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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
49struct 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
56static 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
73static 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
83static 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
95static 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
105static 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
122static 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
146static 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
157static 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
195static 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
205static 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
213static const struct clk_ops a9periphclk_ops = {
214 .recalc_rate = clk_cpu_periphclk_recalc_rate,
215};
216
217static 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
226static const struct clk_ops a9bclk_ops = {
227 .recalc_rate = clk_cpu_a9bclk_recalc_rate,
228};
229
230static 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
243static 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
255static 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
269static 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
275static __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", ®);
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
319static void __init hb_pll_init(struct device_node *node)
320{
321 hb_clk_init(node, &clk_pll_ops);
322}
323CLK_OF_DECLARE(hb_pll, "calxeda,hb-pll-clock", hb_pll_init);
324
325static void __init hb_a9periph_init(struct device_node *node)
326{
327 hb_clk_init(node, &a9periphclk_ops);
328}
329CLK_OF_DECLARE(hb_a9periph, "calxeda,hb-a9periph-clock", hb_a9periph_init);
330
331static 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}
336CLK_OF_DECLARE(hb_a9bus, "calxeda,hb-a9bus-clock", hb_a9bus_init);
337
338static void __init hb_emmc_init(struct device_node *node)
339{
340 hb_clk_init(node, &periclk_ops);
341}
342CLK_OF_DECLARE(hb_emmc, "calxeda,hb-emmc-clock", hb_emmc_init);