xref: /openbmc/linux/drivers/clk/sunxi-ng/ccu_mp.c (revision 657f477a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Maxime Ripard
4  * Maxime Ripard <maxime.ripard@free-electrons.com>
5  */
6 
7 #include <linux/clk-provider.h>
8 #include <linux/io.h>
9 
10 #include "ccu_gate.h"
11 #include "ccu_mp.h"
12 
ccu_mp_find_best(unsigned long parent,unsigned long rate,unsigned int max_m,unsigned int max_p,unsigned int * m,unsigned int * p)13 static unsigned long ccu_mp_find_best(unsigned long parent, unsigned long rate,
14 				      unsigned int max_m, unsigned int max_p,
15 				      unsigned int *m, unsigned int *p)
16 {
17 	unsigned long best_rate = 0;
18 	unsigned int best_m = 0, best_p = 0;
19 	unsigned int _m, _p;
20 
21 	for (_p = 1; _p <= max_p; _p <<= 1) {
22 		for (_m = 1; _m <= max_m; _m++) {
23 			unsigned long tmp_rate = parent / _p / _m;
24 
25 			if (tmp_rate > rate)
26 				continue;
27 
28 			if ((rate - tmp_rate) < (rate - best_rate)) {
29 				best_rate = tmp_rate;
30 				best_m = _m;
31 				best_p = _p;
32 			}
33 		}
34 	}
35 
36 	*m = best_m;
37 	*p = best_p;
38 
39 	return best_rate;
40 }
41 
ccu_mp_find_best_with_parent_adj(struct clk_hw * hw,unsigned long * parent,unsigned long rate,unsigned int max_m,unsigned int max_p)42 static unsigned long ccu_mp_find_best_with_parent_adj(struct clk_hw *hw,
43 						      unsigned long *parent,
44 						      unsigned long rate,
45 						      unsigned int max_m,
46 						      unsigned int max_p)
47 {
48 	unsigned long parent_rate_saved;
49 	unsigned long parent_rate, now;
50 	unsigned long best_rate = 0;
51 	unsigned int _m, _p, div;
52 	unsigned long maxdiv;
53 
54 	parent_rate_saved = *parent;
55 
56 	/*
57 	 * The maximum divider we can use without overflowing
58 	 * unsigned long in rate * m * p below
59 	 */
60 	maxdiv = max_m * max_p;
61 	maxdiv = min(ULONG_MAX / rate, maxdiv);
62 
63 	for (_p = 1; _p <= max_p; _p <<= 1) {
64 		for (_m = 1; _m <= max_m; _m++) {
65 			div = _m * _p;
66 
67 			if (div > maxdiv)
68 				break;
69 
70 			if (rate * div == parent_rate_saved) {
71 				/*
72 				 * It's the most ideal case if the requested
73 				 * rate can be divided from parent clock without
74 				 * needing to change parent rate, so return the
75 				 * divider immediately.
76 				 */
77 				*parent = parent_rate_saved;
78 				return rate;
79 			}
80 
81 			parent_rate = clk_hw_round_rate(hw, rate * div);
82 			now = parent_rate / div;
83 
84 			if (now <= rate && now > best_rate) {
85 				best_rate = now;
86 				*parent = parent_rate;
87 
88 				if (now == rate)
89 					return rate;
90 			}
91 		}
92 	}
93 
94 	return best_rate;
95 }
96 
ccu_mp_round_rate(struct ccu_mux_internal * mux,struct clk_hw * hw,unsigned long * parent_rate,unsigned long rate,void * data)97 static unsigned long ccu_mp_round_rate(struct ccu_mux_internal *mux,
98 				       struct clk_hw *hw,
99 				       unsigned long *parent_rate,
100 				       unsigned long rate,
101 				       void *data)
102 {
103 	struct ccu_mp *cmp = data;
104 	unsigned int max_m, max_p;
105 	unsigned int m, p;
106 
107 	if (cmp->common.features & CCU_FEATURE_FIXED_POSTDIV)
108 		rate *= cmp->fixed_post_div;
109 
110 	max_m = cmp->m.max ?: 1 << cmp->m.width;
111 	max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1);
112 
113 	if (!clk_hw_can_set_rate_parent(&cmp->common.hw)) {
114 		rate = ccu_mp_find_best(*parent_rate, rate, max_m, max_p, &m, &p);
115 	} else {
116 		rate = ccu_mp_find_best_with_parent_adj(hw, parent_rate, rate,
117 							max_m, max_p);
118 	}
119 
120 	if (cmp->common.features & CCU_FEATURE_FIXED_POSTDIV)
121 		rate /= cmp->fixed_post_div;
122 
123 	return rate;
124 }
125 
ccu_mp_disable(struct clk_hw * hw)126 static void ccu_mp_disable(struct clk_hw *hw)
127 {
128 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
129 
130 	return ccu_gate_helper_disable(&cmp->common, cmp->enable);
131 }
132 
ccu_mp_enable(struct clk_hw * hw)133 static int ccu_mp_enable(struct clk_hw *hw)
134 {
135 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
136 
137 	return ccu_gate_helper_enable(&cmp->common, cmp->enable);
138 }
139 
ccu_mp_is_enabled(struct clk_hw * hw)140 static int ccu_mp_is_enabled(struct clk_hw *hw)
141 {
142 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
143 
144 	return ccu_gate_helper_is_enabled(&cmp->common, cmp->enable);
145 }
146 
ccu_mp_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)147 static unsigned long ccu_mp_recalc_rate(struct clk_hw *hw,
148 					unsigned long parent_rate)
149 {
150 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
151 	unsigned long rate;
152 	unsigned int m, p;
153 	u32 reg;
154 
155 	/* Adjust parent_rate according to pre-dividers */
156 	parent_rate = ccu_mux_helper_apply_prediv(&cmp->common, &cmp->mux, -1,
157 						  parent_rate);
158 
159 	reg = readl(cmp->common.base + cmp->common.reg);
160 
161 	m = reg >> cmp->m.shift;
162 	m &= (1 << cmp->m.width) - 1;
163 	m += cmp->m.offset;
164 	if (!m)
165 		m++;
166 
167 	p = reg >> cmp->p.shift;
168 	p &= (1 << cmp->p.width) - 1;
169 
170 	rate = (parent_rate >> p) / m;
171 	if (cmp->common.features & CCU_FEATURE_FIXED_POSTDIV)
172 		rate /= cmp->fixed_post_div;
173 
174 	return rate;
175 }
176 
ccu_mp_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)177 static int ccu_mp_determine_rate(struct clk_hw *hw,
178 				 struct clk_rate_request *req)
179 {
180 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
181 
182 	return ccu_mux_helper_determine_rate(&cmp->common, &cmp->mux,
183 					     req, ccu_mp_round_rate, cmp);
184 }
185 
ccu_mp_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)186 static int ccu_mp_set_rate(struct clk_hw *hw, unsigned long rate,
187 			   unsigned long parent_rate)
188 {
189 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
190 	unsigned long flags;
191 	unsigned int max_m, max_p;
192 	unsigned int m, p;
193 	u32 reg;
194 
195 	/* Adjust parent_rate according to pre-dividers */
196 	parent_rate = ccu_mux_helper_apply_prediv(&cmp->common, &cmp->mux, -1,
197 						  parent_rate);
198 
199 	max_m = cmp->m.max ?: 1 << cmp->m.width;
200 	max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1);
201 
202 	/* Adjust target rate according to post-dividers */
203 	if (cmp->common.features & CCU_FEATURE_FIXED_POSTDIV)
204 		rate = rate * cmp->fixed_post_div;
205 
206 	ccu_mp_find_best(parent_rate, rate, max_m, max_p, &m, &p);
207 
208 	spin_lock_irqsave(cmp->common.lock, flags);
209 
210 	reg = readl(cmp->common.base + cmp->common.reg);
211 	reg &= ~GENMASK(cmp->m.width + cmp->m.shift - 1, cmp->m.shift);
212 	reg &= ~GENMASK(cmp->p.width + cmp->p.shift - 1, cmp->p.shift);
213 	reg |= (m - cmp->m.offset) << cmp->m.shift;
214 	reg |= ilog2(p) << cmp->p.shift;
215 
216 	writel(reg, cmp->common.base + cmp->common.reg);
217 
218 	spin_unlock_irqrestore(cmp->common.lock, flags);
219 
220 	return 0;
221 }
222 
ccu_mp_get_parent(struct clk_hw * hw)223 static u8 ccu_mp_get_parent(struct clk_hw *hw)
224 {
225 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
226 
227 	return ccu_mux_helper_get_parent(&cmp->common, &cmp->mux);
228 }
229 
ccu_mp_set_parent(struct clk_hw * hw,u8 index)230 static int ccu_mp_set_parent(struct clk_hw *hw, u8 index)
231 {
232 	struct ccu_mp *cmp = hw_to_ccu_mp(hw);
233 
234 	return ccu_mux_helper_set_parent(&cmp->common, &cmp->mux, index);
235 }
236 
237 const struct clk_ops ccu_mp_ops = {
238 	.disable	= ccu_mp_disable,
239 	.enable		= ccu_mp_enable,
240 	.is_enabled	= ccu_mp_is_enabled,
241 
242 	.get_parent	= ccu_mp_get_parent,
243 	.set_parent	= ccu_mp_set_parent,
244 
245 	.determine_rate	= ccu_mp_determine_rate,
246 	.recalc_rate	= ccu_mp_recalc_rate,
247 	.set_rate	= ccu_mp_set_rate,
248 };
249 EXPORT_SYMBOL_NS_GPL(ccu_mp_ops, SUNXI_CCU);
250 
251 /*
252  * Support for MMC timing mode switching
253  *
254  * The MMC clocks on some SoCs support switching between old and
255  * new timing modes. A platform specific API is provided to query
256  * and set the timing mode on supported SoCs.
257  *
258  * In addition, a special class of ccu_mp_ops is provided, which
259  * takes in to account the timing mode switch. When the new timing
260  * mode is active, the clock output rate is halved. This new class
261  * is a wrapper around the generic ccu_mp_ops. When clock rates
262  * are passed through to ccu_mp_ops callbacks, they are doubled
263  * if the new timing mode bit is set, to account for the post
264  * divider. Conversely, when clock rates are passed back, they
265  * are halved if the mode bit is set.
266  */
267 
ccu_mp_mmc_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)268 static unsigned long ccu_mp_mmc_recalc_rate(struct clk_hw *hw,
269 					    unsigned long parent_rate)
270 {
271 	unsigned long rate = ccu_mp_recalc_rate(hw, parent_rate);
272 	struct ccu_common *cm = hw_to_ccu_common(hw);
273 	u32 val = readl(cm->base + cm->reg);
274 
275 	if (val & CCU_MMC_NEW_TIMING_MODE)
276 		return rate / 2;
277 	return rate;
278 }
279 
ccu_mp_mmc_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)280 static int ccu_mp_mmc_determine_rate(struct clk_hw *hw,
281 				     struct clk_rate_request *req)
282 {
283 	struct ccu_common *cm = hw_to_ccu_common(hw);
284 	u32 val = readl(cm->base + cm->reg);
285 	int ret;
286 
287 	/* adjust the requested clock rate */
288 	if (val & CCU_MMC_NEW_TIMING_MODE) {
289 		req->rate *= 2;
290 		req->min_rate *= 2;
291 		req->max_rate *= 2;
292 	}
293 
294 	ret = ccu_mp_determine_rate(hw, req);
295 
296 	/* re-adjust the requested clock rate back */
297 	if (val & CCU_MMC_NEW_TIMING_MODE) {
298 		req->rate /= 2;
299 		req->min_rate /= 2;
300 		req->max_rate /= 2;
301 	}
302 
303 	return ret;
304 }
305 
ccu_mp_mmc_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)306 static int ccu_mp_mmc_set_rate(struct clk_hw *hw, unsigned long rate,
307 			       unsigned long parent_rate)
308 {
309 	struct ccu_common *cm = hw_to_ccu_common(hw);
310 	u32 val = readl(cm->base + cm->reg);
311 
312 	if (val & CCU_MMC_NEW_TIMING_MODE)
313 		rate *= 2;
314 
315 	return ccu_mp_set_rate(hw, rate, parent_rate);
316 }
317 
318 const struct clk_ops ccu_mp_mmc_ops = {
319 	.disable	= ccu_mp_disable,
320 	.enable		= ccu_mp_enable,
321 	.is_enabled	= ccu_mp_is_enabled,
322 
323 	.get_parent	= ccu_mp_get_parent,
324 	.set_parent	= ccu_mp_set_parent,
325 
326 	.determine_rate	= ccu_mp_mmc_determine_rate,
327 	.recalc_rate	= ccu_mp_mmc_recalc_rate,
328 	.set_rate	= ccu_mp_mmc_set_rate,
329 };
330 EXPORT_SYMBOL_NS_GPL(ccu_mp_mmc_ops, SUNXI_CCU);
331