drivers/clk/clk-xgene.c

   1 /*
   2  * clk-xgene.c - AppliedMicro X-Gene Clock Interface
   3  *
   4  * Copyright (c) 2013, Applied Micro Circuits Corporation
   5  * Author: Loc Ho <lho@apm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of
  10  * the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  20  * MA 02111-1307 USA
  21  *
  22  */
  23 #include <linux/module.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/io.h>
  26 #include <linux/of.h>
  27 #include <linux/clkdev.h>
  28 #include <linux/clk-provider.h>
  29 #include <linux/of_address.h>
  30
  31 /* Register SCU_PCPPLL bit fields */
  32 #define N_DIV_RD(src)                   (((src) & 0x000001ff))
  33
  34 /* Register SCU_SOCPLL bit fields */
  35 #define CLKR_RD(src)                    (((src) & 0x07000000)>>24)
  36 #define CLKOD_RD(src)                   (((src) & 0x00300000)>>20)
  37 #define REGSPEC_RESET_F1_MASK           0x00010000
  38 #define CLKF_RD(src)                    (((src) & 0x000001ff))
  39
  40 #define XGENE_CLK_DRIVER_VER            "0.1"
  41
  42 static DEFINE_SPINLOCK(clk_lock);
  43
  44 static inline u32 xgene_clk_read(void __iomem *csr)
  45 {
  46         return readl_relaxed(csr);
  47 }
  48
  49 static inline void xgene_clk_write(u32 data, void __iomem *csr)
  50 {
  51         return writel_relaxed(data, csr);
  52 }
  53
  54 /* PLL Clock */
  55 enum xgene_pll_type {
  56         PLL_TYPE_PCP = 0,
  57         PLL_TYPE_SOC = 1,
  58 };
  59
  60 struct xgene_clk_pll {
  61         struct clk_hw   hw;
  62         void __iomem    *reg;
  63         spinlock_t      *lock;
  64         u32             pll_offset;
  65         enum xgene_pll_type     type;
  66 };
  67
  68 #define to_xgene_clk_pll(_hw) container_of(_hw, struct xgene_clk_pll, hw)
  69
  70 static int xgene_clk_pll_is_enabled(struct clk_hw *hw)
  71 {
  72         struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
  73         u32 data;
  74
  75         data = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
  76         pr_debug("%s pll %s\n", clk_hw_get_name(hw),
  77                 data & REGSPEC_RESET_F1_MASK ? "disabled" : "enabled");
  78
  79         return data & REGSPEC_RESET_F1_MASK ? 0 : 1;
  80 }
  81
  82 static unsigned long xgene_clk_pll_recalc_rate(struct clk_hw *hw,
  83                                 unsigned long parent_rate)
  84 {
  85         struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
  86         unsigned long fref;
  87         unsigned long fvco;
  88         u32 pll;
  89         u32 nref;
  90         u32 nout;
  91         u32 nfb;
  92
  93         pll = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
  94
  95         if (pllclk->type == PLL_TYPE_PCP) {
  96                 /*
  97                  * PLL VCO = Reference clock * NF
  98                  * PCP PLL = PLL_VCO / 2
  99                  */
 100                 nout = 2;
 101                 fvco = parent_rate * (N_DIV_RD(pll) + 4);
 102         } else {
 103                 /*
 104                  * Fref = Reference Clock / NREF;
 105                  * Fvco = Fref * NFB;
 106                  * Fout = Fvco / NOUT;
 107                  */
 108                 nref = CLKR_RD(pll) + 1;
 109                 nout = CLKOD_RD(pll) + 1;
 110                 nfb = CLKF_RD(pll);
 111                 fref = parent_rate / nref;
 112                 fvco = fref * nfb;
 113         }
 114         pr_debug("%s pll recalc rate %ld parent %ld\n", clk_hw_get_name(hw),
 115                 fvco / nout, parent_rate);
 116
 117         return fvco / nout;
 118 }
 119
 120 static const struct clk_ops xgene_clk_pll_ops = {
 121         .is_enabled = xgene_clk_pll_is_enabled,
 122         .recalc_rate = xgene_clk_pll_recalc_rate,
 123 };
 124
 125 static struct clk *xgene_register_clk_pll(struct device *dev,
 126         const char *name, const char *parent_name,
 127         unsigned long flags, void __iomem *reg, u32 pll_offset,
 128         u32 type, spinlock_t *lock)
 129 {
 130         struct xgene_clk_pll *apmclk;
 131         struct clk *clk;
 132         struct clk_init_data init;
 133
 134         /* allocate the APM clock structure */
 135         apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
 136         if (!apmclk) {
 137                 pr_err("%s: could not allocate APM clk\n", __func__);
 138                 return ERR_PTR(-ENOMEM);
 139         }
 140
 141         init.name = name;
 142         init.ops = &xgene_clk_pll_ops;
 143         init.flags = flags;
 144         init.parent_names = parent_name ? &parent_name : NULL;
 145         init.num_parents = parent_name ? 1 : 0;
 146
 147         apmclk->reg = reg;
 148         apmclk->lock = lock;
 149         apmclk->pll_offset = pll_offset;
 150         apmclk->type = type;
 151         apmclk->hw.init = &init;
 152
 153         /* Register the clock */
 154         clk = clk_register(dev, &apmclk->hw);
 155         if (IS_ERR(clk)) {
 156                 pr_err("%s: could not register clk %s\n", __func__, name);
 157                 kfree(apmclk);
 158                 return NULL;
 159         }
 160         return clk;
 161 }
 162
 163 static void xgene_pllclk_init(struct device_node *np, enum xgene_pll_type pll_type)
 164 {
 165         const char *clk_name = np->full_name;
 166         struct clk *clk;
 167         void __iomem *reg;
 168
 169         reg = of_iomap(np, 0);
 170         if (reg == NULL) {
 171                 pr_err("Unable to map CSR register for %s\n", np->full_name);
 172                 return;
 173         }
 174         of_property_read_string(np, "clock-output-names", &clk_name);
 175         clk = xgene_register_clk_pll(NULL,
 176                         clk_name, of_clk_get_parent_name(np, 0),
 177                         CLK_IS_ROOT, reg, 0, pll_type, &clk_lock);
 178         if (!IS_ERR(clk)) {
 179                 of_clk_add_provider(np, of_clk_src_simple_get, clk);
 180                 clk_register_clkdev(clk, clk_name, NULL);
 181                 pr_debug("Add %s clock PLL\n", clk_name);
 182         }
 183 }
 184
 185 static void xgene_socpllclk_init(struct device_node *np)
 186 {
 187         xgene_pllclk_init(np, PLL_TYPE_SOC);
 188 }
 189
 190 static void xgene_pcppllclk_init(struct device_node *np)
 191 {
 192         xgene_pllclk_init(np, PLL_TYPE_PCP);
 193 }
 194
 195 /* IP Clock */
 196 struct xgene_dev_parameters {
 197         void __iomem *csr_reg;          /* CSR for IP clock */
 198         u32 reg_clk_offset;             /* Offset to clock enable CSR */
 199         u32 reg_clk_mask;               /* Mask bit for clock enable */
 200         u32 reg_csr_offset;             /* Offset to CSR reset */
 201         u32 reg_csr_mask;               /* Mask bit for disable CSR reset */
 202         void __iomem *divider_reg;      /* CSR for divider */
 203         u32 reg_divider_offset;         /* Offset to divider register */
 204         u32 reg_divider_shift;          /* Bit shift to divider field */
 205         u32 reg_divider_width;          /* Width of the bit to divider field */
 206 };
 207
 208 struct xgene_clk {
 209         struct clk_hw   hw;
 210         spinlock_t      *lock;
 211         struct xgene_dev_parameters     param;
 212 };
 213
 214 #define to_xgene_clk(_hw) container_of(_hw, struct xgene_clk, hw)
 215
 216 static int xgene_clk_enable(struct clk_hw *hw)
 217 {
 218         struct xgene_clk *pclk = to_xgene_clk(hw);
 219         unsigned long flags = 0;
 220         u32 data;
 221
 222         if (pclk->lock)
 223                 spin_lock_irqsave(pclk->lock, flags);
 224
 225         if (pclk->param.csr_reg != NULL) {
 226                 pr_debug("%s clock enabled\n", clk_hw_get_name(hw));
 227                 /* First enable the clock */
 228                 data = xgene_clk_read(pclk->param.csr_reg +
 229                                         pclk->param.reg_clk_offset);
 230                 data |= pclk->param.reg_clk_mask;
 231                 xgene_clk_write(data, pclk->param.csr_reg +
 232                                         pclk->param.reg_clk_offset);
 233                 pr_debug("%s clk offset 0x%08X mask 0x%08X value 0x%08X\n",
 234                         clk_hw_get_name(hw),
 235                         pclk->param.reg_clk_offset, pclk->param.reg_clk_mask,
 236                         data);
 237
 238                 /* Second enable the CSR */
 239                 data = xgene_clk_read(pclk->param.csr_reg +
 240                                         pclk->param.reg_csr_offset);
 241                 data &= ~pclk->param.reg_csr_mask;
 242                 xgene_clk_write(data, pclk->param.csr_reg +
 243                                         pclk->param.reg_csr_offset);
 244                 pr_debug("%s csr offset 0x%08X mask 0x%08X value 0x%08X\n",
 245                         clk_hw_get_name(hw),
 246                         pclk->param.reg_csr_offset, pclk->param.reg_csr_mask,
 247                         data);
 248         }
 249
 250         if (pclk->lock)
 251                 spin_unlock_irqrestore(pclk->lock, flags);
 252
 253         return 0;
 254 }
 255
 256 static void xgene_clk_disable(struct clk_hw *hw)
 257 {
 258         struct xgene_clk *pclk = to_xgene_clk(hw);
 259         unsigned long flags = 0;
 260         u32 data;
 261
 262         if (pclk->lock)
 263                 spin_lock_irqsave(pclk->lock, flags);
 264
 265         if (pclk->param.csr_reg != NULL) {
 266                 pr_debug("%s clock disabled\n", clk_hw_get_name(hw));
 267                 /* First put the CSR in reset */
 268                 data = xgene_clk_read(pclk->param.csr_reg +
 269                                         pclk->param.reg_csr_offset);
 270                 data |= pclk->param.reg_csr_mask;
 271                 xgene_clk_write(data, pclk->param.csr_reg +
 272                                         pclk->param.reg_csr_offset);
 273
 274                 /* Second disable the clock */
 275                 data = xgene_clk_read(pclk->param.csr_reg +
 276                                         pclk->param.reg_clk_offset);
 277                 data &= ~pclk->param.reg_clk_mask;
 278                 xgene_clk_write(data, pclk->param.csr_reg +
 279                                         pclk->param.reg_clk_offset);
 280         }
 281
 282         if (pclk->lock)
 283                 spin_unlock_irqrestore(pclk->lock, flags);
 284 }
 285
 286 static int xgene_clk_is_enabled(struct clk_hw *hw)
 287 {
 288         struct xgene_clk *pclk = to_xgene_clk(hw);
 289         u32 data = 0;
 290
 291         if (pclk->param.csr_reg != NULL) {
 292                 pr_debug("%s clock checking\n", clk_hw_get_name(hw));
 293                 data = xgene_clk_read(pclk->param.csr_reg +
 294                                         pclk->param.reg_clk_offset);
 295                 pr_debug("%s clock is %s\n", clk_hw_get_name(hw),
 296                         data & pclk->param.reg_clk_mask ? "enabled" :
 297                                                         "disabled");
 298         }
 299
 300         if (pclk->param.csr_reg == NULL)
 301                 return 1;
 302         return data & pclk->param.reg_clk_mask ? 1 : 0;
 303 }
 304
 305 static unsigned long xgene_clk_recalc_rate(struct clk_hw *hw,
 306                                 unsigned long parent_rate)
 307 {
 308         struct xgene_clk *pclk = to_xgene_clk(hw);
 309         u32 data;
 310
 311         if (pclk->param.divider_reg) {
 312                 data = xgene_clk_read(pclk->param.divider_reg +
 313                                         pclk->param.reg_divider_offset);
 314                 data >>= pclk->param.reg_divider_shift;
 315                 data &= (1 << pclk->param.reg_divider_width) - 1;
 316
 317                 pr_debug("%s clock recalc rate %ld parent %ld\n",
 318                         clk_hw_get_name(hw),
 319                         parent_rate / data, parent_rate);
 320
 321                 return parent_rate / data;
 322         } else {
 323                 pr_debug("%s clock recalc rate %ld parent %ld\n",
 324                         clk_hw_get_name(hw), parent_rate, parent_rate);
 325                 return parent_rate;
 326         }
 327 }
 328
 329 static int xgene_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 330                                 unsigned long parent_rate)
 331 {
 332         struct xgene_clk *pclk = to_xgene_clk(hw);
 333         unsigned long flags = 0;
 334         u32 data;
 335         u32 divider;
 336         u32 divider_save;
 337
 338         if (pclk->lock)
 339                 spin_lock_irqsave(pclk->lock, flags);
 340
 341         if (pclk->param.divider_reg) {
 342                 /* Let's compute the divider */
 343                 if (rate > parent_rate)
 344                         rate = parent_rate;
 345                 divider_save = divider = parent_rate / rate; /* Rounded down */
 346                 divider &= (1 << pclk->param.reg_divider_width) - 1;
 347                 divider <<= pclk->param.reg_divider_shift;
 348
 349                 /* Set new divider */
 350                 data = xgene_clk_read(pclk->param.divider_reg +
 351                                 pclk->param.reg_divider_offset);
 352                 data &= ~(((1 << pclk->param.reg_divider_width) - 1)
 353                                 << pclk->param.reg_divider_shift);
 354                 data |= divider;
 355                 xgene_clk_write(data, pclk->param.divider_reg +
 356                                         pclk->param.reg_divider_offset);
 357                 pr_debug("%s clock set rate %ld\n", clk_hw_get_name(hw),
 358                         parent_rate / divider_save);
 359         } else {
 360                 divider_save = 1;
 361         }
 362
 363         if (pclk->lock)
 364                 spin_unlock_irqrestore(pclk->lock, flags);
 365
 366         return parent_rate / divider_save;
 367 }
 368
 369 static long xgene_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 370                                 unsigned long *prate)
 371 {
 372         struct xgene_clk *pclk = to_xgene_clk(hw);
 373         unsigned long parent_rate = *prate;
 374         u32 divider;
 375
 376         if (pclk->param.divider_reg) {
 377                 /* Let's compute the divider */
 378                 if (rate > parent_rate)
 379                         rate = parent_rate;
 380                 divider = parent_rate / rate;   /* Rounded down */
 381         } else {
 382                 divider = 1;
 383         }
 384
 385         return parent_rate / divider;
 386 }
 387
 388 static const struct clk_ops xgene_clk_ops = {
 389         .enable = xgene_clk_enable,
 390         .disable = xgene_clk_disable,
 391         .is_enabled = xgene_clk_is_enabled,
 392         .recalc_rate = xgene_clk_recalc_rate,
 393         .set_rate = xgene_clk_set_rate,
 394         .round_rate = xgene_clk_round_rate,
 395 };
 396
 397 static struct clk *xgene_register_clk(struct device *dev,
 398                 const char *name, const char *parent_name,
 399                 struct xgene_dev_parameters *parameters, spinlock_t *lock)
 400 {
 401         struct xgene_clk *apmclk;
 402         struct clk *clk;
 403         struct clk_init_data init;
 404         int rc;
 405
 406         /* allocate the APM clock structure */
 407         apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
 408         if (!apmclk) {
 409                 pr_err("%s: could not allocate APM clk\n", __func__);
 410                 return ERR_PTR(-ENOMEM);
 411         }
 412
 413         init.name = name;
 414         init.ops = &xgene_clk_ops;
 415         init.flags = 0;
 416         init.parent_names = parent_name ? &parent_name : NULL;
 417         init.num_parents = parent_name ? 1 : 0;
 418
 419         apmclk->lock = lock;
 420         apmclk->hw.init = &init;
 421         apmclk->param = *parameters;
 422
 423         /* Register the clock */
 424         clk = clk_register(dev, &apmclk->hw);
 425         if (IS_ERR(clk)) {
 426                 pr_err("%s: could not register clk %s\n", __func__, name);
 427                 kfree(apmclk);
 428                 return clk;
 429         }
 430
 431         /* Register the clock for lookup */
 432         rc = clk_register_clkdev(clk, name, NULL);
 433         if (rc != 0) {
 434                 pr_err("%s: could not register lookup clk %s\n",
 435                         __func__, name);
 436         }
 437         return clk;
 438 }
 439
 440 static void __init xgene_devclk_init(struct device_node *np)
 441 {
 442         const char *clk_name = np->full_name;
 443         struct clk *clk;
 444         struct resource res;
 445         int rc;
 446         struct xgene_dev_parameters parameters;
 447         int i;
 448
 449         /* Check if the entry is disabled */
 450         if (!of_device_is_available(np))
 451                 return;
 452
 453         /* Parse the DTS register for resource */
 454         parameters.csr_reg = NULL;
 455         parameters.divider_reg = NULL;
 456         for (i = 0; i < 2; i++) {
 457                 void __iomem *map_res;
 458                 rc = of_address_to_resource(np, i, &res);
 459                 if (rc != 0) {
 460                         if (i == 0) {
 461                                 pr_err("no DTS register for %s\n",
 462                                         np->full_name);
 463                                 return;
 464                         }
 465                         break;
 466                 }
 467                 map_res = of_iomap(np, i);
 468                 if (map_res == NULL) {
 469                         pr_err("Unable to map resource %d for %s\n",
 470                                 i, np->full_name);
 471                         goto err;
 472                 }
 473                 if (strcmp(res.name, "div-reg") == 0)
 474                         parameters.divider_reg = map_res;
 475                 else /* if (strcmp(res->name, "csr-reg") == 0) */
 476                         parameters.csr_reg = map_res;
 477         }
 478         if (of_property_read_u32(np, "csr-offset", &parameters.reg_csr_offset))
 479                 parameters.reg_csr_offset = 0;
 480         if (of_property_read_u32(np, "csr-mask", &parameters.reg_csr_mask))
 481                 parameters.reg_csr_mask = 0xF;
 482         if (of_property_read_u32(np, "enable-offset",
 483                                 &parameters.reg_clk_offset))
 484                 parameters.reg_clk_offset = 0x8;
 485         if (of_property_read_u32(np, "enable-mask", &parameters.reg_clk_mask))
 486                 parameters.reg_clk_mask = 0xF;
 487         if (of_property_read_u32(np, "divider-offset",
 488                                 &parameters.reg_divider_offset))
 489                 parameters.reg_divider_offset = 0;
 490         if (of_property_read_u32(np, "divider-width",
 491                                 &parameters.reg_divider_width))
 492                 parameters.reg_divider_width = 0;
 493         if (of_property_read_u32(np, "divider-shift",
 494                                 &parameters.reg_divider_shift))
 495                 parameters.reg_divider_shift = 0;
 496         of_property_read_string(np, "clock-output-names", &clk_name);
 497
 498         clk = xgene_register_clk(NULL, clk_name,
 499                 of_clk_get_parent_name(np, 0), &parameters, &clk_lock);
 500         if (IS_ERR(clk))
 501                 goto err;
 502         pr_debug("Add %s clock\n", clk_name);
 503         rc = of_clk_add_provider(np, of_clk_src_simple_get, clk);
 504         if (rc != 0)
 505                 pr_err("%s: could register provider clk %s\n", __func__,
 506                         np->full_name);
 507
 508         return;
 509
 510 err:
 511         if (parameters.csr_reg)
 512                 iounmap(parameters.csr_reg);
 513         if (parameters.divider_reg)
 514                 iounmap(parameters.divider_reg);
 515 }
 516
 517 CLK_OF_DECLARE(xgene_socpll_clock, "apm,xgene-socpll-clock", xgene_socpllclk_init);
 518 CLK_OF_DECLARE(xgene_pcppll_clock, "apm,xgene-pcppll-clock", xgene_pcppllclk_init);
 519 CLK_OF_DECLARE(xgene_dev_clock, "apm,xgene-device-clock", xgene_devclk_init);