1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *
  4 * Copyright (C) 2014 ARM Limited
  5 */
  6
  7#include <linux/delay.h>
  8#include <linux/err.h>
  9#include <linux/io.h>
 10#include <linux/of.h>
 11#include <linux/platform_device.h>
 12#include <linux/sched/signal.h>
 13#include <linux/slab.h>
 14#include <linux/syscore_ops.h>
 15#include <linux/vexpress.h>
 16
 17
 18#define SYS_CFGDATA		0x0
 19
 20#define SYS_CFGCTRL		0x4
 21#define SYS_CFGCTRL_START	(1 << 31)
 22#define SYS_CFGCTRL_WRITE	(1 << 30)
 23#define SYS_CFGCTRL_DCC(n)	(((n) & 0xf) << 26)
 24#define SYS_CFGCTRL_FUNC(n)	(((n) & 0x3f) << 20)
 25#define SYS_CFGCTRL_SITE(n)	(((n) & 0x3) << 16)
 26#define SYS_CFGCTRL_POSITION(n)	(((n) & 0xf) << 12)
 27#define SYS_CFGCTRL_DEVICE(n)	(((n) & 0xfff) << 0)
 28
 29#define SYS_CFGSTAT		0x8
 30#define SYS_CFGSTAT_ERR		(1 << 1)
 31#define SYS_CFGSTAT_COMPLETE	(1 << 0)
 32
 33
 34struct vexpress_syscfg {
 35	struct device *dev;
 36	void __iomem *base;
 37	struct list_head funcs;
 38};
 39
 40struct vexpress_syscfg_func {
 41	struct list_head list;
 42	struct vexpress_syscfg *syscfg;
 43	struct regmap *regmap;
 44	int num_templates;
 45	u32 template[0]; /* Keep it last! */
 46};
 47
 48
 49static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
 50		int index, bool write, u32 *data)
 51{
 52	struct vexpress_syscfg *syscfg = func->syscfg;
 53	u32 command, status;
 54	int tries;
 55	long timeout;
 56
 57	if (WARN_ON(index >= func->num_templates))
 58		return -EINVAL;
 59
 60	command = readl(syscfg->base + SYS_CFGCTRL);
 61	if (WARN_ON(command & SYS_CFGCTRL_START))
 62		return -EBUSY;
 63
 64	command = func->template[index];
 65	command |= SYS_CFGCTRL_START;
 66	command |= write ? SYS_CFGCTRL_WRITE : 0;
 67
 68	/* Use a canary for reads */
 69	if (!write)
 70		*data = 0xdeadbeef;
 71
 72	dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
 73			func, command, *data);
 74	writel(*data, syscfg->base + SYS_CFGDATA);
 75	writel(0, syscfg->base + SYS_CFGSTAT);
 76	writel(command, syscfg->base + SYS_CFGCTRL);
 77	mb();
 78
 79	/* The operation can take ages... Go to sleep, 100us initially */
 80	tries = 100;
 81	timeout = 100;
 82	do {
 83		if (!irqs_disabled()) {
 84			set_current_state(TASK_INTERRUPTIBLE);
 85			schedule_timeout(usecs_to_jiffies(timeout));
 86			if (signal_pending(current))
 87				return -EINTR;
 88		} else {
 89			udelay(timeout);
 90		}
 91
 92		status = readl(syscfg->base + SYS_CFGSTAT);
 93		if (status & SYS_CFGSTAT_ERR)
 94			return -EFAULT;
 95
 96		if (timeout > 20)
 97			timeout -= 20;
 98	} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
 99	if (WARN_ON_ONCE(!tries))
100		return -ETIMEDOUT;
101
102	if (!write) {
103		*data = readl(syscfg->base + SYS_CFGDATA);
104		dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
105	}
106
107	return 0;
108}
109
110static int vexpress_syscfg_read(void *context, unsigned int index,
111		unsigned int *val)
112{
113	struct vexpress_syscfg_func *func = context;
114
115	return vexpress_syscfg_exec(func, index, false, val);
116}
117
118static int vexpress_syscfg_write(void *context, unsigned int index,
119		unsigned int val)
120{
121	struct vexpress_syscfg_func *func = context;
122
123	return vexpress_syscfg_exec(func, index, true, &val);
124}
125
126static struct regmap_config vexpress_syscfg_regmap_config = {
127	.lock = vexpress_config_lock,
128	.unlock = vexpress_config_unlock,
129	.reg_bits = 32,
130	.val_bits = 32,
131	.reg_read = vexpress_syscfg_read,
132	.reg_write = vexpress_syscfg_write,
133	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
134	.val_format_endian = REGMAP_ENDIAN_LITTLE,
135};
136
137
138static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
139		void *context)
140{
141	int err;
142	struct vexpress_syscfg *syscfg = context;
143	struct vexpress_syscfg_func *func;
144	struct property *prop;
145	const __be32 *val = NULL;
146	__be32 energy_quirk[4];
147	int num;
148	u32 site, position, dcc;
149	int i;
150
151	err = vexpress_config_get_topo(dev->of_node, &site,
152				&position, &dcc);
153	if (err)
154		return ERR_PTR(err);
155
156	prop = of_find_property(dev->of_node,
157			"arm,vexpress-sysreg,func", NULL);
158	if (!prop)
159		return ERR_PTR(-EINVAL);
160
161	num = prop->length / sizeof(u32) / 2;
162	val = prop->value;
163
164	/*
165	 * "arm,vexpress-energy" function used to be described
166	 * by its first device only, now it requires both
167	 */
168	if (num == 1 && of_device_is_compatible(dev->of_node,
169			"arm,vexpress-energy")) {
170		num = 2;
171		energy_quirk[0] = *val;
172		energy_quirk[2] = *val++;
173		energy_quirk[1] = *val;
174		energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
175		val = energy_quirk;
176	}
177
178	func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
179	if (!func)
180		return ERR_PTR(-ENOMEM);
181
182	func->syscfg = syscfg;
183	func->num_templates = num;
184
185	for (i = 0; i < num; i++) {
186		u32 function, device;
187
188		function = be32_to_cpup(val++);
189		device = be32_to_cpup(val++);
190
191		dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
192				func, site, position, dcc,
193				function, device);
194
195		func->template[i] = SYS_CFGCTRL_DCC(dcc);
196		func->template[i] |= SYS_CFGCTRL_SITE(site);
197		func->template[i] |= SYS_CFGCTRL_POSITION(position);
198		func->template[i] |= SYS_CFGCTRL_FUNC(function);
199		func->template[i] |= SYS_CFGCTRL_DEVICE(device);
200	}
201
202	vexpress_syscfg_regmap_config.max_register = num - 1;
203
204	func->regmap = regmap_init(dev, NULL, func,
205			&vexpress_syscfg_regmap_config);
206
207	if (IS_ERR(func->regmap)) {
208		void *err = func->regmap;
209
210		kfree(func);
211		return err;
212	}
213
214	list_add(&func->list, &syscfg->funcs);
215
216	return func->regmap;
217}
218
219static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
220{
221	struct vexpress_syscfg *syscfg = context;
222	struct vexpress_syscfg_func *func, *tmp;
223
224	regmap_exit(regmap);
225
226	list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
227		if (func->regmap == regmap) {
228			list_del(&syscfg->funcs);
229			kfree(func);
230			break;
231		}
232	}
233}
234
235static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
236	.regmap_init = vexpress_syscfg_regmap_init,
237	.regmap_exit = vexpress_syscfg_regmap_exit,
238};
239
240
241static int vexpress_syscfg_probe(struct platform_device *pdev)
242{
243	struct vexpress_syscfg *syscfg;
244	struct resource *res;
245	struct device *bridge;
246
247	syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
248	if (!syscfg)
249		return -ENOMEM;
250	syscfg->dev = &pdev->dev;
251	INIT_LIST_HEAD(&syscfg->funcs);
252
253	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
254	syscfg->base = devm_ioremap_resource(&pdev->dev, res);
255	if (IS_ERR(syscfg->base))
256		return PTR_ERR(syscfg->base);
257
258	/* Must use dev.parent (MFD), as that's where DT phandle points at... */
259	bridge = vexpress_config_bridge_register(pdev->dev.parent,
260			&vexpress_syscfg_bridge_ops, syscfg);
261
262	return PTR_ERR_OR_ZERO(bridge);
263}
264
265static const struct platform_device_id vexpress_syscfg_id_table[] = {
266	{ "vexpress-syscfg", },
267	{},
268};
269
270static struct platform_driver vexpress_syscfg_driver = {
271	.driver.name = "vexpress-syscfg",
272	.id_table = vexpress_syscfg_id_table,
273	.probe = vexpress_syscfg_probe,
274};
275
276static int __init vexpress_syscfg_init(void)
277{
278	return platform_driver_register(&vexpress_syscfg_driver);
279}
280core_initcall(vexpress_syscfg_init);