xref: /freebsd/sys/dev/qcom_clk/qcom_clk_apssdiv.c (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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/clk/clk.h>
35 #include <dev/clk/clk_div.h>
36 #include <dev/clk/clk_fixed.h>
37 #include <dev/clk/clk_mux.h>
38 
39 #include "qcom_clk_freqtbl.h"
40 #include "qcom_clk_apssdiv.h"
41 
42 #include "clkdev_if.h"
43 
44 /*
45  * This is a combination gate, divisor/PLL configuration
46  * for the APSS CPU clock.
47  */
48 
49 #if 0
50 #define DPRINTF(dev, msg...) device_printf(dev, "cpufreq_dt: " msg);
51 #else
52 #define DPRINTF(dev, msg...)
53 #endif
54 
55 struct qcom_clk_apssdiv_sc {
56 	struct clknode *clknode;
57 	uint32_t div_offset;
58 	uint32_t div_width;
59 	uint32_t div_shift;
60 	uint32_t enable_offset;
61 	uint32_t enable_shift;
62 	const struct qcom_clk_freq_tbl *freq_tbl;
63 };
64 
65 static uint64_t
66 qcom_clk_apssdiv_calc_rate(struct clknode *clk, uint64_t freq, uint32_t cdiv)
67 {
68 	uint32_t pre_div;
69 
70 	/*
71 	 * The divisor isn't a linear map with a linear pre-divisor.
72 	 */
73 	if (cdiv > 10) {
74 		pre_div = (cdiv + 1) * 2;
75 	} else {
76 		pre_div = cdiv + 12;
77 	}
78 	/*
79 	 * Multiplier is a fixed "2" here.
80 	 */
81 	return (freq * 2L) / pre_div;
82 }
83 
84 static int
85 qcom_clk_apssdiv_recalc(struct clknode *clk, uint64_t *freq)
86 {
87 	struct qcom_clk_apssdiv_sc *sc;
88 	uint32_t reg, cdiv;
89 
90 	sc = clknode_get_softc(clk);
91 
92 	if (freq == NULL || *freq == 0) {
93 		printf("%s: called; NULL or 0 frequency\n", __func__);
94 		return (ENXIO);
95 	}
96 
97 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
98 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->div_offset, &reg);
99 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
100 	cdiv = (reg >> sc->div_shift) & ((1U << sc->div_width) - 1);
101 
102 	DPRINTF(clknode_get_device(sc->clknode),
103 	    "%s: called; cdiv=0x%x, freq=%llu\n", __func__, cdiv, *freq);
104 
105 	*freq = qcom_clk_apssdiv_calc_rate(clk, *freq, cdiv);
106 
107 	DPRINTF(clknode_get_device(sc->clknode),
108 	    "%s: called; freq is %llu\n", __func__, *freq);
109 	return (0);
110 }
111 
112 #if 0
113 static bool
114 qcom_clk_apssdiv_get_gate_locked(struct qcom_clk_apssdiv_sc *sc)
115 {
116 	uint32_t reg;
117 
118 	if (sc->enable_offset == 0)
119 		return (false);
120 
121 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->enable_offset,
122 	    &reg);
123 
124 	return (!! (reg & (1U << sc->enable_shift)));
125 }
126 #endif
127 
128 static int
129 qcom_clk_apssdiv_init(struct clknode *clk, device_t dev)
130 {
131 
132 	/*
133 	 * There's only a single parent here for an fixed divisor,
134 	 * so just set it to 0; the caller doesn't need to supply it.
135 	 *
136 	 * Note that the freqtbl entries have an upstream clock,
137 	 * but the APSS div/gate only has a single upstream and we
138 	 * don't program anything else specific in here.
139 	 */
140 	clknode_init_parent_idx(clk, 0);
141 
142 	return (0);
143 }
144 
145 static int
146 qcom_clk_apssdiv_set_gate(struct clknode *clk, bool enable)
147 {
148 	struct qcom_clk_apssdiv_sc *sc;
149 	uint32_t reg;
150 
151 	sc = clknode_get_softc(clk);
152 
153 	if (sc->enable_offset == 0) {
154 		return (ENXIO);
155 	}
156 
157 	DPRINTF(clknode_get_device(sc->clknode),
158 	    "%s: called; enable=%d\n", __func__, enable);
159 
160 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
161 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->enable_offset,
162 	    &reg);
163 	if (enable) {
164 		reg |= (1U << sc->enable_shift);
165 	} else {
166 		reg &= ~(1U << sc->enable_shift);
167 	}
168 	CLKDEV_WRITE_4(clknode_get_device(sc->clknode), sc->enable_offset,
169 	    reg);
170 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
171 
172 	return (0);
173 }
174 
175 /*
176  * Set frequency
177  *
178  * fin - the parent frequency, if exists
179  * fout - starts as the requested frequency, ends with the configured
180  *        or dry-run frequency
181  * Flags - CLK_SET_DRYRUN, CLK_SET_ROUND_UP, CLK_SET_ROUND_DOWN
182  * retval - 0, ERANGE
183  */
184 static int
185 qcom_clk_apssdiv_set_freq(struct clknode *clk, uint64_t fin, uint64_t *fout,
186     int flags, int *stop)
187 {
188 	const struct qcom_clk_freq_tbl *f;
189 	struct qcom_clk_apssdiv_sc *sc;
190 	uint64_t f_freq;
191 	uint32_t reg;
192 
193 	sc = clknode_get_softc(clk);
194 
195 	/* There are no further PLLs to set in this chain */
196 	*stop = 1;
197 
198 	/* Search the table for a suitable frequency */
199 	f = qcom_clk_freq_tbl_lookup(sc->freq_tbl, *fout);
200 	if (f == NULL) {
201 		return (ERANGE);
202 	}
203 
204 	/*
205 	 * Calculate what the resultant frequency would be based on the
206 	 * parent PLL.
207 	 */
208 	f_freq = qcom_clk_apssdiv_calc_rate(clk, fin, f->pre_div);
209 
210 	DPRINTF(clknode_get_device(sc->clknode),
211 	    "%s: dryrun: %d, fin=%llu fout=%llu f_freq=%llu pre_div=%u"
212 	    " target_freq=%llu\n",
213 	    __func__,
214 	    !! (flags & CLK_SET_DRYRUN),
215 	    fin, *fout, f_freq, f->pre_div, f->freq);
216 
217 	if (flags & CLK_SET_DRYRUN) {
218 		*fout = f_freq;
219 		return (0);
220 	}
221 
222 	/*
223 	 * Program in the new pre-divisor.
224 	 */
225 	CLKDEV_DEVICE_LOCK(clknode_get_device(sc->clknode));
226 	CLKDEV_READ_4(clknode_get_device(sc->clknode), sc->div_offset, &reg);
227 	reg &= ~(((1U << sc->div_width) - 1) << sc->div_shift);
228 	reg |= (f->pre_div << sc->div_shift);
229 	CLKDEV_WRITE_4(clknode_get_device(sc->clknode), sc->div_offset, reg);
230 	CLKDEV_DEVICE_UNLOCK(clknode_get_device(sc->clknode));
231 
232 	/*
233 	 * The linux driver notes there's no status/completion bit to poll.
234 	 * So sleep for a bit and hope that's enough time for it to
235 	 * settle.
236 	 */
237 	DELAY(1);
238 
239 	*fout = f_freq;
240 
241 	return (0);
242 }
243 
244 static clknode_method_t qcom_clk_apssdiv_methods[] = {
245 	/* Device interface */
246 	CLKNODEMETHOD(clknode_init,		qcom_clk_apssdiv_init),
247 	CLKNODEMETHOD(clknode_recalc_freq,	qcom_clk_apssdiv_recalc),
248 	CLKNODEMETHOD(clknode_set_gate,		qcom_clk_apssdiv_set_gate),
249 	CLKNODEMETHOD(clknode_set_freq,		qcom_clk_apssdiv_set_freq),
250 	CLKNODEMETHOD_END
251 };
252 
253 DEFINE_CLASS_1(qcom_clk_apssdiv, qcom_clk_apssdiv_class,
254     qcom_clk_apssdiv_methods, sizeof(struct qcom_clk_apssdiv_sc),
255     clknode_class);
256 
257 int
258 qcom_clk_apssdiv_register(struct clkdom *clkdom,
259     struct qcom_clk_apssdiv_def *clkdef)
260 {
261 	struct clknode *clk;
262 	struct qcom_clk_apssdiv_sc *sc;
263 
264 	clk = clknode_create(clkdom, &qcom_clk_apssdiv_class, &clkdef->clkdef);
265 	if (clk == NULL)
266 		return (1);
267 
268 	sc = clknode_get_softc(clk);
269 	sc->clknode = clk;
270 
271 	sc->div_offset = clkdef->div_offset;
272 	sc->div_width = clkdef->div_width;
273 	sc->div_shift = clkdef->div_shift;
274 	sc->freq_tbl = clkdef->freq_tbl;
275 	sc->enable_offset = clkdef->enable_offset;
276 	sc->enable_shift = clkdef->enable_shift;
277 
278 	clknode_register(clkdom, clk);
279 
280 	return (0);
281 }
282