1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018 NVIDIA CORPORATION.  All rights reserved.
4  *
5  * based on clk-mux.c
6  *
7  * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
8  * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
9  * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
10  *
11  */
12 
13 #include <linux/clk-provider.h>
14 #include <linux/err.h>
15 #include <linux/io.h>
16 #include <linux/types.h>
17 
18 #include "clk.h"
19 
20 #define DIV_MASK GENMASK(7, 0)
21 #define MUX_SHIFT 29
22 #define MUX_MASK GENMASK(MUX_SHIFT + 2, MUX_SHIFT)
23 #define SDMMC_MUL 2
24 
25 #define get_max_div(d) DIV_MASK
26 #define get_div_field(val) ((val) & DIV_MASK)
27 #define get_mux_field(val) (((val) & MUX_MASK) >> MUX_SHIFT)
28 
29 static const char * const mux_sdmmc_parents[] = {
30 	"pll_p", "pll_c4_out2", "pll_c4_out0", "pll_c4_out1", "clk_m"
31 };
32 
33 static const u8 mux_lj_idx[] = {
34 	[0] = 0, [1] = 1, [2] = 2, [3] = 5, [4] = 6
35 };
36 
37 static const u8 mux_non_lj_idx[] = {
38 	[0] = 0, [1] = 3, [2] = 7, [3] = 4, [4] = 6
39 };
40 
41 static u8 clk_sdmmc_mux_get_parent(struct clk_hw *hw)
42 {
43 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
44 	int num_parents, i;
45 	u32 src, val;
46 	const u8 *mux_idx;
47 
48 	num_parents = clk_hw_get_num_parents(hw);
49 
50 	val = readl_relaxed(sdmmc_mux->reg);
51 	src = get_mux_field(val);
52 	if (get_div_field(val))
53 		mux_idx = mux_non_lj_idx;
54 	else
55 		mux_idx = mux_lj_idx;
56 
57 	for (i = 0; i < num_parents; i++) {
58 		if (mux_idx[i] == src)
59 			return i;
60 	}
61 
62 	WARN(1, "Unknown parent selector %d\n", src);
63 
64 	return 0;
65 }
66 
67 static int clk_sdmmc_mux_set_parent(struct clk_hw *hw, u8 index)
68 {
69 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
70 	u32 val;
71 
72 
73 	val = readl_relaxed(sdmmc_mux->reg);
74 	if (get_div_field(val))
75 		index = mux_non_lj_idx[index];
76 	else
77 		index = mux_lj_idx[index];
78 
79 	val &= ~MUX_MASK;
80 	val |= index << MUX_SHIFT;
81 
82 	writel(val, sdmmc_mux->reg);
83 
84 	return 0;
85 }
86 
87 static unsigned long clk_sdmmc_mux_recalc_rate(struct clk_hw *hw,
88 					       unsigned long parent_rate)
89 {
90 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
91 	u32 val;
92 	int div;
93 	u64 rate = parent_rate;
94 
95 	val = readl_relaxed(sdmmc_mux->reg);
96 	div = get_div_field(val);
97 
98 	div += SDMMC_MUL;
99 
100 	rate *= SDMMC_MUL;
101 	rate += div - 1;
102 	do_div(rate, div);
103 
104 	return rate;
105 }
106 
107 static int clk_sdmmc_mux_determine_rate(struct clk_hw *hw,
108 					struct clk_rate_request *req)
109 {
110 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
111 	int div;
112 	unsigned long output_rate = req->best_parent_rate;
113 
114 	req->rate = max(req->rate, req->min_rate);
115 	req->rate = min(req->rate, req->max_rate);
116 
117 	if (!req->rate)
118 		return output_rate;
119 
120 	div = div_frac_get(req->rate, output_rate, 8, 1, sdmmc_mux->div_flags);
121 	if (div < 0)
122 		div = 0;
123 
124 	if (sdmmc_mux->div_flags & TEGRA_DIVIDER_ROUND_UP)
125 		req->rate =  DIV_ROUND_UP(output_rate * SDMMC_MUL,
126 					  div + SDMMC_MUL);
127 	else
128 		req->rate =  output_rate * SDMMC_MUL / (div + SDMMC_MUL);
129 
130 	return 0;
131 }
132 
133 static int clk_sdmmc_mux_set_rate(struct clk_hw *hw, unsigned long rate,
134 				  unsigned long parent_rate)
135 {
136 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
137 	int div;
138 	unsigned long flags = 0;
139 	u32 val;
140 	u8 src;
141 
142 	div = div_frac_get(rate, parent_rate, 8, 1, sdmmc_mux->div_flags);
143 	if (div < 0)
144 		return div;
145 
146 	if (sdmmc_mux->lock)
147 		spin_lock_irqsave(sdmmc_mux->lock, flags);
148 
149 	src = clk_sdmmc_mux_get_parent(hw);
150 	if (div)
151 		src = mux_non_lj_idx[src];
152 	else
153 		src = mux_lj_idx[src];
154 
155 	val = src << MUX_SHIFT;
156 	val |= div;
157 	writel(val, sdmmc_mux->reg);
158 	fence_udelay(2, sdmmc_mux->reg);
159 
160 	if (sdmmc_mux->lock)
161 		spin_unlock_irqrestore(sdmmc_mux->lock, flags);
162 
163 	return 0;
164 }
165 
166 static int clk_sdmmc_mux_is_enabled(struct clk_hw *hw)
167 {
168 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
169 	const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
170 	struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
171 
172 	__clk_hw_set_clk(gate_hw, hw);
173 
174 	return gate_ops->is_enabled(gate_hw);
175 }
176 
177 static int clk_sdmmc_mux_enable(struct clk_hw *hw)
178 {
179 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
180 	const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
181 	struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
182 
183 	__clk_hw_set_clk(gate_hw, hw);
184 
185 	return gate_ops->enable(gate_hw);
186 }
187 
188 static void clk_sdmmc_mux_disable(struct clk_hw *hw)
189 {
190 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
191 	const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
192 	struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
193 
194 	gate_ops->disable(gate_hw);
195 }
196 
197 static void clk_sdmmc_mux_disable_unused(struct clk_hw *hw)
198 {
199 	struct tegra_sdmmc_mux *sdmmc_mux = to_clk_sdmmc_mux(hw);
200 	const struct clk_ops *gate_ops = sdmmc_mux->gate_ops;
201 	struct clk_hw *gate_hw = &sdmmc_mux->gate.hw;
202 
203 	gate_ops->disable_unused(gate_hw);
204 }
205 
206 static void clk_sdmmc_mux_restore_context(struct clk_hw *hw)
207 {
208 	struct clk_hw *parent = clk_hw_get_parent(hw);
209 	unsigned long parent_rate = clk_hw_get_rate(parent);
210 	unsigned long rate = clk_hw_get_rate(hw);
211 	int parent_id;
212 
213 	parent_id = clk_hw_get_parent_index(hw);
214 	if (WARN_ON(parent_id < 0))
215 		return;
216 
217 	clk_sdmmc_mux_set_parent(hw, parent_id);
218 	clk_sdmmc_mux_set_rate(hw, rate, parent_rate);
219 }
220 
221 static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
222 	.get_parent = clk_sdmmc_mux_get_parent,
223 	.set_parent = clk_sdmmc_mux_set_parent,
224 	.determine_rate = clk_sdmmc_mux_determine_rate,
225 	.recalc_rate = clk_sdmmc_mux_recalc_rate,
226 	.set_rate = clk_sdmmc_mux_set_rate,
227 	.is_enabled = clk_sdmmc_mux_is_enabled,
228 	.enable = clk_sdmmc_mux_enable,
229 	.disable = clk_sdmmc_mux_disable,
230 	.disable_unused = clk_sdmmc_mux_disable_unused,
231 	.restore_context = clk_sdmmc_mux_restore_context,
232 };
233 
234 struct clk *tegra_clk_register_sdmmc_mux_div(const char *name,
235 	void __iomem *clk_base, u32 offset, u32 clk_num, u8 div_flags,
236 	unsigned long flags, void *lock)
237 {
238 	struct clk *clk;
239 	struct clk_init_data init;
240 	const struct tegra_clk_periph_regs *bank;
241 	struct tegra_sdmmc_mux *sdmmc_mux;
242 
243 	init.ops = &tegra_clk_sdmmc_mux_ops;
244 	init.name = name;
245 	init.flags = flags;
246 	init.parent_names = mux_sdmmc_parents;
247 	init.num_parents = ARRAY_SIZE(mux_sdmmc_parents);
248 
249 	bank = get_reg_bank(clk_num);
250 	if (!bank)
251 		return ERR_PTR(-EINVAL);
252 
253 	sdmmc_mux = kzalloc(sizeof(*sdmmc_mux), GFP_KERNEL);
254 	if (!sdmmc_mux)
255 		return ERR_PTR(-ENOMEM);
256 
257 	/* Data in .init is copied by clk_register(), so stack variable OK */
258 	sdmmc_mux->hw.init = &init;
259 	sdmmc_mux->reg = clk_base + offset;
260 	sdmmc_mux->lock = lock;
261 	sdmmc_mux->gate.clk_base = clk_base;
262 	sdmmc_mux->gate.regs = bank;
263 	sdmmc_mux->gate.enable_refcnt = periph_clk_enb_refcnt;
264 	sdmmc_mux->gate.clk_num = clk_num;
265 	sdmmc_mux->gate.flags = TEGRA_PERIPH_ON_APB;
266 	sdmmc_mux->div_flags = div_flags;
267 	sdmmc_mux->gate_ops = &tegra_clk_periph_gate_ops;
268 
269 	clk = clk_register(NULL, &sdmmc_mux->hw);
270 	if (IS_ERR(clk)) {
271 		kfree(sdmmc_mux);
272 		return clk;
273 	}
274 
275 	sdmmc_mux->gate.hw.clk = clk;
276 
277 	return clk;
278 }
279