drivers/net/can/c_can/c_can_platform.c

   1 /*
   2  * Platform CAN bus driver for Bosch C_CAN controller
   3  *
   4  * Copyright (C) 2010 ST Microelectronics
   5  * Bhupesh Sharma <bhupesh.sharma@st.com>
   6  *
   7  * Borrowed heavily from the C_CAN driver originally written by:
   8  * Copyright (C) 2007
   9  * - Sascha Hauer, Marc Kleine-Budde, Pengutronix <s.hauer@pengutronix.de>
  10  * - Simon Kallweit, intefo AG <simon.kallweit@intefo.ch>
  11  *
  12  * Bosch C_CAN controller is compliant to CAN protocol version 2.0 part A and B.
  13  * Bosch C_CAN user manual can be obtained from:
  14  * http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/
  15  * users_manual_c_can.pdf
  16  *
  17  * This file is licensed under the terms of the GNU General Public
  18  * License version 2. This program is licensed "as is" without any
  19  * warranty of any kind, whether express or implied.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/if_ether.h>
  29 #include <linux/list.h>
  30 #include <linux/io.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/clk.h>
  34 #include <linux/of.h>
  35 #include <linux/of_device.h>
  36 #include <linux/mfd/syscon.h>
  37 #include <linux/regmap.h>
  38
  39 #include <linux/can/dev.h>
  40
  41 #include "c_can.h"
  42
  43 #define DCAN_RAM_INIT_BIT BIT(3)
  44
  45 static DEFINE_SPINLOCK(raminit_lock);
  46
  47 /* 16-bit c_can registers can be arranged differently in the memory
  48  * architecture of different implementations. For example: 16-bit
  49  * registers can be aligned to a 16-bit boundary or 32-bit boundary etc.
  50  * Handle the same by providing a common read/write interface.
  51  */
  52 static u16 c_can_plat_read_reg_aligned_to_16bit(const struct c_can_priv *priv,
  53                                                 enum reg index)
  54 {
  55         return readw(priv->base + priv->regs[index]);
  56 }
  57
  58 static void c_can_plat_write_reg_aligned_to_16bit(const struct c_can_priv *priv,
  59                                                   enum reg index, u16 val)
  60 {
  61         writew(val, priv->base + priv->regs[index]);
  62 }
  63
  64 static u16 c_can_plat_read_reg_aligned_to_32bit(const struct c_can_priv *priv,
  65                                                 enum reg index)
  66 {
  67         return readw(priv->base + 2 * priv->regs[index]);
  68 }
  69
  70 static void c_can_plat_write_reg_aligned_to_32bit(const struct c_can_priv *priv,
  71                                                   enum reg index, u16 val)
  72 {
  73         writew(val, priv->base + 2 * priv->regs[index]);
  74 }
  75
  76 static void c_can_hw_raminit_wait_syscon(const struct c_can_priv *priv,
  77                                          u32 mask, u32 val)
  78 {
  79         const struct c_can_raminit *raminit = &priv->raminit_sys;
  80         int timeout = 0;
  81         u32 ctrl = 0;
  82
  83         /* We look only at the bits of our instance. */
  84         val &= mask;
  85         do {
  86                 udelay(1);
  87                 timeout++;
  88
  89                 regmap_read(raminit->syscon, raminit->reg, &ctrl);
  90                 if (timeout == 1000) {
  91                         dev_err(&priv->dev->dev, "%s: time out\n", __func__);
  92                         break;
  93                 }
  94         } while ((ctrl & mask) != val);
  95 }
  96
  97 static void c_can_hw_raminit_syscon(const struct c_can_priv *priv, bool enable)
  98 {
  99         const struct c_can_raminit *raminit = &priv->raminit_sys;
 100         u32 ctrl = 0;
 101         u32 mask;
 102
 103         spin_lock(&raminit_lock);
 104
 105         mask = 1 << raminit->bits.start | 1 << raminit->bits.done;
 106         regmap_read(raminit->syscon, raminit->reg, &ctrl);
 107
 108         /* We clear the start bit first. The start bit is
 109          * looking at the 0 -> transition, but is not self clearing;
 110          * NOTE: DONE must be written with 1 to clear it.
 111          * We can't clear the DONE bit here using regmap_update_bits()
 112          * as it will bypass the write if initial condition is START:0 DONE:1
 113          * e.g. on DRA7 which needs START pulse.
 114          */
 115         ctrl &= ~mask;  /* START = 0, DONE = 0 */
 116         regmap_update_bits(raminit->syscon, raminit->reg, mask, ctrl);
 117
 118         /* check if START bit is 0. Ignore DONE bit for now
 119          * as it can be either 0 or 1.
 120          */
 121         c_can_hw_raminit_wait_syscon(priv, 1 << raminit->bits.start, ctrl);
 122
 123         if (enable) {
 124                 /* Clear DONE bit & set START bit. */
 125                 ctrl |= 1 << raminit->bits.start;
 126                 /* DONE must be written with 1 to clear it */
 127                 ctrl |= 1 << raminit->bits.done;
 128                 regmap_update_bits(raminit->syscon, raminit->reg, mask, ctrl);
 129                 /* prevent further clearing of DONE bit */
 130                 ctrl &= ~(1 << raminit->bits.done);
 131                 /* clear START bit if start pulse is needed */
 132                 if (raminit->needs_pulse) {
 133                         ctrl &= ~(1 << raminit->bits.start);
 134                         regmap_update_bits(raminit->syscon, raminit->reg,
 135                                            mask, ctrl);
 136                 }
 137
 138                 ctrl |= 1 << raminit->bits.done;
 139                 c_can_hw_raminit_wait_syscon(priv, mask, ctrl);
 140         }
 141         spin_unlock(&raminit_lock);
 142 }
 143
 144 static u32 c_can_plat_read_reg32(const struct c_can_priv *priv, enum reg index)
 145 {
 146         u32 val;
 147
 148         val = priv->read_reg(priv, index);
 149         val |= ((u32)priv->read_reg(priv, index + 1)) << 16;
 150
 151         return val;
 152 }
 153
 154 static void c_can_plat_write_reg32(const struct c_can_priv *priv,
 155                                    enum reg index, u32 val)
 156 {
 157         priv->write_reg(priv, index + 1, val >> 16);
 158         priv->write_reg(priv, index, val);
 159 }
 160
 161 static u32 d_can_plat_read_reg32(const struct c_can_priv *priv, enum reg index)
 162 {
 163         return readl(priv->base + priv->regs[index]);
 164 }
 165
 166 static void d_can_plat_write_reg32(const struct c_can_priv *priv,
 167                                    enum reg index, u32 val)
 168 {
 169         writel(val, priv->base + priv->regs[index]);
 170 }
 171
 172 static void c_can_hw_raminit_wait(const struct c_can_priv *priv, u32 mask)
 173 {
 174         while (priv->read_reg32(priv, C_CAN_FUNCTION_REG) & mask)
 175                 udelay(1);
 176 }
 177
 178 static void c_can_hw_raminit(const struct c_can_priv *priv, bool enable)
 179 {
 180         u32 ctrl;
 181
 182         ctrl = priv->read_reg32(priv, C_CAN_FUNCTION_REG);
 183         ctrl &= ~DCAN_RAM_INIT_BIT;
 184         priv->write_reg32(priv, C_CAN_FUNCTION_REG, ctrl);
 185         c_can_hw_raminit_wait(priv, ctrl);
 186
 187         if (enable) {
 188                 ctrl |= DCAN_RAM_INIT_BIT;
 189                 priv->write_reg32(priv, C_CAN_FUNCTION_REG, ctrl);
 190                 c_can_hw_raminit_wait(priv, ctrl);
 191         }
 192 }
 193
 194 static const struct c_can_driver_data c_can_drvdata = {
 195         .id = BOSCH_C_CAN,
 196 };
 197
 198 static const struct c_can_driver_data d_can_drvdata = {
 199         .id = BOSCH_D_CAN,
 200 };
 201
 202 static const struct raminit_bits dra7_raminit_bits[] = {
 203         [0] = { .start = 3, .done = 1, },
 204         [1] = { .start = 5, .done = 2, },
 205 };
 206
 207 static const struct c_can_driver_data dra7_dcan_drvdata = {
 208         .id = BOSCH_D_CAN,
 209         .raminit_num = ARRAY_SIZE(dra7_raminit_bits),
 210         .raminit_bits = dra7_raminit_bits,
 211         .raminit_pulse = true,
 212 };
 213
 214 static const struct raminit_bits am3352_raminit_bits[] = {
 215         [0] = { .start = 0, .done = 8, },
 216         [1] = { .start = 1, .done = 9, },
 217 };
 218
 219 static const struct c_can_driver_data am3352_dcan_drvdata = {
 220         .id = BOSCH_D_CAN,
 221         .raminit_num = ARRAY_SIZE(am3352_raminit_bits),
 222         .raminit_bits = am3352_raminit_bits,
 223 };
 224
 225 static const struct platform_device_id c_can_id_table[] = {
 226         {
 227                 .name = KBUILD_MODNAME,
 228                 .driver_data = (kernel_ulong_t)&c_can_drvdata,
 229         },
 230         {
 231                 .name = "c_can",
 232                 .driver_data = (kernel_ulong_t)&c_can_drvdata,
 233         },
 234         {
 235                 .name = "d_can",
 236                 .driver_data = (kernel_ulong_t)&d_can_drvdata,
 237         },
 238         { /* sentinel */ },
 239 };
 240 MODULE_DEVICE_TABLE(platform, c_can_id_table);
 241
 242 static const struct of_device_id c_can_of_table[] = {
 243         { .compatible = "bosch,c_can", .data = &c_can_drvdata },
 244         { .compatible = "bosch,d_can", .data = &d_can_drvdata },
 245         { .compatible = "ti,dra7-d_can", .data = &dra7_dcan_drvdata },
 246         { .compatible = "ti,am3352-d_can", .data = &am3352_dcan_drvdata },
 247         { .compatible = "ti,am4372-d_can", .data = &am3352_dcan_drvdata },
 248         { /* sentinel */ },
 249 };
 250 MODULE_DEVICE_TABLE(of, c_can_of_table);
 251
 252 static int c_can_plat_probe(struct platform_device *pdev)
 253 {
 254         int ret;
 255         void __iomem *addr;
 256         struct net_device *dev;
 257         struct c_can_priv *priv;
 258         const struct of_device_id *match;
 259         struct resource *mem;
 260         int irq;
 261         struct clk *clk;
 262         const struct c_can_driver_data *drvdata;
 263         struct device_node *np = pdev->dev.of_node;
 264
 265         match = of_match_device(c_can_of_table, &pdev->dev);
 266         if (match) {
 267                 drvdata = match->data;
 268         } else if (pdev->id_entry->driver_data) {
 269                 drvdata = (struct c_can_driver_data *)
 270                         platform_get_device_id(pdev)->driver_data;
 271         } else {
 272                 return -ENODEV;
 273         }
 274
 275         /* get the appropriate clk */
 276         clk = devm_clk_get(&pdev->dev, NULL);
 277         if (IS_ERR(clk)) {
 278                 ret = PTR_ERR(clk);
 279                 goto exit;
 280         }
 281
 282         /* get the platform data */
 283         irq = platform_get_irq(pdev, 0);
 284         if (irq <= 0) {
 285                 ret = -ENODEV;
 286                 goto exit;
 287         }
 288
 289         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 290         addr = devm_ioremap_resource(&pdev->dev, mem);
 291         if (IS_ERR(addr)) {
 292                 ret =  PTR_ERR(addr);
 293                 goto exit;
 294         }
 295
 296         /* allocate the c_can device */
 297         dev = alloc_c_can_dev();
 298         if (!dev) {
 299                 ret = -ENOMEM;
 300                 goto exit;
 301         }
 302
 303         priv = netdev_priv(dev);
 304         switch (drvdata->id) {
 305         case BOSCH_C_CAN:
 306                 priv->regs = reg_map_c_can;
 307                 switch (mem->flags & IORESOURCE_MEM_TYPE_MASK) {
 308                 case IORESOURCE_MEM_32BIT:
 309                         priv->read_reg = c_can_plat_read_reg_aligned_to_32bit;
 310                         priv->write_reg = c_can_plat_write_reg_aligned_to_32bit;
 311                         priv->read_reg32 = c_can_plat_read_reg32;
 312                         priv->write_reg32 = c_can_plat_write_reg32;
 313                         break;
 314                 case IORESOURCE_MEM_16BIT:
 315                 default:
 316                         priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
 317                         priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
 318                         priv->read_reg32 = c_can_plat_read_reg32;
 319                         priv->write_reg32 = c_can_plat_write_reg32;
 320                         break;
 321                 }
 322                 break;
 323         case BOSCH_D_CAN:
 324                 priv->regs = reg_map_d_can;
 325                 priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
 326                 priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
 327                 priv->read_reg32 = d_can_plat_read_reg32;
 328                 priv->write_reg32 = d_can_plat_write_reg32;
 329
 330                 /* Check if we need custom RAMINIT via syscon. Mostly for TI
 331                  * platforms. Only supported with DT boot.
 332                  */
 333                 if (np && of_property_read_bool(np, "syscon-raminit")) {
 334                         u32 id;
 335                         struct c_can_raminit *raminit = &priv->raminit_sys;
 336
 337                         ret = -EINVAL;
 338                         raminit->syscon = syscon_regmap_lookup_by_phandle(np,
 339                                                                           "syscon-raminit");
 340                         if (IS_ERR(raminit->syscon)) {
 341                                 /* can fail with -EPROBE_DEFER */
 342                                 ret = PTR_ERR(raminit->syscon);
 343                                 free_c_can_dev(dev);
 344                                 return ret;
 345                         }
 346
 347                         if (of_property_read_u32_index(np, "syscon-raminit", 1,
 348                                                        &raminit->reg)) {
 349                                 dev_err(&pdev->dev,
 350                                         "couldn't get the RAMINIT reg. offset!\n");
 351                                 goto exit_free_device;
 352                         }
 353
 354                         if (of_property_read_u32_index(np, "syscon-raminit", 2,
 355                                                        &id)) {
 356                                 dev_err(&pdev->dev,
 357                                         "couldn't get the CAN instance ID\n");
 358                                 goto exit_free_device;
 359                         }
 360
 361                         if (id >= drvdata->raminit_num) {
 362                                 dev_err(&pdev->dev,
 363                                         "Invalid CAN instance ID\n");
 364                                 goto exit_free_device;
 365                         }
 366
 367                         raminit->bits = drvdata->raminit_bits[id];
 368                         raminit->needs_pulse = drvdata->raminit_pulse;
 369
 370                         priv->raminit = c_can_hw_raminit_syscon;
 371                 } else {
 372                         priv->raminit = c_can_hw_raminit;
 373                 }
 374                 break;
 375         default:
 376                 ret = -EINVAL;
 377                 goto exit_free_device;
 378         }
 379
 380         dev->irq = irq;
 381         priv->base = addr;
 382         priv->device = &pdev->dev;
 383         priv->can.clock.freq = clk_get_rate(clk);
 384         priv->priv = clk;
 385         priv->type = drvdata->id;
 386
 387         platform_set_drvdata(pdev, dev);
 388         SET_NETDEV_DEV(dev, &pdev->dev);
 389
 390         pm_runtime_enable(priv->device);
 391         ret = register_c_can_dev(dev);
 392         if (ret) {
 393                 dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
 394                         KBUILD_MODNAME, ret);
 395                 goto exit_free_device;
 396         }
 397
 398         dev_info(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
 399                  KBUILD_MODNAME, priv->base, dev->irq);
 400         return 0;
 401
 402 exit_free_device:
 403         pm_runtime_disable(priv->device);
 404         free_c_can_dev(dev);
 405 exit:
 406         dev_err(&pdev->dev, "probe failed\n");
 407
 408         return ret;
 409 }
 410
 411 static int c_can_plat_remove(struct platform_device *pdev)
 412 {
 413         struct net_device *dev = platform_get_drvdata(pdev);
 414         struct c_can_priv *priv = netdev_priv(dev);
 415
 416         unregister_c_can_dev(dev);
 417         pm_runtime_disable(priv->device);
 418         free_c_can_dev(dev);
 419
 420         return 0;
 421 }
 422
 423 #ifdef CONFIG_PM
 424 static int c_can_suspend(struct platform_device *pdev, pm_message_t state)
 425 {
 426         int ret;
 427         struct net_device *ndev = platform_get_drvdata(pdev);
 428         struct c_can_priv *priv = netdev_priv(ndev);
 429
 430         if (priv->type != BOSCH_D_CAN) {
 431                 dev_warn(&pdev->dev, "Not supported\n");
 432                 return 0;
 433         }
 434
 435         if (netif_running(ndev)) {
 436                 netif_stop_queue(ndev);
 437                 netif_device_detach(ndev);
 438         }
 439
 440         ret = c_can_power_down(ndev);
 441         if (ret) {
 442                 netdev_err(ndev, "failed to enter power down mode\n");
 443                 return ret;
 444         }
 445
 446         priv->can.state = CAN_STATE_SLEEPING;
 447
 448         return 0;
 449 }
 450
 451 static int c_can_resume(struct platform_device *pdev)
 452 {
 453         int ret;
 454         struct net_device *ndev = platform_get_drvdata(pdev);
 455         struct c_can_priv *priv = netdev_priv(ndev);
 456
 457         if (priv->type != BOSCH_D_CAN) {
 458                 dev_warn(&pdev->dev, "Not supported\n");
 459                 return 0;
 460         }
 461
 462         ret = c_can_power_up(ndev);
 463         if (ret) {
 464                 netdev_err(ndev, "Still in power down mode\n");
 465                 return ret;
 466         }
 467
 468         priv->can.state = CAN_STATE_ERROR_ACTIVE;
 469
 470         if (netif_running(ndev)) {
 471                 netif_device_attach(ndev);
 472                 netif_start_queue(ndev);
 473         }
 474
 475         return 0;
 476 }
 477 #else
 478 #define c_can_suspend NULL
 479 #define c_can_resume NULL
 480 #endif
 481
 482 static struct platform_driver c_can_plat_driver = {
 483         .driver = {
 484                 .name = KBUILD_MODNAME,
 485                 .of_match_table = c_can_of_table,
 486         },
 487         .probe = c_can_plat_probe,
 488         .remove = c_can_plat_remove,
 489         .suspend = c_can_suspend,
 490         .resume = c_can_resume,
 491         .id_table = c_can_id_table,
 492 };
 493
 494 module_platform_driver(c_can_plat_driver);
 495
 496 MODULE_AUTHOR("Bhupesh Sharma <bhupesh.sharma@st.com>");
 497 MODULE_LICENSE("GPL v2");
 498 MODULE_DESCRIPTION("Platform CAN bus driver for Bosch C_CAN controller");