1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * R-Car Gen4 Clock Pulse Generator
4  *
5  * Copyright (C) 2021 Renesas Electronics Corp.
6  *
7  * Based on rcar-gen3-cpg.c
8  *
9  * Copyright (C) 2015-2018 Glider bvba
10  * Copyright (C) 2019 Renesas Electronics Corp.
11  */
12 
13 #include <linux/bitfield.h>
14 #include <linux/clk.h>
15 #include <linux/clk-provider.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/io.h>
20 #include <linux/slab.h>
21 
22 #include "renesas-cpg-mssr.h"
23 #include "rcar-gen4-cpg.h"
24 #include "rcar-cpg-lib.h"
25 
26 static const struct rcar_gen4_cpg_pll_config *cpg_pll_config __initconst;
27 static unsigned int cpg_clk_extalr __initdata;
28 static u32 cpg_mode __initdata;
29 
30 /*
31  * Z0 Clock & Z1 Clock
32  */
33 #define CPG_FRQCRB			0x00000804
34 #define CPG_FRQCRB_KICK			BIT(31)
35 #define CPG_FRQCRC			0x00000808
36 
37 struct cpg_z_clk {
38 	struct clk_hw hw;
39 	void __iomem *reg;
40 	void __iomem *kick_reg;
41 	unsigned long max_rate;		/* Maximum rate for normal mode */
42 	unsigned int fixed_div;
43 	u32 mask;
44 };
45 
46 #define to_z_clk(_hw)	container_of(_hw, struct cpg_z_clk, hw)
47 
48 static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
49 					   unsigned long parent_rate)
50 {
51 	struct cpg_z_clk *zclk = to_z_clk(hw);
52 	unsigned int mult;
53 	u32 val;
54 
55 	val = readl(zclk->reg) & zclk->mask;
56 	mult = 32 - (val >> __ffs(zclk->mask));
57 
58 	return DIV_ROUND_CLOSEST_ULL((u64)parent_rate * mult,
59 				     32 * zclk->fixed_div);
60 }
61 
62 static int cpg_z_clk_determine_rate(struct clk_hw *hw,
63 				    struct clk_rate_request *req)
64 {
65 	struct cpg_z_clk *zclk = to_z_clk(hw);
66 	unsigned int min_mult, max_mult, mult;
67 	unsigned long rate, prate;
68 
69 	rate = min(req->rate, req->max_rate);
70 	if (rate <= zclk->max_rate) {
71 		/* Set parent rate to initial value for normal modes */
72 		prate = zclk->max_rate;
73 	} else {
74 		/* Set increased parent rate for boost modes */
75 		prate = rate;
76 	}
77 	req->best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
78 						  prate * zclk->fixed_div);
79 
80 	prate = req->best_parent_rate / zclk->fixed_div;
81 	min_mult = max(div64_ul(req->min_rate * 32ULL, prate), 1ULL);
82 	max_mult = min(div64_ul(req->max_rate * 32ULL, prate), 32ULL);
83 	if (max_mult < min_mult)
84 		return -EINVAL;
85 
86 	mult = DIV_ROUND_CLOSEST_ULL(rate * 32ULL, prate);
87 	mult = clamp(mult, min_mult, max_mult);
88 
89 	req->rate = DIV_ROUND_CLOSEST_ULL((u64)prate * mult, 32);
90 	return 0;
91 }
92 
93 static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate,
94 			      unsigned long parent_rate)
95 {
96 	struct cpg_z_clk *zclk = to_z_clk(hw);
97 	unsigned int mult;
98 	unsigned int i;
99 
100 	mult = DIV64_U64_ROUND_CLOSEST(rate * 32ULL * zclk->fixed_div,
101 				       parent_rate);
102 	mult = clamp(mult, 1U, 32U);
103 
104 	if (readl(zclk->kick_reg) & CPG_FRQCRB_KICK)
105 		return -EBUSY;
106 
107 	cpg_reg_modify(zclk->reg, zclk->mask, (32 - mult) << __ffs(zclk->mask));
108 
109 	/*
110 	 * Set KICK bit in FRQCRB to update hardware setting and wait for
111 	 * clock change completion.
112 	 */
113 	cpg_reg_modify(zclk->kick_reg, 0, CPG_FRQCRB_KICK);
114 
115 	/*
116 	 * Note: There is no HW information about the worst case latency.
117 	 *
118 	 * Using experimental measurements, it seems that no more than
119 	 * ~10 iterations are needed, independently of the CPU rate.
120 	 * Since this value might be dependent on external xtal rate, pll1
121 	 * rate or even the other emulation clocks rate, use 1000 as a
122 	 * "super" safe value.
123 	 */
124 	for (i = 1000; i; i--) {
125 		if (!(readl(zclk->kick_reg) & CPG_FRQCRB_KICK))
126 			return 0;
127 
128 		cpu_relax();
129 	}
130 
131 	return -ETIMEDOUT;
132 }
133 
134 static const struct clk_ops cpg_z_clk_ops = {
135 	.recalc_rate = cpg_z_clk_recalc_rate,
136 	.determine_rate = cpg_z_clk_determine_rate,
137 	.set_rate = cpg_z_clk_set_rate,
138 };
139 
140 static struct clk * __init cpg_z_clk_register(const char *name,
141 					      const char *parent_name,
142 					      void __iomem *reg,
143 					      unsigned int div,
144 					      unsigned int offset)
145 {
146 	struct clk_init_data init = {};
147 	struct cpg_z_clk *zclk;
148 	struct clk *clk;
149 
150 	zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
151 	if (!zclk)
152 		return ERR_PTR(-ENOMEM);
153 
154 	init.name = name;
155 	init.ops = &cpg_z_clk_ops;
156 	init.flags = CLK_SET_RATE_PARENT;
157 	init.parent_names = &parent_name;
158 	init.num_parents = 1;
159 
160 	zclk->reg = reg + CPG_FRQCRC;
161 	zclk->kick_reg = reg + CPG_FRQCRB;
162 	zclk->hw.init = &init;
163 	zclk->mask = GENMASK(offset + 4, offset);
164 	zclk->fixed_div = div; /* PLLVCO x 1/div x SYS-CPU divider */
165 
166 	clk = clk_register(NULL, &zclk->hw);
167 	if (IS_ERR(clk)) {
168 		kfree(zclk);
169 		return clk;
170 	}
171 
172 	zclk->max_rate = clk_hw_get_rate(clk_hw_get_parent(&zclk->hw)) /
173 			 zclk->fixed_div;
174 	return clk;
175 }
176 
177 /*
178  * RPC Clocks
179  */
180 static const struct clk_div_table cpg_rpcsrc_div_table[] = {
181 	{ 0, 4 }, { 1, 6 }, { 2, 5 }, { 3, 6 }, { 0, 0 },
182 };
183 
184 struct clk * __init rcar_gen4_cpg_clk_register(struct device *dev,
185 	const struct cpg_core_clk *core, const struct cpg_mssr_info *info,
186 	struct clk **clks, void __iomem *base,
187 	struct raw_notifier_head *notifiers)
188 {
189 	const struct clk *parent;
190 	unsigned int mult = 1;
191 	unsigned int div = 1;
192 	u32 value;
193 
194 	parent = clks[core->parent & 0xffff];	/* some types use high bits */
195 	if (IS_ERR(parent))
196 		return ERR_CAST(parent);
197 
198 	switch (core->type) {
199 	case CLK_TYPE_GEN4_MAIN:
200 		div = cpg_pll_config->extal_div;
201 		break;
202 
203 	case CLK_TYPE_GEN4_PLL1:
204 		mult = cpg_pll_config->pll1_mult;
205 		div = cpg_pll_config->pll1_div;
206 		break;
207 
208 	case CLK_TYPE_GEN4_PLL2:
209 		mult = cpg_pll_config->pll2_mult;
210 		div = cpg_pll_config->pll2_div;
211 		break;
212 
213 	case CLK_TYPE_GEN4_PLL3:
214 		mult = cpg_pll_config->pll3_mult;
215 		div = cpg_pll_config->pll3_div;
216 		break;
217 
218 	case CLK_TYPE_GEN4_PLL4:
219 		mult = cpg_pll_config->pll4_mult;
220 		div = cpg_pll_config->pll4_div;
221 		break;
222 
223 	case CLK_TYPE_GEN4_PLL5:
224 		mult = cpg_pll_config->pll5_mult;
225 		div = cpg_pll_config->pll5_div;
226 		break;
227 
228 	case CLK_TYPE_GEN4_PLL6:
229 		mult = cpg_pll_config->pll6_mult;
230 		div = cpg_pll_config->pll6_div;
231 		break;
232 
233 	case CLK_TYPE_GEN4_PLL2X_3X:
234 		value = readl(base + core->offset);
235 		mult = (((value >> 24) & 0x7f) + 1) * 2;
236 		break;
237 
238 	case CLK_TYPE_GEN4_Z:
239 		return cpg_z_clk_register(core->name, __clk_get_name(parent),
240 					  base, core->div, core->offset);
241 
242 	case CLK_TYPE_GEN4_SDSRC:
243 		div = ((readl(base + SD0CKCR1) >> 29) & 0x03) + 4;
244 		break;
245 
246 	case CLK_TYPE_GEN4_SDH:
247 		return cpg_sdh_clk_register(core->name, base + core->offset,
248 					   __clk_get_name(parent), notifiers);
249 
250 	case CLK_TYPE_GEN4_SD:
251 		return cpg_sd_clk_register(core->name, base + core->offset,
252 					   __clk_get_name(parent));
253 
254 	case CLK_TYPE_GEN4_MDSEL:
255 		/*
256 		 * Clock selectable between two parents and two fixed dividers
257 		 * using a mode pin
258 		 */
259 		if (cpg_mode & BIT(core->offset)) {
260 			div = core->div & 0xffff;
261 		} else {
262 			parent = clks[core->parent >> 16];
263 			if (IS_ERR(parent))
264 				return ERR_CAST(parent);
265 			div = core->div >> 16;
266 		}
267 		mult = 1;
268 		break;
269 
270 	case CLK_TYPE_GEN4_OSC:
271 		/*
272 		 * Clock combining OSC EXTAL predivider and a fixed divider
273 		 */
274 		div = cpg_pll_config->osc_prediv * core->div;
275 		break;
276 
277 	case CLK_TYPE_GEN4_RPCSRC:
278 		return clk_register_divider_table(NULL, core->name,
279 						  __clk_get_name(parent), 0,
280 						  base + CPG_RPCCKCR, 3, 2, 0,
281 						  cpg_rpcsrc_div_table,
282 						  &cpg_lock);
283 
284 	case CLK_TYPE_GEN4_RPC:
285 		return cpg_rpc_clk_register(core->name, base + CPG_RPCCKCR,
286 					    __clk_get_name(parent), notifiers);
287 
288 	case CLK_TYPE_GEN4_RPCD2:
289 		return cpg_rpcd2_clk_register(core->name, base + CPG_RPCCKCR,
290 					      __clk_get_name(parent));
291 
292 	default:
293 		return ERR_PTR(-EINVAL);
294 	}
295 
296 	return clk_register_fixed_factor(NULL, core->name,
297 					 __clk_get_name(parent), 0, mult, div);
298 }
299 
300 int __init rcar_gen4_cpg_init(const struct rcar_gen4_cpg_pll_config *config,
301 			      unsigned int clk_extalr, u32 mode)
302 {
303 	cpg_pll_config = config;
304 	cpg_clk_extalr = clk_extalr;
305 	cpg_mode = mode;
306 
307 	spin_lock_init(&cpg_lock);
308 
309 	return 0;
310 }
311