1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2014 Broadcom Corporation
3 
4 #include <linux/kernel.h>
5 #include <linux/slab.h>
6 #include <linux/err.h>
7 #include <linux/clk-provider.h>
8 #include <linux/io.h>
9 #include <linux/of.h>
10 #include <linux/clkdev.h>
11 #include <linux/of_address.h>
12 
13 #include "clk-iproc.h"
14 
15 #define IPROC_CLK_MAX_FREQ_POLICY                    0x3
16 #define IPROC_CLK_POLICY_FREQ_OFFSET                 0x008
17 #define IPROC_CLK_POLICY_FREQ_POLICY_FREQ_SHIFT      8
18 #define IPROC_CLK_POLICY_FREQ_POLICY_FREQ_MASK       0x7
19 
20 #define IPROC_CLK_PLLARMA_OFFSET                     0xc00
21 #define IPROC_CLK_PLLARMA_LOCK_SHIFT                 28
22 #define IPROC_CLK_PLLARMA_PDIV_SHIFT                 24
23 #define IPROC_CLK_PLLARMA_PDIV_MASK                  0xf
24 #define IPROC_CLK_PLLARMA_NDIV_INT_SHIFT             8
25 #define IPROC_CLK_PLLARMA_NDIV_INT_MASK              0x3ff
26 
27 #define IPROC_CLK_PLLARMB_OFFSET                     0xc04
28 #define IPROC_CLK_PLLARMB_NDIV_FRAC_MASK             0xfffff
29 
30 #define IPROC_CLK_PLLARMC_OFFSET                     0xc08
31 #define IPROC_CLK_PLLARMC_BYPCLK_EN_SHIFT            8
32 #define IPROC_CLK_PLLARMC_MDIV_MASK                  0xff
33 
34 #define IPROC_CLK_PLLARMCTL5_OFFSET                  0xc20
35 #define IPROC_CLK_PLLARMCTL5_H_MDIV_MASK             0xff
36 
37 #define IPROC_CLK_PLLARM_OFFSET_OFFSET               0xc24
38 #define IPROC_CLK_PLLARM_SW_CTL_SHIFT                29
39 #define IPROC_CLK_PLLARM_NDIV_INT_OFFSET_SHIFT       20
40 #define IPROC_CLK_PLLARM_NDIV_INT_OFFSET_MASK        0xff
41 #define IPROC_CLK_PLLARM_NDIV_FRAC_OFFSET_MASK       0xfffff
42 
43 #define IPROC_CLK_ARM_DIV_OFFSET                     0xe00
44 #define IPROC_CLK_ARM_DIV_PLL_SELECT_OVERRIDE_SHIFT  4
45 #define IPROC_CLK_ARM_DIV_ARM_PLL_SELECT_MASK        0xf
46 
47 #define IPROC_CLK_POLICY_DBG_OFFSET                  0xec0
48 #define IPROC_CLK_POLICY_DBG_ACT_FREQ_SHIFT          12
49 #define IPROC_CLK_POLICY_DBG_ACT_FREQ_MASK           0x7
50 
51 enum iproc_arm_pll_fid {
52 	ARM_PLL_FID_CRYSTAL_CLK   = 0,
53 	ARM_PLL_FID_SYS_CLK       = 2,
54 	ARM_PLL_FID_CH0_SLOW_CLK  = 6,
55 	ARM_PLL_FID_CH1_FAST_CLK  = 7
56 };
57 
58 struct iproc_arm_pll {
59 	struct clk_hw hw;
60 	void __iomem *base;
61 	unsigned long rate;
62 };
63 
64 #define to_iproc_arm_pll(hw) container_of(hw, struct iproc_arm_pll, hw)
65 
66 static unsigned int __get_fid(struct iproc_arm_pll *pll)
67 {
68 	u32 val;
69 	unsigned int policy, fid, active_fid;
70 
71 	val = readl(pll->base + IPROC_CLK_ARM_DIV_OFFSET);
72 	if (val & (1 << IPROC_CLK_ARM_DIV_PLL_SELECT_OVERRIDE_SHIFT))
73 		policy = val & IPROC_CLK_ARM_DIV_ARM_PLL_SELECT_MASK;
74 	else
75 		policy = 0;
76 
77 	/* something is seriously wrong */
78 	BUG_ON(policy > IPROC_CLK_MAX_FREQ_POLICY);
79 
80 	val = readl(pll->base + IPROC_CLK_POLICY_FREQ_OFFSET);
81 	fid = (val >> (IPROC_CLK_POLICY_FREQ_POLICY_FREQ_SHIFT * policy)) &
82 		IPROC_CLK_POLICY_FREQ_POLICY_FREQ_MASK;
83 
84 	val = readl(pll->base + IPROC_CLK_POLICY_DBG_OFFSET);
85 	active_fid = IPROC_CLK_POLICY_DBG_ACT_FREQ_MASK &
86 		(val >> IPROC_CLK_POLICY_DBG_ACT_FREQ_SHIFT);
87 	if (fid != active_fid) {
88 		pr_debug("%s: fid override %u->%u\n", __func__,	fid,
89 				active_fid);
90 		fid = active_fid;
91 	}
92 
93 	pr_debug("%s: active fid: %u\n", __func__, fid);
94 
95 	return fid;
96 }
97 
98 /*
99  * Determine the mdiv (post divider) based on the frequency ID being used.
100  * There are 4 sources that can be used to derive the output clock rate:
101  *    - 25 MHz Crystal
102  *    - System clock
103  *    - PLL channel 0 (slow clock)
104  *    - PLL channel 1 (fast clock)
105  */
106 static int __get_mdiv(struct iproc_arm_pll *pll)
107 {
108 	unsigned int fid;
109 	int mdiv;
110 	u32 val;
111 
112 	fid = __get_fid(pll);
113 
114 	switch (fid) {
115 	case ARM_PLL_FID_CRYSTAL_CLK:
116 	case ARM_PLL_FID_SYS_CLK:
117 		mdiv = 1;
118 		break;
119 
120 	case ARM_PLL_FID_CH0_SLOW_CLK:
121 		val = readl(pll->base + IPROC_CLK_PLLARMC_OFFSET);
122 		mdiv = val & IPROC_CLK_PLLARMC_MDIV_MASK;
123 		if (mdiv == 0)
124 			mdiv = 256;
125 		break;
126 
127 	case ARM_PLL_FID_CH1_FAST_CLK:
128 		val = readl(pll->base +	IPROC_CLK_PLLARMCTL5_OFFSET);
129 		mdiv = val & IPROC_CLK_PLLARMCTL5_H_MDIV_MASK;
130 		if (mdiv == 0)
131 			mdiv = 256;
132 		break;
133 
134 	default:
135 		mdiv = -EFAULT;
136 	}
137 
138 	return mdiv;
139 }
140 
141 static unsigned int __get_ndiv(struct iproc_arm_pll *pll)
142 {
143 	u32 val;
144 	unsigned int ndiv_int, ndiv_frac, ndiv;
145 
146 	val = readl(pll->base + IPROC_CLK_PLLARM_OFFSET_OFFSET);
147 	if (val & (1 << IPROC_CLK_PLLARM_SW_CTL_SHIFT)) {
148 		/*
149 		 * offset mode is active. Read the ndiv from the PLLARM OFFSET
150 		 * register
151 		 */
152 		ndiv_int = (val >> IPROC_CLK_PLLARM_NDIV_INT_OFFSET_SHIFT) &
153 			IPROC_CLK_PLLARM_NDIV_INT_OFFSET_MASK;
154 		if (ndiv_int == 0)
155 			ndiv_int = 256;
156 
157 		ndiv_frac = val & IPROC_CLK_PLLARM_NDIV_FRAC_OFFSET_MASK;
158 	} else {
159 		/* offset mode not active */
160 		val = readl(pll->base + IPROC_CLK_PLLARMA_OFFSET);
161 		ndiv_int = (val >> IPROC_CLK_PLLARMA_NDIV_INT_SHIFT) &
162 			IPROC_CLK_PLLARMA_NDIV_INT_MASK;
163 		if (ndiv_int == 0)
164 			ndiv_int = 1024;
165 
166 		val = readl(pll->base + IPROC_CLK_PLLARMB_OFFSET);
167 		ndiv_frac = val & IPROC_CLK_PLLARMB_NDIV_FRAC_MASK;
168 	}
169 
170 	ndiv = (ndiv_int << 20) | ndiv_frac;
171 
172 	return ndiv;
173 }
174 
175 /*
176  * The output frequency of the ARM PLL is calculated based on the ARM PLL
177  * divider values:
178  *   pdiv = ARM PLL pre-divider
179  *   ndiv = ARM PLL multiplier
180  *   mdiv = ARM PLL post divider
181  *
182  * The frequency is calculated by:
183  *   ((ndiv * parent clock rate) / pdiv) / mdiv
184  */
185 static unsigned long iproc_arm_pll_recalc_rate(struct clk_hw *hw,
186 		unsigned long parent_rate)
187 {
188 	struct iproc_arm_pll *pll = to_iproc_arm_pll(hw);
189 	u32 val;
190 	int mdiv;
191 	u64 ndiv;
192 	unsigned int pdiv;
193 
194 	/* in bypass mode, use parent rate */
195 	val = readl(pll->base + IPROC_CLK_PLLARMC_OFFSET);
196 	if (val & (1 << IPROC_CLK_PLLARMC_BYPCLK_EN_SHIFT)) {
197 		pll->rate = parent_rate;
198 		return pll->rate;
199 	}
200 
201 	/* PLL needs to be locked */
202 	val = readl(pll->base + IPROC_CLK_PLLARMA_OFFSET);
203 	if (!(val & (1 << IPROC_CLK_PLLARMA_LOCK_SHIFT))) {
204 		pll->rate = 0;
205 		return 0;
206 	}
207 
208 	pdiv = (val >> IPROC_CLK_PLLARMA_PDIV_SHIFT) &
209 		IPROC_CLK_PLLARMA_PDIV_MASK;
210 	if (pdiv == 0)
211 		pdiv = 16;
212 
213 	ndiv = __get_ndiv(pll);
214 	mdiv = __get_mdiv(pll);
215 	if (mdiv <= 0) {
216 		pll->rate = 0;
217 		return 0;
218 	}
219 	pll->rate = (ndiv * parent_rate) >> 20;
220 	pll->rate = (pll->rate / pdiv) / mdiv;
221 
222 	pr_debug("%s: ARM PLL rate: %lu. parent rate: %lu\n", __func__,
223 		 pll->rate, parent_rate);
224 	pr_debug("%s: ndiv_int: %u, pdiv: %u, mdiv: %d\n", __func__,
225 		 (unsigned int)(ndiv >> 20), pdiv, mdiv);
226 
227 	return pll->rate;
228 }
229 
230 static const struct clk_ops iproc_arm_pll_ops = {
231 	.recalc_rate = iproc_arm_pll_recalc_rate,
232 };
233 
234 void __init iproc_armpll_setup(struct device_node *node)
235 {
236 	int ret;
237 	struct iproc_arm_pll *pll;
238 	struct clk_init_data init;
239 	const char *parent_name;
240 
241 	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
242 	if (WARN_ON(!pll))
243 		return;
244 
245 	pll->base = of_iomap(node, 0);
246 	if (WARN_ON(!pll->base))
247 		goto err_free_pll;
248 
249 	init.name = node->name;
250 	init.ops = &iproc_arm_pll_ops;
251 	init.flags = 0;
252 	parent_name = of_clk_get_parent_name(node, 0);
253 	init.parent_names = (parent_name ? &parent_name : NULL);
254 	init.num_parents = (parent_name ? 1 : 0);
255 	pll->hw.init = &init;
256 
257 	ret = clk_hw_register(NULL, &pll->hw);
258 	if (WARN_ON(ret))
259 		goto err_iounmap;
260 
261 	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &pll->hw);
262 	if (WARN_ON(ret))
263 		goto err_clk_unregister;
264 
265 	return;
266 
267 err_clk_unregister:
268 	clk_hw_unregister(&pll->hw);
269 err_iounmap:
270 	iounmap(pll->base);
271 err_free_pll:
272 	kfree(pll);
273 }
274