Merge remote-tracking branch 'livepatching/for-next'
[deliverable/linux.git] / drivers / clk / rockchip / clk-cpu.c
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1/*
2 * Copyright (c) 2014 MundoReader S.L.
3 * Author: Heiko Stuebner <heiko@sntech.de>
4 *
5 * based on clk/samsung/clk-cpu.c
6 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
7 * Author: Thomas Abraham <thomas.ab@samsung.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * A CPU clock is defined as a clock supplied to a CPU or a group of CPUs.
14 * The CPU clock is typically derived from a hierarchy of clock
15 * blocks which includes mux and divider blocks. There are a number of other
16 * auxiliary clocks supplied to the CPU domain such as the debug blocks and AXI
17 * clock for CPU domain. The rates of these auxiliary clocks are related to the
18 * CPU clock rate and this relation is usually specified in the hardware manual
19 * of the SoC or supplied after the SoC characterization.
20 *
21 * The below implementation of the CPU clock allows the rate changes of the CPU
22 * clock and the corresponding rate changes of the auxillary clocks of the CPU
23 * domain. The platform clock driver provides a clock register configuration
24 * for each configurable rate which is then used to program the clock hardware
25 * registers to acheive a fast co-oridinated rate change for all the CPU domain
26 * clocks.
27 *
28 * On a rate change request for the CPU clock, the rate change is propagated
29 * upto the PLL supplying the clock to the CPU domain clock blocks. While the
30 * CPU domain PLL is reconfigured, the CPU domain clocks are driven using an
31 * alternate clock source. If required, the alternate clock source is divided
32 * down in order to keep the output clock rate within the previous OPP limits.
33 */
34
35#include <linux/of.h>
36#include <linux/slab.h>
37#include <linux/io.h>
f684ff8b 38#include <linux/clk.h>
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39#include <linux/clk-provider.h>
40#include "clk.h"
41
42/**
43 * struct rockchip_cpuclk: information about clock supplied to a CPU core.
44 * @hw: handle between ccf and cpu clock.
45 * @alt_parent: alternate parent clock to use when switching the speed
46 * of the primary parent clock.
47 * @reg_base: base register for cpu-clock values.
48 * @clk_nb: clock notifier registered for changes in clock speed of the
49 * primary parent clock.
50 * @rate_count: number of rates in the rate_table
51 * @rate_table: pll-rates and their associated dividers
52 * @reg_data: cpu-specific register settings
53 * @lock: clock lock
54 */
55struct rockchip_cpuclk {
56 struct clk_hw hw;
57
58 struct clk_mux cpu_mux;
59 const struct clk_ops *cpu_mux_ops;
60
61 struct clk *alt_parent;
62 void __iomem *reg_base;
63 struct notifier_block clk_nb;
64 unsigned int rate_count;
65 struct rockchip_cpuclk_rate_table *rate_table;
66 const struct rockchip_cpuclk_reg_data *reg_data;
67 spinlock_t *lock;
68};
69
70#define to_rockchip_cpuclk_hw(hw) container_of(hw, struct rockchip_cpuclk, hw)
71#define to_rockchip_cpuclk_nb(nb) \
72 container_of(nb, struct rockchip_cpuclk, clk_nb)
73
74static const struct rockchip_cpuclk_rate_table *rockchip_get_cpuclk_settings(
75 struct rockchip_cpuclk *cpuclk, unsigned long rate)
76{
77 const struct rockchip_cpuclk_rate_table *rate_table =
78 cpuclk->rate_table;
79 int i;
80
81 for (i = 0; i < cpuclk->rate_count; i++) {
82 if (rate == rate_table[i].prate)
83 return &rate_table[i];
84 }
85
86 return NULL;
87}
88
89static unsigned long rockchip_cpuclk_recalc_rate(struct clk_hw *hw,
90 unsigned long parent_rate)
91{
92 struct rockchip_cpuclk *cpuclk = to_rockchip_cpuclk_hw(hw);
93 const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data;
94 u32 clksel0 = readl_relaxed(cpuclk->reg_base + reg_data->core_reg);
95
96 clksel0 >>= reg_data->div_core_shift;
97 clksel0 &= reg_data->div_core_mask;
98 return parent_rate / (clksel0 + 1);
99}
100
101static const struct clk_ops rockchip_cpuclk_ops = {
102 .recalc_rate = rockchip_cpuclk_recalc_rate,
103};
104
105static void rockchip_cpuclk_set_dividers(struct rockchip_cpuclk *cpuclk,
106 const struct rockchip_cpuclk_rate_table *rate)
107{
108 int i;
109
110 /* alternate parent is active now. set the dividers */
111 for (i = 0; i < ARRAY_SIZE(rate->divs); i++) {
112 const struct rockchip_cpuclk_clksel *clksel = &rate->divs[i];
113
114 if (!clksel->reg)
115 continue;
116
117 pr_debug("%s: setting reg 0x%x to 0x%x\n",
118 __func__, clksel->reg, clksel->val);
fc6d875e 119 writel(clksel->val, cpuclk->reg_base + clksel->reg);
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120 }
121}
122
123static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk,
124 struct clk_notifier_data *ndata)
125{
126 const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data;
127 unsigned long alt_prate, alt_div;
a5e1baf7 128 unsigned long flags;
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129
130 alt_prate = clk_get_rate(cpuclk->alt_parent);
131
a5e1baf7 132 spin_lock_irqsave(cpuclk->lock, flags);
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133
134 /*
135 * If the old parent clock speed is less than the clock speed
136 * of the alternate parent, then it should be ensured that at no point
137 * the armclk speed is more than the old_rate until the dividers are
138 * set.
139 */
140 if (alt_prate > ndata->old_rate) {
141 /* calculate dividers */
142 alt_div = DIV_ROUND_UP(alt_prate, ndata->old_rate) - 1;
143 if (alt_div > reg_data->div_core_mask) {
144 pr_warn("%s: limiting alt-divider %lu to %d\n",
145 __func__, alt_div, reg_data->div_core_mask);
146 alt_div = reg_data->div_core_mask;
147 }
148
149 /*
150 * Change parents and add dividers in a single transaction.
151 *
152 * NOTE: we do this in a single transaction so we're never
153 * dividing the primary parent by the extra dividers that were
154 * needed for the alt.
155 */
156 pr_debug("%s: setting div %lu as alt-rate %lu > old-rate %lu\n",
157 __func__, alt_div, alt_prate, ndata->old_rate);
158
159 writel(HIWORD_UPDATE(alt_div, reg_data->div_core_mask,
160 reg_data->div_core_shift) |
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161 HIWORD_UPDATE(reg_data->mux_core_alt,
162 reg_data->mux_core_mask,
163 reg_data->mux_core_shift),
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164 cpuclk->reg_base + reg_data->core_reg);
165 } else {
166 /* select alternate parent */
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167 writel(HIWORD_UPDATE(reg_data->mux_core_alt,
168 reg_data->mux_core_mask,
169 reg_data->mux_core_shift),
170 cpuclk->reg_base + reg_data->core_reg);
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171 }
172
a5e1baf7 173 spin_unlock_irqrestore(cpuclk->lock, flags);
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174 return 0;
175}
176
177static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk,
178 struct clk_notifier_data *ndata)
179{
180 const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data;
181 const struct rockchip_cpuclk_rate_table *rate;
a5e1baf7 182 unsigned long flags;
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183
184 rate = rockchip_get_cpuclk_settings(cpuclk, ndata->new_rate);
185 if (!rate) {
186 pr_err("%s: Invalid rate : %lu for cpuclk\n",
187 __func__, ndata->new_rate);
188 return -EINVAL;
189 }
190
a5e1baf7 191 spin_lock_irqsave(cpuclk->lock, flags);
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192
193 if (ndata->old_rate < ndata->new_rate)
194 rockchip_cpuclk_set_dividers(cpuclk, rate);
195
196 /*
197 * post-rate change event, re-mux to primary parent and remove dividers.
198 *
199 * NOTE: we do this in a single transaction so we're never dividing the
200 * primary parent by the extra dividers that were needed for the alt.
201 */
202
203 writel(HIWORD_UPDATE(0, reg_data->div_core_mask,
204 reg_data->div_core_shift) |
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205 HIWORD_UPDATE(reg_data->mux_core_main,
206 reg_data->mux_core_mask,
207 reg_data->mux_core_shift),
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208 cpuclk->reg_base + reg_data->core_reg);
209
210 if (ndata->old_rate > ndata->new_rate)
211 rockchip_cpuclk_set_dividers(cpuclk, rate);
212
a5e1baf7 213 spin_unlock_irqrestore(cpuclk->lock, flags);
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214 return 0;
215}
216
217/*
218 * This clock notifier is called when the frequency of the parent clock
219 * of cpuclk is to be changed. This notifier handles the setting up all
220 * the divider clocks, remux to temporary parent and handling the safe
221 * frequency levels when using temporary parent.
222 */
223static int rockchip_cpuclk_notifier_cb(struct notifier_block *nb,
224 unsigned long event, void *data)
225{
226 struct clk_notifier_data *ndata = data;
227 struct rockchip_cpuclk *cpuclk = to_rockchip_cpuclk_nb(nb);
228 int ret = 0;
229
230 pr_debug("%s: event %lu, old_rate %lu, new_rate: %lu\n",
231 __func__, event, ndata->old_rate, ndata->new_rate);
232 if (event == PRE_RATE_CHANGE)
233 ret = rockchip_cpuclk_pre_rate_change(cpuclk, ndata);
234 else if (event == POST_RATE_CHANGE)
235 ret = rockchip_cpuclk_post_rate_change(cpuclk, ndata);
236
237 return notifier_from_errno(ret);
238}
239
240struct clk *rockchip_clk_register_cpuclk(const char *name,
4a1caed3 241 const char *const *parent_names, u8 num_parents,
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242 const struct rockchip_cpuclk_reg_data *reg_data,
243 const struct rockchip_cpuclk_rate_table *rates,
244 int nrates, void __iomem *reg_base, spinlock_t *lock)
245{
246 struct rockchip_cpuclk *cpuclk;
247 struct clk_init_data init;
248 struct clk *clk, *cclk;
249 int ret;
250
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251 if (num_parents < 2) {
252 pr_err("%s: needs at least two parent clocks\n", __func__);
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253 return ERR_PTR(-EINVAL);
254 }
255
256 cpuclk = kzalloc(sizeof(*cpuclk), GFP_KERNEL);
257 if (!cpuclk)
258 return ERR_PTR(-ENOMEM);
259
260 init.name = name;
268aebaa 261 init.parent_names = &parent_names[reg_data->mux_core_main];
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262 init.num_parents = 1;
263 init.ops = &rockchip_cpuclk_ops;
264
265 /* only allow rate changes when we have a rate table */
266 init.flags = (nrates > 0) ? CLK_SET_RATE_PARENT : 0;
267
268 /* disallow automatic parent changes by ccf */
269 init.flags |= CLK_SET_RATE_NO_REPARENT;
270
271 init.flags |= CLK_GET_RATE_NOCACHE;
272
273 cpuclk->reg_base = reg_base;
274 cpuclk->lock = lock;
275 cpuclk->reg_data = reg_data;
276 cpuclk->clk_nb.notifier_call = rockchip_cpuclk_notifier_cb;
277 cpuclk->hw.init = &init;
278
268aebaa 279 cpuclk->alt_parent = __clk_lookup(parent_names[reg_data->mux_core_alt]);
f6fba5f6 280 if (!cpuclk->alt_parent) {
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281 pr_err("%s: could not lookup alternate parent: (%d)\n",
282 __func__, reg_data->mux_core_alt);
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283 ret = -EINVAL;
284 goto free_cpuclk;
285 }
286
287 ret = clk_prepare_enable(cpuclk->alt_parent);
288 if (ret) {
289 pr_err("%s: could not enable alternate parent\n",
290 __func__);
291 goto free_cpuclk;
292 }
293
268aebaa 294 clk = __clk_lookup(parent_names[reg_data->mux_core_main]);
f6fba5f6 295 if (!clk) {
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296 pr_err("%s: could not lookup parent clock: (%d) %s\n",
297 __func__, reg_data->mux_core_main,
298 parent_names[reg_data->mux_core_main]);
f6fba5f6 299 ret = -EINVAL;
282312d1 300 goto free_alt_parent;
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301 }
302
303 ret = clk_notifier_register(clk, &cpuclk->clk_nb);
304 if (ret) {
305 pr_err("%s: failed to register clock notifier for %s\n",
306 __func__, name);
282312d1 307 goto free_alt_parent;
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308 }
309
310 if (nrates > 0) {
311 cpuclk->rate_count = nrates;
312 cpuclk->rate_table = kmemdup(rates,
313 sizeof(*rates) * nrates,
314 GFP_KERNEL);
315 if (!cpuclk->rate_table) {
316 pr_err("%s: could not allocate memory for cpuclk rates\n",
317 __func__);
318 ret = -ENOMEM;
319 goto unregister_notifier;
320 }
321 }
322
323 cclk = clk_register(NULL, &cpuclk->hw);
3183c0d5 324 if (IS_ERR(cclk)) {
f6fba5f6 325 pr_err("%s: could not register cpuclk %s\n", __func__, name);
3183c0d5 326 ret = PTR_ERR(cclk);
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327 goto free_rate_table;
328 }
329
330 return cclk;
331
332free_rate_table:
333 kfree(cpuclk->rate_table);
334unregister_notifier:
335 clk_notifier_unregister(clk, &cpuclk->clk_nb);
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336free_alt_parent:
337 clk_disable_unprepare(cpuclk->alt_parent);
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338free_cpuclk:
339 kfree(cpuclk);
340 return ERR_PTR(ret);
341}
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