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1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * CPU frequency scaling support for Armada 37xx platform. | |
4 | * | |
5 | * Copyright (C) 2017 Marvell | |
6 | * | |
7 | * Gregory CLEMENT <gregory.clement@free-electrons.com> | |
8 | */ | |
9 | ||
10 | #include <linux/clk.h> | |
11 | #include <linux/cpu.h> | |
12 | #include <linux/cpufreq.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/io.h> | |
16 | #include <linux/mfd/syscon.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/of_address.h> | |
19 | #include <linux/of_device.h> | |
20 | #include <linux/of_irq.h> | |
21 | #include <linux/platform_device.h> | |
22 | #include <linux/pm_opp.h> | |
23 | #include <linux/regmap.h> | |
24 | #include <linux/slab.h> | |
25 | ||
26 | /* Power management in North Bridge register set */ | |
27 | #define ARMADA_37XX_NB_L0L1 0x18 | |
28 | #define ARMADA_37XX_NB_L2L3 0x1C | |
29 | #define ARMADA_37XX_NB_TBG_DIV_OFF 13 | |
30 | #define ARMADA_37XX_NB_TBG_DIV_MASK 0x7 | |
31 | #define ARMADA_37XX_NB_CLK_SEL_OFF 11 | |
32 | #define ARMADA_37XX_NB_CLK_SEL_MASK 0x1 | |
33 | #define ARMADA_37XX_NB_CLK_SEL_TBG 0x1 | |
34 | #define ARMADA_37XX_NB_TBG_SEL_OFF 9 | |
35 | #define ARMADA_37XX_NB_TBG_SEL_MASK 0x3 | |
36 | #define ARMADA_37XX_NB_VDD_SEL_OFF 6 | |
37 | #define ARMADA_37XX_NB_VDD_SEL_MASK 0x3 | |
38 | #define ARMADA_37XX_NB_CONFIG_SHIFT 16 | |
39 | #define ARMADA_37XX_NB_DYN_MOD 0x24 | |
40 | #define ARMADA_37XX_NB_CLK_SEL_EN BIT(26) | |
41 | #define ARMADA_37XX_NB_TBG_EN BIT(28) | |
42 | #define ARMADA_37XX_NB_DIV_EN BIT(29) | |
43 | #define ARMADA_37XX_NB_VDD_EN BIT(30) | |
44 | #define ARMADA_37XX_NB_DFS_EN BIT(31) | |
45 | #define ARMADA_37XX_NB_CPU_LOAD 0x30 | |
46 | #define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3 | |
47 | #define ARMADA_37XX_DVFS_LOAD_0 0 | |
48 | #define ARMADA_37XX_DVFS_LOAD_1 1 | |
49 | #define ARMADA_37XX_DVFS_LOAD_2 2 | |
50 | #define ARMADA_37XX_DVFS_LOAD_3 3 | |
51 | ||
52 | /* | |
53 | * On Armada 37xx the Power management manages 4 level of CPU load, | |
54 | * each level can be associated with a CPU clock source, a CPU | |
55 | * divider, a VDD level, etc... | |
56 | */ | |
57 | #define LOAD_LEVEL_NR 4 | |
58 | ||
59 | struct armada_37xx_dvfs { | |
60 | u32 cpu_freq_max; | |
61 | u8 divider[LOAD_LEVEL_NR]; | |
62 | }; | |
63 | ||
64 | static struct armada_37xx_dvfs armada_37xx_dvfs[] = { | |
65 | {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, | |
66 | {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} }, | |
67 | {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} }, | |
68 | {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} }, | |
69 | }; | |
70 | ||
71 | static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq) | |
72 | { | |
73 | int i; | |
74 | ||
75 | for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) { | |
76 | if (freq == armada_37xx_dvfs[i].cpu_freq_max) | |
77 | return &armada_37xx_dvfs[i]; | |
78 | } | |
79 | ||
80 | pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000); | |
81 | return NULL; | |
82 | } | |
83 | ||
84 | /* | |
85 | * Setup the four level managed by the hardware. Once the four level | |
86 | * will be configured then the DVFS will be enabled. | |
87 | */ | |
88 | static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base, | |
89 | struct clk *clk, u8 *divider) | |
90 | { | |
91 | int load_lvl; | |
92 | struct clk *parent; | |
93 | ||
94 | for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) { | |
95 | unsigned int reg, mask, val, offset = 0; | |
96 | ||
97 | if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1) | |
98 | reg = ARMADA_37XX_NB_L0L1; | |
99 | else | |
100 | reg = ARMADA_37XX_NB_L2L3; | |
101 | ||
102 | if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 || | |
103 | load_lvl == ARMADA_37XX_DVFS_LOAD_2) | |
104 | offset += ARMADA_37XX_NB_CONFIG_SHIFT; | |
105 | ||
106 | /* Set cpu clock source, for all the level we use TBG */ | |
107 | val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF; | |
108 | mask = (ARMADA_37XX_NB_CLK_SEL_MASK | |
109 | << ARMADA_37XX_NB_CLK_SEL_OFF); | |
110 | ||
111 | /* | |
112 | * Set cpu divider based on the pre-computed array in | |
113 | * order to have balanced step. | |
114 | */ | |
115 | val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF; | |
116 | mask |= (ARMADA_37XX_NB_TBG_DIV_MASK | |
117 | << ARMADA_37XX_NB_TBG_DIV_OFF); | |
118 | ||
119 | /* Set VDD divider which is actually the load level. */ | |
120 | val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF; | |
121 | mask |= (ARMADA_37XX_NB_VDD_SEL_MASK | |
122 | << ARMADA_37XX_NB_VDD_SEL_OFF); | |
123 | ||
124 | val <<= offset; | |
125 | mask <<= offset; | |
126 | ||
127 | regmap_update_bits(base, reg, mask, val); | |
128 | } | |
129 | ||
130 | /* | |
131 | * Set cpu clock source, for all the level we keep the same | |
132 | * clock source that the one already configured. For this one | |
133 | * we need to use the clock framework | |
134 | */ | |
135 | parent = clk_get_parent(clk); | |
136 | clk_set_parent(clk, parent); | |
137 | } | |
138 | ||
139 | static void __init armada37xx_cpufreq_disable_dvfs(struct regmap *base) | |
140 | { | |
141 | unsigned int reg = ARMADA_37XX_NB_DYN_MOD, | |
142 | mask = ARMADA_37XX_NB_DFS_EN; | |
143 | ||
144 | regmap_update_bits(base, reg, mask, 0); | |
145 | } | |
146 | ||
147 | static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base) | |
148 | { | |
149 | unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD, | |
150 | mask = ARMADA_37XX_NB_CPU_LOAD_MASK; | |
151 | ||
152 | /* Start with the highest load (0) */ | |
153 | val = ARMADA_37XX_DVFS_LOAD_0; | |
154 | regmap_update_bits(base, reg, mask, val); | |
155 | ||
156 | /* Now enable DVFS for the CPUs */ | |
157 | reg = ARMADA_37XX_NB_DYN_MOD; | |
158 | mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN | | |
159 | ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN | | |
160 | ARMADA_37XX_NB_DFS_EN; | |
161 | ||
162 | regmap_update_bits(base, reg, mask, mask); | |
163 | } | |
164 | ||
165 | static int __init armada37xx_cpufreq_driver_init(void) | |
166 | { | |
167 | struct armada_37xx_dvfs *dvfs; | |
168 | struct platform_device *pdev; | |
169 | unsigned int cur_frequency; | |
170 | struct regmap *nb_pm_base; | |
171 | struct device *cpu_dev; | |
172 | int load_lvl, ret; | |
173 | struct clk *clk; | |
174 | ||
175 | nb_pm_base = | |
176 | syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm"); | |
177 | ||
178 | if (IS_ERR(nb_pm_base)) | |
179 | return -ENODEV; | |
180 | ||
181 | /* Before doing any configuration on the DVFS first, disable it */ | |
182 | armada37xx_cpufreq_disable_dvfs(nb_pm_base); | |
183 | ||
184 | /* | |
185 | * On CPU 0 register the operating points supported (which are | |
186 | * the nominal CPU frequency and full integer divisions of | |
187 | * it). | |
188 | */ | |
189 | cpu_dev = get_cpu_device(0); | |
190 | if (!cpu_dev) { | |
191 | dev_err(cpu_dev, "Cannot get CPU\n"); | |
192 | return -ENODEV; | |
193 | } | |
194 | ||
195 | clk = clk_get(cpu_dev, 0); | |
196 | if (IS_ERR(clk)) { | |
197 | dev_err(cpu_dev, "Cannot get clock for CPU0\n"); | |
198 | return PTR_ERR(clk); | |
199 | } | |
200 | ||
201 | /* Get nominal (current) CPU frequency */ | |
202 | cur_frequency = clk_get_rate(clk); | |
203 | if (!cur_frequency) { | |
204 | dev_err(cpu_dev, "Failed to get clock rate for CPU\n"); | |
205 | return -EINVAL; | |
206 | } | |
207 | ||
208 | dvfs = armada_37xx_cpu_freq_info_get(cur_frequency); | |
209 | if (!dvfs) | |
210 | return -EINVAL; | |
211 | ||
212 | armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider); | |
213 | ||
214 | for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR; | |
215 | load_lvl++) { | |
216 | unsigned long freq = cur_frequency / dvfs->divider[load_lvl]; | |
217 | ||
218 | ret = dev_pm_opp_add(cpu_dev, freq, 0); | |
219 | if (ret) { | |
220 | /* clean-up the already added opp before leaving */ | |
221 | while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) { | |
222 | freq = cur_frequency / dvfs->divider[load_lvl]; | |
223 | dev_pm_opp_remove(cpu_dev, freq); | |
224 | } | |
225 | return ret; | |
226 | } | |
227 | } | |
228 | ||
229 | /* Now that everything is setup, enable the DVFS at hardware level */ | |
230 | armada37xx_cpufreq_enable_dvfs(nb_pm_base); | |
231 | ||
232 | pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0); | |
233 | ||
234 | return PTR_ERR_OR_ZERO(pdev); | |
235 | } | |
236 | /* late_initcall, to guarantee the driver is loaded after A37xx clock driver */ | |
237 | late_initcall(armada37xx_cpufreq_driver_init); | |
238 | ||
239 | MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>"); | |
240 | MODULE_DESCRIPTION("Armada 37xx cpufreq driver"); | |
241 | MODULE_LICENSE("GPL"); |