kernel/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 #include <asm/setup.h>
  31
  32 /* Register SCU_PCPPLL bit fields */
  33 #define N_DIV_RD(src)                   (((src) & 0x000001ff))
  34
  35 /* Register SCU_SOCPLL bit fields */
  36 #define CLKR_RD(src)                    (((src) & 0x07000000)>>24)
  37 #define CLKOD_RD(src)                   (((src) & 0x00300000)>>20)
  38 #define REGSPEC_RESET_F1_MASK           0x00010000
  39 #define CLKF_RD(src)                    (((src) & 0x000001ff))
  40
  41 #define XGENE_CLK_DRIVER_VER            "0.1"
  42
  43 static DEFINE_SPINLOCK(clk_lock);
  44
  45 static inline u32 xgene_clk_read(void *csr)
  46 {
  47         return readl_relaxed(csr);
  48 }
  49
  50 static inline void xgene_clk_write(u32 data, void *csr)
  51 {
  52         return writel_relaxed(data, csr);
  53 }
  54
  55 /* PLL Clock */
  56 enum xgene_pll_type {
  57         PLL_TYPE_PCP = 0,
  58         PLL_TYPE_SOC = 1,
  59 };
  60
  61 struct xgene_clk_pll {
  62         struct clk_hw   hw;
  63         const char      *name;
  64         void __iomem    *reg;
  65         spinlock_t      *lock;
  66         u32             pll_offset;
  67         enum xgene_pll_type     type;
  68 };
  69
  70 #define to_xgene_clk_pll(_hw) container_of(_hw, struct xgene_clk_pll, hw)
  71
  72 static int xgene_clk_pll_is_enabled(struct clk_hw *hw)
  73 {
  74         struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
  75         u32 data;
  76
  77         data = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
  78         pr_debug("%s pll %s\n", pllclk->name,
  79                 data & REGSPEC_RESET_F1_MASK ? "disabled" : "enabled");
  80
  81         return data & REGSPEC_RESET_F1_MASK ? 0 : 1;
  82 }
  83
  84 static unsigned long xgene_clk_pll_recalc_rate(struct clk_hw *hw,
  85                                 unsigned long parent_rate)
  86 {
  87         struct xgene_clk_pll *pllclk = to_xgene_clk_pll(hw);
  88         unsigned long fref;
  89         unsigned long fvco;
  90         u32 pll;
  91         u32 nref;
  92         u32 nout;
  93         u32 nfb;
  94
  95         pll = xgene_clk_read(pllclk->reg + pllclk->pll_offset);
  96
  97         if (pllclk->type == PLL_TYPE_PCP) {
  98                 /*
  99                  * PLL VCO = Reference clock * NF
 100                  * PCP PLL = PLL_VCO / 2
 101                  */
 102                 nout = 2;
 103                 fvco = parent_rate * (N_DIV_RD(pll) + 4);
 104         } else {
 105                 /*
 106                  * Fref = Reference Clock / NREF;
 107                  * Fvco = Fref * NFB;
 108                  * Fout = Fvco / NOUT;
 109                  */
 110                 nref = CLKR_RD(pll) + 1;
 111                 nout = CLKOD_RD(pll) + 1;
 112                 nfb = CLKF_RD(pll);
 113                 fref = parent_rate / nref;
 114                 fvco = fref * nfb;
 115         }
 116         pr_debug("%s pll recalc rate %ld parent %ld\n", pllclk->name,
 117                 fvco / nout, parent_rate);
 118
 119         return fvco / nout;
 120 }
 121
 122 const struct clk_ops xgene_clk_pll_ops = {
 123         .is_enabled = xgene_clk_pll_is_enabled,
 124         .recalc_rate = xgene_clk_pll_recalc_rate,
 125 };
 126
 127 static struct clk *xgene_register_clk_pll(struct device *dev,
 128         const char *name, const char *parent_name,
 129         unsigned long flags, void __iomem *reg, u32 pll_offset,
 130         u32 type, spinlock_t *lock)
 131 {
 132         struct xgene_clk_pll *apmclk;
 133         struct clk *clk;
 134         struct clk_init_data init;
 135
 136         /* allocate the APM clock structure */
 137         apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
 138         if (!apmclk) {
 139                 pr_err("%s: could not allocate APM clk\n", __func__);
 140                 return ERR_PTR(-ENOMEM);
 141         }
 142
 143         init.name = name;
 144         init.ops = &xgene_clk_pll_ops;
 145         init.flags = flags;
 146         init.parent_names = parent_name ? &parent_name : NULL;
 147         init.num_parents = parent_name ? 1 : 0;
 148
 149         apmclk->name = name;
 150         apmclk->reg = reg;
 151         apmclk->lock = lock;
 152         apmclk->pll_offset = pll_offset;
 153         apmclk->type = type;
 154         apmclk->hw.init = &init;
 155
 156         /* Register the clock */
 157         clk = clk_register(dev, &apmclk->hw);
 158         if (IS_ERR(clk)) {
 159                 pr_err("%s: could not register clk %s\n", __func__, name);
 160                 kfree(apmclk);
 161                 return NULL;
 162         }
 163         return clk;
 164 }
 165
 166 static void xgene_pllclk_init(struct device_node *np, enum xgene_pll_type pll_type)
 167 {
 168         const char *clk_name = np->full_name;
 169         struct clk *clk;
 170         void *reg;
 171
 172         reg = of_iomap(np, 0);
 173         if (reg == NULL) {
 174                 pr_err("Unable to map CSR register for %s\n", np->full_name);
 175                 return;
 176         }
 177         of_property_read_string(np, "clock-output-names", &clk_name);
 178         clk = xgene_register_clk_pll(NULL,
 179                         clk_name, of_clk_get_parent_name(np, 0),
 180                         CLK_IS_ROOT, reg, 0, pll_type, &clk_lock);
 181         if (!IS_ERR(clk)) {
 182                 of_clk_add_provider(np, of_clk_src_simple_get, clk);
 183                 clk_register_clkdev(clk, clk_name, NULL);
 184                 pr_debug("Add %s clock PLL\n", clk_name);
 185         }
 186 }
 187
 188 static void xgene_socpllclk_init(struct device_node *np)
 189 {
 190         xgene_pllclk_init(np, PLL_TYPE_SOC);
 191 }
 192
 193 static void xgene_pcppllclk_init(struct device_node *np)
 194 {
 195         xgene_pllclk_init(np, PLL_TYPE_PCP);
 196 }
 197
 198 /* IP Clock */
 199 struct xgene_dev_parameters {
 200         void __iomem *csr_reg;          /* CSR for IP clock */
 201         u32 reg_clk_offset;             /* Offset to clock enable CSR */
 202         u32 reg_clk_mask;               /* Mask bit for clock enable */
 203         u32 reg_csr_offset;             /* Offset to CSR reset */
 204         u32 reg_csr_mask;               /* Mask bit for disable CSR reset */
 205         void __iomem *divider_reg;      /* CSR for divider */
 206         u32 reg_divider_offset;         /* Offset to divider register */
 207         u32 reg_divider_shift;          /* Bit shift to divider field */
 208         u32 reg_divider_width;          /* Width of the bit to divider field */
 209 };
 210
 211 struct xgene_clk {
 212         struct clk_hw   hw;
 213         const char      *name;
 214         spinlock_t      *lock;
 215         struct xgene_dev_parameters     param;
 216 };
 217
 218 #define to_xgene_clk(_hw) container_of(_hw, struct xgene_clk, hw)
 219
 220 static int xgene_clk_enable(struct clk_hw *hw)
 221 {
 222         struct xgene_clk *pclk = to_xgene_clk(hw);
 223         unsigned long flags = 0;
 224         u32 data;
 225
 226         if (pclk->lock)
 227                 spin_lock_irqsave(pclk->lock, flags);
 228
 229         if (pclk->param.csr_reg != NULL) {
 230                 pr_debug("%s clock enabled\n", pclk->name);
 231                 /* First enable the clock */
 232                 data = xgene_clk_read(pclk->param.csr_reg +
 233                                         pclk->param.reg_clk_offset);
 234                 data |= pclk->param.reg_clk_mask;
 235                 xgene_clk_write(data, pclk->param.csr_reg +
 236                                         pclk->param.reg_clk_offset);
 237                 pr_debug("%s clock PADDR base 0x%016LX clk offset 0x%08X mask 0x%08X value 0x%08X\n",
 238                         pclk->name, __pa(pclk->param.csr_reg),
 239                         pclk->param.reg_clk_offset, pclk->param.reg_clk_mask,
 240                         data);
 241
 242                 /* Second enable the CSR */
 243                 data = xgene_clk_read(pclk->param.csr_reg +
 244                                         pclk->param.reg_csr_offset);
 245                 data &= ~pclk->param.reg_csr_mask;
 246                 xgene_clk_write(data, pclk->param.csr_reg +
 247                                         pclk->param.reg_csr_offset);
 248                 pr_debug("%s CSR RESET PADDR base 0x%016LX csr offset 0x%08X mask 0x%08X value 0x%08X\n",
 249                         pclk->name, __pa(pclk->param.csr_reg),
 250                         pclk->param.reg_csr_offset, pclk->param.reg_csr_mask,
 251                         data);
 252         }
 253
 254         if (pclk->lock)
 255                 spin_unlock_irqrestore(pclk->lock, flags);
 256
 257         return 0;
 258 }
 259
 260 static void xgene_clk_disable(struct clk_hw *hw)
 261 {
 262         struct xgene_clk *pclk = to_xgene_clk(hw);
 263         unsigned long flags = 0;
 264         u32 data;
 265
 266         if (pclk->lock)
 267                 spin_lock_irqsave(pclk->lock, flags);
 268
 269         if (pclk->param.csr_reg != NULL) {
 270                 pr_debug("%s clock disabled\n", pclk->name);
 271                 /* First put the CSR in reset */
 272                 data = xgene_clk_read(pclk->param.csr_reg +
 273                                         pclk->param.reg_csr_offset);
 274                 data |= pclk->param.reg_csr_mask;
 275                 xgene_clk_write(data, pclk->param.csr_reg +
 276                                         pclk->param.reg_csr_offset);
 277
 278                 /* Second disable the clock */
 279                 data = xgene_clk_read(pclk->param.csr_reg +
 280                                         pclk->param.reg_clk_offset);
 281                 data &= ~pclk->param.reg_clk_mask;
 282                 xgene_clk_write(data, pclk->param.csr_reg +
 283                                         pclk->param.reg_clk_offset);
 284         }
 285
 286         if (pclk->lock)
 287                 spin_unlock_irqrestore(pclk->lock, flags);
 288 }
 289
 290 static int xgene_clk_is_enabled(struct clk_hw *hw)
 291 {
 292         struct xgene_clk *pclk = to_xgene_clk(hw);
 293         u32 data = 0;
 294
 295         if (pclk->param.csr_reg != NULL) {
 296                 pr_debug("%s clock checking\n", pclk->name);
 297                 data = xgene_clk_read(pclk->param.csr_reg +
 298                                         pclk->param.reg_clk_offset);
 299                 pr_debug("%s clock is %s\n", pclk->name,
 300                         data & pclk->param.reg_clk_mask ? "enabled" :
 301                                                         "disabled");
 302         }
 303
 304         if (pclk->param.csr_reg == NULL)
 305                 return 1;
 306         return data & pclk->param.reg_clk_mask ? 1 : 0;
 307 }
 308
 309 static unsigned long xgene_clk_recalc_rate(struct clk_hw *hw,
 310                                 unsigned long parent_rate)
 311 {
 312         struct xgene_clk *pclk = to_xgene_clk(hw);
 313         u32 data;
 314
 315         if (pclk->param.divider_reg) {
 316                 data = xgene_clk_read(pclk->param.divider_reg +
 317                                         pclk->param.reg_divider_offset);
 318                 data >>= pclk->param.reg_divider_shift;
 319                 data &= (1 << pclk->param.reg_divider_width) - 1;
 320
 321                 pr_debug("%s clock recalc rate %ld parent %ld\n",
 322                         pclk->name, parent_rate / data, parent_rate);
 323                 return parent_rate / data;
 324         } else {
 325                 pr_debug("%s clock recalc rate %ld parent %ld\n",
 326                         pclk->name, parent_rate, parent_rate);
 327                 return parent_rate;
 328         }
 329 }
 330
 331 static int xgene_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 332                                 unsigned long parent_rate)
 333 {
 334         struct xgene_clk *pclk = to_xgene_clk(hw);
 335         unsigned long flags = 0;
 336         u32 data;
 337         u32 divider;
 338         u32 divider_save;
 339
 340         if (pclk->lock)
 341                 spin_lock_irqsave(pclk->lock, flags);
 342
 343         if (pclk->param.divider_reg) {
 344                 /* Let's compute the divider */
 345                 if (rate > parent_rate)
 346                         rate = parent_rate;
 347                 divider_save = divider = parent_rate / rate; /* Rounded down */
 348                 divider &= (1 << pclk->param.reg_divider_width) - 1;
 349                 divider <<= pclk->param.reg_divider_shift;
 350
 351                 /* Set new divider */
 352                 data = xgene_clk_read(pclk->param.divider_reg +
 353                                 pclk->param.reg_divider_offset);
 354                 data &= ~((1 << pclk->param.reg_divider_width) - 1);
 355                 data |= divider;
 356                 xgene_clk_write(data, pclk->param.divider_reg +
 357                                         pclk->param.reg_divider_offset);
 358                 pr_debug("%s clock set rate %ld\n", pclk->name,
 359                         parent_rate / divider_save);
 360         } else {
 361                 divider_save = 1;
 362         }
 363
 364         if (pclk->lock)
 365                 spin_unlock_irqrestore(pclk->lock, flags);
 366
 367         return parent_rate / divider_save;
 368 }
 369
 370 static long xgene_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 371                                 unsigned long *prate)
 372 {
 373         struct xgene_clk *pclk = to_xgene_clk(hw);
 374         unsigned long parent_rate = *prate;
 375         u32 divider;
 376
 377         if (pclk->param.divider_reg) {
 378                 /* Let's compute the divider */
 379                 if (rate > parent_rate)
 380                         rate = parent_rate;
 381                 divider = parent_rate / rate;   /* Rounded down */
 382         } else {
 383                 divider = 1;
 384         }
 385
 386         return parent_rate / divider;
 387 }
 388
 389 const struct clk_ops xgene_clk_ops = {
 390         .enable = xgene_clk_enable,
 391         .disable = xgene_clk_disable,
 392         .is_enabled = xgene_clk_is_enabled,
 393         .recalc_rate = xgene_clk_recalc_rate,
 394         .set_rate = xgene_clk_set_rate,
 395         .round_rate = xgene_clk_round_rate,
 396 };
 397
 398 static struct clk *xgene_register_clk(struct device *dev,
 399                 const char *name, const char *parent_name,
 400                 struct xgene_dev_parameters *parameters, spinlock_t *lock)
 401 {
 402         struct xgene_clk *apmclk;
 403         struct clk *clk;
 404         struct clk_init_data init;
 405         int rc;
 406
 407         /* allocate the APM clock structure */
 408         apmclk = kzalloc(sizeof(*apmclk), GFP_KERNEL);
 409         if (!apmclk) {
 410                 pr_err("%s: could not allocate APM clk\n", __func__);
 411                 return ERR_PTR(-ENOMEM);
 412         }
 413
 414         init.name = name;
 415         init.ops = &xgene_clk_ops;
 416         init.flags = 0;
 417         init.parent_names = parent_name ? &parent_name : NULL;
 418         init.num_parents = parent_name ? 1 : 0;
 419
 420         apmclk->name = name;
 421         apmclk->lock = lock;
 422         apmclk->hw.init = &init;
 423         apmclk->param = *parameters;
 424
 425         /* Register the clock */
 426         clk = clk_register(dev, &apmclk->hw);
 427         if (IS_ERR(clk)) {
 428                 pr_err("%s: could not register clk %s\n", __func__, name);
 429                 kfree(apmclk);
 430                 return clk;
 431         }
 432
 433         /* Register the clock for lookup */
 434         rc = clk_register_clkdev(clk, name, NULL);
 435         if (rc != 0) {
 436                 pr_err("%s: could not register lookup clk %s\n",
 437                         __func__, name);
 438         }
 439         return clk;
 440 }
 441
 442 static void __init xgene_devclk_init(struct device_node *np)
 443 {
 444         const char *clk_name = np->full_name;
 445         struct clk *clk;
 446         struct resource res;
 447         int rc;
 448         struct xgene_dev_parameters parameters;
 449         int i;
 450
 451         /* Check if the entry is disabled */
 452         if (!of_device_is_available(np))
 453                 return;
 454
 455         /* Parse the DTS register for resource */
 456         parameters.csr_reg = NULL;
 457         parameters.divider_reg = NULL;
 458         for (i = 0; i < 2; i++) {
 459                 void *map_res;
 460                 rc = of_address_to_resource(np, i, &res);
 461                 if (rc != 0) {
 462                         if (i == 0) {
 463                                 pr_err("no DTS register for %s\n",
 464                                         np->full_name);
 465                                 return;
 466                         }
 467                         break;
 468                 }
 469                 map_res = of_iomap(np, i);
 470                 if (map_res == NULL) {
 471                         pr_err("Unable to map resource %d for %s\n",
 472                                 i, np->full_name);
 473                         goto err;
 474                 }
 475                 if (strcmp(res.name, "div-reg") == 0)
 476                         parameters.divider_reg = map_res;
 477                 else /* if (strcmp(res->name, "csr-reg") == 0) */
 478                         parameters.csr_reg = map_res;
 479         }
 480         if (of_property_read_u32(np, "csr-offset", &parameters.reg_csr_offset))
 481                 parameters.reg_csr_offset = 0;
 482         if (of_property_read_u32(np, "csr-mask", &parameters.reg_csr_mask))
 483                 parameters.reg_csr_mask = 0xF;
 484         if (of_property_read_u32(np, "enable-offset",
 485                                 &parameters.reg_clk_offset))
 486                 parameters.reg_clk_offset = 0x8;
 487         if (of_property_read_u32(np, "enable-mask", &parameters.reg_clk_mask))
 488                 parameters.reg_clk_mask = 0xF;
 489         if (of_property_read_u32(np, "divider-offset",
 490                                 &parameters.reg_divider_offset))
 491                 parameters.reg_divider_offset = 0;
 492         if (of_property_read_u32(np, "divider-width",
 493                                 &parameters.reg_divider_width))
 494                 parameters.reg_divider_width = 0;
 495         if (of_property_read_u32(np, "divider-shift",
 496                                 &parameters.reg_divider_shift))
 497                 parameters.reg_divider_shift = 0;
 498         of_property_read_string(np, "clock-output-names", &clk_name);
 499
 500         clk = xgene_register_clk(NULL, clk_name,
 501                 of_clk_get_parent_name(np, 0), &parameters, &clk_lock);
 502         if (IS_ERR(clk))
 503                 goto err;
 504         pr_debug("Add %s clock\n", clk_name);
 505         rc = of_clk_add_provider(np, of_clk_src_simple_get, clk);
 506         if (rc != 0)
 507                 pr_err("%s: could register provider clk %s\n", __func__,
 508                         np->full_name);
 509
 510         return;
 511
 512 err:
 513         if (parameters.csr_reg)
 514                 iounmap(parameters.csr_reg);
 515         if (parameters.divider_reg)
 516                 iounmap(parameters.divider_reg);
 517 }
 518
 519 CLK_OF_DECLARE(xgene_socpll_clock, "apm,xgene-socpll-clock", xgene_socpllclk_init);
 520 CLK_OF_DECLARE(xgene_pcppll_clock, "apm,xgene-pcppll-clock", xgene_pcppllclk_init);
 521 CLK_OF_DECLARE(xgene_dev_clock, "apm,xgene-device-clock", xgene_devclk_init);