xref: /freebsd/sys/dev/qcom_clk/qcom_clk_ro_div.c (revision d5b0e70f7e04d971691517ce1304d86a1e367e2e)
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 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/bus.h>
32 #include <sys/lock.h>
33 #include <sys/mutex.h>
34 #include <sys/rman.h>
35 #include <machine/bus.h>
36 
37 #include <dev/extres/clk/clk.h>
38 #include <dev/extres/clk/clk_div.h>
39 #include <dev/extres/clk/clk_fixed.h>
40 #include <dev/extres/clk/clk_mux.h>
41 
42 #include "qcom_clk_ro_div.h"
43 
44 #include "clkdev_if.h"
45 
46 #if 0
47 #define DPRINTF(dev, msg...) device_printf(dev, "cpufreq_dt: " msg);
48 #else
49 #define DPRINTF(dev, msg...)
50 #endif
51 
52 /*
53  * This is a read-only divisor table node.
54  * It represents some divisor that is setup by the boot environment
55  * and we don't have any need for the driver to go and fiddle with.
56  *
57  * It likely should just live in the extres/clk code.
58  */
59 
60 struct qcom_clk_ro_div_sc {
61 	struct clknode	*clknode;
62 	uint32_t offset;
63 	uint32_t shift;
64 	uint32_t width;
65 	struct qcom_clk_ro_div_tbl *div_tbl;
66 };
67 
68 static int
69 qcom_clk_ro_div_recalc(struct clknode *clk, uint64_t *freq)
70 {
71 	struct qcom_clk_ro_div_sc *sc;
72 	uint32_t reg, idx, div = 1;
73 	int i;
74 
75 	sc = clknode_get_softc(clk);
76 
77 	if (freq == NULL || *freq == 0) {
78 		printf("%s: called; NULL or 0 frequency\n", __func__);
79 		return (ENXIO);
80 	}
81 
82 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
83 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->offset, &reg);
84 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
85 
86 	idx = (reg >> sc->shift) & ((1U << sc->width) - 1);
87 
88 	for (i = 0; (sc->div_tbl[i].div != 0); i++) {
89 		if (idx == sc->div_tbl[i].val) {
90 			div = sc->div_tbl[i].div;
91 			break;
92 		}
93 	}
94 
95 	DPRINTF(clknode_get_device(sc->clknode),
96 	    "%s: freq=%llu, idx=%u, div=%u, out_freq=%llu\n",
97 	    __func__,
98 	    *freq,
99 	    idx,
100 	    div,
101 	    *freq / div);
102 
103 	*freq = *freq / div;
104 	return (0);
105 }
106 
107 static int
108 qcom_clk_ro_div_init(struct clknode *clk, device_t dev)
109 {
110 
111 	/*
112 	 * There's only a single parent here for this divisor,
113 	 * so just set it to 0; the caller doesn't need to supply it.
114 	 */
115 	clknode_init_parent_idx(clk, 0);
116 
117 	return (0);
118 }
119 
120 static clknode_method_t qcom_clk_ro_div_methods[] = {
121 	/* Device interface */
122 	CLKNODEMETHOD(clknode_init,		qcom_clk_ro_div_init),
123 	CLKNODEMETHOD(clknode_recalc_freq,	qcom_clk_ro_div_recalc),
124 	CLKNODEMETHOD_END
125 };
126 
127 DEFINE_CLASS_1(qcom_clk_fepll, qcom_clk_ro_div_class,
128    qcom_clk_ro_div_methods, sizeof(struct qcom_clk_ro_div_sc),
129    clknode_class);
130 
131 int
132 qcom_clk_ro_div_register(struct clkdom *clkdom,
133     struct qcom_clk_ro_div_def *clkdef)
134 {
135 	struct clknode *clk;
136 	struct qcom_clk_ro_div_sc *sc;
137 
138 	clk = clknode_create(clkdom, &qcom_clk_ro_div_class,
139 	    &clkdef->clkdef);
140 	if (clk == NULL)
141 		return (1);
142 
143 	sc = clknode_get_softc(clk);
144 	sc->clknode = clk;
145 	sc->offset = clkdef->offset;
146 	sc->shift = clkdef->shift;
147 	sc->width = clkdef->width;
148 	sc->div_tbl = clkdef->div_tbl;
149 
150 	clknode_register(clkdom, clk);
151 
152 	return (0);
153 }
154