drivers/net/can/mscan/mpc5xxx_can.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CAN bus driver for the Freescale MPC5xxx embedded CPU.
   4  *
   5  * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>,
   6  *                         Varma Electronics Oy
   7  * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
   8  * Copyright (C) 2009 Wolfram Sang, Pengutronix <kernel@pengutronix.de>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/can/dev.h>
  17 #include <linux/of_platform.h>
  18 #include <sysdev/fsl_soc.h>
  19 #include <linux/clk.h>
  20 #include <linux/io.h>
  21 #include <asm/mpc52xx.h>
  22
  23 #include "mscan.h"
  24
  25 #define DRV_NAME "mpc5xxx_can"
  26
  27 struct mpc5xxx_can_data {
  28         unsigned int type;
  29         u32 (*get_clock)(struct platform_device *ofdev, const char *clock_name,
  30                          int *mscan_clksrc);
  31         void (*put_clock)(struct platform_device *ofdev);
  32 };
  33
  34 #ifdef CONFIG_PPC_MPC52xx
  35 static const struct of_device_id mpc52xx_cdm_ids[] = {
  36         { .compatible = "fsl,mpc5200-cdm", },
  37         {}
  38 };
  39
  40 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
  41                                  const char *clock_name, int *mscan_clksrc)
  42 {
  43         unsigned int pvr;
  44         struct mpc52xx_cdm  __iomem *cdm;
  45         struct device_node *np_cdm;
  46         unsigned int freq;
  47         u32 val;
  48
  49         pvr = mfspr(SPRN_PVR);
  50
  51         /*
  52          * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock
  53          * (IP_CLK) can be selected as MSCAN clock source. According to
  54          * the MPC5200 user's manual, the oscillator clock is the better
  55          * choice as it has less jitter. For this reason, it is selected
  56          * by default. Unfortunately, it can not be selected for the old
  57          * MPC5200 Rev. A chips due to a hardware bug (check errata).
  58          */
  59         if (clock_name && strcmp(clock_name, "ip") == 0)
  60                 *mscan_clksrc = MSCAN_CLKSRC_BUS;
  61         else
  62                 *mscan_clksrc = MSCAN_CLKSRC_XTAL;
  63
  64         freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node);
  65         if (!freq)
  66                 return 0;
  67
  68         if (*mscan_clksrc == MSCAN_CLKSRC_BUS || pvr == 0x80822011)
  69                 return freq;
  70
  71         /* Determine SYS_XTAL_IN frequency from the clock domain settings */
  72         np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids);
  73         if (!np_cdm) {
  74                 dev_err(&ofdev->dev, "can't get clock node!\n");
  75                 return 0;
  76         }
  77         cdm = of_iomap(np_cdm, 0);
  78         if (!cdm) {
  79                 of_node_put(np_cdm);
  80                 dev_err(&ofdev->dev, "can't map clock node!\n");
  81                 return 0;
  82         }
  83
  84         if (in_8(&cdm->ipb_clk_sel) & 0x1)
  85                 freq *= 2;
  86         val = in_be32(&cdm->rstcfg);
  87
  88         freq *= (val & (1 << 5)) ? 8 : 4;
  89         freq /= (val & (1 << 6)) ? 12 : 16;
  90
  91         of_node_put(np_cdm);
  92         iounmap(cdm);
  93
  94         return freq;
  95 }
  96 #else /* !CONFIG_PPC_MPC52xx */
  97 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
  98                                  const char *clock_name, int *mscan_clksrc)
  99 {
 100         return 0;
 101 }
 102 #endif /* CONFIG_PPC_MPC52xx */
 103
 104 #ifdef CONFIG_PPC_MPC512x
 105 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
 106                                  const char *clock_source, int *mscan_clksrc)
 107 {
 108         struct device_node *np;
 109         u32 clockdiv;
 110         enum {
 111                 CLK_FROM_AUTO,
 112                 CLK_FROM_IPS,
 113                 CLK_FROM_SYS,
 114                 CLK_FROM_REF,
 115         } clk_from;
 116         struct clk *clk_in, *clk_can;
 117         unsigned long freq_calc;
 118         struct mscan_priv *priv;
 119         struct clk *clk_ipg;
 120
 121         /* the caller passed in the clock source spec that was read from
 122          * the device tree, get the optional clock divider as well
 123          */
 124         np = ofdev->dev.of_node;
 125         clockdiv = 1;
 126         of_property_read_u32(np, "fsl,mscan-clock-divider", &clockdiv);
 127         dev_dbg(&ofdev->dev, "device tree specs: clk src[%s] div[%d]\n",
 128                 clock_source ? clock_source : "<NULL>", clockdiv);
 129
 130         /* when clock-source is 'ip', the CANCTL1[CLKSRC] bit needs to
 131          * get set, and the 'ips' clock is the input to the MSCAN
 132          * component
 133          *
 134          * for clock-source values of 'ref' or 'sys' the CANCTL1[CLKSRC]
 135          * bit needs to get cleared, an optional clock-divider may have
 136          * been specified (the default value is 1), the appropriate
 137          * MSCAN related MCLK is the input to the MSCAN component
 138          *
 139          * in the absence of a clock-source spec, first an optimal clock
 140          * gets determined based on the 'sys' clock, if that fails the
 141          * 'ref' clock is used
 142          */
 143         clk_from = CLK_FROM_AUTO;
 144         if (clock_source) {
 145                 /* interpret the device tree's spec for the clock source */
 146                 if (!strcmp(clock_source, "ip"))
 147                         clk_from = CLK_FROM_IPS;
 148                 else if (!strcmp(clock_source, "sys"))
 149                         clk_from = CLK_FROM_SYS;
 150                 else if (!strcmp(clock_source, "ref"))
 151                         clk_from = CLK_FROM_REF;
 152                 else
 153                         goto err_invalid;
 154                 dev_dbg(&ofdev->dev, "got a clk source spec[%d]\n", clk_from);
 155         }
 156         if (clk_from == CLK_FROM_AUTO) {
 157                 /* no spec so far, try the 'sys' clock; round to the
 158                  * next MHz and see if we can get a multiple of 16MHz
 159                  */
 160                 dev_dbg(&ofdev->dev, "no clk source spec, trying SYS\n");
 161                 clk_in = devm_clk_get(&ofdev->dev, "sys");
 162                 if (IS_ERR(clk_in))
 163                         goto err_notavail;
 164                 freq_calc = clk_get_rate(clk_in);
 165                 freq_calc +=  499999;
 166                 freq_calc /= 1000000;
 167                 freq_calc *= 1000000;
 168                 if ((freq_calc % 16000000) == 0) {
 169                         clk_from = CLK_FROM_SYS;
 170                         clockdiv = freq_calc / 16000000;
 171                         dev_dbg(&ofdev->dev,
 172                                 "clk fit, sys[%lu] div[%d] freq[%lu]\n",
 173                                 freq_calc, clockdiv, freq_calc / clockdiv);
 174                 }
 175         }
 176         if (clk_from == CLK_FROM_AUTO) {
 177                 /* no spec so far, use the 'ref' clock */
 178                 dev_dbg(&ofdev->dev, "no clk source spec, trying REF\n");
 179                 clk_in = devm_clk_get(&ofdev->dev, "ref");
 180                 if (IS_ERR(clk_in))
 181                         goto err_notavail;
 182                 clk_from = CLK_FROM_REF;
 183                 freq_calc = clk_get_rate(clk_in);
 184                 dev_dbg(&ofdev->dev,
 185                         "clk fit, ref[%lu] (no div) freq[%lu]\n",
 186                         freq_calc, freq_calc);
 187         }
 188
 189         /* select IPS or MCLK as the MSCAN input (returned to the caller),
 190          * setup the MCLK mux source and rate if applicable, apply the
 191          * optionally specified or derived above divider, and determine
 192          * the actual resulting clock rate to return to the caller
 193          */
 194         switch (clk_from) {
 195         case CLK_FROM_IPS:
 196                 clk_can = devm_clk_get(&ofdev->dev, "ips");
 197                 if (IS_ERR(clk_can))
 198                         goto err_notavail;
 199                 priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 200                 priv->clk_can = clk_can;
 201                 freq_calc = clk_get_rate(clk_can);
 202                 *mscan_clksrc = MSCAN_CLKSRC_IPS;
 203                 dev_dbg(&ofdev->dev, "clk from IPS, clksrc[%d] freq[%lu]\n",
 204                         *mscan_clksrc, freq_calc);
 205                 break;
 206         case CLK_FROM_SYS:
 207         case CLK_FROM_REF:
 208                 clk_can = devm_clk_get(&ofdev->dev, "mclk");
 209                 if (IS_ERR(clk_can))
 210                         goto err_notavail;
 211                 priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 212                 priv->clk_can = clk_can;
 213                 if (clk_from == CLK_FROM_SYS)
 214                         clk_in = devm_clk_get(&ofdev->dev, "sys");
 215                 if (clk_from == CLK_FROM_REF)
 216                         clk_in = devm_clk_get(&ofdev->dev, "ref");
 217                 if (IS_ERR(clk_in))
 218                         goto err_notavail;
 219                 clk_set_parent(clk_can, clk_in);
 220                 freq_calc = clk_get_rate(clk_in);
 221                 freq_calc /= clockdiv;
 222                 clk_set_rate(clk_can, freq_calc);
 223                 freq_calc = clk_get_rate(clk_can);
 224                 *mscan_clksrc = MSCAN_CLKSRC_BUS;
 225                 dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n",
 226                         *mscan_clksrc, freq_calc);
 227                 break;
 228         default:
 229                 goto err_invalid;
 230         }
 231
 232         /* the above clk_can item is used for the bitrate, access to
 233          * the peripheral's register set needs the clk_ipg item
 234          */
 235         clk_ipg = devm_clk_get(&ofdev->dev, "ipg");
 236         if (IS_ERR(clk_ipg))
 237                 goto err_notavail_ipg;
 238         if (clk_prepare_enable(clk_ipg))
 239                 goto err_notavail_ipg;
 240         priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 241         priv->clk_ipg = clk_ipg;
 242
 243         /* return the determined clock source rate */
 244         return freq_calc;
 245
 246 err_invalid:
 247         dev_err(&ofdev->dev, "invalid clock source specification\n");
 248         /* clock source rate could not get determined */
 249         return 0;
 250
 251 err_notavail:
 252         dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n");
 253         /* clock source rate could not get determined */
 254         return 0;
 255
 256 err_notavail_ipg:
 257         dev_err(&ofdev->dev, "cannot acquire or setup register clock\n");
 258         /* clock source rate could not get determined */
 259         return 0;
 260 }
 261
 262 static void mpc512x_can_put_clock(struct platform_device *ofdev)
 263 {
 264         struct mscan_priv *priv;
 265
 266         priv = netdev_priv(dev_get_drvdata(&ofdev->dev));
 267         if (priv->clk_ipg)
 268                 clk_disable_unprepare(priv->clk_ipg);
 269 }
 270 #else /* !CONFIG_PPC_MPC512x */
 271 static u32 mpc512x_can_get_clock(struct platform_device *ofdev,
 272                                  const char *clock_name, int *mscan_clksrc)
 273 {
 274         return 0;
 275 }
 276 #define mpc512x_can_put_clock NULL
 277 #endif /* CONFIG_PPC_MPC512x */
 278
 279 static const struct of_device_id mpc5xxx_can_table[];
 280 static int mpc5xxx_can_probe(struct platform_device *ofdev)
 281 {
 282         const struct of_device_id *match;
 283         const struct mpc5xxx_can_data *data;
 284         struct device_node *np = ofdev->dev.of_node;
 285         struct net_device *dev;
 286         struct mscan_priv *priv;
 287         void __iomem *base;
 288         const char *clock_name = NULL;
 289         int irq, mscan_clksrc = 0;
 290         int err = -ENOMEM;
 291
 292         match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
 293         if (!match)
 294                 return -EINVAL;
 295         data = match->data;
 296
 297         base = of_iomap(np, 0);
 298         if (!base) {
 299                 dev_err(&ofdev->dev, "couldn't ioremap\n");
 300                 return err;
 301         }
 302
 303         irq = irq_of_parse_and_map(np, 0);
 304         if (!irq) {
 305                 dev_err(&ofdev->dev, "no irq found\n");
 306                 err = -ENODEV;
 307                 goto exit_unmap_mem;
 308         }
 309
 310         dev = alloc_mscandev();
 311         if (!dev)
 312                 goto exit_dispose_irq;
 313         platform_set_drvdata(ofdev, dev);
 314         SET_NETDEV_DEV(dev, &ofdev->dev);
 315
 316         priv = netdev_priv(dev);
 317         priv->reg_base = base;
 318         dev->irq = irq;
 319
 320         clock_name = of_get_property(np, "fsl,mscan-clock-source", NULL);
 321
 322         BUG_ON(!data);
 323         priv->type = data->type;
 324         priv->can.clock.freq = data->get_clock(ofdev, clock_name,
 325                                                &mscan_clksrc);
 326         if (!priv->can.clock.freq) {
 327                 dev_err(&ofdev->dev, "couldn't get MSCAN clock properties\n");
 328                 goto exit_free_mscan;
 329         }
 330
 331         err = register_mscandev(dev, mscan_clksrc);
 332         if (err) {
 333                 dev_err(&ofdev->dev, "registering %s failed (err=%d)\n",
 334                         DRV_NAME, err);
 335                 goto exit_free_mscan;
 336         }
 337
 338         dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n",
 339                  priv->reg_base, dev->irq, priv->can.clock.freq);
 340
 341         return 0;
 342
 343 exit_free_mscan:
 344         free_candev(dev);
 345 exit_dispose_irq:
 346         irq_dispose_mapping(irq);
 347 exit_unmap_mem:
 348         iounmap(base);
 349
 350         return err;
 351 }
 352
 353 static int mpc5xxx_can_remove(struct platform_device *ofdev)
 354 {
 355         const struct of_device_id *match;
 356         const struct mpc5xxx_can_data *data;
 357         struct net_device *dev = platform_get_drvdata(ofdev);
 358         struct mscan_priv *priv = netdev_priv(dev);
 359
 360         match = of_match_device(mpc5xxx_can_table, &ofdev->dev);
 361         data = match ? match->data : NULL;
 362
 363         unregister_mscandev(dev);
 364         if (data && data->put_clock)
 365                 data->put_clock(ofdev);
 366         iounmap(priv->reg_base);
 367         irq_dispose_mapping(dev->irq);
 368         free_candev(dev);
 369
 370         return 0;
 371 }
 372
 373 #ifdef CONFIG_PM
 374 static struct mscan_regs saved_regs;
 375 static int mpc5xxx_can_suspend(struct platform_device *ofdev, pm_message_t state)
 376 {
 377         struct net_device *dev = platform_get_drvdata(ofdev);
 378         struct mscan_priv *priv = netdev_priv(dev);
 379         struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
 380
 381         _memcpy_fromio(&saved_regs, regs, sizeof(*regs));
 382
 383         return 0;
 384 }
 385
 386 static int mpc5xxx_can_resume(struct platform_device *ofdev)
 387 {
 388         struct net_device *dev = platform_get_drvdata(ofdev);
 389         struct mscan_priv *priv = netdev_priv(dev);
 390         struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
 391
 392         regs->canctl0 |= MSCAN_INITRQ;
 393         while (!(regs->canctl1 & MSCAN_INITAK))
 394                 udelay(10);
 395
 396         regs->canctl1 = saved_regs.canctl1;
 397         regs->canbtr0 = saved_regs.canbtr0;
 398         regs->canbtr1 = saved_regs.canbtr1;
 399         regs->canidac = saved_regs.canidac;
 400
 401         /* restore masks, buffers etc. */
 402         _memcpy_toio(&regs->canidar1_0, (void *)&saved_regs.canidar1_0,
 403                      sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0));
 404
 405         regs->canctl0 &= ~MSCAN_INITRQ;
 406         regs->cantbsel = saved_regs.cantbsel;
 407         regs->canrier = saved_regs.canrier;
 408         regs->cantier = saved_regs.cantier;
 409         regs->canctl0 = saved_regs.canctl0;
 410
 411         return 0;
 412 }
 413 #endif
 414
 415 static const struct mpc5xxx_can_data mpc5200_can_data = {
 416         .type = MSCAN_TYPE_MPC5200,
 417         .get_clock = mpc52xx_can_get_clock,
 418         /* .put_clock not applicable */
 419 };
 420
 421 static const struct mpc5xxx_can_data mpc5121_can_data = {
 422         .type = MSCAN_TYPE_MPC5121,
 423         .get_clock = mpc512x_can_get_clock,
 424         .put_clock = mpc512x_can_put_clock,
 425 };
 426
 427 static const struct of_device_id mpc5xxx_can_table[] = {
 428         { .compatible = "fsl,mpc5200-mscan", .data = &mpc5200_can_data, },
 429         /* Note that only MPC5121 Rev. 2 (and later) is supported */
 430         { .compatible = "fsl,mpc5121-mscan", .data = &mpc5121_can_data, },
 431         {},
 432 };
 433 MODULE_DEVICE_TABLE(of, mpc5xxx_can_table);
 434
 435 static struct platform_driver mpc5xxx_can_driver = {
 436         .driver = {
 437                 .name = "mpc5xxx_can",
 438                 .of_match_table = mpc5xxx_can_table,
 439         },
 440         .probe = mpc5xxx_can_probe,
 441         .remove = mpc5xxx_can_remove,
 442 #ifdef CONFIG_PM
 443         .suspend = mpc5xxx_can_suspend,
 444         .resume = mpc5xxx_can_resume,
 445 #endif
 446 };
 447
 448 module_platform_driver(mpc5xxx_can_driver);
 449
 450 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 451 MODULE_DESCRIPTION("Freescale MPC5xxx CAN driver");
 452 MODULE_LICENSE("GPL v2");