1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2007 PA Semi, Inc
4  *
5  * Authors: Egor Martovetsky <egor@pasemi.com>
6  *	    Olof Johansson <olof@lixom.net>
7  *
8  * Maintained by: Olof Johansson <olof@lixom.net>
9  *
10  * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
11  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
12  */
13 
14 #include <linux/cpufreq.h>
15 #include <linux/timer.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
18 
19 #include <asm/hw_irq.h>
20 #include <asm/io.h>
21 #include <asm/prom.h>
22 #include <asm/time.h>
23 #include <asm/smp.h>
24 
25 #define SDCASR_REG		0x0100
26 #define SDCASR_REG_STRIDE	0x1000
27 #define SDCPWR_CFGA0_REG	0x0100
28 #define SDCPWR_PWST0_REG	0x0000
29 #define SDCPWR_GIZTIME_REG	0x0440
30 
31 /* SDCPWR_GIZTIME_REG fields */
32 #define SDCPWR_GIZTIME_GR	0x80000000
33 #define SDCPWR_GIZTIME_LONGLOCK	0x000000ff
34 
35 /* Offset of ASR registers from SDC base */
36 #define SDCASR_OFFSET		0x120000
37 
38 static void __iomem *sdcpwr_mapbase;
39 static void __iomem *sdcasr_mapbase;
40 
41 /* Current astate, is used when waking up from power savings on
42  * one core, in case the other core has switched states during
43  * the idle time.
44  */
45 static int current_astate;
46 
47 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
48 static struct cpufreq_frequency_table pas_freqs[] = {
49 	{0, 0,	0},
50 	{0, 1,	0},
51 	{0, 2,	0},
52 	{0, 3,	0},
53 	{0, 4,	0},
54 	{0, 0,	CPUFREQ_TABLE_END},
55 };
56 
57 /*
58  * hardware specific functions
59  */
60 
61 static int get_astate_freq(int astate)
62 {
63 	u32 ret;
64 	ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
65 
66 	return ret & 0x3f;
67 }
68 
69 static int get_cur_astate(int cpu)
70 {
71 	u32 ret;
72 
73 	ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
74 	ret = (ret >> (cpu * 4)) & 0x7;
75 
76 	return ret;
77 }
78 
79 static int get_gizmo_latency(void)
80 {
81 	u32 giztime, ret;
82 
83 	giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
84 
85 	/* just provide the upper bound */
86 	if (giztime & SDCPWR_GIZTIME_GR)
87 		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
88 	else
89 		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
90 
91 	return ret;
92 }
93 
94 static void set_astate(int cpu, unsigned int astate)
95 {
96 	unsigned long flags;
97 
98 	/* Return if called before init has run */
99 	if (unlikely(!sdcasr_mapbase))
100 		return;
101 
102 	local_irq_save(flags);
103 
104 	out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
105 
106 	local_irq_restore(flags);
107 }
108 
109 int check_astate(void)
110 {
111 	return get_cur_astate(hard_smp_processor_id());
112 }
113 
114 void restore_astate(int cpu)
115 {
116 	set_astate(cpu, current_astate);
117 }
118 
119 /*
120  * cpufreq functions
121  */
122 
123 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
124 {
125 	struct cpufreq_frequency_table *pos;
126 	const u32 *max_freqp;
127 	u32 max_freq;
128 	int cur_astate, idx;
129 	struct resource res;
130 	struct device_node *cpu, *dn;
131 	int err = -ENODEV;
132 
133 	cpu = of_get_cpu_node(policy->cpu, NULL);
134 
135 	of_node_put(cpu);
136 	if (!cpu)
137 		goto out;
138 
139 	dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
140 	if (!dn)
141 		dn = of_find_compatible_node(NULL, NULL,
142 					     "pasemi,pwrficient-sdc");
143 	if (!dn)
144 		goto out;
145 	err = of_address_to_resource(dn, 0, &res);
146 	of_node_put(dn);
147 	if (err)
148 		goto out;
149 	sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
150 	if (!sdcasr_mapbase) {
151 		err = -EINVAL;
152 		goto out;
153 	}
154 
155 	dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
156 	if (!dn)
157 		dn = of_find_compatible_node(NULL, NULL,
158 					     "pasemi,pwrficient-gizmo");
159 	if (!dn) {
160 		err = -ENODEV;
161 		goto out_unmap_sdcasr;
162 	}
163 	err = of_address_to_resource(dn, 0, &res);
164 	of_node_put(dn);
165 	if (err)
166 		goto out_unmap_sdcasr;
167 	sdcpwr_mapbase = ioremap(res.start, 0x1000);
168 	if (!sdcpwr_mapbase) {
169 		err = -EINVAL;
170 		goto out_unmap_sdcasr;
171 	}
172 
173 	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
174 
175 	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
176 	if (!max_freqp) {
177 		err = -EINVAL;
178 		goto out_unmap_sdcpwr;
179 	}
180 
181 	/* we need the freq in kHz */
182 	max_freq = *max_freqp / 1000;
183 
184 	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
185 	pr_debug("initializing frequency table\n");
186 
187 	/* initialize frequency table */
188 	cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
189 		pos->frequency = get_astate_freq(pos->driver_data) * 100000;
190 		pr_debug("%d: %d\n", idx, pos->frequency);
191 	}
192 
193 	cur_astate = get_cur_astate(policy->cpu);
194 	pr_debug("current astate is at %d\n",cur_astate);
195 
196 	policy->cur = pas_freqs[cur_astate].frequency;
197 	ppc_proc_freq = policy->cur * 1000ul;
198 
199 	cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
200 	return 0;
201 
202 out_unmap_sdcpwr:
203 	iounmap(sdcpwr_mapbase);
204 
205 out_unmap_sdcasr:
206 	iounmap(sdcasr_mapbase);
207 out:
208 	return err;
209 }
210 
211 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
212 {
213 	/*
214 	 * We don't support CPU hotplug. Don't unmap after the system
215 	 * has already made it to a running state.
216 	 */
217 	if (system_state >= SYSTEM_RUNNING)
218 		return 0;
219 
220 	if (sdcasr_mapbase)
221 		iounmap(sdcasr_mapbase);
222 	if (sdcpwr_mapbase)
223 		iounmap(sdcpwr_mapbase);
224 
225 	return 0;
226 }
227 
228 static int pas_cpufreq_target(struct cpufreq_policy *policy,
229 			      unsigned int pas_astate_new)
230 {
231 	int i;
232 
233 	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
234 		 policy->cpu,
235 		 pas_freqs[pas_astate_new].frequency,
236 		 pas_freqs[pas_astate_new].driver_data);
237 
238 	current_astate = pas_astate_new;
239 
240 	for_each_online_cpu(i)
241 		set_astate(i, pas_astate_new);
242 
243 	ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
244 	return 0;
245 }
246 
247 static struct cpufreq_driver pas_cpufreq_driver = {
248 	.name		= "pas-cpufreq",
249 	.flags		= CPUFREQ_CONST_LOOPS,
250 	.init		= pas_cpufreq_cpu_init,
251 	.exit		= pas_cpufreq_cpu_exit,
252 	.verify		= cpufreq_generic_frequency_table_verify,
253 	.target_index	= pas_cpufreq_target,
254 	.attr		= cpufreq_generic_attr,
255 };
256 
257 /*
258  * module init and destoy
259  */
260 
261 static int __init pas_cpufreq_init(void)
262 {
263 	if (!of_machine_is_compatible("PA6T-1682M") &&
264 	    !of_machine_is_compatible("pasemi,pwrficient"))
265 		return -ENODEV;
266 
267 	return cpufreq_register_driver(&pas_cpufreq_driver);
268 }
269 
270 static void __exit pas_cpufreq_exit(void)
271 {
272 	cpufreq_unregister_driver(&pas_cpufreq_driver);
273 }
274 
275 module_init(pas_cpufreq_init);
276 module_exit(pas_cpufreq_exit);
277 
278 MODULE_LICENSE("GPL");
279 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
280