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
34 struct vexpress_syscfg {
35 struct device *dev;
36 void __iomem *base;
37 struct list_head funcs;
38 };
39
40 struct 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
vexpress_syscfg_exec(struct vexpress_syscfg_func * func,int index,bool write,u32 * data)49 static 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
vexpress_syscfg_read(void * context,unsigned int index,unsigned int * val)110 static 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
vexpress_syscfg_write(void * context,unsigned int index,unsigned int val)118 static 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
126 static 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
vexpress_syscfg_regmap_init(struct device * dev,void * context)138 static 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
vexpress_syscfg_regmap_exit(struct regmap * regmap,void * context)219 static 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
235 static 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
vexpress_syscfg_probe(struct platform_device * pdev)241 static 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
265 static const struct platform_device_id vexpress_syscfg_id_table[] = {
266 { "vexpress-syscfg", },
267 {},
268 };
269
270 static 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
vexpress_syscfg_init(void)276 static int __init vexpress_syscfg_init(void)
277 {
278 return platform_driver_register(&vexpress_syscfg_driver);
279 }
280 core_initcall(vexpress_syscfg_init);
281
