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0ac65fc9 JL |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (c) 2015-2020, NVIDIA CORPORATION. All rights reserved. | |
4 | */ | |
5 | ||
6 | #include <linux/bitfield.h> | |
7 | #include <linux/clk.h> | |
8 | #include <linux/clk-provider.h> | |
9 | #include <linux/clk/tegra.h> | |
10 | #include <linux/device.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/io.h> | |
13 | #include <linux/slab.h> | |
14 | ||
15 | #define CLK_SOURCE_EMC 0x19c | |
16 | #define CLK_SOURCE_EMC_2X_CLK_SRC GENMASK(31, 29) | |
17 | #define CLK_SOURCE_EMC_MC_EMC_SAME_FREQ BIT(16) | |
18 | #define CLK_SOURCE_EMC_2X_CLK_DIVISOR GENMASK(7, 0) | |
19 | ||
20 | #define CLK_SRC_PLLM 0 | |
21 | #define CLK_SRC_PLLC 1 | |
22 | #define CLK_SRC_PLLP 2 | |
23 | #define CLK_SRC_CLK_M 3 | |
24 | #define CLK_SRC_PLLM_UD 4 | |
25 | #define CLK_SRC_PLLMB_UD 5 | |
26 | #define CLK_SRC_PLLMB 6 | |
27 | #define CLK_SRC_PLLP_UD 7 | |
28 | ||
29 | struct tegra210_clk_emc { | |
30 | struct clk_hw hw; | |
31 | void __iomem *regs; | |
32 | ||
33 | struct tegra210_clk_emc_provider *provider; | |
34 | ||
35 | struct clk *parents[8]; | |
36 | }; | |
37 | ||
38 | static inline struct tegra210_clk_emc * | |
39 | to_tegra210_clk_emc(struct clk_hw *hw) | |
40 | { | |
41 | return container_of(hw, struct tegra210_clk_emc, hw); | |
42 | } | |
43 | ||
44 | static const char *tegra210_clk_emc_parents[] = { | |
45 | "pll_m", "pll_c", "pll_p", "clk_m", "pll_m_ud", "pll_mb_ud", | |
46 | "pll_mb", "pll_p_ud", | |
47 | }; | |
48 | ||
49 | static u8 tegra210_clk_emc_get_parent(struct clk_hw *hw) | |
50 | { | |
51 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw); | |
52 | u32 value; | |
53 | u8 src; | |
54 | ||
55 | value = readl_relaxed(emc->regs + CLK_SOURCE_EMC); | |
56 | src = FIELD_GET(CLK_SOURCE_EMC_2X_CLK_SRC, value); | |
57 | ||
58 | return src; | |
59 | } | |
60 | ||
61 | static unsigned long tegra210_clk_emc_recalc_rate(struct clk_hw *hw, | |
62 | unsigned long parent_rate) | |
63 | { | |
64 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw); | |
65 | u32 value, div; | |
66 | ||
67 | /* | |
68 | * CCF assumes that neither the parent nor its rate will change during | |
69 | * ->set_rate(), so the parent rate passed in here was cached from the | |
70 | * parent before the ->set_rate() call. | |
71 | * | |
72 | * This can lead to wrong results being reported for the EMC clock if | |
73 | * the parent and/or parent rate have changed as part of the EMC rate | |
74 | * change sequence. Fix this by overriding the parent clock with what | |
75 | * we know to be the correct value after the rate change. | |
76 | */ | |
77 | parent_rate = clk_hw_get_rate(clk_hw_get_parent(hw)); | |
78 | ||
79 | value = readl_relaxed(emc->regs + CLK_SOURCE_EMC); | |
80 | ||
81 | div = FIELD_GET(CLK_SOURCE_EMC_2X_CLK_DIVISOR, value); | |
82 | div += 2; | |
83 | ||
84 | return DIV_ROUND_UP(parent_rate * 2, div); | |
85 | } | |
86 | ||
87 | static long tegra210_clk_emc_round_rate(struct clk_hw *hw, unsigned long rate, | |
88 | unsigned long *prate) | |
89 | { | |
90 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw); | |
91 | struct tegra210_clk_emc_provider *provider = emc->provider; | |
92 | unsigned int i; | |
93 | ||
94 | if (!provider || !provider->configs || provider->num_configs == 0) | |
95 | return clk_hw_get_rate(hw); | |
96 | ||
97 | for (i = 0; i < provider->num_configs; i++) { | |
98 | if (provider->configs[i].rate >= rate) | |
99 | return provider->configs[i].rate; | |
100 | } | |
101 | ||
102 | return provider->configs[i - 1].rate; | |
103 | } | |
104 | ||
105 | static struct clk *tegra210_clk_emc_find_parent(struct tegra210_clk_emc *emc, | |
106 | u8 index) | |
107 | { | |
108 | struct clk_hw *parent = clk_hw_get_parent_by_index(&emc->hw, index); | |
109 | const char *name = clk_hw_get_name(parent); | |
110 | ||
111 | /* XXX implement cache? */ | |
112 | ||
113 | return __clk_lookup(name); | |
114 | } | |
115 | ||
116 | static int tegra210_clk_emc_set_rate(struct clk_hw *hw, unsigned long rate, | |
117 | unsigned long parent_rate) | |
118 | { | |
119 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw); | |
120 | struct tegra210_clk_emc_provider *provider = emc->provider; | |
121 | struct tegra210_clk_emc_config *config; | |
122 | struct device *dev = provider->dev; | |
123 | struct clk_hw *old, *new, *parent; | |
124 | u8 old_idx, new_idx, index; | |
125 | struct clk *clk; | |
126 | unsigned int i; | |
127 | int err; | |
128 | ||
129 | if (!provider || !provider->configs || provider->num_configs == 0) | |
130 | return -EINVAL; | |
131 | ||
132 | for (i = 0; i < provider->num_configs; i++) { | |
133 | if (provider->configs[i].rate >= rate) { | |
134 | config = &provider->configs[i]; | |
135 | break; | |
136 | } | |
137 | } | |
138 | ||
139 | if (i == provider->num_configs) | |
140 | config = &provider->configs[i - 1]; | |
141 | ||
142 | old_idx = tegra210_clk_emc_get_parent(hw); | |
143 | new_idx = FIELD_GET(CLK_SOURCE_EMC_2X_CLK_SRC, config->value); | |
144 | ||
145 | old = clk_hw_get_parent_by_index(hw, old_idx); | |
146 | new = clk_hw_get_parent_by_index(hw, new_idx); | |
147 | ||
148 | /* if the rate has changed... */ | |
149 | if (config->parent_rate != clk_hw_get_rate(old)) { | |
150 | /* ... but the clock source remains the same ... */ | |
151 | if (new_idx == old_idx) { | |
152 | /* ... switch to the alternative clock source. */ | |
153 | switch (new_idx) { | |
154 | case CLK_SRC_PLLM: | |
155 | new_idx = CLK_SRC_PLLMB; | |
156 | break; | |
157 | ||
158 | case CLK_SRC_PLLM_UD: | |
159 | new_idx = CLK_SRC_PLLMB_UD; | |
160 | break; | |
161 | ||
162 | case CLK_SRC_PLLMB_UD: | |
163 | new_idx = CLK_SRC_PLLM_UD; | |
164 | break; | |
165 | ||
166 | case CLK_SRC_PLLMB: | |
167 | new_idx = CLK_SRC_PLLM; | |
168 | break; | |
169 | } | |
170 | ||
171 | /* | |
172 | * This should never happen because we can't deal with | |
173 | * it. | |
174 | */ | |
175 | if (WARN_ON(new_idx == old_idx)) | |
176 | return -EINVAL; | |
177 | ||
178 | new = clk_hw_get_parent_by_index(hw, new_idx); | |
179 | } | |
180 | ||
181 | index = new_idx; | |
182 | parent = new; | |
183 | } else { | |
184 | index = old_idx; | |
185 | parent = old; | |
186 | } | |
187 | ||
188 | clk = tegra210_clk_emc_find_parent(emc, index); | |
189 | if (IS_ERR(clk)) { | |
190 | err = PTR_ERR(clk); | |
191 | dev_err(dev, "failed to get parent clock for index %u: %d\n", | |
192 | index, err); | |
193 | return err; | |
194 | } | |
195 | ||
196 | /* set the new parent clock to the required rate */ | |
197 | if (clk_get_rate(clk) != config->parent_rate) { | |
198 | err = clk_set_rate(clk, config->parent_rate); | |
199 | if (err < 0) { | |
200 | dev_err(dev, "failed to set rate %lu Hz for %pC: %d\n", | |
201 | config->parent_rate, clk, err); | |
202 | return err; | |
203 | } | |
204 | } | |
205 | ||
206 | /* enable the new parent clock */ | |
207 | if (parent != old) { | |
208 | err = clk_prepare_enable(clk); | |
209 | if (err < 0) { | |
210 | dev_err(dev, "failed to enable parent clock %pC: %d\n", | |
211 | clk, err); | |
212 | return err; | |
213 | } | |
214 | } | |
215 | ||
216 | /* update the EMC source configuration to reflect the new parent */ | |
217 | config->value &= ~CLK_SOURCE_EMC_2X_CLK_SRC; | |
218 | config->value |= FIELD_PREP(CLK_SOURCE_EMC_2X_CLK_SRC, index); | |
219 | ||
220 | /* | |
221 | * Finally, switch the EMC programming with both old and new parent | |
222 | * clocks enabled. | |
223 | */ | |
224 | err = provider->set_rate(dev, config); | |
225 | if (err < 0) { | |
226 | dev_err(dev, "failed to set EMC rate to %lu Hz: %d\n", rate, | |
227 | err); | |
228 | ||
229 | /* | |
230 | * If we're unable to switch to the new EMC frequency, we no | |
231 | * longer need the new parent to be enabled. | |
232 | */ | |
233 | if (parent != old) | |
234 | clk_disable_unprepare(clk); | |
235 | ||
236 | return err; | |
237 | } | |
238 | ||
239 | /* reparent to new parent clock and disable the old parent clock */ | |
240 | if (parent != old) { | |
241 | clk = tegra210_clk_emc_find_parent(emc, old_idx); | |
242 | if (IS_ERR(clk)) { | |
243 | err = PTR_ERR(clk); | |
244 | dev_err(dev, | |
245 | "failed to get parent clock for index %u: %d\n", | |
246 | old_idx, err); | |
247 | return err; | |
248 | } | |
249 | ||
250 | clk_hw_reparent(hw, parent); | |
251 | clk_disable_unprepare(clk); | |
252 | } | |
253 | ||
254 | return err; | |
255 | } | |
256 | ||
257 | static const struct clk_ops tegra210_clk_emc_ops = { | |
258 | .get_parent = tegra210_clk_emc_get_parent, | |
259 | .recalc_rate = tegra210_clk_emc_recalc_rate, | |
260 | .round_rate = tegra210_clk_emc_round_rate, | |
261 | .set_rate = tegra210_clk_emc_set_rate, | |
262 | }; | |
263 | ||
264 | struct clk *tegra210_clk_register_emc(struct device_node *np, | |
265 | void __iomem *regs) | |
266 | { | |
267 | struct tegra210_clk_emc *emc; | |
268 | struct clk_init_data init; | |
269 | struct clk *clk; | |
270 | ||
271 | emc = kzalloc(sizeof(*emc), GFP_KERNEL); | |
272 | if (!emc) | |
273 | return ERR_PTR(-ENOMEM); | |
274 | ||
275 | emc->regs = regs; | |
276 | ||
277 | init.name = "emc"; | |
278 | init.ops = &tegra210_clk_emc_ops; | |
279 | init.flags = CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE; | |
280 | init.parent_names = tegra210_clk_emc_parents; | |
281 | init.num_parents = ARRAY_SIZE(tegra210_clk_emc_parents); | |
282 | emc->hw.init = &init; | |
283 | ||
284 | clk = clk_register(NULL, &emc->hw); | |
285 | if (IS_ERR(clk)) { | |
286 | kfree(emc); | |
287 | return clk; | |
288 | } | |
289 | ||
290 | return clk; | |
291 | } | |
292 | ||
293 | int tegra210_clk_emc_attach(struct clk *clk, | |
294 | struct tegra210_clk_emc_provider *provider) | |
295 | { | |
296 | struct clk_hw *hw = __clk_get_hw(clk); | |
297 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(hw); | |
298 | struct device *dev = provider->dev; | |
299 | unsigned int i; | |
300 | int err; | |
301 | ||
302 | if (!try_module_get(provider->owner)) | |
303 | return -ENODEV; | |
304 | ||
305 | for (i = 0; i < provider->num_configs; i++) { | |
306 | struct tegra210_clk_emc_config *config = &provider->configs[i]; | |
307 | struct clk_hw *parent; | |
308 | bool same_freq; | |
309 | u8 div, src; | |
310 | ||
311 | div = FIELD_GET(CLK_SOURCE_EMC_2X_CLK_DIVISOR, config->value); | |
312 | src = FIELD_GET(CLK_SOURCE_EMC_2X_CLK_SRC, config->value); | |
313 | ||
314 | /* do basic sanity checking on the EMC timings */ | |
315 | if (div & 0x1) { | |
316 | dev_err(dev, "invalid odd divider %u for rate %lu Hz\n", | |
317 | div, config->rate); | |
318 | err = -EINVAL; | |
319 | goto put; | |
320 | } | |
321 | ||
322 | same_freq = config->value & CLK_SOURCE_EMC_MC_EMC_SAME_FREQ; | |
323 | ||
324 | if (same_freq != config->same_freq) { | |
325 | dev_err(dev, | |
326 | "ambiguous EMC to MC ratio for rate %lu Hz\n", | |
327 | config->rate); | |
328 | err = -EINVAL; | |
329 | goto put; | |
330 | } | |
331 | ||
332 | parent = clk_hw_get_parent_by_index(hw, src); | |
333 | config->parent = src; | |
334 | ||
335 | if (src == CLK_SRC_PLLM || src == CLK_SRC_PLLM_UD) { | |
336 | config->parent_rate = config->rate * (1 + div / 2); | |
337 | } else { | |
338 | unsigned long rate = config->rate * (1 + div / 2); | |
339 | ||
340 | config->parent_rate = clk_hw_get_rate(parent); | |
341 | ||
342 | if (config->parent_rate != rate) { | |
343 | dev_err(dev, | |
344 | "rate %lu Hz does not match input\n", | |
345 | config->rate); | |
346 | err = -EINVAL; | |
347 | goto put; | |
348 | } | |
349 | } | |
350 | } | |
351 | ||
352 | emc->provider = provider; | |
353 | ||
354 | return 0; | |
355 | ||
356 | put: | |
357 | module_put(provider->owner); | |
358 | return err; | |
359 | } | |
360 | EXPORT_SYMBOL_GPL(tegra210_clk_emc_attach); | |
361 | ||
362 | void tegra210_clk_emc_detach(struct clk *clk) | |
363 | { | |
364 | struct tegra210_clk_emc *emc = to_tegra210_clk_emc(__clk_get_hw(clk)); | |
365 | ||
366 | module_put(emc->provider->owner); | |
367 | emc->provider = NULL; | |
368 | } | |
369 | EXPORT_SYMBOL_GPL(tegra210_clk_emc_detach); |