xref: /openbmc/linux/drivers/clk/clk-highbank.c (revision 3e30a927) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2011-2012 Calxeda, Inc.
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/slab.h>
8 #include <linux/err.h>
9 #include <linux/clk-provider.h>
10 #include <linux/io.h>
11 #include <linux/of.h>
12 #include <linux/of_address.h>
13 
14 #define HB_PLL_LOCK_500		0x20000000
15 #define HB_PLL_LOCK		0x10000000
16 #define HB_PLL_DIVF_SHIFT	20
17 #define HB_PLL_DIVF_MASK	0x0ff00000
18 #define HB_PLL_DIVQ_SHIFT	16
19 #define HB_PLL_DIVQ_MASK	0x00070000
20 #define HB_PLL_DIVR_SHIFT	8
21 #define HB_PLL_DIVR_MASK	0x00001f00
22 #define HB_PLL_RANGE_SHIFT	4
23 #define HB_PLL_RANGE_MASK	0x00000070
24 #define HB_PLL_BYPASS		0x00000008
25 #define HB_PLL_RESET		0x00000004
26 #define HB_PLL_EXT_BYPASS	0x00000002
27 #define HB_PLL_EXT_ENA		0x00000001
28 
29 #define HB_PLL_VCO_MIN_FREQ	2133000000
30 #define HB_PLL_MAX_FREQ		HB_PLL_VCO_MIN_FREQ
31 #define HB_PLL_MIN_FREQ		(HB_PLL_VCO_MIN_FREQ / 64)
32 
33 #define HB_A9_BCLK_DIV_MASK	0x00000006
34 #define HB_A9_BCLK_DIV_SHIFT	1
35 #define HB_A9_PCLK_DIV		0x00000001
36 
37 struct hb_clk {
38         struct clk_hw	hw;
39 	void __iomem	*reg;
40 	char *parent_name;
41 };
42 #define to_hb_clk(p) container_of(p, struct hb_clk, hw)
43 
44 static int clk_pll_prepare(struct clk_hw *hwclk)
45 	{
46 	struct hb_clk *hbclk = to_hb_clk(hwclk);
47 	u32 reg;
48 
49 	reg = readl(hbclk->reg);
50 	reg &= ~HB_PLL_RESET;
51 	writel(reg, hbclk->reg);
52 
53 	while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
54 		;
55 	while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
56 		;
57 
58 	return 0;
59 }
60 
61 static void clk_pll_unprepare(struct clk_hw *hwclk)
62 {
63 	struct hb_clk *hbclk = to_hb_clk(hwclk);
64 	u32 reg;
65 
66 	reg = readl(hbclk->reg);
67 	reg |= HB_PLL_RESET;
68 	writel(reg, hbclk->reg);
69 }
70 
71 static int clk_pll_enable(struct clk_hw *hwclk)
72 {
73 	struct hb_clk *hbclk = to_hb_clk(hwclk);
74 	u32 reg;
75 
76 	reg = readl(hbclk->reg);
77 	reg |= HB_PLL_EXT_ENA;
78 	writel(reg, hbclk->reg);
79 
80 	return 0;
81 }
82 
83 static void clk_pll_disable(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 
93 static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
94 					 unsigned long parent_rate)
95 {
96 	struct hb_clk *hbclk = to_hb_clk(hwclk);
97 	unsigned long divf, divq, vco_freq, reg;
98 
99 	reg = readl(hbclk->reg);
100 	if (reg & HB_PLL_EXT_BYPASS)
101 		return parent_rate;
102 
103 	divf = (reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT;
104 	divq = (reg & HB_PLL_DIVQ_MASK) >> HB_PLL_DIVQ_SHIFT;
105 	vco_freq = parent_rate * (divf + 1);
106 
107 	return vco_freq / (1 << divq);
108 }
109 
110 static void clk_pll_calc(unsigned long rate, unsigned long ref_freq,
111 			u32 *pdivq, u32 *pdivf)
112 {
113 	u32 divq, divf;
114 	unsigned long vco_freq;
115 
116 	if (rate < HB_PLL_MIN_FREQ)
117 		rate = HB_PLL_MIN_FREQ;
118 	if (rate > HB_PLL_MAX_FREQ)
119 		rate = HB_PLL_MAX_FREQ;
120 
121 	for (divq = 1; divq <= 6; divq++) {
122 		if ((rate * (1 << divq)) >= HB_PLL_VCO_MIN_FREQ)
123 			break;
124 	}
125 
126 	vco_freq = rate * (1 << divq);
127 	divf = (vco_freq + (ref_freq / 2)) / ref_freq;
128 	divf--;
129 
130 	*pdivq = divq;
131 	*pdivf = divf;
132 }
133 
134 static long clk_pll_round_rate(struct clk_hw *hwclk, unsigned long rate,
135 			       unsigned long *parent_rate)
136 {
137 	u32 divq, divf;
138 	unsigned long ref_freq = *parent_rate;
139 
140 	clk_pll_calc(rate, ref_freq, &divq, &divf);
141 
142 	return (ref_freq * (divf + 1)) / (1 << divq);
143 }
144 
145 static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
146 			    unsigned long parent_rate)
147 {
148 	struct hb_clk *hbclk = to_hb_clk(hwclk);
149 	u32 divq, divf;
150 	u32 reg;
151 
152 	clk_pll_calc(rate, parent_rate, &divq, &divf);
153 
154 	reg = readl(hbclk->reg);
155 	if (divf != ((reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT)) {
156 		/* Need to re-lock PLL, so put it into bypass mode */
157 		reg |= HB_PLL_EXT_BYPASS;
158 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
159 
160 		writel(reg | HB_PLL_RESET, hbclk->reg);
161 		reg &= ~(HB_PLL_DIVF_MASK | HB_PLL_DIVQ_MASK);
162 		reg |= (divf << HB_PLL_DIVF_SHIFT) | (divq << HB_PLL_DIVQ_SHIFT);
163 		writel(reg | HB_PLL_RESET, hbclk->reg);
164 		writel(reg, hbclk->reg);
165 
166 		while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
167 			;
168 		while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
169 			;
170 		reg |= HB_PLL_EXT_ENA;
171 		reg &= ~HB_PLL_EXT_BYPASS;
172 	} else {
173 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
174 		reg &= ~HB_PLL_DIVQ_MASK;
175 		reg |= divq << HB_PLL_DIVQ_SHIFT;
176 		writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
177 	}
178 	writel(reg, hbclk->reg);
179 
180 	return 0;
181 }
182 
183 static const struct clk_ops clk_pll_ops = {
184 	.prepare = clk_pll_prepare,
185 	.unprepare = clk_pll_unprepare,
186 	.enable = clk_pll_enable,
187 	.disable = clk_pll_disable,
188 	.recalc_rate = clk_pll_recalc_rate,
189 	.round_rate = clk_pll_round_rate,
190 	.set_rate = clk_pll_set_rate,
191 };
192 
193 static unsigned long clk_cpu_periphclk_recalc_rate(struct clk_hw *hwclk,
194 						   unsigned long parent_rate)
195 {
196 	struct hb_clk *hbclk = to_hb_clk(hwclk);
197 	u32 div = (readl(hbclk->reg) & HB_A9_PCLK_DIV) ? 8 : 4;
198 	return parent_rate / div;
199 }
200 
201 static const struct clk_ops a9periphclk_ops = {
202 	.recalc_rate = clk_cpu_periphclk_recalc_rate,
203 };
204 
205 static unsigned long clk_cpu_a9bclk_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_BCLK_DIV_MASK) >> HB_A9_BCLK_DIV_SHIFT;
210 
211 	return parent_rate / (div + 2);
212 }
213 
214 static const struct clk_ops a9bclk_ops = {
215 	.recalc_rate = clk_cpu_a9bclk_recalc_rate,
216 };
217 
218 static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
219 					     unsigned long parent_rate)
220 {
221 	struct hb_clk *hbclk = to_hb_clk(hwclk);
222 	u32 div;
223 
224 	div = readl(hbclk->reg) & 0x1f;
225 	div++;
226 	div *= 2;
227 
228 	return parent_rate / div;
229 }
230 
231 static long clk_periclk_round_rate(struct clk_hw *hwclk, unsigned long rate,
232 				   unsigned long *parent_rate)
233 {
234 	u32 div;
235 
236 	div = *parent_rate / rate;
237 	div++;
238 	div &= ~0x1;
239 
240 	return *parent_rate / div;
241 }
242 
243 static int clk_periclk_set_rate(struct clk_hw *hwclk, unsigned long rate,
244 				unsigned long parent_rate)
245 {
246 	struct hb_clk *hbclk = to_hb_clk(hwclk);
247 	u32 div;
248 
249 	div = parent_rate / rate;
250 	if (div & 0x1)
251 		return -EINVAL;
252 
253 	writel(div >> 1, hbclk->reg);
254 	return 0;
255 }
256 
257 static const struct clk_ops periclk_ops = {
258 	.recalc_rate = clk_periclk_recalc_rate,
259 	.round_rate = clk_periclk_round_rate,
260 	.set_rate = clk_periclk_set_rate,
261 };
262 
263 static void __init hb_clk_init(struct device_node *node, const struct clk_ops *ops, unsigned long clkflags)
264 {
265 	u32 reg;
266 	struct hb_clk *hb_clk;
267 	const char *clk_name = node->name;
268 	const char *parent_name;
269 	struct clk_init_data init;
270 	struct device_node *srnp;
271 	int rc;
272 
273 	rc = of_property_read_u32(node, "reg", &reg);
274 	if (WARN_ON(rc))
275 		return;
276 
277 	hb_clk = kzalloc(sizeof(*hb_clk), GFP_KERNEL);
278 	if (WARN_ON(!hb_clk))
279 		return;
280 
281 	/* Map system registers */
282 	srnp = of_find_compatible_node(NULL, NULL, "calxeda,hb-sregs");
283 	hb_clk->reg = of_iomap(srnp, 0);
284 	of_node_put(srnp);
285 	BUG_ON(!hb_clk->reg);
286 	hb_clk->reg += reg;
287 
288 	of_property_read_string(node, "clock-output-names", &clk_name);
289 
290 	init.name = clk_name;
291 	init.ops = ops;
292 	init.flags = clkflags;
293 	parent_name = of_clk_get_parent_name(node, 0);
294 	init.parent_names = &parent_name;
295 	init.num_parents = 1;
296 
297 	hb_clk->hw.init = &init;
298 
299 	rc = clk_hw_register(NULL, &hb_clk->hw);
300 	if (WARN_ON(rc)) {
301 		kfree(hb_clk);
302 		return;
303 	}
304 	of_clk_add_hw_provider(node, of_clk_hw_simple_get, &hb_clk->hw);
305 }
306 
307 static void __init hb_pll_init(struct device_node *node)
308 {
309 	hb_clk_init(node, &clk_pll_ops, 0);
310 }
311 CLK_OF_DECLARE(hb_pll, "calxeda,hb-pll-clock", hb_pll_init);
312 
313 static void __init hb_a9periph_init(struct device_node *node)
314 {
315 	hb_clk_init(node, &a9periphclk_ops, 0);
316 }
317 CLK_OF_DECLARE(hb_a9periph, "calxeda,hb-a9periph-clock", hb_a9periph_init);
318 
319 static void __init hb_a9bus_init(struct device_node *node)
320 {
321 	hb_clk_init(node, &a9bclk_ops, CLK_IS_CRITICAL);
322 }
323 CLK_OF_DECLARE(hb_a9bus, "calxeda,hb-a9bus-clock", hb_a9bus_init);
324 
325 static void __init hb_emmc_init(struct device_node *node)
326 {
327 	hb_clk_init(node, &periclk_ops, 0);
328 }
329 CLK_OF_DECLARE(hb_emmc, "calxeda,hb-emmc-clock", hb_emmc_init);
330