xref: /openbmc/linux/drivers/clk/clk-highbank.c (revision 293d5b43) 
1 /*
2  * Copyright 2011-2012 Calxeda, Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program.  If not, see <http://www.gnu.org/licenses/>.
15  */
16 
17 #include <linux/kernel.h>
18 #include <linux/slab.h>
19 #include <linux/err.h>
20 #include <linux/clk.h>
21 #include <linux/clk-provider.h>
22 #include <linux/io.h>
23 #include <linux/of.h>
24 #include <linux/of_address.h>
25 
26 #define HB_PLL_LOCK_500		0x20000000
27 #define HB_PLL_LOCK		0x10000000
28 #define HB_PLL_DIVF_SHIFT	20
29 #define HB_PLL_DIVF_MASK	0x0ff00000
30 #define HB_PLL_DIVQ_SHIFT	16
31 #define HB_PLL_DIVQ_MASK	0x00070000
32 #define HB_PLL_DIVR_SHIFT	8
33 #define HB_PLL_DIVR_MASK	0x00001f00
34 #define HB_PLL_RANGE_SHIFT	4
35 #define HB_PLL_RANGE_MASK	0x00000070
36 #define HB_PLL_BYPASS		0x00000008
37 #define HB_PLL_RESET		0x00000004
38 #define HB_PLL_EXT_BYPASS	0x00000002
39 #define HB_PLL_EXT_ENA		0x00000001
40 
41 #define HB_PLL_VCO_MIN_FREQ	2133000000
42 #define HB_PLL_MAX_FREQ		HB_PLL_VCO_MIN_FREQ
43 #define HB_PLL_MIN_FREQ		(HB_PLL_VCO_MIN_FREQ / 64)
44 
45 #define HB_A9_BCLK_DIV_MASK	0x00000006
46 #define HB_A9_BCLK_DIV_SHIFT	1
47 #define HB_A9_PCLK_DIV		0x00000001
48 
49 struct hb_clk {
50         struct clk_hw	hw;
51 	void __iomem	*reg;
52 	char *parent_name;
53 };
54 #define to_hb_clk(p) container_of(p, struct hb_clk, hw)
55 
56 static int clk_pll_prepare(struct clk_hw *hwclk)
57 	{
58 	struct hb_clk *hbclk = to_hb_clk(hwclk);
59 	u32 reg;
60 
61 	reg = readl(hbclk->reg);
62 	reg &= ~HB_PLL_RESET;
63 	writel(reg, hbclk->reg);
64 
65 	while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
66 		;
67 	while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
68 		;
69 
70 	return 0;
71 }
72 
73 static void clk_pll_unprepare(struct clk_hw *hwclk)
74 {
75 	struct hb_clk *hbclk = to_hb_clk(hwclk);
76 	u32 reg;
77 
78 	reg = readl(hbclk->reg);
79 	reg |= HB_PLL_RESET;
80 	writel(reg, hbclk->reg);
81 }
82 
83 static int clk_pll_enable(struct clk_hw *hwclk)
84 {
85 	struct hb_clk *hbclk = to_hb_clk(hwclk);
86 	u32 reg;
87 
88 	reg = readl(hbclk->reg);
89 	reg |= HB_PLL_EXT_ENA;
90 	writel(reg, hbclk->reg);
91 
92 	return 0;
93 }
94 
95 static void clk_pll_disable(struct clk_hw *hwclk)
96 {
97 	struct hb_clk *hbclk = to_hb_clk(hwclk);
98 	u32 reg;
99 
100 	reg = readl(hbclk->reg);
101 	reg &= ~HB_PLL_EXT_ENA;
102 	writel(reg, hbclk->reg);
103 }
104 
105 static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
106 					 unsigned long parent_rate)
107 {
108 	struct hb_clk *hbclk = to_hb_clk(hwclk);
109 	unsigned long divf, divq, vco_freq, reg;
110 
111 	reg = readl(hbclk->reg);
112 	if (reg & HB_PLL_EXT_BYPASS)
113 		return parent_rate;
114 
115 	divf = (reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT;
116 	divq = (reg & HB_PLL_DIVQ_MASK) >> HB_PLL_DIVQ_SHIFT;
117 	vco_freq = parent_rate * (divf + 1);
118 
119 	return vco_freq / (1 << divq);
120 }
121 
122 static void clk_pll_calc(unsigned long rate, unsigned long ref_freq,
123 			u32 *pdivq, u32 *pdivf)
124 {
125 	u32 divq, divf;
126 	unsigned long vco_freq;
127 
128 	if (rate < HB_PLL_MIN_FREQ)
129 		rate = HB_PLL_MIN_FREQ;
130 	if (rate > HB_PLL_MAX_FREQ)
131 		rate = HB_PLL_MAX_FREQ;
132 
133 	for (divq = 1; divq <= 6; divq++) {
134 		if ((rate * (1 << divq)) >= HB_PLL_VCO_MIN_FREQ)
135 			break;
136 	}
137 
138 	vco_freq = rate * (1 << divq);
139 	divf = (vco_freq + (ref_freq / 2)) / ref_freq;
140 	divf--;
141 
142 	*pdivq = divq;
143 	*pdivf = divf;
144 }
145 
146 static long clk_pll_round_rate(struct clk_hw *hwclk, unsigned long rate,
147 			       unsigned long *parent_rate)
148 {
149 	u32 divq, divf;
150 	unsigned long ref_freq = *parent_rate;
151 
152 	clk_pll_calc(rate, ref_freq, &divq, &divf);
153 
154 	return (ref_freq * (divf + 1)) / (1 << divq);
155 }
156 
157 static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
158 			    unsigned long parent_rate)
159 {
160 	struct hb_clk *hbclk = to_hb_clk(hwclk);
161 	u32 divq, divf;
162 	u32 reg;
163 
164 	clk_pll_calc(rate, parent_rate, &divq, &divf);
165 
166 	reg = readl(hbclk->reg);
167 	if (divf != ((reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT)) {
168 		/* Need to re-lock PLL, so put it into bypass mode */
169 		reg |= HB_PLL_EXT_BYPASS;
170 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
171 
172 		writel(reg | HB_PLL_RESET, hbclk->reg);
173 		reg &= ~(HB_PLL_DIVF_MASK | HB_PLL_DIVQ_MASK);
174 		reg |= (divf << HB_PLL_DIVF_SHIFT) | (divq << HB_PLL_DIVQ_SHIFT);
175 		writel(reg | HB_PLL_RESET, hbclk->reg);
176 		writel(reg, hbclk->reg);
177 
178 		while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
179 			;
180 		while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
181 			;
182 		reg |= HB_PLL_EXT_ENA;
183 		reg &= ~HB_PLL_EXT_BYPASS;
184 	} else {
185 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
186 		reg &= ~HB_PLL_DIVQ_MASK;
187 		reg |= divq << HB_PLL_DIVQ_SHIFT;
188 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
189 	}
190 	writel(reg, hbclk->reg);
191 
192 	return 0;
193 }
194 
195 static const struct clk_ops clk_pll_ops = {
196 	.prepare = clk_pll_prepare,
197 	.unprepare = clk_pll_unprepare,
198 	.enable = clk_pll_enable,
199 	.disable = clk_pll_disable,
200 	.recalc_rate = clk_pll_recalc_rate,
201 	.round_rate = clk_pll_round_rate,
202 	.set_rate = clk_pll_set_rate,
203 };
204 
205 static unsigned long clk_cpu_periphclk_recalc_rate(struct clk_hw *hwclk,
206 						   unsigned long parent_rate)
207 {
208 	struct hb_clk *hbclk = to_hb_clk(hwclk);
209 	u32 div = (readl(hbclk->reg) & HB_A9_PCLK_DIV) ? 8 : 4;
210 	return parent_rate / div;
211 }
212 
213 static const struct clk_ops a9periphclk_ops = {
214 	.recalc_rate = clk_cpu_periphclk_recalc_rate,
215 };
216 
217 static unsigned long clk_cpu_a9bclk_recalc_rate(struct clk_hw *hwclk,
218 						unsigned long parent_rate)
219 {
220 	struct hb_clk *hbclk = to_hb_clk(hwclk);
221 	u32 div = (readl(hbclk->reg) & HB_A9_BCLK_DIV_MASK) >> HB_A9_BCLK_DIV_SHIFT;
222 
223 	return parent_rate / (div + 2);
224 }
225 
226 static const struct clk_ops a9bclk_ops = {
227 	.recalc_rate = clk_cpu_a9bclk_recalc_rate,
228 };
229 
230 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
231 					     unsigned long parent_rate)
232 {
233 	struct hb_clk *hbclk = to_hb_clk(hwclk);
234 	u32 div;
235 
236 	div = readl(hbclk->reg) & 0x1f;
237 	div++;
238 	div *= 2;
239 
240 	return parent_rate / div;
241 }
242 
243 static long clk_periclk_round_rate(struct clk_hw *hwclk, unsigned long rate,
244 				   unsigned long *parent_rate)
245 {
246 	u32 div;
247 
248 	div = *parent_rate / rate;
249 	div++;
250 	div &= ~0x1;
251 
252 	return *parent_rate / div;
253 }
254 
255 static int clk_periclk_set_rate(struct clk_hw *hwclk, unsigned long rate,
256 				unsigned long parent_rate)
257 {
258 	struct hb_clk *hbclk = to_hb_clk(hwclk);
259 	u32 div;
260 
261 	div = parent_rate / rate;
262 	if (div & 0x1)
263 		return -EINVAL;
264 
265 	writel(div >> 1, hbclk->reg);
266 	return 0;
267 }
268 
269 static const struct clk_ops periclk_ops = {
270 	.recalc_rate = clk_periclk_recalc_rate,
271 	.round_rate = clk_periclk_round_rate,
272 	.set_rate = clk_periclk_set_rate,
273 };
274 
275 static __init struct clk *hb_clk_init(struct device_node *node, const struct clk_ops *ops)
276 {
277 	u32 reg;
278 	struct hb_clk *hb_clk;
279 	const char *clk_name = node->name;
280 	const char *parent_name;
281 	struct clk_init_data init;
282 	struct device_node *srnp;
283 	int rc;
284 
285 	rc = of_property_read_u32(node, "reg", &reg);
286 	if (WARN_ON(rc))
287 		return NULL;
288 
289 	hb_clk = kzalloc(sizeof(*hb_clk), GFP_KERNEL);
290 	if (WARN_ON(!hb_clk))
291 		return NULL;
292 
293 	/* Map system registers */
294 	srnp = of_find_compatible_node(NULL, NULL, "calxeda,hb-sregs");
295 	hb_clk->reg = of_iomap(srnp, 0);
296 	BUG_ON(!hb_clk->reg);
297 	hb_clk->reg += reg;
298 
299 	of_property_read_string(node, "clock-output-names", &clk_name);
300 
301 	init.name = clk_name;
302 	init.ops = ops;
303 	init.flags = 0;
304 	parent_name = of_clk_get_parent_name(node, 0);
305 	init.parent_names = &parent_name;
306 	init.num_parents = 1;
307 
308 	hb_clk->hw.init = &init;
309 
310 	rc = clk_hw_register(NULL, &hb_clk->hw);
311 	if (WARN_ON(rc)) {
312 		kfree(hb_clk);
313 		return NULL;
314 	}
315 	rc = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &hb_clk->hw);
316 	return hb_clk->hw.clk;
317 }
318 
319 static void __init hb_pll_init(struct device_node *node)
320 {
321 	hb_clk_init(node, &clk_pll_ops);
322 }
323 CLK_OF_DECLARE(hb_pll, "calxeda,hb-pll-clock", hb_pll_init);
324 
325 static void __init hb_a9periph_init(struct device_node *node)
326 {
327 	hb_clk_init(node, &a9periphclk_ops);
328 }
329 CLK_OF_DECLARE(hb_a9periph, "calxeda,hb-a9periph-clock", hb_a9periph_init);
330 
331 static void __init hb_a9bus_init(struct device_node *node)
332 {
333 	struct clk *clk = hb_clk_init(node, &a9bclk_ops);
334 	clk_prepare_enable(clk);
335 }
336 CLK_OF_DECLARE(hb_a9bus, "calxeda,hb-a9bus-clock", hb_a9bus_init);
337 
338 static void __init hb_emmc_init(struct device_node *node)
339 {
340 	hb_clk_init(node, &periclk_ops);
341 }
342 CLK_OF_DECLARE(hb_emmc, "calxeda,hb-emmc-clock", hb_emmc_init);
343