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/signal.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
41 struct vexpress_syscfg {
42 struct device *dev;
43 void __iomem *base;
44 struct list_head funcs;
45 };
46
47 struct 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
vexpress_syscfg_exec(struct vexpress_syscfg_func * func,int index,bool write,u32 * data)56 static 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
vexpress_syscfg_read(void * context,unsigned int index,unsigned int * val)117 static 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
vexpress_syscfg_write(void * context,unsigned int index,unsigned int val)125 static 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
133 static struct 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
vexpress_syscfg_regmap_init(struct device * dev,void * context)145 static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
146 void *context)
147 {
148 int err;
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 err = vexpress_config_get_topo(dev->of_node, &site,
159 &position, &dcc);
160 if (err)
161 return ERR_PTR(err);
162
163 prop = of_find_property(dev->of_node,
164 "arm,vexpress-sysreg,func", NULL);
165 if (!prop)
166 return ERR_PTR(-EINVAL);
167
168 num = prop->length / sizeof(u32) / 2;
169 val = prop->value;
170
171 /*
172 * "arm,vexpress-energy" function used to be described
173 * by its first device only, now it requires both
174 */
175 if (num == 1 && of_device_is_compatible(dev->of_node,
176 "arm,vexpress-energy")) {
177 num = 2;
178 energy_quirk[0] = *val;
179 energy_quirk[2] = *val++;
180 energy_quirk[1] = *val;
181 energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
182 val = energy_quirk;
183 }
184
185 func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
186 if (!func)
187 return ERR_PTR(-ENOMEM);
188
189 func->syscfg = syscfg;
190 func->num_templates = num;
191
192 for (i = 0; i < num; i++) {
193 u32 function, device;
194
195 function = be32_to_cpup(val++);
196 device = be32_to_cpup(val++);
197
198 dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
199 func, site, position, dcc,
200 function, device);
201
202 func->template[i] = SYS_CFGCTRL_DCC(dcc);
203 func->template[i] |= SYS_CFGCTRL_SITE(site);
204 func->template[i] |= SYS_CFGCTRL_POSITION(position);
205 func->template[i] |= SYS_CFGCTRL_FUNC(function);
206 func->template[i] |= SYS_CFGCTRL_DEVICE(device);
207 }
208
209 vexpress_syscfg_regmap_config.max_register = num - 1;
210
211 func->regmap = regmap_init(dev, NULL, func,
212 &vexpress_syscfg_regmap_config);
213
214 if (IS_ERR(func->regmap)) {
215 void *err = func->regmap;
216
217 kfree(func);
218 return err;
219 }
220
221 list_add(&func->list, &syscfg->funcs);
222
223 return func->regmap;
224 }
225
vexpress_syscfg_regmap_exit(struct regmap * regmap,void * context)226 static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
227 {
228 struct vexpress_syscfg *syscfg = context;
229 struct vexpress_syscfg_func *func, *tmp;
230
231 regmap_exit(regmap);
232
233 list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
234 if (func->regmap == regmap) {
235 list_del(&syscfg->funcs);
236 kfree(func);
237 break;
238 }
239 }
240 }
241
242 static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
243 .regmap_init = vexpress_syscfg_regmap_init,
244 .regmap_exit = vexpress_syscfg_regmap_exit,
245 };
246
247
vexpress_syscfg_probe(struct platform_device * pdev)248 static int vexpress_syscfg_probe(struct platform_device *pdev)
249 {
250 struct vexpress_syscfg *syscfg;
251 struct resource *res;
252 struct device *bridge;
253
254 syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
255 if (!syscfg)
256 return -ENOMEM;
257 syscfg->dev = &pdev->dev;
258 INIT_LIST_HEAD(&syscfg->funcs);
259
260 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
261 syscfg->base = devm_ioremap_resource(&pdev->dev, res);
262 if (IS_ERR(syscfg->base))
263 return PTR_ERR(syscfg->base);
264
265 /* Must use dev.parent (MFD), as that's where DT phandle points at... */
266 bridge = vexpress_config_bridge_register(pdev->dev.parent,
267 &vexpress_syscfg_bridge_ops, syscfg);
268
269 return PTR_ERR_OR_ZERO(bridge);
270 }
271
272 static const struct platform_device_id vexpress_syscfg_id_table[] = {
273 { "vexpress-syscfg", },
274 {},
275 };
276
277 static struct platform_driver vexpress_syscfg_driver = {
278 .driver.name = "vexpress-syscfg",
279 .id_table = vexpress_syscfg_id_table,
280 .probe = vexpress_syscfg_probe,
281 };
282
vexpress_syscfg_init(void)283 static int __init vexpress_syscfg_init(void)
284 {
285 return platform_driver_register(&vexpress_syscfg_driver);
286 }
287 core_initcall(vexpress_syscfg_init);
288