1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * R-Car Gen2 Clock Pulse Generator
4  *
5  * Copyright (C) 2016 Cogent Embedded Inc.
6  */
7 
8 #include <linux/bug.h>
9 #include <linux/clk.h>
10 #include <linux/clk-provider.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/slab.h>
16 #include <linux/sys_soc.h>
17 
18 #include "renesas-cpg-mssr.h"
19 #include "rcar-gen2-cpg.h"
20 
21 #define CPG_FRQCRB		0x0004
22 #define CPG_FRQCRB_KICK		BIT(31)
23 #define CPG_SDCKCR		0x0074
24 #define CPG_PLL0CR		0x00d8
25 #define CPG_PLL0CR_STC_SHIFT	24
26 #define CPG_PLL0CR_STC_MASK	(0x7f << CPG_PLL0CR_STC_SHIFT)
27 #define CPG_FRQCRC		0x00e0
28 #define CPG_FRQCRC_ZFC_SHIFT	8
29 #define CPG_FRQCRC_ZFC_MASK	(0x1f << CPG_FRQCRC_ZFC_SHIFT)
30 #define CPG_ADSPCKCR		0x025c
31 #define CPG_RCANCKCR		0x0270
32 
33 static spinlock_t cpg_lock;
34 
35 /*
36  * Z Clock
37  *
38  * Traits of this clock:
39  * prepare - clk_prepare only ensures that parents are prepared
40  * enable - clk_enable only ensures that parents are enabled
41  * rate - rate is adjustable.  clk->rate = parent->rate * mult / 32
42  * parent - fixed parent.  No clk_set_parent support
43  */
44 
45 struct cpg_z_clk {
46 	struct clk_hw hw;
47 	void __iomem *reg;
48 	void __iomem *kick_reg;
49 };
50 
51 #define to_z_clk(_hw)	container_of(_hw, struct cpg_z_clk, hw)
52 
53 static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
54 					   unsigned long parent_rate)
55 {
56 	struct cpg_z_clk *zclk = to_z_clk(hw);
57 	unsigned int mult;
58 	unsigned int val;
59 
60 	val = (readl(zclk->reg) & CPG_FRQCRC_ZFC_MASK) >> CPG_FRQCRC_ZFC_SHIFT;
61 	mult = 32 - val;
62 
63 	return div_u64((u64)parent_rate * mult, 32);
64 }
65 
66 static int cpg_z_clk_determine_rate(struct clk_hw *hw,
67 				    struct clk_rate_request *req)
68 {
69 	unsigned long prate = req->best_parent_rate;
70 	unsigned int min_mult, max_mult, mult;
71 
72 	min_mult = max(div64_ul(req->min_rate * 32ULL, prate), 1ULL);
73 	max_mult = min(div64_ul(req->max_rate * 32ULL, prate), 32ULL);
74 	if (max_mult < min_mult)
75 		return -EINVAL;
76 
77 	mult = div64_ul(req->rate * 32ULL, prate);
78 	mult = clamp(mult, min_mult, max_mult);
79 
80 	req->rate = div_u64((u64)prate * mult, 32);
81 	return 0;
82 }
83 
84 static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
85 			      unsigned long parent_rate)
86 {
87 	struct cpg_z_clk *zclk = to_z_clk(hw);
88 	unsigned int mult;
89 	u32 val, kick;
90 	unsigned int i;
91 
92 	mult = div64_ul(rate * 32ULL, parent_rate);
93 	mult = clamp(mult, 1U, 32U);
94 
95 	if (readl(zclk->kick_reg) & CPG_FRQCRB_KICK)
96 		return -EBUSY;
97 
98 	val = readl(zclk->reg);
99 	val &= ~CPG_FRQCRC_ZFC_MASK;
100 	val |= (32 - mult) << CPG_FRQCRC_ZFC_SHIFT;
101 	writel(val, zclk->reg);
102 
103 	/*
104 	 * Set KICK bit in FRQCRB to update hardware setting and wait for
105 	 * clock change completion.
106 	 */
107 	kick = readl(zclk->kick_reg);
108 	kick |= CPG_FRQCRB_KICK;
109 	writel(kick, zclk->kick_reg);
110 
111 	/*
112 	 * Note: There is no HW information about the worst case latency.
113 	 *
114 	 * Using experimental measurements, it seems that no more than
115 	 * ~10 iterations are needed, independently of the CPU rate.
116 	 * Since this value might be dependent on external xtal rate, pll1
117 	 * rate or even the other emulation clocks rate, use 1000 as a
118 	 * "super" safe value.
119 	 */
120 	for (i = 1000; i; i--) {
121 		if (!(readl(zclk->kick_reg) & CPG_FRQCRB_KICK))
122 			return 0;
123 
124 		cpu_relax();
125 	}
126 
127 	return -ETIMEDOUT;
128 }
129 
130 static const struct clk_ops cpg_z_clk_ops = {
131 	.recalc_rate = cpg_z_clk_recalc_rate,
132 	.determine_rate = cpg_z_clk_determine_rate,
133 	.set_rate = cpg_z_clk_set_rate,
134 };
135 
136 static struct clk * __init cpg_z_clk_register(const char *name,
137 					      const char *parent_name,
138 					      void __iomem *base)
139 {
140 	struct clk_init_data init = {};
141 	struct cpg_z_clk *zclk;
142 	struct clk *clk;
143 
144 	zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
145 	if (!zclk)
146 		return ERR_PTR(-ENOMEM);
147 
148 	init.name = name;
149 	init.ops = &cpg_z_clk_ops;
150 	init.parent_names = &parent_name;
151 	init.num_parents = 1;
152 
153 	zclk->reg = base + CPG_FRQCRC;
154 	zclk->kick_reg = base + CPG_FRQCRB;
155 	zclk->hw.init = &init;
156 
157 	clk = clk_register(NULL, &zclk->hw);
158 	if (IS_ERR(clk))
159 		kfree(zclk);
160 
161 	return clk;
162 }
163 
164 static struct clk * __init cpg_rcan_clk_register(const char *name,
165 						 const char *parent_name,
166 						 void __iomem *base)
167 {
168 	struct clk_fixed_factor *fixed;
169 	struct clk_gate *gate;
170 	struct clk *clk;
171 
172 	fixed = kzalloc(sizeof(*fixed), GFP_KERNEL);
173 	if (!fixed)
174 		return ERR_PTR(-ENOMEM);
175 
176 	fixed->mult = 1;
177 	fixed->div = 6;
178 
179 	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
180 	if (!gate) {
181 		kfree(fixed);
182 		return ERR_PTR(-ENOMEM);
183 	}
184 
185 	gate->reg = base + CPG_RCANCKCR;
186 	gate->bit_idx = 8;
187 	gate->flags = CLK_GATE_SET_TO_DISABLE;
188 	gate->lock = &cpg_lock;
189 
190 	clk = clk_register_composite(NULL, name, &parent_name, 1, NULL, NULL,
191 				     &fixed->hw, &clk_fixed_factor_ops,
192 				     &gate->hw, &clk_gate_ops, 0);
193 	if (IS_ERR(clk)) {
194 		kfree(gate);
195 		kfree(fixed);
196 	}
197 
198 	return clk;
199 }
200 
201 /* ADSP divisors */
202 static const struct clk_div_table cpg_adsp_div_table[] = {
203 	{  1,  3 }, {  2,  4 }, {  3,  6 }, {  4,  8 },
204 	{  5, 12 }, {  6, 16 }, {  7, 18 }, {  8, 24 },
205 	{ 10, 36 }, { 11, 48 }, {  0,  0 },
206 };
207 
208 static struct clk * __init cpg_adsp_clk_register(const char *name,
209 						 const char *parent_name,
210 						 void __iomem *base)
211 {
212 	struct clk_divider *div;
213 	struct clk_gate *gate;
214 	struct clk *clk;
215 
216 	div = kzalloc(sizeof(*div), GFP_KERNEL);
217 	if (!div)
218 		return ERR_PTR(-ENOMEM);
219 
220 	div->reg = base + CPG_ADSPCKCR;
221 	div->width = 4;
222 	div->table = cpg_adsp_div_table;
223 	div->lock = &cpg_lock;
224 
225 	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
226 	if (!gate) {
227 		kfree(div);
228 		return ERR_PTR(-ENOMEM);
229 	}
230 
231 	gate->reg = base + CPG_ADSPCKCR;
232 	gate->bit_idx = 8;
233 	gate->flags = CLK_GATE_SET_TO_DISABLE;
234 	gate->lock = &cpg_lock;
235 
236 	clk = clk_register_composite(NULL, name, &parent_name, 1, NULL, NULL,
237 				     &div->hw, &clk_divider_ops,
238 				     &gate->hw, &clk_gate_ops, 0);
239 	if (IS_ERR(clk)) {
240 		kfree(gate);
241 		kfree(div);
242 	}
243 
244 	return clk;
245 }
246 
247 /* SDHI divisors */
248 static const struct clk_div_table cpg_sdh_div_table[] = {
249 	{  0,  2 }, {  1,  3 }, {  2,  4 }, {  3,  6 },
250 	{  4,  8 }, {  5, 12 }, {  6, 16 }, {  7, 18 },
251 	{  8, 24 }, { 10, 36 }, { 11, 48 }, {  0,  0 },
252 };
253 
254 static const struct clk_div_table cpg_sd01_div_table[] = {
255 	{  4,  8 }, {  5, 12 }, {  6, 16 }, {  7, 18 },
256 	{  8, 24 }, { 10, 36 }, { 11, 48 }, { 12, 10 },
257 	{  0,  0 },
258 };
259 
260 static const struct rcar_gen2_cpg_pll_config *cpg_pll_config __initdata;
261 static unsigned int cpg_pll0_div __initdata;
262 static u32 cpg_mode __initdata;
263 static u32 cpg_quirks __initdata;
264 
265 #define SD_SKIP_FIRST	BIT(0)		/* Skip first clock in SD table */
266 
267 static const struct soc_device_attribute cpg_quirks_match[] __initconst = {
268 	{
269 		.soc_id = "r8a77470",
270 		.data = (void *)SD_SKIP_FIRST,
271 	},
272 	{ /* sentinel */ }
273 };
274 
275 struct clk * __init rcar_gen2_cpg_clk_register(struct device *dev,
276 	const struct cpg_core_clk *core, const struct cpg_mssr_info *info,
277 	struct clk **clks, void __iomem *base,
278 	struct raw_notifier_head *notifiers)
279 {
280 	const struct clk_div_table *table = NULL;
281 	const struct clk *parent;
282 	const char *parent_name;
283 	unsigned int mult = 1;
284 	unsigned int div = 1;
285 	unsigned int shift;
286 
287 	parent = clks[core->parent];
288 	if (IS_ERR(parent))
289 		return ERR_CAST(parent);
290 
291 	parent_name = __clk_get_name(parent);
292 
293 	switch (core->type) {
294 	/* R-Car Gen2 */
295 	case CLK_TYPE_GEN2_MAIN:
296 		div = cpg_pll_config->extal_div;
297 		break;
298 
299 	case CLK_TYPE_GEN2_PLL0:
300 		/*
301 		 * PLL0 is a  configurable multiplier clock except on R-Car
302 		 * V2H/E2. Register the PLL0 clock as a fixed factor clock for
303 		 * now as there's no generic multiplier clock implementation and
304 		 * we  currently  have no need to change  the multiplier value.
305 		 */
306 		mult = cpg_pll_config->pll0_mult;
307 		div  = cpg_pll0_div;
308 		if (!mult) {
309 			u32 pll0cr = readl(base + CPG_PLL0CR);
310 
311 			mult = (((pll0cr & CPG_PLL0CR_STC_MASK) >>
312 				 CPG_PLL0CR_STC_SHIFT) + 1) * 2;
313 		}
314 		break;
315 
316 	case CLK_TYPE_GEN2_PLL1:
317 		mult = cpg_pll_config->pll1_mult / 2;
318 		break;
319 
320 	case CLK_TYPE_GEN2_PLL3:
321 		mult = cpg_pll_config->pll3_mult;
322 		break;
323 
324 	case CLK_TYPE_GEN2_Z:
325 		return cpg_z_clk_register(core->name, parent_name, base);
326 
327 	case CLK_TYPE_GEN2_LB:
328 		div = cpg_mode & BIT(18) ? 36 : 24;
329 		break;
330 
331 	case CLK_TYPE_GEN2_ADSP:
332 		return cpg_adsp_clk_register(core->name, parent_name, base);
333 
334 	case CLK_TYPE_GEN2_SDH:
335 		table = cpg_sdh_div_table;
336 		shift = 8;
337 		break;
338 
339 	case CLK_TYPE_GEN2_SD0:
340 		table = cpg_sd01_div_table;
341 		if (cpg_quirks & SD_SKIP_FIRST)
342 			table++;
343 
344 		shift = 4;
345 		break;
346 
347 	case CLK_TYPE_GEN2_SD1:
348 		table = cpg_sd01_div_table;
349 		if (cpg_quirks & SD_SKIP_FIRST)
350 			table++;
351 
352 		shift = 0;
353 		break;
354 
355 	case CLK_TYPE_GEN2_QSPI:
356 		div = (cpg_mode & (BIT(3) | BIT(2) | BIT(1))) == BIT(2) ?
357 		      8 : 10;
358 		break;
359 
360 	case CLK_TYPE_GEN2_RCAN:
361 		return cpg_rcan_clk_register(core->name, parent_name, base);
362 
363 	default:
364 		return ERR_PTR(-EINVAL);
365 	}
366 
367 	if (!table)
368 		return clk_register_fixed_factor(NULL, core->name, parent_name,
369 						 0, mult, div);
370 	else
371 		return clk_register_divider_table(NULL, core->name,
372 						  parent_name, 0,
373 						  base + CPG_SDCKCR, shift, 4,
374 						  0, table, &cpg_lock);
375 }
376 
377 int __init rcar_gen2_cpg_init(const struct rcar_gen2_cpg_pll_config *config,
378 			      unsigned int pll0_div, u32 mode)
379 {
380 	const struct soc_device_attribute *attr;
381 
382 	cpg_pll_config = config;
383 	cpg_pll0_div = pll0_div;
384 	cpg_mode = mode;
385 	attr = soc_device_match(cpg_quirks_match);
386 	if (attr)
387 		cpg_quirks = (uintptr_t)attr->data;
388 	pr_debug("%s: mode = 0x%x quirks = 0x%x\n", __func__, mode, cpg_quirks);
389 
390 	spin_lock_init(&cpg_lock);
391 
392 	return 0;
393 }
394