xref: /openbmc/linux/arch/powerpc/platforms/4xx/cpm.c (revision 81d7cac4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PowerPC 4xx Clock and Power Management
4  *
5  * Copyright (C) 2010, Applied Micro Circuits Corporation
6  * Victor Gallardo (vgallardo@apm.com)
7  *
8  * Based on arch/powerpc/platforms/44x/idle.c:
9  * Jerone Young <jyoung5@us.ibm.com>
10  * Copyright 2008 IBM Corp.
11  *
12  * Based on arch/powerpc/sysdev/fsl_pmc.c:
13  * Anton Vorontsov <avorontsov@ru.mvista.com>
14  * Copyright 2009  MontaVista Software, Inc.
15  *
16  * See file CREDITS for list of people who contributed to this
17  * project.
18  */
19 
20 #include <linux/kernel.h>
21 #include <linux/of.h>
22 #include <linux/sysfs.h>
23 #include <linux/cpu.h>
24 #include <linux/suspend.h>
25 #include <asm/dcr.h>
26 #include <asm/dcr-native.h>
27 #include <asm/machdep.h>
28 
29 #define CPM_ER	0
30 #define CPM_FR	1
31 #define CPM_SR	2
32 
33 #define CPM_IDLE_WAIT	0
34 #define CPM_IDLE_DOZE	1
35 
36 struct cpm {
37 	dcr_host_t	dcr_host;
38 	unsigned int	dcr_offset[3];
39 	unsigned int	powersave_off;
40 	unsigned int	unused;
41 	unsigned int	idle_doze;
42 	unsigned int	standby;
43 	unsigned int	suspend;
44 };
45 
46 static struct cpm cpm;
47 
48 struct cpm_idle_mode {
49 	unsigned int enabled;
50 	const char  *name;
51 };
52 
53 static struct cpm_idle_mode idle_mode[] = {
54 	[CPM_IDLE_WAIT] = { 1, "wait" }, /* default */
55 	[CPM_IDLE_DOZE] = { 0, "doze" },
56 };
57 
cpm_set(unsigned int cpm_reg,unsigned int mask)58 static unsigned int cpm_set(unsigned int cpm_reg, unsigned int mask)
59 {
60 	unsigned int value;
61 
62 	/* CPM controller supports 3 different types of sleep interface
63 	 * known as class 1, 2 and 3. For class 1 units, they are
64 	 * unconditionally put to sleep when the corresponding CPM bit is
65 	 * set. For class 2 and 3 units this is not case; if they can be
66 	 * put to sleep, they will. Here we do not verify, we just
67 	 * set them and expect them to eventually go off when they can.
68 	 */
69 	value = dcr_read(cpm.dcr_host, cpm.dcr_offset[cpm_reg]);
70 	dcr_write(cpm.dcr_host, cpm.dcr_offset[cpm_reg], value | mask);
71 
72 	/* return old state, to restore later if needed */
73 	return value;
74 }
75 
cpm_idle_wait(void)76 static void cpm_idle_wait(void)
77 {
78 	unsigned long msr_save;
79 
80 	/* save off initial state */
81 	msr_save = mfmsr();
82 	/* sync required when CPM0_ER[CPU] is set */
83 	mb();
84 	/* set wait state MSR */
85 	mtmsr(msr_save|MSR_WE|MSR_EE|MSR_CE|MSR_DE);
86 	isync();
87 	/* return to initial state */
88 	mtmsr(msr_save);
89 	isync();
90 }
91 
cpm_idle_sleep(unsigned int mask)92 static void cpm_idle_sleep(unsigned int mask)
93 {
94 	unsigned int er_save;
95 
96 	/* update CPM_ER state */
97 	er_save = cpm_set(CPM_ER, mask);
98 
99 	/* go to wait state so that CPM0_ER[CPU] can take effect */
100 	cpm_idle_wait();
101 
102 	/* restore CPM_ER state */
103 	dcr_write(cpm.dcr_host, cpm.dcr_offset[CPM_ER], er_save);
104 }
105 
cpm_idle_doze(void)106 static void cpm_idle_doze(void)
107 {
108 	cpm_idle_sleep(cpm.idle_doze);
109 }
110 
cpm_idle_config(int mode)111 static void cpm_idle_config(int mode)
112 {
113 	int i;
114 
115 	if (idle_mode[mode].enabled)
116 		return;
117 
118 	for (i = 0; i < ARRAY_SIZE(idle_mode); i++)
119 		idle_mode[i].enabled = 0;
120 
121 	idle_mode[mode].enabled = 1;
122 }
123 
cpm_idle_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)124 static ssize_t cpm_idle_show(struct kobject *kobj,
125 			     struct kobj_attribute *attr, char *buf)
126 {
127 	char *s = buf;
128 	int i;
129 
130 	for (i = 0; i < ARRAY_SIZE(idle_mode); i++) {
131 		if (idle_mode[i].enabled)
132 			s += sprintf(s, "[%s] ", idle_mode[i].name);
133 		else
134 			s += sprintf(s, "%s ", idle_mode[i].name);
135 	}
136 
137 	*(s-1) = '\n'; /* convert the last space to a newline */
138 
139 	return s - buf;
140 }
141 
cpm_idle_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t n)142 static ssize_t cpm_idle_store(struct kobject *kobj,
143 			      struct kobj_attribute *attr,
144 			      const char *buf, size_t n)
145 {
146 	int i;
147 	char *p;
148 	int len;
149 
150 	p = memchr(buf, '\n', n);
151 	len = p ? p - buf : n;
152 
153 	for (i = 0; i < ARRAY_SIZE(idle_mode); i++) {
154 		if (strncmp(buf, idle_mode[i].name, len) == 0) {
155 			cpm_idle_config(i);
156 			return n;
157 		}
158 	}
159 
160 	return -EINVAL;
161 }
162 
163 static struct kobj_attribute cpm_idle_attr =
164 	__ATTR(idle, 0644, cpm_idle_show, cpm_idle_store);
165 
cpm_idle_config_sysfs(void)166 static void __init cpm_idle_config_sysfs(void)
167 {
168 	struct device *dev;
169 	unsigned long ret;
170 
171 	dev = get_cpu_device(0);
172 
173 	ret = sysfs_create_file(&dev->kobj,
174 				&cpm_idle_attr.attr);
175 	if (ret)
176 		printk(KERN_WARNING
177 		       "cpm: failed to create idle sysfs entry\n");
178 }
179 
cpm_idle(void)180 static void cpm_idle(void)
181 {
182 	if (idle_mode[CPM_IDLE_DOZE].enabled)
183 		cpm_idle_doze();
184 	else
185 		cpm_idle_wait();
186 }
187 
cpm_suspend_valid(suspend_state_t state)188 static int cpm_suspend_valid(suspend_state_t state)
189 {
190 	switch (state) {
191 	case PM_SUSPEND_STANDBY:
192 		return !!cpm.standby;
193 	case PM_SUSPEND_MEM:
194 		return !!cpm.suspend;
195 	default:
196 		return 0;
197 	}
198 }
199 
cpm_suspend_standby(unsigned int mask)200 static void cpm_suspend_standby(unsigned int mask)
201 {
202 	unsigned long tcr_save;
203 
204 	/* disable decrement interrupt */
205 	tcr_save = mfspr(SPRN_TCR);
206 	mtspr(SPRN_TCR, tcr_save & ~TCR_DIE);
207 
208 	/* go to sleep state */
209 	cpm_idle_sleep(mask);
210 
211 	/* restore decrement interrupt */
212 	mtspr(SPRN_TCR, tcr_save);
213 }
214 
cpm_suspend_enter(suspend_state_t state)215 static int cpm_suspend_enter(suspend_state_t state)
216 {
217 	switch (state) {
218 	case PM_SUSPEND_STANDBY:
219 		cpm_suspend_standby(cpm.standby);
220 		break;
221 	case PM_SUSPEND_MEM:
222 		cpm_suspend_standby(cpm.suspend);
223 		break;
224 	}
225 
226 	return 0;
227 }
228 
229 static const struct platform_suspend_ops cpm_suspend_ops = {
230 	.valid		= cpm_suspend_valid,
231 	.enter		= cpm_suspend_enter,
232 };
233 
cpm_get_uint_property(struct device_node * np,const char * name)234 static int __init cpm_get_uint_property(struct device_node *np,
235 				 const char *name)
236 {
237 	int len;
238 	const unsigned int *prop = of_get_property(np, name, &len);
239 
240 	if (prop == NULL || len < sizeof(u32))
241 		return 0;
242 
243 	return *prop;
244 }
245 
cpm_init(void)246 static int __init cpm_init(void)
247 {
248 	struct device_node *np;
249 	int dcr_base, dcr_len;
250 	int ret = 0;
251 
252 	if (!cpm.powersave_off) {
253 		cpm_idle_config(CPM_IDLE_WAIT);
254 		ppc_md.power_save = &cpm_idle;
255 	}
256 
257 	np = of_find_compatible_node(NULL, NULL, "ibm,cpm");
258 	if (!np) {
259 		ret = -EINVAL;
260 		goto out;
261 	}
262 
263 	dcr_base = dcr_resource_start(np, 0);
264 	dcr_len = dcr_resource_len(np, 0);
265 
266 	if (dcr_base == 0 || dcr_len == 0) {
267 		printk(KERN_ERR "cpm: could not parse dcr property for %pOF\n",
268 		       np);
269 		ret = -EINVAL;
270 		goto node_put;
271 	}
272 
273 	cpm.dcr_host = dcr_map(np, dcr_base, dcr_len);
274 
275 	if (!DCR_MAP_OK(cpm.dcr_host)) {
276 		printk(KERN_ERR "cpm: failed to map dcr property for %pOF\n",
277 		       np);
278 		ret = -EINVAL;
279 		goto node_put;
280 	}
281 
282 	/* All 4xx SoCs with a CPM controller have one of two
283 	 * different order for the CPM registers. Some have the
284 	 * CPM registers in the following order (ER,FR,SR). The
285 	 * others have them in the following order (SR,ER,FR).
286 	 */
287 
288 	if (cpm_get_uint_property(np, "er-offset") == 0) {
289 		cpm.dcr_offset[CPM_ER] = 0;
290 		cpm.dcr_offset[CPM_FR] = 1;
291 		cpm.dcr_offset[CPM_SR] = 2;
292 	} else {
293 		cpm.dcr_offset[CPM_ER] = 1;
294 		cpm.dcr_offset[CPM_FR] = 2;
295 		cpm.dcr_offset[CPM_SR] = 0;
296 	}
297 
298 	/* Now let's see what IPs to turn off for the following modes */
299 
300 	cpm.unused = cpm_get_uint_property(np, "unused-units");
301 	cpm.idle_doze = cpm_get_uint_property(np, "idle-doze");
302 	cpm.standby = cpm_get_uint_property(np, "standby");
303 	cpm.suspend = cpm_get_uint_property(np, "suspend");
304 
305 	/* If some IPs are unused let's turn them off now */
306 
307 	if (cpm.unused) {
308 		cpm_set(CPM_ER, cpm.unused);
309 		cpm_set(CPM_FR, cpm.unused);
310 	}
311 
312 	/* Now let's export interfaces */
313 
314 	if (!cpm.powersave_off && cpm.idle_doze)
315 		cpm_idle_config_sysfs();
316 
317 	if (cpm.standby || cpm.suspend)
318 		suspend_set_ops(&cpm_suspend_ops);
319 node_put:
320 	of_node_put(np);
321 out:
322 	return ret;
323 }
324 
325 late_initcall(cpm_init);
326 
cpm_powersave_off(char * arg)327 static int __init cpm_powersave_off(char *arg)
328 {
329 	cpm.powersave_off = 1;
330 	return 1;
331 }
332 __setup("powersave=off", cpm_powersave_off);
333