summaryrefslogtreecommitdiffstats
path: root/drivers/misc/vexpress-syscfg.c
blob: 6c3591cdf8555ff00e576c33c55a2bdbce3ea61e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Copyright (C) 2014 ARM Limited
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/syscore_ops.h>
#include <linux/vexpress.h>


#define SYS_CFGDATA		0x0

#define SYS_CFGCTRL		0x4
#define SYS_CFGCTRL_START	(1 << 31)
#define SYS_CFGCTRL_WRITE	(1 << 30)
#define SYS_CFGCTRL_DCC(n)	(((n) & 0xf) << 26)
#define SYS_CFGCTRL_FUNC(n)	(((n) & 0x3f) << 20)
#define SYS_CFGCTRL_SITE(n)	(((n) & 0x3) << 16)
#define SYS_CFGCTRL_POSITION(n)	(((n) & 0xf) << 12)
#define SYS_CFGCTRL_DEVICE(n)	(((n) & 0xfff) << 0)

#define SYS_CFGSTAT		0x8
#define SYS_CFGSTAT_ERR		(1 << 1)
#define SYS_CFGSTAT_COMPLETE	(1 << 0)


struct vexpress_syscfg {
	struct device *dev;
	void __iomem *base;
	struct list_head funcs;
};

struct vexpress_syscfg_func {
	struct list_head list;
	struct vexpress_syscfg *syscfg;
	struct regmap *regmap;
	int num_templates;
	u32 template[0]; /* Keep it last! */
};


static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
		int index, bool write, u32 *data)
{
	struct vexpress_syscfg *syscfg = func->syscfg;
	u32 command, status;
	int tries;
	long timeout;

	if (WARN_ON(index > func->num_templates))
		return -EINVAL;

	command = readl(syscfg->base + SYS_CFGCTRL);
	if (WARN_ON(command & SYS_CFGCTRL_START))
		return -EBUSY;

	command = func->template[index];
	command |= SYS_CFGCTRL_START;
	command |= write ? SYS_CFGCTRL_WRITE : 0;

	/* Use a canary for reads */
	if (!write)
		*data = 0xdeadbeef;

	dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
			func, command, *data);
	writel(*data, syscfg->base + SYS_CFGDATA);
	writel(0, syscfg->base + SYS_CFGSTAT);
	writel(command, syscfg->base + SYS_CFGCTRL);
	mb();

	/* The operation can take ages... Go to sleep, 100us initially */
	tries = 100;
	timeout = 100;
	do {
		if (!irqs_disabled()) {
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(usecs_to_jiffies(timeout));
			if (signal_pending(current))
				return -EINTR;
		} else {
			udelay(timeout);
		}

		status = readl(syscfg->base + SYS_CFGSTAT);
		if (status & SYS_CFGSTAT_ERR)
			return -EFAULT;

		if (timeout > 20)
			timeout -= 20;
	} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
	if (WARN_ON_ONCE(!tries))
		return -ETIMEDOUT;

	if (!write) {
		*data = readl(syscfg->base + SYS_CFGDATA);
		dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
	}

	return 0;
}

static int vexpress_syscfg_read(void *context, unsigned int index,
		unsigned int *val)
{
	struct vexpress_syscfg_func *func = context;

	return vexpress_syscfg_exec(func, index, false, val);
}

static int vexpress_syscfg_write(void *context, unsigned int index,
		unsigned int val)
{
	struct vexpress_syscfg_func *func = context;

	return vexpress_syscfg_exec(func, index, true, &val);
}

static struct regmap_config vexpress_syscfg_regmap_config = {
	.lock = vexpress_config_lock,
	.unlock = vexpress_config_unlock,
	.reg_bits = 32,
	.val_bits = 32,
	.reg_read = vexpress_syscfg_read,
	.reg_write = vexpress_syscfg_write,
	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
};


static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
		void *context)
{
	int err;
	struct vexpress_syscfg *syscfg = context;
	struct vexpress_syscfg_func *func;
	struct property *prop;
	const __be32 *val = NULL;
	__be32 energy_quirk[4];
	int num;
	u32 site, position, dcc;
	int i;

	err = vexpress_config_get_topo(dev->of_node, &site,
				&position, &dcc);
	if (err)
		return ERR_PTR(err);

	prop = of_find_property(dev->of_node,
			"arm,vexpress-sysreg,func", NULL);
	if (!prop)
		return ERR_PTR(-EINVAL);

	num = prop->length / sizeof(u32) / 2;
	val = prop->value;

	/*
	 * "arm,vexpress-energy" function used to be described
	 * by its first device only, now it requires both
	 */
	if (num == 1 && of_device_is_compatible(dev->of_node,
			"arm,vexpress-energy")) {
		num = 2;
		energy_quirk[0] = *val;
		energy_quirk[2] = *val++;
		energy_quirk[1] = *val;
		energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
		val = energy_quirk;
	}

	func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
	if (!func)
		return ERR_PTR(-ENOMEM);

	func->syscfg = syscfg;
	func->num_templates = num;

	for (i = 0; i < num; i++) {
		u32 function, device;

		function = be32_to_cpup(val++);
		device = be32_to_cpup(val++);

		dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
				func, site, position, dcc,
				function, device);

		func->template[i] = SYS_CFGCTRL_DCC(dcc);
		func->template[i] |= SYS_CFGCTRL_SITE(site);
		func->template[i] |= SYS_CFGCTRL_POSITION(position);
		func->template[i] |= SYS_CFGCTRL_FUNC(function);
		func->template[i] |= SYS_CFGCTRL_DEVICE(device);
	}

	vexpress_syscfg_regmap_config.max_register = num - 1;

	func->regmap = regmap_init(dev, NULL, func,
			&vexpress_syscfg_regmap_config);

	if (IS_ERR(func->regmap)) {
		void *err = func->regmap;

		kfree(func);
		return err;
	}

	list_add(&func->list, &syscfg->funcs);

	return func->regmap;
}

static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
{
	struct vexpress_syscfg *syscfg = context;
	struct vexpress_syscfg_func *func, *tmp;

	regmap_exit(regmap);

	list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
		if (func->regmap == regmap) {
			list_del(&syscfg->funcs);
			kfree(func);
			break;
		}
	}
}

static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
	.regmap_init = vexpress_syscfg_regmap_init,
	.regmap_exit = vexpress_syscfg_regmap_exit,
};


static int vexpress_syscfg_probe(struct platform_device *pdev)
{
	struct vexpress_syscfg *syscfg;
	struct resource *res;
	struct device *bridge;

	syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
	if (!syscfg)
		return -ENOMEM;
	syscfg->dev = &pdev->dev;
	INIT_LIST_HEAD(&syscfg->funcs);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	syscfg->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(syscfg->base))
		return PTR_ERR(syscfg->base);

	/* Must use dev.parent (MFD), as that's where DT phandle points at... */
	bridge = vexpress_config_bridge_register(pdev->dev.parent,
			&vexpress_syscfg_bridge_ops, syscfg);

	return PTR_ERR_OR_ZERO(bridge);
}

static const struct platform_device_id vexpress_syscfg_id_table[] = {
	{ "vexpress-syscfg", },
	{},
};

static struct platform_driver vexpress_syscfg_driver = {
	.driver.name = "vexpress-syscfg",
	.id_table = vexpress_syscfg_id_table,
	.probe = vexpress_syscfg_probe,
};

static int __init vexpress_syscfg_init(void)
{
	return platform_driver_register(&vexpress_syscfg_driver);
}
core_initcall(vexpress_syscfg_init);