drivers/net/can/mscan/mpc5xxx_can.c

   1 /*
   2  * CAN bus driver for the Freescale MPC5xxx embedded CPU.
   3  *
   4  * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>,
   5  *                         Varma Electronics Oy
   6  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   7  * Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the version 2 of the GNU General Public License
  11  * as published by the Free Software Foundation
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/can/dev.h>
  28 #include <linux/of_platform.h>
  29 #include <sysdev/fsl_soc.h>
  30 #include <linux/clk.h>
  31 #include <linux/io.h>
  32 #include <asm/mpc52xx.h>
  33
  34 #include "mscan.h"
  35
  36 #define DRV_NAME "mpc5xxx_can"
  37
  38 struct mpc5xxx_can_data {
  39         unsigned int type;
  40         u32 (*get_clock)(struct platform_device *ofdev, const char *clock_name,
  41                          int *mscan_clksrc);
  42         void (*put_clock)(struct platform_device *ofdev);
  43 };
  44
  45 #ifdef CONFIG_PPC_MPC52xx
  46 static struct of_device_id mpc52xx_cdm_ids[] = {
  47         { .compatible = "fsl,mpc5200-cdm", },
  48         {}
  49 };
  50
  51 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
  52                                  const char *clock_name, int *mscan_clksrc)
  53 {
  54         unsigned int pvr;
  55         struct mpc52xx_cdm  __iomem *cdm;
  56         struct device_node *np_cdm;
  57         unsigned int freq;
  58         u32 val;
  59
  60         pvr = mfspr(SPRN_PVR);
  61
  62         /*
  63          * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
  64          * (IP_CLK) can be selected as MSCAN clock source. According to
  65          * the MPC5200 user's manual, the oscillator clock is the better
  66          * choice as it has less jitter. For this reason, it is selected
  67          * by default. Unfortunately, it can not be selected for the old
  68          * MPC5200 Rev. A chips due to a hardware bug (check errata).
  69          */
  70         if (clock_name && strcmp(clock_name, "ip") == 0)
  71                 *mscan_clksrc = MSCAN_CLKSRC_BUS;
  72         else
  73                 *mscan_clksrc = MSCAN_CLKSRC_XTAL;
  74
  75         freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node);
  76         if (!freq)
  77                 return 0;
  78
  79         if (*mscan_clksrc == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
  80                 return freq;
  81
  82         /* Determine SYS_XTAL_IN frequency from the clock domain settings */
  83         np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids);
  84         if (!np_cdm) {
  85                 dev_err(&ofdev->dev, "can't get clock node!\n");
  86                 return 0;
  87         }
  88         cdm = of_iomap(np_cdm, 0);
  89
  90         if (in_8(&cdm->ipb_clk_sel) & 0x1)
  91                 freq *= 2;
  92         val = in_be32(&cdm->rstcfg);
  93
  94         freq *= (val & (1 << 5)) ? 8 : 4;
  95         freq /= (val & (1 << 6)) ? 12 : 16;
  96
  97         of_node_put(np_cdm);
  98         iounmap(cdm);
  99
 100         return freq;
 101 }
 102 #else /* !CONFIG_PPC_MPC52xx */
 103 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
 104                                  const char *clock_name, int *mscan_clksrc)
 105 {
 106         return 0;
 107 }
 108 #endif /* CONFIG_PPC_MPC52xx */
 109
 110 #ifdef CONFIG_PPC_MPC512x
 111 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
 112                                  const char *clock_source, int *mscan_clksrc)
 113 {
 114         struct device_node *np;
 115         u32 clockdiv;
 116         enum {
 117                 CLK_FROM_AUTO,
 118                 CLK_FROM_IPS,
 119                 CLK_FROM_SYS,
 120                 CLK_FROM_REF,
 121         } clk_from;
 122         struct clk *clk_in, *clk_can;
 123         unsigned long freq_calc;
 124         struct mscan_priv *priv;
 125         struct clk *clk_ipg;
 126
 127         /* the caller passed in the clock source spec that was read from
 128          * the device tree, get the optional clock divider as well
 129          */
 130         np = ofdev->dev.of_node;
 131         clockdiv = 1;
 132         of_property_read_u32(np, "fsl,mscan-clock-divider", &clockdiv);
 133         dev_dbg(&ofdev->dev, "device tree specs: clk src[%s] div[%d]\n",
 134                 clock_source ? clock_source : "<NULL>", clockdiv);
 135
 136         /* when clock-source is 'ip', the CANCTL1[CLKSRC] bit needs to
 137          * get set, and the 'ips' clock is the input to the MSCAN
 138          * component
 139          *
 140          * for clock-source values of 'ref' or 'sys' the CANCTL1[CLKSRC]
 141          * bit needs to get cleared, an optional clock-divider may have
 142          * been specified (the default value is 1), the appropriate
 143          * MSCAN related MCLK is the input to the MSCAN component
 144          *
 145          * in the absence of a clock-source spec, first an optimal clock
 146          * gets determined based on the 'sys' clock, if that fails the
 147          * 'ref' clock is used
 148          */
 149         clk_from = CLK_FROM_AUTO;
 150         if (clock_source) {
 151                 /* interpret the device tree's spec for the clock source */
 152                 if (!strcmp(clock_source, "ip"))
 153                         clk_from = CLK_FROM_IPS;
 154                 else if (!strcmp(clock_source, "sys"))
 155                         clk_from = CLK_FROM_SYS;
 156                 else if (!strcmp(clock_source, "ref"))
 157                         clk_from = CLK_FROM_REF;
 158                 else
 159                         goto err_invalid;
 160                 dev_dbg(&ofdev->dev, "got a clk source spec[%d]\n", clk_from);
 161         }
 162         if (clk_from == CLK_FROM_AUTO) {
 163                 /* no spec so far, try the 'sys' clock; round to the
 164                  * next MHz and see if we can get a multiple of 16MHz
 165                  */
 166                 dev_dbg(&ofdev->dev, "no clk source spec, trying SYS\n");
 167                 clk_in = devm_clk_get(&ofdev->dev, "sys");
 168                 if (IS_ERR(clk_in))
 169                         goto err_notavail;
 170                 freq_calc = clk_get_rate(clk_in);
 171                 freq_calc +=  499999;
 172                 freq_calc /= 1000000;
 173                 freq_calc *= 1000000;
 174                 if ((freq_calc % 16000000) == 0) {
 175                         clk_from = CLK_FROM_SYS;
 176                         clockdiv = freq_calc / 16000000;
 177                         dev_dbg(&ofdev->dev,
 178                                 "clk fit, sys[%lu] div[%d] freq[%lu]\n",
 179                                 freq_calc, clockdiv, freq_calc / clockdiv);
 180                 }
 181         }
 182         if (clk_from == CLK_FROM_AUTO) {
 183                 /* no spec so far, use the 'ref' clock */
 184                 dev_dbg(&ofdev->dev, "no clk source spec, trying REF\n");
 185                 clk_in = devm_clk_get(&ofdev->dev, "ref");
 186                 if (IS_ERR(clk_in))
 187                         goto err_notavail;
 188                 clk_from = CLK_FROM_REF;
 189                 freq_calc = clk_get_rate(clk_in);
 190                 dev_dbg(&ofdev->dev,
 191                         "clk fit, ref[%lu] (no div) freq[%lu]\n",
 192                         freq_calc, freq_calc);
 193         }
 194
 195         /* select IPS or MCLK as the MSCAN input (returned to the caller),
 196          * setup the MCLK mux source and rate if applicable, apply the
 197          * optionally specified or derived above divider, and determine
 198          * the actual resulting clock rate to return to the caller
 199          */
 200         switch (clk_from) {
 201         case CLK_FROM_IPS:
 202                 clk_can = devm_clk_get(&ofdev->dev, "ips");
 203                 if (IS_ERR(clk_can))
 204                         goto err_notavail;
 205                 priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 206                 priv->clk_can = clk_can;
 207                 freq_calc = clk_get_rate(clk_can);
 208                 *mscan_clksrc = MSCAN_CLKSRC_IPS;
 209                 dev_dbg(&ofdev->dev, "clk from IPS, clksrc[%d] freq[%lu]\n",
 210                         *mscan_clksrc, freq_calc);
 211                 break;
 212         case CLK_FROM_SYS:
 213         case CLK_FROM_REF:
 214                 clk_can = devm_clk_get(&ofdev->dev, "mclk");
 215                 if (IS_ERR(clk_can))
 216                         goto err_notavail;
 217                 priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 218                 priv->clk_can = clk_can;
 219                 if (clk_from == CLK_FROM_SYS)
 220                         clk_in = devm_clk_get(&ofdev->dev, "sys");
 221                 if (clk_from == CLK_FROM_REF)
 222                         clk_in = devm_clk_get(&ofdev->dev, "ref");
 223                 if (IS_ERR(clk_in))
 224                         goto err_notavail;
 225                 clk_set_parent(clk_can, clk_in);
 226                 freq_calc = clk_get_rate(clk_in);
 227                 freq_calc /= clockdiv;
 228                 clk_set_rate(clk_can, freq_calc);
 229                 freq_calc = clk_get_rate(clk_can);
 230                 *mscan_clksrc = MSCAN_CLKSRC_BUS;
 231                 dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n",
 232                         *mscan_clksrc, freq_calc);
 233                 break;
 234         default:
 235                 goto err_invalid;
 236         }
 237
 238         /* the above clk_can item is used for the bitrate, access to
 239          * the peripheral's register set needs the clk_ipg item
 240          */
 241         clk_ipg = devm_clk_get(&ofdev->dev, "ipg");
 242         if (IS_ERR(clk_ipg))
 243                 goto err_notavail_ipg;
 244         if (clk_prepare_enable(clk_ipg))
 245                 goto err_notavail_ipg;
 246         priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 247         priv->clk_ipg = clk_ipg;
 248
 249         /* return the determined clock source rate */
 250         return freq_calc;
 251
 252 err_invalid:
 253         dev_err(&ofdev->dev, "invalid clock source specification\n");
 254         /* clock source rate could not get determined */
 255         return 0;
 256
 257 err_notavail:
 258         dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n");
 259         /* clock source rate could not get determined */
 260         return 0;
 261
 262 err_notavail_ipg:
 263         dev_err(&ofdev->dev, "cannot acquire or setup register clock\n");
 264         /* clock source rate could not get determined */
 265         return 0;
 266 }
 267
 268 static void mpc512x_can_put_clock(struct platform_device *ofdev)
 269 {
 270         struct mscan_priv *priv;
 271
 272         priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 273         if (priv->clk_ipg)
 274                 clk_disable_unprepare(priv->clk_ipg);
 275 }
 276 #else /* !CONFIG_PPC_MPC512x */
 277 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
 278                                  const char *clock_name, int *mscan_clksrc)
 279 {
 280         return 0;
 281 }
 282 #define mpc512x_can_put_clock NULL
 283 #endif /* CONFIG_PPC_MPC512x */
 284
 285 static const struct of_device_id mpc5xxx_can_table[];
 286 static int mpc5xxx_can_probe(struct platform_device *ofdev)
 287 {
 288         const struct of_device_id *match;
 289         const struct mpc5xxx_can_data *data;
 290         struct device_node *np = ofdev->dev.of_node;
 291         struct net_device *dev;
 292         struct mscan_priv *priv;
 293         void __iomem *base;
 294         const char *clock_name = NULL;
 295         int irq, mscan_clksrc = 0;
 296         int err = -ENOMEM;
 297
 298         match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
 299         if (!match)
 300                 return -EINVAL;
 301         data = match->data;
 302
 303         base = of_iomap(np, 0);
 304         if (!base) {
 305                 dev_err(&ofdev->dev, "couldn't ioremap\n");
 306                 return err;
 307         }
 308
 309         irq = irq_of_parse_and_map(np, 0);
 310         if (!irq) {
 311                 dev_err(&ofdev->dev, "no irq found\n");
 312                 err = -ENODEV;
 313                 goto exit_unmap_mem;
 314         }
 315
 316         dev = alloc_mscandev();
 317         if (!dev)
 318                 goto exit_dispose_irq;
 319         platform_set_drvdata(ofdev, dev);
 320         SET_NETDEV_DEV(dev, &ofdev->dev);
 321
 322         priv = netdev_priv(dev);
 323         priv->reg_base = base;
 324         dev->irq = irq;
 325
 326         clock_name = of_get_property(np, "fsl,mscan-clock-source", NULL);
 327
 328         BUG_ON(!data);
 329         priv->type = data->type;
 330         priv->can.clock.freq = data->get_clock(ofdev, clock_name,
 331                                                &mscan_clksrc);
 332         if (!priv->can.clock.freq) {
 333                 dev_err(&ofdev->dev, "couldn't get MSCAN clock properties\n");
 334                 goto exit_free_mscan;
 335         }
 336
 337         err = register_mscandev(dev, mscan_clksrc);
 338         if (err) {
 339                 dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
 340                         DRV_NAME, err);
 341                 goto exit_free_mscan;
 342         }
 343
 344         dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n",
 345                  priv->reg_base, dev->irq, priv->can.clock.freq);
 346
 347         return 0;
 348
 349 exit_free_mscan:
 350         free_candev(dev);
 351 exit_dispose_irq:
 352         irq_dispose_mapping(irq);
 353 exit_unmap_mem:
 354         iounmap(base);
 355
 356         return err;
 357 }
 358
 359 static int mpc5xxx_can_remove(struct platform_device *ofdev)
 360 {
 361         const struct of_device_id *match;
 362         const struct mpc5xxx_can_data *data;
 363         struct net_device *dev = platform_get_drvdata(ofdev);
 364         struct mscan_priv *priv = netdev_priv(dev);
 365
 366         match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
 367         data = match ? match->data : NULL;
 368
 369         unregister_mscandev(dev);
 370         if (data && data->put_clock)
 371                 data->put_clock(ofdev);
 372         iounmap(priv->reg_base);
 373         irq_dispose_mapping(dev->irq);
 374         free_candev(dev);
 375
 376         return 0;
 377 }
 378
 379 #ifdef CONFIG_PM
 380 static struct mscan_regs saved_regs;
 381 static int mpc5xxx_can_suspend(struct platform_device *ofdev, pm_message_t state)
 382 {
 383         struct net_device *dev = platform_get_drvdata(ofdev);
 384         struct mscan_priv *priv = netdev_priv(dev);
 385         struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
 386
 387         _memcpy_fromio(&saved_regs, regs, sizeof(*regs));
 388
 389         return 0;
 390 }
 391
 392 static int mpc5xxx_can_resume(struct platform_device *ofdev)
 393 {
 394         struct net_device *dev = platform_get_drvdata(ofdev);
 395         struct mscan_priv *priv = netdev_priv(dev);
 396         struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
 397
 398         regs->canctl0 |= MSCAN_INITRQ;
 399         while (!(regs->canctl1 & MSCAN_INITAK))
 400                 udelay(10);
 401
 402         regs->canctl1 = saved_regs.canctl1;
 403         regs->canbtr0 = saved_regs.canbtr0;
 404         regs->canbtr1 = saved_regs.canbtr1;
 405         regs->canidac = saved_regs.canidac;
 406
 407         /* restore masks, buffers etc. */
 408         _memcpy_toio(&regs->canidar1_0, (void *)&saved_regs.canidar1_0,
 409                      sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0));
 410
 411         regs->canctl0 &= ~MSCAN_INITRQ;
 412         regs->cantbsel = saved_regs.cantbsel;
 413         regs->canrier = saved_regs.canrier;
 414         regs->cantier = saved_regs.cantier;
 415         regs->canctl0 = saved_regs.canctl0;
 416
 417         return 0;
 418 }
 419 #endif
 420
 421 static const struct mpc5xxx_can_data mpc5200_can_data = {
 422         .type = MSCAN_TYPE_MPC5200,
 423         .get_clock = mpc52xx_can_get_clock,
 424         /* .put_clock not applicable */
 425 };
 426
 427 static const struct mpc5xxx_can_data mpc5121_can_data = {
 428         .type = MSCAN_TYPE_MPC5121,
 429         .get_clock = mpc512x_can_get_clock,
 430         .put_clock = mpc512x_can_put_clock,
 431 };
 432
 433 static const struct of_device_id mpc5xxx_can_table[] = {
 434         { .compatible = "fsl,mpc5200-mscan", .data = &mpc5200_can_data, },
 435         /* Note that only MPC5121 Rev. 2 (and later) is supported */
 436         { .compatible = "fsl,mpc5121-mscan", .data = &mpc5121_can_data, },
 437         {},
 438 };
 439 MODULE_DEVICE_TABLE(of, mpc5xxx_can_table);
 440
 441 static struct platform_driver mpc5xxx_can_driver = {
 442         .driver = {
 443                 .name = "mpc5xxx_can",
 444                 .of_match_table = mpc5xxx_can_table,
 445         },
 446         .probe = mpc5xxx_can_probe,
 447         .remove = mpc5xxx_can_remove,
 448 #ifdef CONFIG_PM
 449         .suspend = mpc5xxx_can_suspend,
 450         .resume = mpc5xxx_can_resume,
 451 #endif
 452 };
 453
 454 module_platform_driver(mpc5xxx_can_driver);
 455
 456 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 457 MODULE_DESCRIPTION("Freescale MPC5xxx CAN driver");
 458 MODULE_LICENSE("GPL v2");