xref: /linux/drivers/clk/qcom/clk-cbf-8996.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2022, 2023 Linaro Ltd.
4  */
5 #include <linux/bitfield.h>
6 #include <linux/clk.h>
7 #include <linux/clk-provider.h>
8 #include <linux/interconnect-clk.h>
9 #include <linux/interconnect-provider.h>
10 #include <linux/of.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 
15 #include <dt-bindings/interconnect/qcom,msm8996-cbf.h>
16 
17 #include "clk-alpha-pll.h"
18 #include "clk-regmap.h"
19 
20 /* Need to match the order of clocks in DT binding */
21 enum {
22 	DT_XO,
23 	DT_APCS_AUX,
24 };
25 
26 enum {
27 	CBF_XO_INDEX,
28 	CBF_PLL_INDEX,
29 	CBF_DIV_INDEX,
30 	CBF_APCS_AUX_INDEX,
31 };
32 
33 #define DIV_THRESHOLD		600000000
34 
35 #define CBF_MUX_OFFSET		0x18
36 #define CBF_MUX_PARENT_MASK		GENMASK(1, 0)
37 #define CBF_MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK GENMASK(5, 4)
38 #define CBF_MUX_AUTO_CLK_SEL_ALWAYS_ON_GPLL0_SEL \
39 	FIELD_PREP(CBF_MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK, 0x03)
40 #define CBF_MUX_AUTO_CLK_SEL_BIT	BIT(6)
41 
42 #define CBF_PLL_OFFSET 0xf000
43 
44 static struct alpha_pll_config cbfpll_config = {
45 	.l = 72,
46 	.config_ctl_val = 0x200d4828,
47 	.config_ctl_hi_val = 0x006,
48 	.test_ctl_val = 0x1c000000,
49 	.test_ctl_hi_val = 0x00004000,
50 	.pre_div_mask = BIT(12),
51 	.post_div_mask = 0x3 << 8,
52 	.post_div_val = 0x1 << 8,
53 	.main_output_mask = BIT(0),
54 	.early_output_mask = BIT(3),
55 };
56 
57 static struct clk_alpha_pll cbf_pll = {
58 	.offset = CBF_PLL_OFFSET,
59 	.regs = clk_alpha_pll_regs[CLK_ALPHA_PLL_TYPE_HUAYRA_APSS],
60 	.flags = SUPPORTS_DYNAMIC_UPDATE | SUPPORTS_FSM_MODE,
61 	.clkr.hw.init = &(struct clk_init_data){
62 		.name = "cbf_pll",
63 		.parent_data = (const struct clk_parent_data[]) {
64 			{ .index = DT_XO, },
65 		},
66 		.num_parents = 1,
67 		.ops = &clk_alpha_pll_hwfsm_ops,
68 	},
69 };
70 
71 static struct clk_fixed_factor cbf_pll_postdiv = {
72 	.mult = 1,
73 	.div = 2,
74 	.hw.init = &(struct clk_init_data){
75 		.name = "cbf_pll_postdiv",
76 		.parent_hws = (const struct clk_hw*[]){
77 			&cbf_pll.clkr.hw
78 		},
79 		.num_parents = 1,
80 		.ops = &clk_fixed_factor_ops,
81 		.flags = CLK_SET_RATE_PARENT,
82 	},
83 };
84 
85 static const struct clk_parent_data cbf_mux_parent_data[] = {
86 	{ .index = DT_XO },
87 	{ .hw = &cbf_pll.clkr.hw },
88 	{ .hw = &cbf_pll_postdiv.hw },
89 	{ .index = DT_APCS_AUX },
90 };
91 
92 struct clk_cbf_8996_mux {
93 	u32 reg;
94 	struct notifier_block nb;
95 	struct clk_regmap clkr;
96 };
97 
98 static struct clk_cbf_8996_mux *to_clk_cbf_8996_mux(struct clk_regmap *clkr)
99 {
100 	return container_of(clkr, struct clk_cbf_8996_mux, clkr);
101 }
102 
103 static int cbf_clk_notifier_cb(struct notifier_block *nb, unsigned long event,
104 			       void *data);
105 
106 static u8 clk_cbf_8996_mux_get_parent(struct clk_hw *hw)
107 {
108 	struct clk_regmap *clkr = to_clk_regmap(hw);
109 	struct clk_cbf_8996_mux *mux = to_clk_cbf_8996_mux(clkr);
110 	u32 val;
111 
112 	regmap_read(clkr->regmap, mux->reg, &val);
113 
114 	return FIELD_GET(CBF_MUX_PARENT_MASK, val);
115 }
116 
117 static int clk_cbf_8996_mux_set_parent(struct clk_hw *hw, u8 index)
118 {
119 	struct clk_regmap *clkr = to_clk_regmap(hw);
120 	struct clk_cbf_8996_mux *mux = to_clk_cbf_8996_mux(clkr);
121 	u32 val;
122 
123 	val = FIELD_PREP(CBF_MUX_PARENT_MASK, index);
124 
125 	return regmap_update_bits(clkr->regmap, mux->reg, CBF_MUX_PARENT_MASK, val);
126 }
127 
128 static int clk_cbf_8996_mux_determine_rate(struct clk_hw *hw,
129 					   struct clk_rate_request *req)
130 {
131 	struct clk_hw *parent;
132 
133 	if (req->rate < (DIV_THRESHOLD / cbf_pll_postdiv.div))
134 		return -EINVAL;
135 
136 	if (req->rate < DIV_THRESHOLD)
137 		parent = clk_hw_get_parent_by_index(hw, CBF_DIV_INDEX);
138 	else
139 		parent = clk_hw_get_parent_by_index(hw, CBF_PLL_INDEX);
140 
141 	if (!parent)
142 		return -EINVAL;
143 
144 	req->best_parent_rate = clk_hw_round_rate(parent, req->rate);
145 	req->best_parent_hw = parent;
146 
147 	return 0;
148 }
149 
150 static const struct clk_ops clk_cbf_8996_mux_ops = {
151 	.set_parent = clk_cbf_8996_mux_set_parent,
152 	.get_parent = clk_cbf_8996_mux_get_parent,
153 	.determine_rate = clk_cbf_8996_mux_determine_rate,
154 };
155 
156 static struct clk_cbf_8996_mux cbf_mux = {
157 	.reg = CBF_MUX_OFFSET,
158 	.nb.notifier_call = cbf_clk_notifier_cb,
159 	.clkr.hw.init = &(struct clk_init_data) {
160 		.name = "cbf_mux",
161 		.parent_data = cbf_mux_parent_data,
162 		.num_parents = ARRAY_SIZE(cbf_mux_parent_data),
163 		.ops = &clk_cbf_8996_mux_ops,
164 		/* CPU clock is critical and should never be gated */
165 		.flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL,
166 	},
167 };
168 
169 static int cbf_clk_notifier_cb(struct notifier_block *nb, unsigned long event,
170 			       void *data)
171 {
172 	struct clk_notifier_data *cnd = data;
173 
174 	switch (event) {
175 	case PRE_RATE_CHANGE:
176 		/*
177 		 * Avoid overvolting. clk_core_set_rate_nolock() walks from top
178 		 * to bottom, so it will change the rate of the PLL before
179 		 * chaging the parent of PMUX. This can result in pmux getting
180 		 * clocked twice the expected rate.
181 		 *
182 		 * Manually switch to PLL/2 here.
183 		 */
184 		if (cnd->old_rate > DIV_THRESHOLD &&
185 		    cnd->new_rate < DIV_THRESHOLD)
186 			clk_cbf_8996_mux_set_parent(&cbf_mux.clkr.hw, CBF_DIV_INDEX);
187 		break;
188 	case ABORT_RATE_CHANGE:
189 		/* Revert manual change */
190 		if (cnd->new_rate < DIV_THRESHOLD &&
191 		    cnd->old_rate > DIV_THRESHOLD)
192 			clk_cbf_8996_mux_set_parent(&cbf_mux.clkr.hw, CBF_PLL_INDEX);
193 		break;
194 	default:
195 		break;
196 	}
197 
198 	return notifier_from_errno(0);
199 };
200 
201 static struct clk_hw *cbf_msm8996_hw_clks[] = {
202 	&cbf_pll_postdiv.hw,
203 };
204 
205 static struct clk_regmap *cbf_msm8996_clks[] = {
206 	&cbf_pll.clkr,
207 	&cbf_mux.clkr,
208 };
209 
210 static const struct regmap_config cbf_msm8996_regmap_config = {
211 	.reg_bits		= 32,
212 	.reg_stride		= 4,
213 	.val_bits		= 32,
214 	.max_register		= 0x10000,
215 	.fast_io		= true,
216 	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
217 };
218 
219 #ifdef CONFIG_INTERCONNECT
220 
221 /* Random ID that doesn't clash with main qnoc and OSM */
222 #define CBF_MASTER_NODE 2000
223 
224 static int qcom_msm8996_cbf_icc_register(struct platform_device *pdev, struct clk_hw *cbf_hw)
225 {
226 	struct device *dev = &pdev->dev;
227 	struct clk *clk = devm_clk_hw_get_clk(dev, cbf_hw, "cbf");
228 	const struct icc_clk_data data[] = {
229 		{
230 			.clk = clk,
231 			.name = "cbf",
232 			.master_id = MASTER_CBF_M4M,
233 			.slave_id = SLAVE_CBF_M4M,
234 		},
235 	};
236 	struct icc_provider *provider;
237 
238 	provider = icc_clk_register(dev, CBF_MASTER_NODE, ARRAY_SIZE(data), data);
239 	if (IS_ERR(provider))
240 		return PTR_ERR(provider);
241 
242 	platform_set_drvdata(pdev, provider);
243 
244 	return 0;
245 }
246 
247 static void qcom_msm8996_cbf_icc_remove(struct platform_device *pdev)
248 {
249 	struct icc_provider *provider = platform_get_drvdata(pdev);
250 
251 	icc_clk_unregister(provider);
252 }
253 #define qcom_msm8996_cbf_icc_sync_state icc_sync_state
254 #else
255 static int qcom_msm8996_cbf_icc_register(struct platform_device *pdev,  struct clk_hw *cbf_hw)
256 {
257 	dev_warn(&pdev->dev, "CONFIG_INTERCONNECT is disabled, CBF clock is fixed\n");
258 
259 	return 0;
260 }
261 #define qcom_msm8996_cbf_icc_remove(pdev) { }
262 #define qcom_msm8996_cbf_icc_sync_state NULL
263 #endif
264 
265 static int qcom_msm8996_cbf_probe(struct platform_device *pdev)
266 {
267 	void __iomem *base;
268 	struct regmap *regmap;
269 	struct device *dev = &pdev->dev;
270 	int i, ret;
271 
272 	base = devm_platform_ioremap_resource(pdev, 0);
273 	if (IS_ERR(base))
274 		return PTR_ERR(base);
275 
276 	regmap = devm_regmap_init_mmio(dev, base, &cbf_msm8996_regmap_config);
277 	if (IS_ERR(regmap))
278 		return PTR_ERR(regmap);
279 
280 	/* Select GPLL0 for 300MHz for the CBF clock */
281 	regmap_write(regmap, CBF_MUX_OFFSET, 0x3);
282 
283 	/* Ensure write goes through before PLLs are reconfigured */
284 	udelay(5);
285 
286 	/* Set the auto clock sel always-on source to GPLL0/2 (300MHz) */
287 	regmap_update_bits(regmap, CBF_MUX_OFFSET,
288 			   CBF_MUX_AUTO_CLK_SEL_ALWAYS_ON_MASK,
289 			   CBF_MUX_AUTO_CLK_SEL_ALWAYS_ON_GPLL0_SEL);
290 
291 	clk_alpha_pll_configure(&cbf_pll, regmap, &cbfpll_config);
292 
293 	/* Wait for PLL(s) to lock */
294 	udelay(50);
295 
296 	/* Enable auto clock selection for CBF */
297 	regmap_update_bits(regmap, CBF_MUX_OFFSET,
298 			   CBF_MUX_AUTO_CLK_SEL_BIT,
299 			   CBF_MUX_AUTO_CLK_SEL_BIT);
300 
301 	/* Ensure write goes through before muxes are switched */
302 	udelay(5);
303 
304 	/* Switch CBF to use the primary PLL */
305 	regmap_update_bits(regmap, CBF_MUX_OFFSET, CBF_MUX_PARENT_MASK, 0x1);
306 
307 	if (of_device_is_compatible(dev->of_node, "qcom,msm8996pro-cbf")) {
308 		cbfpll_config.post_div_val = 0x3 << 8;
309 		cbf_pll_postdiv.div = 4;
310 	}
311 
312 	for (i = 0; i < ARRAY_SIZE(cbf_msm8996_hw_clks); i++) {
313 		ret = devm_clk_hw_register(dev, cbf_msm8996_hw_clks[i]);
314 		if (ret)
315 			return ret;
316 	}
317 
318 	for (i = 0; i < ARRAY_SIZE(cbf_msm8996_clks); i++) {
319 		ret = devm_clk_register_regmap(dev, cbf_msm8996_clks[i]);
320 		if (ret)
321 			return ret;
322 	}
323 
324 	ret = devm_clk_notifier_register(dev, cbf_mux.clkr.hw.clk, &cbf_mux.nb);
325 	if (ret)
326 		return ret;
327 
328 	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, &cbf_mux.clkr.hw);
329 	if (ret)
330 		return ret;
331 
332 	return qcom_msm8996_cbf_icc_register(pdev, &cbf_mux.clkr.hw);
333 }
334 
335 static void qcom_msm8996_cbf_remove(struct platform_device *pdev)
336 {
337 	qcom_msm8996_cbf_icc_remove(pdev);
338 }
339 
340 static const struct of_device_id qcom_msm8996_cbf_match_table[] = {
341 	{ .compatible = "qcom,msm8996-cbf" },
342 	{ .compatible = "qcom,msm8996pro-cbf" },
343 	{ /* sentinel */ },
344 };
345 MODULE_DEVICE_TABLE(of, qcom_msm8996_cbf_match_table);
346 
347 static struct platform_driver qcom_msm8996_cbf_driver = {
348 	.probe = qcom_msm8996_cbf_probe,
349 	.remove = qcom_msm8996_cbf_remove,
350 	.driver = {
351 		.name = "qcom-msm8996-cbf",
352 		.of_match_table = qcom_msm8996_cbf_match_table,
353 		.sync_state = qcom_msm8996_cbf_icc_sync_state,
354 	},
355 };
356 
357 /* Register early enough to fix the clock to be used for other cores */
358 static int __init qcom_msm8996_cbf_init(void)
359 {
360 	return platform_driver_register(&qcom_msm8996_cbf_driver);
361 }
362 postcore_initcall(qcom_msm8996_cbf_init);
363 
364 static void __exit qcom_msm8996_cbf_exit(void)
365 {
366 	platform_driver_unregister(&qcom_msm8996_cbf_driver);
367 }
368 module_exit(qcom_msm8996_cbf_exit);
369 
370 MODULE_DESCRIPTION("QCOM MSM8996 CPU Bus Fabric Clock Driver");
371 MODULE_LICENSE("GPL");
372