xref: /openbmc/linux/drivers/clk/x86/clk-pmc-atom.c (revision b830f94f) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs
4  *
5  * Copyright (C) 2016, Intel Corporation
6  * Author: Irina Tirdea <irina.tirdea@intel.com>
7  */
8 
9 #include <linux/clk-provider.h>
10 #include <linux/clkdev.h>
11 #include <linux/err.h>
12 #include <linux/io.h>
13 #include <linux/platform_data/x86/clk-pmc-atom.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 
17 #define PLT_CLK_NAME_BASE	"pmc_plt_clk"
18 
19 #define PMC_CLK_CTL_OFFSET		0x60
20 #define PMC_CLK_CTL_SIZE		4
21 #define PMC_CLK_NUM			6
22 #define PMC_CLK_CTL_GATED_ON_D3		0x0
23 #define PMC_CLK_CTL_FORCE_ON		0x1
24 #define PMC_CLK_CTL_FORCE_OFF		0x2
25 #define PMC_CLK_CTL_RESERVED		0x3
26 #define PMC_MASK_CLK_CTL		GENMASK(1, 0)
27 #define PMC_MASK_CLK_FREQ		BIT(2)
28 #define PMC_CLK_FREQ_XTAL		(0 << 2)	/* 25 MHz */
29 #define PMC_CLK_FREQ_PLL		(1 << 2)	/* 19.2 MHz */
30 
31 struct clk_plt_fixed {
32 	struct clk_hw *clk;
33 	struct clk_lookup *lookup;
34 };
35 
36 struct clk_plt {
37 	struct clk_hw hw;
38 	void __iomem *reg;
39 	struct clk_lookup *lookup;
40 	/* protect access to PMC registers */
41 	spinlock_t lock;
42 };
43 
44 #define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
45 
46 struct clk_plt_data {
47 	struct clk_plt_fixed **parents;
48 	u8 nparents;
49 	struct clk_plt *clks[PMC_CLK_NUM];
50 	struct clk_lookup *mclk_lookup;
51 	struct clk_lookup *ether_clk_lookup;
52 };
53 
54 /* Return an index in parent table */
55 static inline int plt_reg_to_parent(int reg)
56 {
57 	switch (reg & PMC_MASK_CLK_FREQ) {
58 	default:
59 	case PMC_CLK_FREQ_XTAL:
60 		return 0;
61 	case PMC_CLK_FREQ_PLL:
62 		return 1;
63 	}
64 }
65 
66 /* Return clk index of parent */
67 static inline int plt_parent_to_reg(int index)
68 {
69 	switch (index) {
70 	default:
71 	case 0:
72 		return PMC_CLK_FREQ_XTAL;
73 	case 1:
74 		return PMC_CLK_FREQ_PLL;
75 	}
76 }
77 
78 /* Abstract status in simpler enabled/disabled value */
79 static inline int plt_reg_to_enabled(int reg)
80 {
81 	switch (reg & PMC_MASK_CLK_CTL) {
82 	case PMC_CLK_CTL_GATED_ON_D3:
83 	case PMC_CLK_CTL_FORCE_ON:
84 		return 1;	/* enabled */
85 	case PMC_CLK_CTL_FORCE_OFF:
86 	case PMC_CLK_CTL_RESERVED:
87 	default:
88 		return 0;	/* disabled */
89 	}
90 }
91 
92 static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
93 {
94 	u32 tmp;
95 	unsigned long flags;
96 
97 	spin_lock_irqsave(&clk->lock, flags);
98 
99 	tmp = readl(clk->reg);
100 	tmp = (tmp & ~mask) | (val & mask);
101 	writel(tmp, clk->reg);
102 
103 	spin_unlock_irqrestore(&clk->lock, flags);
104 }
105 
106 static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
107 {
108 	struct clk_plt *clk = to_clk_plt(hw);
109 
110 	plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
111 
112 	return 0;
113 }
114 
115 static u8 plt_clk_get_parent(struct clk_hw *hw)
116 {
117 	struct clk_plt *clk = to_clk_plt(hw);
118 	u32 value;
119 
120 	value = readl(clk->reg);
121 
122 	return plt_reg_to_parent(value);
123 }
124 
125 static int plt_clk_enable(struct clk_hw *hw)
126 {
127 	struct clk_plt *clk = to_clk_plt(hw);
128 
129 	plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
130 
131 	return 0;
132 }
133 
134 static void plt_clk_disable(struct clk_hw *hw)
135 {
136 	struct clk_plt *clk = to_clk_plt(hw);
137 
138 	plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
139 }
140 
141 static int plt_clk_is_enabled(struct clk_hw *hw)
142 {
143 	struct clk_plt *clk = to_clk_plt(hw);
144 	u32 value;
145 
146 	value = readl(clk->reg);
147 
148 	return plt_reg_to_enabled(value);
149 }
150 
151 static const struct clk_ops plt_clk_ops = {
152 	.enable = plt_clk_enable,
153 	.disable = plt_clk_disable,
154 	.is_enabled = plt_clk_is_enabled,
155 	.get_parent = plt_clk_get_parent,
156 	.set_parent = plt_clk_set_parent,
157 	.determine_rate = __clk_mux_determine_rate,
158 };
159 
160 static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
161 					const struct pmc_clk_data *pmc_data,
162 					const char **parent_names,
163 					int num_parents)
164 {
165 	struct clk_plt *pclk;
166 	struct clk_init_data init;
167 	int ret;
168 
169 	pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
170 	if (!pclk)
171 		return ERR_PTR(-ENOMEM);
172 
173 	init.name =  kasprintf(GFP_KERNEL, "%s_%d", PLT_CLK_NAME_BASE, id);
174 	init.ops = &plt_clk_ops;
175 	init.flags = 0;
176 	init.parent_names = parent_names;
177 	init.num_parents = num_parents;
178 
179 	pclk->hw.init = &init;
180 	pclk->reg = pmc_data->base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
181 	spin_lock_init(&pclk->lock);
182 
183 	/*
184 	 * On some systems, the pmc_plt_clocks already enabled by the
185 	 * firmware are being marked as critical to avoid them being
186 	 * gated by the clock framework.
187 	 */
188 	if (pmc_data->critical && plt_clk_is_enabled(&pclk->hw))
189 		init.flags |= CLK_IS_CRITICAL;
190 
191 	ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
192 	if (ret) {
193 		pclk = ERR_PTR(ret);
194 		goto err_free_init;
195 	}
196 
197 	pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
198 	if (!pclk->lookup) {
199 		pclk = ERR_PTR(-ENOMEM);
200 		goto err_free_init;
201 	}
202 
203 err_free_init:
204 	kfree(init.name);
205 	return pclk;
206 }
207 
208 static void plt_clk_unregister(struct clk_plt *pclk)
209 {
210 	clkdev_drop(pclk->lookup);
211 }
212 
213 static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
214 						 const char *name,
215 						 const char *parent_name,
216 						 unsigned long fixed_rate)
217 {
218 	struct clk_plt_fixed *pclk;
219 
220 	pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
221 	if (!pclk)
222 		return ERR_PTR(-ENOMEM);
223 
224 	pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
225 					       0, fixed_rate);
226 	if (IS_ERR(pclk->clk))
227 		return ERR_CAST(pclk->clk);
228 
229 	pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
230 	if (!pclk->lookup) {
231 		clk_hw_unregister_fixed_rate(pclk->clk);
232 		return ERR_PTR(-ENOMEM);
233 	}
234 
235 	return pclk;
236 }
237 
238 static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
239 {
240 	clkdev_drop(pclk->lookup);
241 	clk_hw_unregister_fixed_rate(pclk->clk);
242 }
243 
244 static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
245 					       unsigned int i)
246 {
247 	while (i--)
248 		plt_clk_unregister_fixed_rate(data->parents[i]);
249 }
250 
251 static void plt_clk_free_parent_names_loop(const char **parent_names,
252 					   unsigned int i)
253 {
254 	while (i--)
255 		kfree_const(parent_names[i]);
256 	kfree(parent_names);
257 }
258 
259 static void plt_clk_unregister_loop(struct clk_plt_data *data,
260 				    unsigned int i)
261 {
262 	while (i--)
263 		plt_clk_unregister(data->clks[i]);
264 }
265 
266 static const char **plt_clk_register_parents(struct platform_device *pdev,
267 					     struct clk_plt_data *data,
268 					     const struct pmc_clk *clks)
269 {
270 	const char **parent_names;
271 	unsigned int i;
272 	int err;
273 	int nparents = 0;
274 
275 	data->nparents = 0;
276 	while (clks[nparents].name)
277 		nparents++;
278 
279 	data->parents = devm_kcalloc(&pdev->dev, nparents,
280 				     sizeof(*data->parents), GFP_KERNEL);
281 	if (!data->parents)
282 		return ERR_PTR(-ENOMEM);
283 
284 	parent_names = kcalloc(nparents, sizeof(*parent_names),
285 			       GFP_KERNEL);
286 	if (!parent_names)
287 		return ERR_PTR(-ENOMEM);
288 
289 	for (i = 0; i < nparents; i++) {
290 		data->parents[i] =
291 			plt_clk_register_fixed_rate(pdev, clks[i].name,
292 						    clks[i].parent_name,
293 						    clks[i].freq);
294 		if (IS_ERR(data->parents[i])) {
295 			err = PTR_ERR(data->parents[i]);
296 			goto err_unreg;
297 		}
298 		parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
299 	}
300 
301 	data->nparents = nparents;
302 	return parent_names;
303 
304 err_unreg:
305 	plt_clk_unregister_fixed_rate_loop(data, i);
306 	plt_clk_free_parent_names_loop(parent_names, i);
307 	return ERR_PTR(err);
308 }
309 
310 static void plt_clk_unregister_parents(struct clk_plt_data *data)
311 {
312 	plt_clk_unregister_fixed_rate_loop(data, data->nparents);
313 }
314 
315 static int plt_clk_probe(struct platform_device *pdev)
316 {
317 	const struct pmc_clk_data *pmc_data;
318 	const char **parent_names;
319 	struct clk_plt_data *data;
320 	unsigned int i;
321 	int err;
322 
323 	pmc_data = dev_get_platdata(&pdev->dev);
324 	if (!pmc_data || !pmc_data->clks)
325 		return -EINVAL;
326 
327 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
328 	if (!data)
329 		return -ENOMEM;
330 
331 	parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
332 	if (IS_ERR(parent_names))
333 		return PTR_ERR(parent_names);
334 
335 	for (i = 0; i < PMC_CLK_NUM; i++) {
336 		data->clks[i] = plt_clk_register(pdev, i, pmc_data,
337 						 parent_names, data->nparents);
338 		if (IS_ERR(data->clks[i])) {
339 			err = PTR_ERR(data->clks[i]);
340 			goto err_unreg_clk_plt;
341 		}
342 	}
343 	data->mclk_lookup = clkdev_hw_create(&data->clks[3]->hw, "mclk", NULL);
344 	if (!data->mclk_lookup) {
345 		err = -ENOMEM;
346 		goto err_unreg_clk_plt;
347 	}
348 
349 	data->ether_clk_lookup = clkdev_hw_create(&data->clks[4]->hw,
350 						  "ether_clk", NULL);
351 	if (!data->ether_clk_lookup) {
352 		err = -ENOMEM;
353 		goto err_drop_mclk;
354 	}
355 
356 	plt_clk_free_parent_names_loop(parent_names, data->nparents);
357 
358 	platform_set_drvdata(pdev, data);
359 	return 0;
360 
361 err_drop_mclk:
362 	clkdev_drop(data->mclk_lookup);
363 err_unreg_clk_plt:
364 	plt_clk_unregister_loop(data, i);
365 	plt_clk_unregister_parents(data);
366 	plt_clk_free_parent_names_loop(parent_names, data->nparents);
367 	return err;
368 }
369 
370 static int plt_clk_remove(struct platform_device *pdev)
371 {
372 	struct clk_plt_data *data;
373 
374 	data = platform_get_drvdata(pdev);
375 
376 	clkdev_drop(data->ether_clk_lookup);
377 	clkdev_drop(data->mclk_lookup);
378 	plt_clk_unregister_loop(data, PMC_CLK_NUM);
379 	plt_clk_unregister_parents(data);
380 	return 0;
381 }
382 
383 static struct platform_driver plt_clk_driver = {
384 	.driver = {
385 		.name = "clk-pmc-atom",
386 	},
387 	.probe = plt_clk_probe,
388 	.remove = plt_clk_remove,
389 };
390 builtin_platform_driver(plt_clk_driver);
391