drivers/clk/bcm/clk-kona.h

   1 /*
   2  * Copyright (C) 2013 Broadcom Corporation
   3  * Copyright 2013 Linaro Limited
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation version 2.
   8  *
   9  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  10  * kind, whether express or implied; without even the implied warranty
  11  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #ifndef _CLK_KONA_H
  16 #define _CLK_KONA_H
  17
  18 #include <linux/kernel.h>
  19 #include <linux/list.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/slab.h>
  22 #include <linux/device.h>
  23 #include <linux/of.h>
  24 #include <linux/clk-provider.h>
  25
  26 #define BILLION         1000000000
  27
  28 /* The common clock framework uses u8 to represent a parent index */
  29 #define PARENT_COUNT_MAX        ((u32)U8_MAX)
  30
  31 #define BAD_CLK_INDEX           U8_MAX  /* Can't ever be valid */
  32 #define BAD_CLK_NAME            ((const char *)-1)
  33
  34 #define BAD_SCALED_DIV_VALUE    U64_MAX
  35
  36 /*
  37  * Utility macros for object flag management.  If possible, flags
  38  * should be defined such that 0 is the desired default value.
  39  */
  40 #define FLAG(type, flag)                BCM_CLK_ ## type ## _FLAGS_ ## flag
  41 #define FLAG_SET(obj, type, flag)       ((obj)->flags |= FLAG(type, flag))
  42 #define FLAG_CLEAR(obj, type, flag)     ((obj)->flags &= ~(FLAG(type, flag)))
  43 #define FLAG_FLIP(obj, type, flag)      ((obj)->flags ^= FLAG(type, flag))
  44 #define FLAG_TEST(obj, type, flag)      (!!((obj)->flags & FLAG(type, flag)))
  45
  46 /* CCU field state tests */
  47
  48 #define ccu_policy_exists(ccu_policy)   ((ccu_policy)->enable.offset != 0)
  49
  50 /* Clock field state tests */
  51
  52 #define policy_exists(policy)           ((policy)->offset != 0)
  53
  54 #define gate_exists(gate)               FLAG_TEST(gate, GATE, EXISTS)
  55 #define gate_is_enabled(gate)           FLAG_TEST(gate, GATE, ENABLED)
  56 #define gate_is_hw_controllable(gate)   FLAG_TEST(gate, GATE, HW)
  57 #define gate_is_sw_controllable(gate)   FLAG_TEST(gate, GATE, SW)
  58 #define gate_is_sw_managed(gate)        FLAG_TEST(gate, GATE, SW_MANAGED)
  59 #define gate_is_no_disable(gate)        FLAG_TEST(gate, GATE, NO_DISABLE)
  60
  61 #define gate_flip_enabled(gate)         FLAG_FLIP(gate, GATE, ENABLED)
  62
  63 #define hyst_exists(hyst)               ((hyst)->offset != 0)
  64
  65 #define divider_exists(div)             FLAG_TEST(div, DIV, EXISTS)
  66 #define divider_is_fixed(div)           FLAG_TEST(div, DIV, FIXED)
  67 #define divider_has_fraction(div)       (!divider_is_fixed(div) && \
  68                                                 (div)->u.s.frac_width > 0)
  69
  70 #define selector_exists(sel)            ((sel)->width != 0)
  71 #define trigger_exists(trig)            FLAG_TEST(trig, TRIG, EXISTS)
  72
  73 #define policy_lvm_en_exists(enable)    ((enable)->offset != 0)
  74 #define policy_ctl_exists(control)      ((control)->offset != 0)
  75
  76 /* Clock type, used to tell common block what it's part of */
  77 enum bcm_clk_type {
  78         bcm_clk_none,           /* undefined clock type */
  79         bcm_clk_bus,
  80         bcm_clk_core,
  81         bcm_clk_peri
  82 };
  83
  84 /*
  85  * CCU policy control for clocks.  Clocks can be enabled or disabled
  86  * based on the CCU policy in effect.  One bit in each policy mask
  87  * register (one per CCU policy) represents whether the clock is
  88  * enabled when that policy is effect or not.  The CCU policy engine
  89  * must be stopped to update these bits, and must be restarted again
  90  * afterward.
  91  */
  92 struct bcm_clk_policy {
  93         u32 offset;             /* first policy mask register offset */
  94         u32 bit;                /* bit used in all mask registers */
  95 };
  96
  97 /* Policy initialization macro */
  98
  99 #define POLICY(_offset, _bit)                                           \
 100         {                                                               \
 101                 .offset = (_offset),                                    \
 102                 .bit = (_bit),                                          \
 103         }
 104
 105 /*
 106  * Gating control and status is managed by a 32-bit gate register.
 107  *
 108  * There are several types of gating available:
 109  * - (no gate)
 110  *     A clock with no gate is assumed to be always enabled.
 111  * - hardware-only gating (auto-gating)
 112  *     Enabling or disabling clocks with this type of gate is
 113  *     managed automatically by the hardware.  Such clocks can be
 114  *     considered by the software to be enabled.  The current status
 115  *     of auto-gated clocks can be read from the gate status bit.
 116  * - software-only gating
 117  *     Auto-gating is not available for this type of clock.
 118  *     Instead, software manages whether it's enabled by setting or
 119  *     clearing the enable bit.  The current gate status of a gate
 120  *     under software control can be read from the gate status bit.
 121  *     To ensure a change to the gating status is complete, the
 122  *     status bit can be polled to verify that the gate has entered
 123  *     the desired state.
 124  * - selectable hardware or software gating
 125  *     Gating for this type of clock can be configured to be either
 126  *     under software or hardware control.  Which type is in use is
 127  *     determined by the hw_sw_sel bit of the gate register.
 128  */
 129 struct bcm_clk_gate {
 130         u32 offset;             /* gate register offset */
 131         u32 status_bit;         /* 0: gate is disabled; 0: gatge is enabled */
 132         u32 en_bit;             /* 0: disable; 1: enable */
 133         u32 hw_sw_sel_bit;      /* 0: hardware gating; 1: software gating */
 134         u32 flags;              /* BCM_CLK_GATE_FLAGS_* below */
 135 };
 136
 137 /*
 138  * Gate flags:
 139  *   HW         means this gate can be auto-gated
 140  *   SW         means the state of this gate can be software controlled
 141  *   NO_DISABLE means this gate is (only) enabled if under software control
 142  *   SW_MANAGED means the status of this gate is under software control
 143  *   ENABLED    means this software-managed gate is *supposed* to be enabled
 144  */
 145 #define BCM_CLK_GATE_FLAGS_EXISTS       ((u32)1 << 0)   /* Gate is valid */
 146 #define BCM_CLK_GATE_FLAGS_HW           ((u32)1 << 1)   /* Can auto-gate */
 147 #define BCM_CLK_GATE_FLAGS_SW           ((u32)1 << 2)   /* Software control */
 148 #define BCM_CLK_GATE_FLAGS_NO_DISABLE   ((u32)1 << 3)   /* HW or enabled */
 149 #define BCM_CLK_GATE_FLAGS_SW_MANAGED   ((u32)1 << 4)   /* SW now in control */
 150 #define BCM_CLK_GATE_FLAGS_ENABLED      ((u32)1 << 5)   /* If SW_MANAGED */
 151
 152 /*
 153  * Gate initialization macros.
 154  *
 155  * Any gate initially under software control will be enabled.
 156  */
 157
 158 /* A hardware/software gate initially under software control */
 159 #define HW_SW_GATE(_offset, _status_bit, _en_bit, _hw_sw_sel_bit)       \
 160         {                                                               \
 161                 .offset = (_offset),                                    \
 162                 .status_bit = (_status_bit),                            \
 163                 .en_bit = (_en_bit),                                    \
 164                 .hw_sw_sel_bit = (_hw_sw_sel_bit),                      \
 165                 .flags = FLAG(GATE, HW)|FLAG(GATE, SW)|                 \
 166                         FLAG(GATE, SW_MANAGED)|FLAG(GATE, ENABLED)|     \
 167                         FLAG(GATE, EXISTS),                             \
 168         }
 169
 170 /* A hardware/software gate initially under hardware control */
 171 #define HW_SW_GATE_AUTO(_offset, _status_bit, _en_bit, _hw_sw_sel_bit)  \
 172         {                                                               \
 173                 .offset = (_offset),                                    \
 174                 .status_bit = (_status_bit),                            \
 175                 .en_bit = (_en_bit),                                    \
 176                 .hw_sw_sel_bit = (_hw_sw_sel_bit),                      \
 177                 .flags = FLAG(GATE, HW)|FLAG(GATE, SW)|                 \
 178                         FLAG(GATE, EXISTS),                             \
 179         }
 180
 181 /* A hardware-or-enabled gate (enabled if not under hardware control) */
 182 #define HW_ENABLE_GATE(_offset, _status_bit, _en_bit, _hw_sw_sel_bit)   \
 183         {                                                               \
 184                 .offset = (_offset),                                    \
 185                 .status_bit = (_status_bit),                            \
 186                 .en_bit = (_en_bit),                                    \
 187                 .hw_sw_sel_bit = (_hw_sw_sel_bit),                      \
 188                 .flags = FLAG(GATE, HW)|FLAG(GATE, SW)|                 \
 189                         FLAG(GATE, NO_DISABLE)|FLAG(GATE, EXISTS),      \
 190         }
 191
 192 /* A software-only gate */
 193 #define SW_ONLY_GATE(_offset, _status_bit, _en_bit)                     \
 194         {                                                               \
 195                 .offset = (_offset),                                    \
 196                 .status_bit = (_status_bit),                            \
 197                 .en_bit = (_en_bit),                                    \
 198                 .flags = FLAG(GATE, SW)|FLAG(GATE, SW_MANAGED)|         \
 199                         FLAG(GATE, ENABLED)|FLAG(GATE, EXISTS),         \
 200         }
 201
 202 /* A hardware-only gate */
 203 #define HW_ONLY_GATE(_offset, _status_bit)                              \
 204         {                                                               \
 205                 .offset = (_offset),                                    \
 206                 .status_bit = (_status_bit),                            \
 207                 .flags = FLAG(GATE, HW)|FLAG(GATE, EXISTS),             \
 208         }
 209
 210 /* Gate hysteresis for clocks */
 211 struct bcm_clk_hyst {
 212         u32 offset;             /* hyst register offset (normally CLKGATE) */
 213         u32 en_bit;             /* bit used to enable hysteresis */
 214         u32 val_bit;            /* if enabled: 0 = low delay; 1 = high delay */
 215 };
 216
 217 /* Hysteresis initialization macro */
 218
 219 #define HYST(_offset, _en_bit, _val_bit)                                \
 220         {                                                               \
 221                 .offset = (_offset),                                    \
 222                 .en_bit = (_en_bit),                                    \
 223                 .val_bit = (_val_bit),                                  \
 224         }
 225
 226 /*
 227  * Each clock can have zero, one, or two dividers which change the
 228  * output rate of the clock.  Each divider can be either fixed or
 229  * variable.  If there are two dividers, they are the "pre-divider"
 230  * and the "regular" or "downstream" divider.  If there is only one,
 231  * there is no pre-divider.
 232  *
 233  * A fixed divider is any non-zero (positive) value, and it
 234  * indicates how the input rate is affected by the divider.
 235  *
 236  * The value of a variable divider is maintained in a sub-field of a
 237  * 32-bit divider register.  The position of the field in the
 238  * register is defined by its offset and width.  The value recorded
 239  * in this field is always 1 less than the value it represents.
 240  *
 241  * In addition, a variable divider can indicate that some subset
 242  * of its bits represent a "fractional" part of the divider.  Such
 243  * bits comprise the low-order portion of the divider field, and can
 244  * be viewed as representing the portion of the divider that lies to
 245  * the right of the decimal point.  Most variable dividers have zero
 246  * fractional bits.  Variable dividers with non-zero fraction width
 247  * still record a value 1 less than the value they represent; the
 248  * added 1 does *not* affect the low-order bit in this case, it
 249  * affects the bits above the fractional part only.  (Often in this
 250  * code a divider field value is distinguished from the value it
 251  * represents by referring to the latter as a "divisor".)
 252  *
 253  * In order to avoid dealing with fractions, divider arithmetic is
 254  * performed using "scaled" values.  A scaled value is one that's
 255  * been left-shifted by the fractional width of a divider.  Dividing
 256  * a scaled value by a scaled divisor produces the desired quotient
 257  * without loss of precision and without any other special handling
 258  * for fractions.
 259  *
 260  * The recorded value of a variable divider can be modified.  To
 261  * modify either divider (or both), a clock must be enabled (i.e.,
 262  * using its gate).  In addition, a trigger register (described
 263  * below) must be used to commit the change, and polled to verify
 264  * the change is complete.
 265  */
 266 struct bcm_clk_div {
 267         union {
 268                 struct {        /* variable divider */
 269                         u32 offset;     /* divider register offset */
 270                         u32 shift;      /* field shift */
 271                         u32 width;      /* field width */
 272                         u32 frac_width; /* field fraction width */
 273
 274                         u64 scaled_div; /* scaled divider value */
 275                 } s;
 276                 u32 fixed;      /* non-zero fixed divider value */
 277         } u;
 278         u32 flags;              /* BCM_CLK_DIV_FLAGS_* below */
 279 };
 280
 281 /*
 282  * Divider flags:
 283  *   EXISTS means this divider exists
 284  *   FIXED means it is a fixed-rate divider
 285  */
 286 #define BCM_CLK_DIV_FLAGS_EXISTS        ((u32)1 << 0)   /* Divider is valid */
 287 #define BCM_CLK_DIV_FLAGS_FIXED         ((u32)1 << 1)   /* Fixed-value */
 288
 289 /* Divider initialization macros */
 290
 291 /* A fixed (non-zero) divider */
 292 #define FIXED_DIVIDER(_value)                                           \
 293         {                                                               \
 294                 .u.fixed = (_value),                                    \
 295                 .flags = FLAG(DIV, EXISTS)|FLAG(DIV, FIXED),            \
 296         }
 297
 298 /* A divider with an integral divisor */
 299 #define DIVIDER(_offset, _shift, _width)                                \
 300         {                                                               \
 301                 .u.s.offset = (_offset),                                \
 302                 .u.s.shift = (_shift),                                  \
 303                 .u.s.width = (_width),                                  \
 304                 .u.s.scaled_div = BAD_SCALED_DIV_VALUE,                 \
 305                 .flags = FLAG(DIV, EXISTS),                             \
 306         }
 307
 308 /* A divider whose divisor has an integer and fractional part */
 309 #define FRAC_DIVIDER(_offset, _shift, _width, _frac_width)              \
 310         {                                                               \
 311                 .u.s.offset = (_offset),                                \
 312                 .u.s.shift = (_shift),                                  \
 313                 .u.s.width = (_width),                                  \
 314                 .u.s.frac_width = (_frac_width),                        \
 315                 .u.s.scaled_div = BAD_SCALED_DIV_VALUE,                 \
 316                 .flags = FLAG(DIV, EXISTS),                             \
 317         }
 318
 319 /*
 320  * Clocks may have multiple "parent" clocks.  If there is more than
 321  * one, a selector must be specified to define which of the parent
 322  * clocks is currently in use.  The selected clock is indicated in a
 323  * sub-field of a 32-bit selector register.  The range of
 324  * representable selector values typically exceeds the number of
 325  * available parent clocks.  Occasionally the reset value of a
 326  * selector field is explicitly set to a (specific) value that does
 327  * not correspond to a defined input clock.
 328  *
 329  * We register all known parent clocks with the common clock code
 330  * using a packed array (i.e., no empty slots) of (parent) clock
 331  * names, and refer to them later using indexes into that array.
 332  * We maintain an array of selector values indexed by common clock
 333  * index values in order to map between these common clock indexes
 334  * and the selector values used by the hardware.
 335  *
 336  * Like dividers, a selector can be modified, but to do so a clock
 337  * must be enabled, and a trigger must be used to commit the change.
 338  */
 339 struct bcm_clk_sel {
 340         u32 offset;             /* selector register offset */
 341         u32 shift;              /* field shift */
 342         u32 width;              /* field width */
 343
 344         u32 parent_count;       /* number of entries in parent_sel[] */
 345         u32 *parent_sel;        /* array of parent selector values */
 346         u8 clk_index;           /* current selected index in parent_sel[] */
 347 };
 348
 349 /* Selector initialization macro */
 350 #define SELECTOR(_offset, _shift, _width)                               \
 351         {                                                               \
 352                 .offset = (_offset),                                    \
 353                 .shift = (_shift),                                      \
 354                 .width = (_width),                                      \
 355                 .clk_index = BAD_CLK_INDEX,                             \
 356         }
 357
 358 /*
 359  * Making changes to a variable divider or a selector for a clock
 360  * requires the use of a trigger.  A trigger is defined by a single
 361  * bit within a register.  To signal a change, a 1 is written into
 362  * that bit.  To determine when the change has been completed, that
 363  * trigger bit is polled; the read value will be 1 while the change
 364  * is in progress, and 0 when it is complete.
 365  *
 366  * Occasionally a clock will have more than one trigger.  In this
 367  * case, the "pre-trigger" will be used when changing a clock's
 368  * selector and/or its pre-divider.
 369  */
 370 struct bcm_clk_trig {
 371         u32 offset;             /* trigger register offset */
 372         u32 bit;                /* trigger bit */
 373         u32 flags;              /* BCM_CLK_TRIG_FLAGS_* below */
 374 };
 375
 376 /*
 377  * Trigger flags:
 378  *   EXISTS means this trigger exists
 379  */
 380 #define BCM_CLK_TRIG_FLAGS_EXISTS       ((u32)1 << 0)   /* Trigger is valid */
 381
 382 /* Trigger initialization macro */
 383 #define TRIGGER(_offset, _bit)                                          \
 384         {                                                               \
 385                 .offset = (_offset),                                    \
 386                 .bit = (_bit),                                          \
 387                 .flags = FLAG(TRIG, EXISTS),                            \
 388         }
 389
 390 struct peri_clk_data {
 391         struct bcm_clk_policy policy;
 392         struct bcm_clk_gate gate;
 393         struct bcm_clk_hyst hyst;
 394         struct bcm_clk_trig pre_trig;
 395         struct bcm_clk_div pre_div;
 396         struct bcm_clk_trig trig;
 397         struct bcm_clk_div div;
 398         struct bcm_clk_sel sel;
 399         const char *clocks[];   /* must be last; use CLOCKS() to declare */
 400 };
 401 #define CLOCKS(...)     { __VA_ARGS__, NULL, }
 402 #define NO_CLOCKS       { NULL, }       /* Must use of no parent clocks */
 403
 404 struct kona_clk {
 405         struct clk_hw hw;
 406         struct clk_init_data init_data; /* includes name of this clock */
 407         struct ccu_data *ccu;   /* ccu this clock is associated with */
 408         enum bcm_clk_type type;
 409         union {
 410                 void *data;
 411                 struct peri_clk_data *peri;
 412         } u;
 413 };
 414 #define to_kona_clk(_hw) \
 415         container_of(_hw, struct kona_clk, hw)
 416
 417 /* Initialization macro for an entry in a CCU's kona_clks[] array. */
 418 #define KONA_CLK(_ccu_name, _clk_name, _type)                           \
 419         {                                                               \
 420                 .init_data      = {                                     \
 421                         .name = #_clk_name,                             \
 422                         .ops = &kona_ ## _type ## _clk_ops,             \
 423                 },                                                      \
 424                 .ccu            = &_ccu_name ## _ccu_data,              \
 425                 .type           = bcm_clk_ ## _type,                    \
 426                 .u.data         = &_clk_name ## _data,                  \
 427         }
 428 #define LAST_KONA_CLK   { .type = bcm_clk_none }
 429
 430 /*
 431  * CCU policy control.  To enable software update of the policy
 432  * tables the CCU policy engine must be stopped by setting the
 433  * software update enable bit (LVM_EN).  After an update the engine
 434  * is restarted using the GO bit and either the GO_ATL or GO_AC bit.
 435  */
 436 struct bcm_lvm_en {
 437         u32 offset;             /* LVM_EN register offset */
 438         u32 bit;                /* POLICY_CONFIG_EN bit in register */
 439 };
 440
 441 /* Policy enable initialization macro */
 442 #define CCU_LVM_EN(_offset, _bit)                                       \
 443         {                                                               \
 444                 .offset = (_offset),                                    \
 445                 .bit = (_bit),                                          \
 446         }
 447
 448 struct bcm_policy_ctl {
 449         u32 offset;             /* POLICY_CTL register offset */
 450         u32 go_bit;
 451         u32 atl_bit;            /* GO, GO_ATL, and GO_AC bits */
 452         u32 ac_bit;
 453 };
 454
 455 /* Policy control initialization macro */
 456 #define CCU_POLICY_CTL(_offset, _go_bit, _ac_bit, _atl_bit)             \
 457         {                                                               \
 458                 .offset = (_offset),                                    \
 459                 .go_bit = (_go_bit),                                    \
 460                 .ac_bit = (_ac_bit),                                    \
 461                 .atl_bit = (_atl_bit),                                  \
 462         }
 463
 464 struct ccu_policy {
 465         struct bcm_lvm_en enable;
 466         struct bcm_policy_ctl control;
 467 };
 468
 469 /*
 470  * Each CCU defines a mapped area of memory containing registers
 471  * used to manage clocks implemented by the CCU.  Access to memory
 472  * within the CCU's space is serialized by a spinlock.  Before any
 473  * (other) address can be written, a special access "password" value
 474  * must be written to its WR_ACCESS register (located at the base
 475  * address of the range).  We keep track of the name of each CCU as
 476  * it is set up, and maintain them in a list.
 477  */
 478 struct ccu_data {
 479         void __iomem *base;     /* base of mapped address space */
 480         spinlock_t lock;        /* serialization lock */
 481         bool write_enabled;     /* write access is currently enabled */
 482         struct ccu_policy policy;
 483         struct device_node *node;
 484         size_t clk_num;
 485         const char *name;
 486         u32 range;              /* byte range of address space */
 487         struct kona_clk kona_clks[];    /* must be last */
 488 };
 489
 490 /* Initialization for common fields in a Kona ccu_data structure */
 491 #define KONA_CCU_COMMON(_prefix, _name, _ccuname)                           \
 492         .name           = #_name "_ccu",                                    \
 493         .lock           = __SPIN_LOCK_UNLOCKED(_name ## _ccu_data.lock),    \
 494         .clk_num        = _prefix ## _ ## _ccuname ## _CCU_CLOCK_COUNT
 495
 496 /* Exported globals */
 497
 498 extern struct clk_ops kona_peri_clk_ops;
 499
 500 /* Externally visible functions */
 501
 502 extern u64 scaled_div_max(struct bcm_clk_div *div);
 503 extern u64 scaled_div_build(struct bcm_clk_div *div, u32 div_value,
 504                                 u32 billionths);
 505
 506 extern void __init kona_dt_ccu_setup(struct ccu_data *ccu,
 507                                 struct device_node *node);
 508 extern bool __init kona_ccu_init(struct ccu_data *ccu);
 509
 510 #endif /* _CLK_KONA_H */