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dbb8fd34 | 1 | /* |
22d42399 BD |
2 | * Copyright 2008 Simtec Electronics |
3 | * http://armlinux.simtec.co.uk/ | |
4 | * Ben Dooks <ben@simtec.co.uk> | |
5 | * | |
6 | * S3C2412 CPU Frequency scalling | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/init.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/interrupt.h> | |
16 | #include <linux/ioport.h> | |
17 | #include <linux/cpufreq.h> | |
4a858cfc | 18 | #include <linux/device.h> |
22d42399 BD |
19 | #include <linux/delay.h> |
20 | #include <linux/clk.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/io.h> | |
23 | ||
24 | #include <asm/mach/arch.h> | |
25 | #include <asm/mach/map.h> | |
26 | ||
27 | #include <mach/regs-clock.h> | |
f023f8dd | 28 | #include <mach/s3c2412.h> |
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29 | |
30 | #include <plat/cpu.h> | |
22d42399 BD |
31 | #include <plat/cpu-freq-core.h> |
32 | ||
33 | /* our clock resources. */ | |
34 | static struct clk *xtal; | |
35 | static struct clk *fclk; | |
36 | static struct clk *hclk; | |
37 | static struct clk *armclk; | |
38 | ||
39 | /* HDIV: 1, 2, 3, 4, 6, 8 */ | |
40 | ||
41 | static int s3c2412_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg) | |
42 | { | |
43 | unsigned int hdiv, pdiv, armdiv, dvs; | |
44 | unsigned long hclk, fclk, armclk, armdiv_clk; | |
45 | unsigned long hclk_max; | |
46 | ||
47 | fclk = cfg->freq.fclk; | |
48 | armclk = cfg->freq.armclk; | |
49 | hclk_max = cfg->max.hclk; | |
50 | ||
51 | /* We can't run hclk above armclk as at the best we have to | |
52 | * have armclk and hclk in dvs mode. */ | |
53 | ||
54 | if (hclk_max > armclk) | |
55 | hclk_max = armclk; | |
56 | ||
57 | s3c_freq_dbg("%s: fclk=%lu, armclk=%lu, hclk_max=%lu\n", | |
58 | __func__, fclk, armclk, hclk_max); | |
59 | s3c_freq_dbg("%s: want f=%lu, arm=%lu, h=%lu, p=%lu\n", | |
60 | __func__, cfg->freq.fclk, cfg->freq.armclk, | |
61 | cfg->freq.hclk, cfg->freq.pclk); | |
62 | ||
63 | armdiv = fclk / armclk; | |
64 | ||
65 | if (armdiv < 1) | |
66 | armdiv = 1; | |
67 | if (armdiv > 2) | |
68 | armdiv = 2; | |
69 | ||
70 | cfg->divs.arm_divisor = armdiv; | |
71 | armdiv_clk = fclk / armdiv; | |
72 | ||
73 | hdiv = armdiv_clk / hclk_max; | |
74 | if (hdiv < 1) | |
75 | hdiv = 1; | |
76 | ||
77 | cfg->freq.hclk = hclk = armdiv_clk / hdiv; | |
78 | ||
79 | /* set dvs depending on whether we reached armclk or not. */ | |
80 | cfg->divs.dvs = dvs = armclk < armdiv_clk; | |
81 | ||
82 | /* update the actual armclk we achieved. */ | |
83 | cfg->freq.armclk = dvs ? hclk : armdiv_clk; | |
84 | ||
85 | s3c_freq_dbg("%s: armclk %lu, hclk %lu, armdiv %d, hdiv %d, dvs %d\n", | |
86 | __func__, armclk, hclk, armdiv, hdiv, cfg->divs.dvs); | |
87 | ||
88 | if (hdiv > 4) | |
89 | goto invalid; | |
90 | ||
91 | pdiv = (hclk > cfg->max.pclk) ? 2 : 1; | |
92 | ||
93 | if ((hclk / pdiv) > cfg->max.pclk) | |
94 | pdiv++; | |
95 | ||
96 | cfg->freq.pclk = hclk / pdiv; | |
97 | ||
98 | s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv); | |
99 | ||
100 | if (pdiv > 2) | |
101 | goto invalid; | |
102 | ||
103 | pdiv *= hdiv; | |
104 | ||
105 | /* store the result, and then return */ | |
106 | ||
107 | cfg->divs.h_divisor = hdiv * armdiv; | |
108 | cfg->divs.p_divisor = pdiv * armdiv; | |
109 | ||
110 | return 0; | |
111 | ||
dbb8fd34 | 112 | invalid: |
22d42399 BD |
113 | return -EINVAL; |
114 | } | |
115 | ||
116 | static void s3c2412_cpufreq_setdivs(struct s3c_cpufreq_config *cfg) | |
117 | { | |
118 | unsigned long clkdiv; | |
119 | unsigned long olddiv; | |
120 | ||
121 | olddiv = clkdiv = __raw_readl(S3C2410_CLKDIVN); | |
122 | ||
123 | /* clear off current clock info */ | |
124 | ||
125 | clkdiv &= ~S3C2412_CLKDIVN_ARMDIVN; | |
126 | clkdiv &= ~S3C2412_CLKDIVN_HDIVN_MASK; | |
127 | clkdiv &= ~S3C2412_CLKDIVN_PDIVN; | |
128 | ||
129 | if (cfg->divs.arm_divisor == 2) | |
130 | clkdiv |= S3C2412_CLKDIVN_ARMDIVN; | |
131 | ||
132 | clkdiv |= ((cfg->divs.h_divisor / cfg->divs.arm_divisor) - 1); | |
133 | ||
134 | if (cfg->divs.p_divisor != cfg->divs.h_divisor) | |
135 | clkdiv |= S3C2412_CLKDIVN_PDIVN; | |
136 | ||
137 | s3c_freq_dbg("%s: div %08lx => %08lx\n", __func__, olddiv, clkdiv); | |
138 | __raw_writel(clkdiv, S3C2410_CLKDIVN); | |
139 | ||
140 | clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk); | |
141 | } | |
142 | ||
143 | static void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) | |
144 | { | |
145 | struct s3c_cpufreq_board *board = cfg->board; | |
146 | unsigned long refresh; | |
147 | ||
148 | s3c_freq_dbg("%s: refresh %u ns, hclk %lu\n", __func__, | |
149 | board->refresh, cfg->freq.hclk); | |
150 | ||
151 | /* Reduce both the refresh time (in ns) and the frequency (in MHz) | |
152 | * by 10 each to ensure that we do not overflow 32 bit numbers. This | |
153 | * should work for HCLK up to 133MHz and refresh period up to 30usec. | |
154 | */ | |
155 | ||
156 | refresh = (board->refresh / 10); | |
157 | refresh *= (cfg->freq.hclk / 100); | |
158 | refresh /= (1 * 1000 * 1000); /* 10^6 */ | |
159 | ||
160 | s3c_freq_dbg("%s: setting refresh 0x%08lx\n", __func__, refresh); | |
161 | __raw_writel(refresh, S3C2412_REFRESH); | |
162 | } | |
163 | ||
164 | /* set the default cpu frequency information, based on an 200MHz part | |
165 | * as we have no other way of detecting the speed rating in software. | |
166 | */ | |
167 | ||
168 | static struct s3c_cpufreq_info s3c2412_cpufreq_info = { | |
169 | .max = { | |
170 | .fclk = 200000000, | |
171 | .hclk = 100000000, | |
172 | .pclk = 50000000, | |
173 | }, | |
174 | ||
175 | .latency = 5000000, /* 5ms */ | |
176 | ||
177 | .locktime_m = 150, | |
178 | .locktime_u = 150, | |
179 | .locktime_bits = 16, | |
180 | ||
181 | .name = "s3c2412", | |
182 | .set_refresh = s3c2412_cpufreq_setrefresh, | |
183 | .set_divs = s3c2412_cpufreq_setdivs, | |
184 | .calc_divs = s3c2412_cpufreq_calcdivs, | |
185 | ||
140780ab BD |
186 | .calc_iotiming = s3c2412_iotiming_calc, |
187 | .set_iotiming = s3c2412_iotiming_set, | |
188 | .get_iotiming = s3c2412_iotiming_get, | |
189 | ||
e6d197a6 | 190 | .debug_io_show = s3c_cpufreq_debugfs_call(s3c2412_iotiming_debugfs), |
22d42399 BD |
191 | }; |
192 | ||
04511a6f HS |
193 | static int s3c2412_cpufreq_add(struct device *dev, |
194 | struct subsys_interface *sif) | |
22d42399 BD |
195 | { |
196 | unsigned long fclk_rate; | |
197 | ||
198 | hclk = clk_get(NULL, "hclk"); | |
199 | if (IS_ERR(hclk)) { | |
200 | printk(KERN_ERR "%s: cannot find hclk clock\n", __func__); | |
201 | return -ENOENT; | |
202 | } | |
203 | ||
204 | fclk = clk_get(NULL, "fclk"); | |
205 | if (IS_ERR(fclk)) { | |
206 | printk(KERN_ERR "%s: cannot find fclk clock\n", __func__); | |
207 | goto err_fclk; | |
208 | } | |
209 | ||
210 | fclk_rate = clk_get_rate(fclk); | |
211 | if (fclk_rate > 200000000) { | |
212 | printk(KERN_INFO | |
213 | "%s: fclk %ld MHz, assuming 266MHz capable part\n", | |
214 | __func__, fclk_rate / 1000000); | |
215 | s3c2412_cpufreq_info.max.fclk = 266000000; | |
216 | s3c2412_cpufreq_info.max.hclk = 133000000; | |
217 | s3c2412_cpufreq_info.max.pclk = 66000000; | |
218 | } | |
219 | ||
220 | armclk = clk_get(NULL, "armclk"); | |
221 | if (IS_ERR(armclk)) { | |
222 | printk(KERN_ERR "%s: cannot find arm clock\n", __func__); | |
223 | goto err_armclk; | |
224 | } | |
225 | ||
226 | xtal = clk_get(NULL, "xtal"); | |
227 | if (IS_ERR(xtal)) { | |
228 | printk(KERN_ERR "%s: cannot find xtal clock\n", __func__); | |
229 | goto err_xtal; | |
230 | } | |
231 | ||
232 | return s3c_cpufreq_register(&s3c2412_cpufreq_info); | |
233 | ||
234 | err_xtal: | |
235 | clk_put(armclk); | |
236 | err_armclk: | |
237 | clk_put(fclk); | |
238 | err_fclk: | |
239 | clk_put(hclk); | |
240 | ||
241 | return -ENOENT; | |
242 | } | |
243 | ||
4a858cfc KS |
244 | static struct subsys_interface s3c2412_cpufreq_interface = { |
245 | .name = "s3c2412_cpufreq", | |
246 | .subsys = &s3c2412_subsys, | |
247 | .add_dev = s3c2412_cpufreq_add, | |
22d42399 BD |
248 | }; |
249 | ||
250 | static int s3c2412_cpufreq_init(void) | |
251 | { | |
4a858cfc | 252 | return subsys_interface_register(&s3c2412_cpufreq_interface); |
22d42399 | 253 | } |
22d42399 | 254 | arch_initcall(s3c2412_cpufreq_init); |