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