drivers/bus/vexpress-config.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (C) 2014 ARM Limited
   5  */
   6
   7 #include <linux/err.h>
   8 #include <linux/init.h>
   9 #include <linux/io.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/of_device.h>
  13 #include <linux/sched/signal.h>
  14 #include <linux/slab.h>
  15 #include <linux/vexpress.h>
  16
  17 #define SYS_CFGDATA             0x0
  18
  19 #define SYS_CFGCTRL             0x4
  20 #define SYS_CFGCTRL_START       (1 << 31)
  21 #define SYS_CFGCTRL_WRITE       (1 << 30)
  22 #define SYS_CFGCTRL_DCC(n)      (((n) & 0xf) << 26)
  23 #define SYS_CFGCTRL_FUNC(n)     (((n) & 0x3f) << 20)
  24 #define SYS_CFGCTRL_SITE(n)     (((n) & 0x3) << 16)
  25 #define SYS_CFGCTRL_POSITION(n) (((n) & 0xf) << 12)
  26 #define SYS_CFGCTRL_DEVICE(n)   (((n) & 0xfff) << 0)
  27
  28 #define SYS_CFGSTAT             0x8
  29 #define SYS_CFGSTAT_ERR         (1 << 1)
  30 #define SYS_CFGSTAT_COMPLETE    (1 << 0)
  31
  32
  33 struct vexpress_syscfg {
  34         struct device *dev;
  35         void __iomem *base;
  36         struct list_head funcs;
  37 };
  38
  39 struct vexpress_syscfg_func {
  40         struct list_head list;
  41         struct vexpress_syscfg *syscfg;
  42         struct regmap *regmap;
  43         int num_templates;
  44         u32 template[]; /* Keep it last! */
  45 };
  46
  47 struct vexpress_config_bridge_ops {
  48         struct regmap * (*regmap_init)(struct device *dev, void *context);
  49         void (*regmap_exit)(struct regmap *regmap, void *context);
  50 };
  51
  52 struct vexpress_config_bridge {
  53         struct vexpress_config_bridge_ops *ops;
  54         void *context;
  55 };
  56
  57
  58 static DEFINE_MUTEX(vexpress_config_mutex);
  59 static struct class *vexpress_config_class;
  60 static u32 vexpress_config_site_master = VEXPRESS_SITE_MASTER;
  61
  62
  63 void vexpress_config_set_master(u32 site)
  64 {
  65         vexpress_config_site_master = site;
  66 }
  67
  68 static void vexpress_config_lock(void *arg)
  69 {
  70         mutex_lock(&vexpress_config_mutex);
  71 }
  72
  73 static void vexpress_config_unlock(void *arg)
  74 {
  75         mutex_unlock(&vexpress_config_mutex);
  76 }
  77
  78
  79 static void vexpress_config_find_prop(struct device_node *node,
  80                 const char *name, u32 *val)
  81 {
  82         /* Default value */
  83         *val = 0;
  84
  85         of_node_get(node);
  86         while (node) {
  87                 if (of_property_read_u32(node, name, val) == 0) {
  88                         of_node_put(node);
  89                         return;
  90                 }
  91                 node = of_get_next_parent(node);
  92         }
  93 }
  94
  95 static int vexpress_config_get_topo(struct device_node *node, u32 *site,
  96                 u32 *position, u32 *dcc)
  97 {
  98         vexpress_config_find_prop(node, "arm,vexpress,site", site);
  99         if (*site == VEXPRESS_SITE_MASTER)
 100                 *site = vexpress_config_site_master;
 101         if (WARN_ON(vexpress_config_site_master == VEXPRESS_SITE_MASTER))
 102                 return -EINVAL;
 103         vexpress_config_find_prop(node, "arm,vexpress,position", position);
 104         vexpress_config_find_prop(node, "arm,vexpress,dcc", dcc);
 105
 106         return 0;
 107 }
 108
 109
 110 static void vexpress_config_devres_release(struct device *dev, void *res)
 111 {
 112         struct vexpress_config_bridge *bridge = dev_get_drvdata(dev->parent);
 113         struct regmap *regmap = res;
 114
 115         bridge->ops->regmap_exit(regmap, bridge->context);
 116 }
 117
 118 struct regmap *devm_regmap_init_vexpress_config(struct device *dev)
 119 {
 120         struct vexpress_config_bridge *bridge;
 121         struct regmap *regmap;
 122         struct regmap **res;
 123
 124         if (WARN_ON(dev->parent->class != vexpress_config_class))
 125                 return ERR_PTR(-ENODEV);
 126
 127         bridge = dev_get_drvdata(dev->parent);
 128         if (WARN_ON(!bridge))
 129                 return ERR_PTR(-EINVAL);
 130
 131         res = devres_alloc(vexpress_config_devres_release, sizeof(*res),
 132                         GFP_KERNEL);
 133         if (!res)
 134                 return ERR_PTR(-ENOMEM);
 135
 136         regmap = (bridge->ops->regmap_init)(dev, bridge->context);
 137         if (IS_ERR(regmap)) {
 138                 devres_free(res);
 139                 return regmap;
 140         }
 141
 142         *res = regmap;
 143         devres_add(dev, res);
 144
 145         return regmap;
 146 }
 147 EXPORT_SYMBOL_GPL(devm_regmap_init_vexpress_config);
 148
 149 static struct device *vexpress_config_bridge_register(struct device *parent,
 150                 struct vexpress_config_bridge_ops *ops, void *context)
 151 {
 152         struct device *dev;
 153         struct vexpress_config_bridge *bridge;
 154
 155         if (!vexpress_config_class) {
 156                 vexpress_config_class = class_create(THIS_MODULE,
 157                                 "vexpress-config");
 158                 if (IS_ERR(vexpress_config_class))
 159                         return (void *)vexpress_config_class;
 160         }
 161
 162         dev = device_create(vexpress_config_class, parent, 0,
 163                         NULL, "%s.bridge", dev_name(parent));
 164
 165         if (IS_ERR(dev))
 166                 return dev;
 167
 168         bridge = devm_kmalloc(dev, sizeof(*bridge), GFP_KERNEL);
 169         if (!bridge) {
 170                 put_device(dev);
 171                 device_unregister(dev);
 172                 return ERR_PTR(-ENOMEM);
 173         }
 174         bridge->ops = ops;
 175         bridge->context = context;
 176
 177         dev_set_drvdata(dev, bridge);
 178
 179         dev_dbg(parent, "Registered bridge '%s', parent node %p\n",
 180                         dev_name(dev), parent->of_node);
 181
 182         return dev;
 183 }
 184
 185
 186 static int vexpress_config_node_match(struct device *dev, const void *data)
 187 {
 188         const struct device_node *node = data;
 189
 190         dev_dbg(dev, "Parent node %p, looking for %p\n",
 191                         dev->parent->of_node, node);
 192
 193         return dev->parent->of_node == node;
 194 }
 195
 196 static int vexpress_config_populate(struct device_node *node)
 197 {
 198         struct device_node *bridge;
 199         struct device *parent;
 200         int ret;
 201
 202         bridge = of_parse_phandle(node, "arm,vexpress,config-bridge", 0);
 203         if (!bridge)
 204                 return -EINVAL;
 205
 206         parent = class_find_device(vexpress_config_class, NULL, bridge,
 207                         vexpress_config_node_match);
 208         of_node_put(bridge);
 209         if (WARN_ON(!parent))
 210                 return -ENODEV;
 211
 212         ret = of_platform_populate(node, NULL, NULL, parent);
 213
 214         put_device(parent);
 215
 216         return ret;
 217 }
 218
 219 static int __init vexpress_config_init(void)
 220 {
 221         int err = 0;
 222         struct device_node *node;
 223
 224         /* Need the config devices early, before the "normal" devices... */
 225         for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") {
 226                 err = vexpress_config_populate(node);
 227                 if (err) {
 228                         of_node_put(node);
 229                         break;
 230                 }
 231         }
 232
 233         return err;
 234 }
 235 postcore_initcall(vexpress_config_init);
 236
 237 static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
 238                 int index, bool write, u32 *data)
 239 {
 240         struct vexpress_syscfg *syscfg = func->syscfg;
 241         u32 command, status;
 242         int tries;
 243         long timeout;
 244
 245         if (WARN_ON(index >= func->num_templates))
 246                 return -EINVAL;
 247
 248         command = readl(syscfg->base + SYS_CFGCTRL);
 249         if (WARN_ON(command & SYS_CFGCTRL_START))
 250                 return -EBUSY;
 251
 252         command = func->template[index];
 253         command |= SYS_CFGCTRL_START;
 254         command |= write ? SYS_CFGCTRL_WRITE : 0;
 255
 256         /* Use a canary for reads */
 257         if (!write)
 258                 *data = 0xdeadbeef;
 259
 260         dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
 261                         func, command, *data);
 262         writel(*data, syscfg->base + SYS_CFGDATA);
 263         writel(0, syscfg->base + SYS_CFGSTAT);
 264         writel(command, syscfg->base + SYS_CFGCTRL);
 265         mb();
 266
 267         /* The operation can take ages... Go to sleep, 100us initially */
 268         tries = 100;
 269         timeout = 100;
 270         do {
 271                 if (!irqs_disabled()) {
 272                         set_current_state(TASK_INTERRUPTIBLE);
 273                         schedule_timeout(usecs_to_jiffies(timeout));
 274                         if (signal_pending(current))
 275                                 return -EINTR;
 276                 } else {
 277                         udelay(timeout);
 278                 }
 279
 280                 status = readl(syscfg->base + SYS_CFGSTAT);
 281                 if (status & SYS_CFGSTAT_ERR)
 282                         return -EFAULT;
 283
 284                 if (timeout > 20)
 285                         timeout -= 20;
 286         } while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
 287         if (WARN_ON_ONCE(!tries))
 288                 return -ETIMEDOUT;
 289
 290         if (!write) {
 291                 *data = readl(syscfg->base + SYS_CFGDATA);
 292                 dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int vexpress_syscfg_read(void *context, unsigned int index,
 299                 unsigned int *val)
 300 {
 301         struct vexpress_syscfg_func *func = context;
 302
 303         return vexpress_syscfg_exec(func, index, false, val);
 304 }
 305
 306 static int vexpress_syscfg_write(void *context, unsigned int index,
 307                 unsigned int val)
 308 {
 309         struct vexpress_syscfg_func *func = context;
 310
 311         return vexpress_syscfg_exec(func, index, true, &val);
 312 }
 313
 314 static struct regmap_config vexpress_syscfg_regmap_config = {
 315         .lock = vexpress_config_lock,
 316         .unlock = vexpress_config_unlock,
 317         .reg_bits = 32,
 318         .val_bits = 32,
 319         .reg_read = vexpress_syscfg_read,
 320         .reg_write = vexpress_syscfg_write,
 321         .reg_format_endian = REGMAP_ENDIAN_LITTLE,
 322         .val_format_endian = REGMAP_ENDIAN_LITTLE,
 323 };
 324
 325
 326 static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
 327                 void *context)
 328 {
 329         int err;
 330         struct vexpress_syscfg *syscfg = context;
 331         struct vexpress_syscfg_func *func;
 332         struct property *prop;
 333         const __be32 *val = NULL;
 334         __be32 energy_quirk[4];
 335         int num;
 336         u32 site, position, dcc;
 337         int i;
 338
 339         err = vexpress_config_get_topo(dev->of_node, &site,
 340                                 &position, &dcc);
 341         if (err)
 342                 return ERR_PTR(err);
 343
 344         prop = of_find_property(dev->of_node,
 345                         "arm,vexpress-sysreg,func", NULL);
 346         if (!prop)
 347                 return ERR_PTR(-EINVAL);
 348
 349         num = prop->length / sizeof(u32) / 2;
 350         val = prop->value;
 351
 352         /*
 353          * "arm,vexpress-energy" function used to be described
 354          * by its first device only, now it requires both
 355          */
 356         if (num == 1 && of_device_is_compatible(dev->of_node,
 357                         "arm,vexpress-energy")) {
 358                 num = 2;
 359                 energy_quirk[0] = *val;
 360                 energy_quirk[2] = *val++;
 361                 energy_quirk[1] = *val;
 362                 energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
 363                 val = energy_quirk;
 364         }
 365
 366         func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
 367         if (!func)
 368                 return ERR_PTR(-ENOMEM);
 369
 370         func->syscfg = syscfg;
 371         func->num_templates = num;
 372
 373         for (i = 0; i < num; i++) {
 374                 u32 function, device;
 375
 376                 function = be32_to_cpup(val++);
 377                 device = be32_to_cpup(val++);
 378
 379                 dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
 380                                 func, site, position, dcc,
 381                                 function, device);
 382
 383                 func->template[i] = SYS_CFGCTRL_DCC(dcc);
 384                 func->template[i] |= SYS_CFGCTRL_SITE(site);
 385                 func->template[i] |= SYS_CFGCTRL_POSITION(position);
 386                 func->template[i] |= SYS_CFGCTRL_FUNC(function);
 387                 func->template[i] |= SYS_CFGCTRL_DEVICE(device);
 388         }
 389
 390         vexpress_syscfg_regmap_config.max_register = num - 1;
 391
 392         func->regmap = regmap_init(dev, NULL, func,
 393                         &vexpress_syscfg_regmap_config);
 394
 395         if (IS_ERR(func->regmap)) {
 396                 void *err = func->regmap;
 397
 398                 kfree(func);
 399                 return err;
 400         }
 401
 402         list_add(&func->list, &syscfg->funcs);
 403
 404         return func->regmap;
 405 }
 406
 407 static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
 408 {
 409         struct vexpress_syscfg *syscfg = context;
 410         struct vexpress_syscfg_func *func, *tmp;
 411
 412         regmap_exit(regmap);
 413
 414         list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
 415                 if (func->regmap == regmap) {
 416                         list_del(&syscfg->funcs);
 417                         kfree(func);
 418                         break;
 419                 }
 420         }
 421 }
 422
 423 static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
 424         .regmap_init = vexpress_syscfg_regmap_init,
 425         .regmap_exit = vexpress_syscfg_regmap_exit,
 426 };
 427
 428
 429 static int vexpress_syscfg_probe(struct platform_device *pdev)
 430 {
 431         struct vexpress_syscfg *syscfg;
 432         struct resource *res;
 433         struct device *bridge;
 434
 435         syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
 436         if (!syscfg)
 437                 return -ENOMEM;
 438         syscfg->dev = &pdev->dev;
 439         INIT_LIST_HEAD(&syscfg->funcs);
 440
 441         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 442         syscfg->base = devm_ioremap_resource(&pdev->dev, res);
 443         if (IS_ERR(syscfg->base))
 444                 return PTR_ERR(syscfg->base);
 445
 446         /* Must use dev.parent (MFD), as that's where DT phandle points at... */
 447         bridge = vexpress_config_bridge_register(pdev->dev.parent,
 448                         &vexpress_syscfg_bridge_ops, syscfg);
 449
 450         return PTR_ERR_OR_ZERO(bridge);
 451 }
 452
 453 static const struct platform_device_id vexpress_syscfg_id_table[] = {
 454         { "vexpress-syscfg", },
 455         {},
 456 };
 457
 458 static struct platform_driver vexpress_syscfg_driver = {
 459         .driver.name = "vexpress-syscfg",
 460         .id_table = vexpress_syscfg_id_table,
 461         .probe = vexpress_syscfg_probe,
 462 };
 463
 464 static int __init vexpress_syscfg_init(void)
 465 {
 466         return platform_driver_register(&vexpress_syscfg_driver);
 467 }
 468 core_initcall(vexpress_syscfg_init);