbl[i].div != 0); i++) {
87 		if (idx == sc->div_tbl[i].val) {
88 			div = sc->div_tbl[i].div;
89 			break;
90 		}
91 	}
92 
93 	DPRINTF(clknode_get_device(sc->clknode),
94 	    "%s: freq=%llu, idx=%u, div=%u, out_freq=%llu\n",
95 	    __func__,
96 	    *freq,
97 	    idx,
98 	    div,
99 	    *freq / div);
100 
101 	*freq = *freq / div;
102 	return (0);
103 }
104 
105 static int
106 qcom_clk_ro_div_init(struct clknode *clk, device_t dev)
107 {
108 
109 	/*
110 	 * There's only a single parent here for this divisor,
111 	 * so just set it to 0; the caller doesn't need to supply it.
112 	 */
113 	clknode_init_parent_idx(clk, 0);
114 
115 	return (0);
116 }
117 
118 static clknode_method_t qcom_clk_ro_div_methods[] = {
119 	/* Device interface */
120 	CLKNODEMETHOD(clknode_init,		qcom_clk_ro_div_init),
121 	CLKNODEMETHOD(clknode_recalc_freq,	qcom_clk_ro_div_recalc),
122 	CLKNODEMETHOD_END
123 };
124 
125 DEFINE_CLASS_1(qcom_clk_fepll, qcom_clk_ro_div_class,
126    qcom_clk_ro_div_methods, sizeof(struct qcom_clk_ro_div_sc),
127    clknode_class);
128 
129 int
130 qcom_clk_ro_div_register(struct clkdom *clkdom,
131     struct qcom_clk_ro_div_def *clkdef)
132 {
133 	struct clknode *clk;
134 	struct qcom_clk_ro_div_sc *sc;
135 
136 	clk = clknode_create(clkdom, &qcom_clk_ro_div_class,
137 	    &clkdef->clkdef);
138 	if (clk == NULL)
139 		return (1);
140 
141 	sc = clknode_get_softc(clk);
142 	sc->clknode = clk;
143 	sc->offset = clkdef->offset;
144 	sc->shift = clkdef->shift;
145 	sc->width = clkdef->width;
146 	sc->div_tbl = clkdef->div_tbl;
147 
148 	clknode_register(clkdom, clk);
149 
150 	return (0);
151 }
152