vexpress-syscfg.c revision b86e1926be37c77deeb176466d98678feab04066 
1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2014 ARM Limited
12 */
13
14#include <linux/delay.h>
15#include <linux/err.h>
16#include <linux/io.h>
17#include <linux/of.h>
18#include <linux/platform_device.h>
19#include <linux/sched.h>
20#include <linux/slab.h>
21#include <linux/syscore_ops.h>
22#include <linux/vexpress.h>
23
24
25#define SYS_CFGDATA		0x0
26
27#define SYS_CFGCTRL		0x4
28#define SYS_CFGCTRL_START	(1 << 31)
29#define SYS_CFGCTRL_WRITE	(1 << 30)
30#define SYS_CFGCTRL_DCC(n)	(((n) & 0xf) << 26)
31#define SYS_CFGCTRL_FUNC(n)	(((n) & 0x3f) << 20)
32#define SYS_CFGCTRL_SITE(n)	(((n) & 0x3) << 16)
33#define SYS_CFGCTRL_POSITION(n)	(((n) & 0xf) << 12)
34#define SYS_CFGCTRL_DEVICE(n)	(((n) & 0xfff) << 0)
35
36#define SYS_CFGSTAT		0x8
37#define SYS_CFGSTAT_ERR		(1 << 1)
38#define SYS_CFGSTAT_COMPLETE	(1 << 0)
39
40
41struct vexpress_syscfg {
42	struct device *dev;
43	void __iomem *base;
44	struct list_head funcs;
45};
46
47struct vexpress_syscfg_func {
48	struct list_head list;
49	struct vexpress_syscfg *syscfg;
50	struct regmap *regmap;
51	int num_templates;
52	u32 template[0]; /* Keep it last! */
53};
54
55
56static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
57		int index, bool write, u32 *data)
58{
59	struct vexpress_syscfg *syscfg = func->syscfg;
60	u32 command, status;
61	int tries;
62	long timeout;
63
64	if (WARN_ON(index > func->num_templates))
65		return -EINVAL;
66
67	command = readl(syscfg->base + SYS_CFGCTRL);
68	if (WARN_ON(command & SYS_CFGCTRL_START))
69		return -EBUSY;
70
71	command = func->template[index];
72	command |= SYS_CFGCTRL_START;
73	command |= write ? SYS_CFGCTRL_WRITE : 0;
74
75	/* Use a canary for reads */
76	if (!write)
77		*data = 0xdeadbeef;
78
79	dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
80			func, command, *data);
81	writel(*data, syscfg->base + SYS_CFGDATA);
82	writel(0, syscfg->base + SYS_CFGSTAT);
83	writel(command, syscfg->base + SYS_CFGCTRL);
84	mb();
85
86	/* The operation can take ages... Go to sleep, 100us initially */
87	tries = 100;
88	timeout = 100;
89	do {
90		if (!irqs_disabled()) {
91			set_current_state(TASK_INTERRUPTIBLE);
92			schedule_timeout(usecs_to_jiffies(timeout));
93			if (signal_pending(current))
94				return -EINTR;
95		} else {
96			udelay(timeout);
97		}
98
99		status = readl(syscfg->base + SYS_CFGSTAT);
100		if (status & SYS_CFGSTAT_ERR)
101			return -EFAULT;
102
103		if (timeout > 20)
104			timeout -= 20;
105	} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
106	if (WARN_ON_ONCE(!tries))
107		return -ETIMEDOUT;
108
109	if (!write) {
110		*data = readl(syscfg->base + SYS_CFGDATA);
111		dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
112	}
113
114	return 0;
115}
116
117static int vexpress_syscfg_read(void *context, unsigned int index,
118		unsigned int *val)
119{
120	struct vexpress_syscfg_func *func = context;
121
122	return vexpress_syscfg_exec(func, index, false, val);
123}
124
125static int vexpress_syscfg_write(void *context, unsigned int index,
126		unsigned int val)
127{
128	struct vexpress_syscfg_func *func = context;
129
130	return vexpress_syscfg_exec(func, index, true, &val);
131}
132
133struct regmap_config vexpress_syscfg_regmap_config = {
134	.lock = vexpress_config_lock,
135	.unlock = vexpress_config_unlock,
136	.reg_bits = 32,
137	.val_bits = 32,
138	.reg_read = vexpress_syscfg_read,
139	.reg_write = vexpress_syscfg_write,
140	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
141	.val_format_endian = REGMAP_ENDIAN_LITTLE,
142};
143
144
145static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
146		void *context)
147{
148	struct platform_device *pdev = to_platform_device(dev);
149	struct vexpress_syscfg *syscfg = context;
150	struct vexpress_syscfg_func *func;
151	struct property *prop;
152	const __be32 *val = NULL;
153	__be32 energy_quirk[4];
154	int num;
155	u32 site, position, dcc;
156	int i;
157
158	if (dev->of_node) {
159		int err = vexpress_config_get_topo(dev->of_node, &site,
160				&position, &dcc);
161
162		if (err)
163			return ERR_PTR(err);
164
165		prop = of_find_property(dev->of_node,
166				"arm,vexpress-sysreg,func", NULL);
167		if (!prop)
168			return ERR_PTR(-EINVAL);
169
170		num = prop->length / sizeof(u32) / 2;
171		val = prop->value;
172	} else {
173		if (pdev->num_resources != 1 ||
174				pdev->resource[0].flags != IORESOURCE_BUS)
175			return ERR_PTR(-EFAULT);
176
177		site = pdev->resource[0].start;
178		if (site == VEXPRESS_SITE_MASTER)
179			site = vexpress_config_get_master();
180		position = 0;
181		dcc = 0;
182		num = 1;
183	}
184
185	/*
186	 * "arm,vexpress-energy" function used to be described
187	 * by its first device only, now it requires both
188	 */
189	if (num == 1 && of_device_is_compatible(dev->of_node,
190			"arm,vexpress-energy")) {
191		num = 2;
192		energy_quirk[0] = *val;
193		energy_quirk[2] = *val++;
194		energy_quirk[1] = *val;
195		energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
196		val = energy_quirk;
197	}
198
199	func = kzalloc(sizeof(*func) + sizeof(*func->template) * num,
200			GFP_KERNEL);
201	if (!func)
202		return ERR_PTR(-ENOMEM);
203
204	func->syscfg = syscfg;
205	func->num_templates = num;
206
207	for (i = 0; i < num; i++) {
208		u32 function, device;
209
210		if (dev->of_node) {
211			function = be32_to_cpup(val++);
212			device = be32_to_cpup(val++);
213		} else {
214			function = pdev->resource[0].end;
215			device = pdev->id;
216		}
217
218		dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
219				func, site, position, dcc,
220				function, device);
221
222		func->template[i] = SYS_CFGCTRL_DCC(dcc);
223		func->template[i] |= SYS_CFGCTRL_SITE(site);
224		func->template[i] |= SYS_CFGCTRL_POSITION(position);
225		func->template[i] |= SYS_CFGCTRL_FUNC(function);
226		func->template[i] |= SYS_CFGCTRL_DEVICE(device);
227	}
228
229	vexpress_syscfg_regmap_config.max_register = num - 1;
230
231	func->regmap = regmap_init(dev, NULL, func,
232			&vexpress_syscfg_regmap_config);
233
234	if (IS_ERR(func->regmap)) {
235		void *err = func->regmap;
236
237		kfree(func);
238		return err;
239	}
240
241	list_add(&func->list, &syscfg->funcs);
242
243	return func->regmap;
244}
245
246static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
247{
248	struct vexpress_syscfg *syscfg = context;
249	struct vexpress_syscfg_func *func, *tmp;
250
251	regmap_exit(regmap);
252
253	list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
254		if (func->regmap == regmap) {
255			list_del(&syscfg->funcs);
256			kfree(func);
257			break;
258		}
259	}
260}
261
262static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
263	.regmap_init = vexpress_syscfg_regmap_init,
264	.regmap_exit = vexpress_syscfg_regmap_exit,
265};
266
267
268/* Non-DT hack, to be gone... */
269static struct device *vexpress_syscfg_bridge;
270
271int vexpress_syscfg_device_register(struct platform_device *pdev)
272{
273	pdev->dev.parent = vexpress_syscfg_bridge;
274
275	return platform_device_register(pdev);
276}
277
278
279int vexpress_syscfg_probe(struct platform_device *pdev)
280{
281	struct vexpress_syscfg *syscfg;
282	struct resource *res;
283	struct device *bridge;
284
285	syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
286	if (!syscfg)
287		return -ENOMEM;
288	syscfg->dev = &pdev->dev;
289	INIT_LIST_HEAD(&syscfg->funcs);
290
291	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
292	if (!devm_request_mem_region(&pdev->dev, res->start,
293			resource_size(res), pdev->name))
294		return -EBUSY;
295
296	syscfg->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
297	if (!syscfg->base)
298		return -EFAULT;
299
300	/* Must use dev.parent (MFD), as that's where DT phandle points at... */
301	bridge = vexpress_config_bridge_register(pdev->dev.parent,
302			&vexpress_syscfg_bridge_ops, syscfg);
303	if (IS_ERR(bridge))
304		return PTR_ERR(bridge);
305
306	/* Non-DT case */
307	if (!pdev->dev.of_node)
308		vexpress_syscfg_bridge = bridge;
309
310	return 0;
311}
312
313static const struct platform_device_id vexpress_syscfg_id_table[] = {
314	{ "vexpress-syscfg", },
315	{},
316};
317
318static struct platform_driver vexpress_syscfg_driver = {
319	.driver.name = "vexpress-syscfg",
320	.id_table = vexpress_syscfg_id_table,
321	.probe = vexpress_syscfg_probe,
322};
323
324static int __init vexpress_syscfg_init(void)
325{
326	return platform_driver_register(&vexpress_syscfg_driver);
327}
328core_initcall(vexpress_syscfg_init);
329