drivers/uio/uio_fsl_elbc_gpcm.c

   1 /* uio_fsl_elbc_gpcm: UIO driver for eLBC/GPCM peripherals
   2
   3    Copyright (C) 2014 Linutronix GmbH
   4      Author: John Ogness <john.ogness@linutronix.de>
   5
   6    This driver provides UIO access to memory of a peripheral connected
   7    to the Freescale enhanced local bus controller (eLBC) interface
   8    using the general purpose chip-select mode (GPCM).
   9
  10    Here is an example of the device tree entries:
  11
  12         localbus@ffe05000 {
  13                 ranges = <0x2 0x0 0x0 0xff810000 0x10000>;
  14
  15                 dpm@2,0 {
  16                         compatible = "fsl,elbc-gpcm-uio";
  17                         reg = <0x2 0x0 0x10000>;
  18                         elbc-gpcm-br = <0xff810800>;
  19                         elbc-gpcm-or = <0xffff09f7>;
  20                         interrupt-parent = <&mpic>;
  21                         interrupts = <4 1>;
  22                         device_type = "netx5152";
  23                         uio_name = "netx_custom";
  24                         netx5152,init-win0-offset = <0x0>;
  25                 };
  26         };
  27
  28    Only the entries reg (to identify bank) and elbc-gpcm-* (initial BR/OR
  29    values) are required. The entries interrupt*, device_type, and uio_name
  30    are optional (as well as any type-specific options such as
  31    netx5152,init-win0-offset). As long as no interrupt handler is needed,
  32    this driver can be used without any type-specific implementation.
  33
  34    The netx5152 type has been tested to work with the netX 51/52 hardware
  35    from Hilscher using the Hilscher userspace netX stack.
  36
  37    The netx5152 type should serve as a model to add new type-specific
  38    devices as needed.
  39 */
  40
  41 #include <linux/module.h>
  42 #include <linux/device.h>
  43 #include <linux/string.h>
  44 #include <linux/slab.h>
  45 #include <linux/platform_device.h>
  46 #include <linux/uio_driver.h>
  47 #include <linux/of_address.h>
  48 #include <linux/of_irq.h>
  49
  50 #include <asm/fsl_lbc.h>
  51
  52 #define MAX_BANKS 8
  53
  54 struct fsl_elbc_gpcm {
  55         struct device *dev;
  56         struct fsl_lbc_regs __iomem *lbc;
  57         u32 bank;
  58         const char *name;
  59
  60         void (*init)(struct uio_info *info);
  61         void (*shutdown)(struct uio_info *info, bool init_err);
  62         irqreturn_t (*irq_handler)(int irq, struct uio_info *info);
  63 };
  64
  65 static ssize_t reg_show(struct device *dev, struct device_attribute *attr,
  66                         char *buf);
  67 static ssize_t reg_store(struct device *dev, struct device_attribute *attr,
  68                          const char *buf, size_t count);
  69
  70 DEVICE_ATTR(reg_br, S_IRUGO|S_IWUSR|S_IWGRP, reg_show, reg_store);
  71 DEVICE_ATTR(reg_or, S_IRUGO|S_IWUSR|S_IWGRP, reg_show, reg_store);
  72
  73 static ssize_t reg_show(struct device *dev, struct device_attribute *attr,
  74                         char *buf)
  75 {
  76         struct platform_device *pdev = to_platform_device(dev);
  77         struct uio_info *info = platform_get_drvdata(pdev);
  78         struct fsl_elbc_gpcm *priv = info->priv;
  79         struct fsl_lbc_bank *bank = &priv->lbc->bank[priv->bank];
  80
  81         if (attr == &dev_attr_reg_br) {
  82                 return scnprintf(buf, PAGE_SIZE, "0x%08x\n",
  83                                  in_be32(&bank->br));
  84
  85         } else if (attr == &dev_attr_reg_or) {
  86                 return scnprintf(buf, PAGE_SIZE, "0x%08x\n",
  87                                  in_be32(&bank->or));
  88         }
  89
  90         return 0;
  91 }
  92
  93 static ssize_t reg_store(struct device *dev, struct device_attribute *attr,
  94                          const char *buf, size_t count)
  95 {
  96         struct platform_device *pdev = to_platform_device(dev);
  97         struct uio_info *info = platform_get_drvdata(pdev);
  98         struct fsl_elbc_gpcm *priv = info->priv;
  99         struct fsl_lbc_bank *bank = &priv->lbc->bank[priv->bank];
 100         unsigned long val;
 101         u32 reg_br_cur;
 102         u32 reg_or_cur;
 103         u32 reg_new;
 104
 105         /* parse use input */
 106         if (kstrtoul(buf, 0, &val) != 0)
 107                 return -EINVAL;
 108         reg_new = (u32)val;
 109
 110         /* read current values */
 111         reg_br_cur = in_be32(&bank->br);
 112         reg_or_cur = in_be32(&bank->or);
 113
 114         if (attr == &dev_attr_reg_br) {
 115                 /* not allowed to change effective base address */
 116                 if ((reg_br_cur & reg_or_cur & BR_BA) !=
 117                     (reg_new & reg_or_cur & BR_BA)) {
 118                         return -EINVAL;
 119                 }
 120
 121                 /* not allowed to change mode */
 122                 if ((reg_new & BR_MSEL) != BR_MS_GPCM)
 123                         return -EINVAL;
 124
 125                 /* write new value (force valid) */
 126                 out_be32(&bank->br, reg_new | BR_V);
 127
 128         } else if (attr == &dev_attr_reg_or) {
 129                 /* not allowed to change access mask */
 130                 if ((reg_or_cur & OR_GPCM_AM) != (reg_new & OR_GPCM_AM))
 131                         return -EINVAL;
 132
 133                 /* write new value */
 134                 out_be32(&bank->or, reg_new);
 135
 136         } else {
 137                 return -EINVAL;
 138         }
 139
 140         return count;
 141 }
 142
 143 #ifdef CONFIG_UIO_FSL_ELBC_GPCM_NETX5152
 144 #define DPM_HOST_WIN0_OFFSET    0xff00
 145 #define DPM_HOST_INT_STAT0      0xe0
 146 #define DPM_HOST_INT_EN0        0xf0
 147 #define DPM_HOST_INT_MASK       0xe600ffff
 148 #define DPM_HOST_INT_GLOBAL_EN  0x80000000
 149
 150 static irqreturn_t netx5152_irq_handler(int irq, struct uio_info *info)
 151 {
 152         void __iomem *reg_int_en = info->mem[0].internal_addr +
 153                                         DPM_HOST_WIN0_OFFSET +
 154                                         DPM_HOST_INT_EN0;
 155         void __iomem *reg_int_stat = info->mem[0].internal_addr +
 156                                         DPM_HOST_WIN0_OFFSET +
 157                                         DPM_HOST_INT_STAT0;
 158
 159         /* check if an interrupt is enabled and active */
 160         if ((ioread32(reg_int_en) & ioread32(reg_int_stat) &
 161              DPM_HOST_INT_MASK) == 0) {
 162                 return IRQ_NONE;
 163         }
 164
 165         /* disable interrupts */
 166         iowrite32(ioread32(reg_int_en) & ~DPM_HOST_INT_GLOBAL_EN, reg_int_en);
 167
 168         return IRQ_HANDLED;
 169 }
 170
 171 static void netx5152_init(struct uio_info *info)
 172 {
 173         unsigned long win0_offset = DPM_HOST_WIN0_OFFSET;
 174         struct fsl_elbc_gpcm *priv = info->priv;
 175         const void *prop;
 176
 177         /* get an optional initial win0 offset */
 178         prop = of_get_property(priv->dev->of_node,
 179                                "netx5152,init-win0-offset", NULL);
 180         if (prop)
 181                 win0_offset = of_read_ulong(prop, 1);
 182
 183         /* disable interrupts */
 184         iowrite32(0, info->mem[0].internal_addr + win0_offset +
 185                      DPM_HOST_INT_EN0);
 186 }
 187
 188 static void netx5152_shutdown(struct uio_info *info, bool init_err)
 189 {
 190         if (init_err)
 191                 return;
 192
 193         /* disable interrupts */
 194         iowrite32(0, info->mem[0].internal_addr + DPM_HOST_WIN0_OFFSET +
 195                      DPM_HOST_INT_EN0);
 196 }
 197 #endif
 198
 199 static void setup_periph(struct fsl_elbc_gpcm *priv,
 200                                    const char *type)
 201 {
 202 #ifdef CONFIG_UIO_FSL_ELBC_GPCM_NETX5152
 203         if (strcmp(type, "netx5152") == 0) {
 204                 priv->irq_handler = netx5152_irq_handler;
 205                 priv->init = netx5152_init;
 206                 priv->shutdown = netx5152_shutdown;
 207                 priv->name = "netX 51/52";
 208                 return;
 209         }
 210 #endif
 211 }
 212
 213 static int check_of_data(struct fsl_elbc_gpcm *priv,
 214                                    struct resource *res,
 215                                    u32 reg_br, u32 reg_or)
 216 {
 217         /* check specified bank */
 218         if (priv->bank >= MAX_BANKS) {
 219                 dev_err(priv->dev, "invalid bank\n");
 220                 return -ENODEV;
 221         }
 222
 223         /* check specified mode (BR_MS_GPCM is 0) */
 224         if ((reg_br & BR_MSEL) != BR_MS_GPCM) {
 225                 dev_err(priv->dev, "unsupported mode\n");
 226                 return -ENODEV;
 227         }
 228
 229         /* check specified mask vs. resource size */
 230         if ((~(reg_or & OR_GPCM_AM) + 1) != resource_size(res)) {
 231                 dev_err(priv->dev, "address mask / size mismatch\n");
 232                 return -ENODEV;
 233         }
 234
 235         /* check specified address */
 236         if ((reg_br & reg_or & BR_BA) != fsl_lbc_addr(res->start)) {
 237                 dev_err(priv->dev, "base address mismatch\n");
 238                 return -ENODEV;
 239         }
 240
 241         return 0;
 242 }
 243
 244 static int get_of_data(struct fsl_elbc_gpcm *priv, struct device_node *node,
 245                        struct resource *res, u32 *reg_br,
 246                        u32 *reg_or, unsigned int *irq, char **name)
 247 {
 248         const char *dt_name;
 249         const char *type;
 250         int ret;
 251
 252         /* get the memory resource */
 253         ret = of_address_to_resource(node, 0, res);
 254         if (ret) {
 255                 dev_err(priv->dev, "failed to get resource\n");
 256                 return ret;
 257         }
 258
 259         /* get the bank number */
 260         ret = of_property_read_u32(node, "reg", &priv->bank);
 261         if (ret) {
 262                 dev_err(priv->dev, "failed to get bank number\n");
 263                 return ret;
 264         }
 265
 266         /* get BR value to set */
 267         ret = of_property_read_u32(node, "elbc-gpcm-br", reg_br);
 268         if (ret) {
 269                 dev_err(priv->dev, "missing elbc-gpcm-br value\n");
 270                 return ret;
 271         }
 272
 273         /* get OR value to set */
 274         ret = of_property_read_u32(node, "elbc-gpcm-or", reg_or);
 275         if (ret) {
 276                 dev_err(priv->dev, "missing elbc-gpcm-or value\n");
 277                 return ret;
 278         }
 279
 280         /* get optional peripheral type */
 281         priv->name = "generic";
 282         if (of_property_read_string(node, "device_type", &type) == 0)
 283                 setup_periph(priv, type);
 284
 285         /* get optional irq value */
 286         *irq = irq_of_parse_and_map(node, 0);
 287
 288         /* sanity check device tree data */
 289         ret = check_of_data(priv, res, *reg_br, *reg_or);
 290         if (ret)
 291                 return ret;
 292
 293         /* get optional uio name */
 294         if (of_property_read_string(node, "uio_name", &dt_name) != 0)
 295                 dt_name = "eLBC_GPCM";
 296         *name = kstrdup(dt_name, GFP_KERNEL);
 297         if (!*name)
 298                 return -ENOMEM;
 299
 300         return 0;
 301 }
 302
 303 static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
 304 {
 305         struct device_node *node = pdev->dev.of_node;
 306         struct fsl_elbc_gpcm *priv;
 307         struct uio_info *info;
 308         char *uio_name = NULL;
 309         struct resource res;
 310         unsigned int irq;
 311         u32 reg_br_cur;
 312         u32 reg_or_cur;
 313         u32 reg_br_new;
 314         u32 reg_or_new;
 315         int ret;
 316
 317         if (!fsl_lbc_ctrl_dev || !fsl_lbc_ctrl_dev->regs)
 318                 return -ENODEV;
 319
 320         /* allocate private data */
 321         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 322         if (!priv)
 323                 return -ENOMEM;
 324         priv->dev = &pdev->dev;
 325         priv->lbc = fsl_lbc_ctrl_dev->regs;
 326
 327         /* get device tree data */
 328         ret = get_of_data(priv, node, &res, &reg_br_new, &reg_or_new,
 329                           &irq, &uio_name);
 330         if (ret)
 331                 goto out_err0;
 332
 333         /* allocate UIO structure */
 334         info = kzalloc(sizeof(*info), GFP_KERNEL);
 335         if (!info) {
 336                 ret = -ENOMEM;
 337                 goto out_err0;
 338         }
 339
 340         /* get current BR/OR values */
 341         reg_br_cur = in_be32(&priv->lbc->bank[priv->bank].br);
 342         reg_or_cur = in_be32(&priv->lbc->bank[priv->bank].or);
 343
 344         /* if bank already configured, make sure it matches */
 345         if ((reg_br_cur & BR_V)) {
 346                 if ((reg_br_cur & BR_MSEL) != BR_MS_GPCM ||
 347                     (reg_br_cur & reg_or_cur & BR_BA)
 348                      != fsl_lbc_addr(res.start)) {
 349                         dev_err(priv->dev,
 350                                 "bank in use by another peripheral\n");
 351                         ret = -ENODEV;
 352                         goto out_err1;
 353                 }
 354
 355                 /* warn if behavior settings changing */
 356                 if ((reg_br_cur & ~(BR_BA | BR_V)) !=
 357                     (reg_br_new & ~(BR_BA | BR_V))) {
 358                         dev_warn(priv->dev,
 359                                  "modifying BR settings: 0x%08x -> 0x%08x",
 360                                  reg_br_cur, reg_br_new);
 361                 }
 362                 if ((reg_or_cur & ~OR_GPCM_AM) != (reg_or_new & ~OR_GPCM_AM)) {
 363                         dev_warn(priv->dev,
 364                                  "modifying OR settings: 0x%08x -> 0x%08x",
 365                                  reg_or_cur, reg_or_new);
 366                 }
 367         }
 368
 369         /* configure the bank (force base address and GPCM) */
 370         reg_br_new &= ~(BR_BA | BR_MSEL);
 371         reg_br_new |= fsl_lbc_addr(res.start) | BR_MS_GPCM | BR_V;
 372         out_be32(&priv->lbc->bank[priv->bank].or, reg_or_new);
 373         out_be32(&priv->lbc->bank[priv->bank].br, reg_br_new);
 374
 375         /* map the memory resource */
 376         info->mem[0].internal_addr = ioremap(res.start, resource_size(&res));
 377         if (!info->mem[0].internal_addr) {
 378                 dev_err(priv->dev, "failed to map chip region\n");
 379                 ret = -ENODEV;
 380                 goto out_err1;
 381         }
 382
 383         /* set all UIO data */
 384         if (node->name)
 385                 info->mem[0].name = kstrdup(node->name, GFP_KERNEL);
 386         info->mem[0].addr = res.start;
 387         info->mem[0].size = resource_size(&res);
 388         info->mem[0].memtype = UIO_MEM_PHYS;
 389         info->priv = priv;
 390         info->name = uio_name;
 391         info->version = "0.0.1";
 392         if (irq != NO_IRQ) {
 393                 if (priv->irq_handler) {
 394                         info->irq = irq;
 395                         info->irq_flags = IRQF_SHARED;
 396                         info->handler = priv->irq_handler;
 397                 } else {
 398                         irq = NO_IRQ;
 399                         dev_warn(priv->dev, "ignoring irq, no handler\n");
 400                 }
 401         }
 402
 403         if (priv->init)
 404                 priv->init(info);
 405
 406         /* register UIO device */
 407         if (uio_register_device(priv->dev, info) != 0) {
 408                 dev_err(priv->dev, "UIO registration failed\n");
 409                 ret = -ENODEV;
 410                 goto out_err2;
 411         }
 412
 413         /* store private data */
 414         platform_set_drvdata(pdev, info);
 415
 416         /* create sysfs files */
 417         ret = device_create_file(priv->dev, &dev_attr_reg_br);
 418         if (ret)
 419                 goto out_err3;
 420         ret = device_create_file(priv->dev, &dev_attr_reg_or);
 421         if (ret)
 422                 goto out_err4;
 423
 424         dev_info(priv->dev,
 425                  "eLBC/GPCM device (%s) at 0x%llx, bank %d, irq=%d\n",
 426                  priv->name, (unsigned long long)res.start, priv->bank,
 427                  irq != NO_IRQ ? irq : -1);
 428
 429         return 0;
 430 out_err4:
 431         device_remove_file(priv->dev, &dev_attr_reg_br);
 432 out_err3:
 433         platform_set_drvdata(pdev, NULL);
 434         uio_unregister_device(info);
 435 out_err2:
 436         if (priv->shutdown)
 437                 priv->shutdown(info, true);
 438         iounmap(info->mem[0].internal_addr);
 439 out_err1:
 440         kfree(info->mem[0].name);
 441         kfree(info);
 442 out_err0:
 443         kfree(uio_name);
 444         kfree(priv);
 445         return ret;
 446 }
 447
 448 static int uio_fsl_elbc_gpcm_remove(struct platform_device *pdev)
 449 {
 450         struct uio_info *info = platform_get_drvdata(pdev);
 451         struct fsl_elbc_gpcm *priv = info->priv;
 452
 453         device_remove_file(priv->dev, &dev_attr_reg_or);
 454         device_remove_file(priv->dev, &dev_attr_reg_br);
 455         platform_set_drvdata(pdev, NULL);
 456         uio_unregister_device(info);
 457         if (priv->shutdown)
 458                 priv->shutdown(info, false);
 459         iounmap(info->mem[0].internal_addr);
 460         kfree(info->mem[0].name);
 461         kfree(info->name);
 462         kfree(info);
 463         kfree(priv);
 464
 465         return 0;
 466
 467 }
 468
 469 static const struct of_device_id uio_fsl_elbc_gpcm_match[] = {
 470         { .compatible = "fsl,elbc-gpcm-uio", },
 471         {}
 472 };
 473 MODULE_DEVICE_TABLE(of, uio_fsl_elbc_gpcm_match);
 474
 475 static struct platform_driver uio_fsl_elbc_gpcm_driver = {
 476         .driver = {
 477                 .name = "fsl,elbc-gpcm-uio",
 478                 .owner = THIS_MODULE,
 479                 .of_match_table = uio_fsl_elbc_gpcm_match,
 480         },
 481         .probe = uio_fsl_elbc_gpcm_probe,
 482         .remove = uio_fsl_elbc_gpcm_remove,
 483 };
 484 module_platform_driver(uio_fsl_elbc_gpcm_driver);
 485
 486 MODULE_LICENSE("GPL");
 487 MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
 488 MODULE_DESCRIPTION("Freescale Enhanced Local Bus Controller GPCM driver");