1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC 4 * 5 * Authors: 6 * Serge Semin <Sergey.Semin@baikalelectronics.ru> 7 * Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru> 8 * 9 * Baikal-T1 CCU Dividers interface driver 10 */ 11 12#define pr_fmt(fmt) "bt1-ccu-div: " fmt 13 14#include <linux/kernel.h> 15#include <linux/printk.h> 16#include <linux/bits.h> 17#include <linux/bitfield.h> 18#include <linux/slab.h> 19#include <linux/clk-provider.h> 20#include <linux/of.h> 21#include <linux/spinlock.h> 22#include <linux/regmap.h> 23#include <linux/delay.h> 24#include <linux/time64.h> 25#include <linux/debugfs.h> 26 27#include "ccu-div.h" 28 29#define CCU_DIV_CTL 0x00 30#define CCU_DIV_CTL_EN BIT(0) 31#define CCU_DIV_CTL_RST BIT(1) 32#define CCU_DIV_CTL_SET_CLKDIV BIT(2) 33#define CCU_DIV_CTL_CLKDIV_FLD 4 34#define CCU_DIV_CTL_CLKDIV_MASK(_width) \ 35 GENMASK((_width) + CCU_DIV_CTL_CLKDIV_FLD - 1, CCU_DIV_CTL_CLKDIV_FLD) 36#define CCU_DIV_CTL_LOCK_SHIFTED BIT(27) 37#define CCU_DIV_CTL_GATE_REF_BUF BIT(28) 38#define CCU_DIV_CTL_LOCK_NORMAL BIT(31) 39 40#define CCU_DIV_LOCK_CHECK_RETRIES 50 41 42#define CCU_DIV_CLKDIV_MIN 0 43#define CCU_DIV_CLKDIV_MAX(_mask) \ 44 ((_mask) >> CCU_DIV_CTL_CLKDIV_FLD) 45 46/* 47 * Use the next two methods until there are generic field setter and 48 * getter available with non-constant mask support. 49 */ 50static inline u32 ccu_div_get(u32 mask, u32 val) 51{ 52 return (val & mask) >> CCU_DIV_CTL_CLKDIV_FLD; 53} 54 55static inline u32 ccu_div_prep(u32 mask, u32 val) 56{ 57 return (val << CCU_DIV_CTL_CLKDIV_FLD) & mask; 58} 59 60static inline unsigned long ccu_div_lock_delay_ns(unsigned long ref_clk, 61 unsigned long div) 62{ 63 u64 ns = 4ULL * (div ?: 1) * NSEC_PER_SEC; 64 65 do_div(ns, ref_clk); 66 67 return ns; 68} 69 70static inline unsigned long ccu_div_calc_freq(unsigned long ref_clk, 71 unsigned long div) 72{ 73 return ref_clk / (div ?: 1); 74} 75 76static int ccu_div_var_update_clkdiv(struct ccu_div *div, 77 unsigned long parent_rate, 78 unsigned long divider) 79{ 80 unsigned long nd; 81 u32 val = 0; 82 u32 lock; 83 int count; 84 85 nd = ccu_div_lock_delay_ns(parent_rate, divider); 86 87 if (div->features & CCU_DIV_LOCK_SHIFTED) 88 lock = CCU_DIV_CTL_LOCK_SHIFTED; 89 else 90 lock = CCU_DIV_CTL_LOCK_NORMAL; 91 92 regmap_update_bits(div->sys_regs, div->reg_ctl, 93 CCU_DIV_CTL_SET_CLKDIV, CCU_DIV_CTL_SET_CLKDIV); 94 95 /* 96 * Until there is nsec-version of readl_poll_timeout() is available 97 * we have to implement the next polling loop. 98 */ 99 count = CCU_DIV_LOCK_CHECK_RETRIES; 100 do { 101 ndelay(nd); 102 regmap_read(div->sys_regs, div->reg_ctl, &val); 103 if (val & lock) 104 return 0; 105 } while (--count); 106 107 return -ETIMEDOUT; 108} 109 110static int ccu_div_var_enable(struct clk_hw *hw) 111{ 112 struct clk_hw *parent_hw = clk_hw_get_parent(hw); 113 struct ccu_div *div = to_ccu_div(hw); 114 unsigned long flags; 115 u32 val = 0; 116 int ret; 117 118 if (!parent_hw) { 119 pr_err("Can't enable '%s' with no parent", clk_hw_get_name(hw)); 120 return -EINVAL; 121 } 122 123 regmap_read(div->sys_regs, div->reg_ctl, &val); 124 if (val & CCU_DIV_CTL_EN) 125 return 0; 126 127 spin_lock_irqsave(&div->lock, flags); 128 ret = ccu_div_var_update_clkdiv(div, clk_hw_get_rate(parent_hw), 129 ccu_div_get(div->mask, val)); 130 if (!ret) 131 regmap_update_bits(div->sys_regs, div->reg_ctl, 132 CCU_DIV_CTL_EN, CCU_DIV_CTL_EN); 133 spin_unlock_irqrestore(&div->lock, flags); 134 if (ret) 135 pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw)); 136 137 return ret; 138} 139 140static int ccu_div_gate_enable(struct clk_hw *hw) 141{ 142 struct ccu_div *div = to_ccu_div(hw); 143 unsigned long flags; 144 145 spin_lock_irqsave(&div->lock, flags); 146 regmap_update_bits(div->sys_regs, div->reg_ctl, 147 CCU_DIV_CTL_EN, CCU_DIV_CTL_EN); 148 spin_unlock_irqrestore(&div->lock, flags); 149 150 return 0; 151} 152 153static void ccu_div_gate_disable(struct clk_hw *hw) 154{ 155 struct ccu_div *div = to_ccu_div(hw); 156 unsigned long flags; 157 158 spin_lock_irqsave(&div->lock, flags); 159 regmap_update_bits(div->sys_regs, div->reg_ctl, CCU_DIV_CTL_EN, 0); 160 spin_unlock_irqrestore(&div->lock, flags); 161} 162 163static int ccu_div_gate_is_enabled(struct clk_hw *hw) 164{ 165 struct ccu_div *div = to_ccu_div(hw); 166 u32 val = 0; 167 168 regmap_read(div->sys_regs, div->reg_ctl, &val); 169 170 return !!(val & CCU_DIV_CTL_EN); 171} 172 173static int ccu_div_buf_enable(struct clk_hw *hw) 174{ 175 struct ccu_div *div = to_ccu_div(hw); 176 unsigned long flags; 177 178 spin_lock_irqsave(&div->lock, flags); 179 regmap_update_bits(div->sys_regs, div->reg_ctl, 180 CCU_DIV_CTL_GATE_REF_BUF, 0); 181 spin_unlock_irqrestore(&div->lock, flags); 182 183 return 0; 184} 185 186static void ccu_div_buf_disable(struct clk_hw *hw) 187{ 188 struct ccu_div *div = to_ccu_div(hw); 189 unsigned long flags; 190 191 spin_lock_irqsave(&div->lock, flags); 192 regmap_update_bits(div->sys_regs, div->reg_ctl, 193 CCU_DIV_CTL_GATE_REF_BUF, CCU_DIV_CTL_GATE_REF_BUF); 194 spin_unlock_irqrestore(&div->lock, flags); 195} 196 197static int ccu_div_buf_is_enabled(struct clk_hw *hw) 198{ 199 struct ccu_div *div = to_ccu_div(hw); 200 u32 val = 0; 201 202 regmap_read(div->sys_regs, div->reg_ctl, &val); 203 204 return !(val & CCU_DIV_CTL_GATE_REF_BUF); 205} 206 207static unsigned long ccu_div_var_recalc_rate(struct clk_hw *hw, 208 unsigned long parent_rate) 209{ 210 struct ccu_div *div = to_ccu_div(hw); 211 unsigned long divider; 212 u32 val = 0; 213 214 regmap_read(div->sys_regs, div->reg_ctl, &val); 215 divider = ccu_div_get(div->mask, val); 216 217 return ccu_div_calc_freq(parent_rate, divider); 218} 219 220static inline unsigned long ccu_div_var_calc_divider(unsigned long rate, 221 unsigned long parent_rate, 222 unsigned int mask) 223{ 224 unsigned long divider; 225 226 divider = parent_rate / rate; 227 return clamp_t(unsigned long, divider, CCU_DIV_CLKDIV_MIN, 228 CCU_DIV_CLKDIV_MAX(mask)); 229} 230 231static long ccu_div_var_round_rate(struct clk_hw *hw, unsigned long rate, 232 unsigned long *parent_rate) 233{ 234 struct ccu_div *div = to_ccu_div(hw); 235 unsigned long divider; 236 237 divider = ccu_div_var_calc_divider(rate, *parent_rate, div->mask); 238 239 return ccu_div_calc_freq(*parent_rate, divider); 240} 241 242/* 243 * This method is used for the clock divider blocks, which support the 244 * on-the-fly rate change. So due to lacking the EN bit functionality 245 * they can't be gated before the rate adjustment. 246 */ 247static int ccu_div_var_set_rate_slow(struct clk_hw *hw, unsigned long rate, 248 unsigned long parent_rate) 249{ 250 struct ccu_div *div = to_ccu_div(hw); 251 unsigned long flags, divider; 252 u32 val; 253 int ret; 254 255 divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask); 256 if (divider == 1 && div->features & CCU_DIV_SKIP_ONE) { 257 divider = 0; 258 } else if (div->features & CCU_DIV_SKIP_ONE_TO_THREE) { 259 if (divider == 1 || divider == 2) 260 divider = 0; 261 else if (divider == 3) 262 divider = 4; 263 } 264 265 val = ccu_div_prep(div->mask, divider); 266 267 spin_lock_irqsave(&div->lock, flags); 268 regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, val); 269 ret = ccu_div_var_update_clkdiv(div, parent_rate, divider); 270 spin_unlock_irqrestore(&div->lock, flags); 271 if (ret) 272 pr_err("Divider '%s' lock timed out\n", clk_hw_get_name(hw)); 273 274 return ret; 275} 276 277/* 278 * This method is used for the clock divider blocks, which don't support 279 * the on-the-fly rate change. 280 */ 281static int ccu_div_var_set_rate_fast(struct clk_hw *hw, unsigned long rate, 282 unsigned long parent_rate) 283{ 284 struct ccu_div *div = to_ccu_div(hw); 285 unsigned long flags, divider; 286 u32 val; 287 288 divider = ccu_div_var_calc_divider(rate, parent_rate, div->mask); 289 val = ccu_div_prep(div->mask, divider); 290 291 /* 292 * Also disable the clock divider block if it was enabled by default 293 * or by the bootloader. 294 */ 295 spin_lock_irqsave(&div->lock, flags); 296 regmap_update_bits(div->sys_regs, div->reg_ctl, 297 div->mask | CCU_DIV_CTL_EN, val); 298 spin_unlock_irqrestore(&div->lock, flags); 299 300 return 0; 301} 302 303static unsigned long ccu_div_fixed_recalc_rate(struct clk_hw *hw, 304 unsigned long parent_rate) 305{ 306 struct ccu_div *div = to_ccu_div(hw); 307 308 return ccu_div_calc_freq(parent_rate, div->divider); 309} 310 311static long ccu_div_fixed_round_rate(struct clk_hw *hw, unsigned long rate, 312 unsigned long *parent_rate) 313{ 314 struct ccu_div *div = to_ccu_div(hw); 315 316 return ccu_div_calc_freq(*parent_rate, div->divider); 317} 318 319static int ccu_div_fixed_set_rate(struct clk_hw *hw, unsigned long rate, 320 unsigned long parent_rate) 321{ 322 return 0; 323} 324 325#ifdef CONFIG_DEBUG_FS 326 327struct ccu_div_dbgfs_bit { 328 struct ccu_div *div; 329 const char *name; 330 u32 mask; 331}; 332 333#define CCU_DIV_DBGFS_BIT_ATTR(_name, _mask) { \ 334 .name = _name, \ 335 .mask = _mask \ 336 } 337 338static const struct ccu_div_dbgfs_bit ccu_div_bits[] = { 339 CCU_DIV_DBGFS_BIT_ATTR("div_en", CCU_DIV_CTL_EN), 340 CCU_DIV_DBGFS_BIT_ATTR("div_rst", CCU_DIV_CTL_RST), 341 CCU_DIV_DBGFS_BIT_ATTR("div_bypass", CCU_DIV_CTL_SET_CLKDIV), 342 CCU_DIV_DBGFS_BIT_ATTR("div_buf", CCU_DIV_CTL_GATE_REF_BUF), 343 CCU_DIV_DBGFS_BIT_ATTR("div_lock", CCU_DIV_CTL_LOCK_NORMAL) 344}; 345 346#define CCU_DIV_DBGFS_BIT_NUM ARRAY_SIZE(ccu_div_bits) 347 348/* 349 * It can be dangerous to change the Divider settings behind clock framework 350 * back, therefore we don't provide any kernel config based compile time option 351 * for this feature to enable. 352 */ 353#undef CCU_DIV_ALLOW_WRITE_DEBUGFS 354#ifdef CCU_DIV_ALLOW_WRITE_DEBUGFS 355 356static int ccu_div_dbgfs_bit_set(void *priv, u64 val) 357{ 358 const struct ccu_div_dbgfs_bit *bit = priv; 359 struct ccu_div *div = bit->div; 360 unsigned long flags; 361 362 spin_lock_irqsave(&div->lock, flags); 363 regmap_update_bits(div->sys_regs, div->reg_ctl, 364 bit->mask, val ? bit->mask : 0); 365 spin_unlock_irqrestore(&div->lock, flags); 366 367 return 0; 368} 369 370static int ccu_div_dbgfs_var_clkdiv_set(void *priv, u64 val) 371{ 372 struct ccu_div *div = priv; 373 unsigned long flags; 374 u32 data; 375 376 val = clamp_t(u64, val, CCU_DIV_CLKDIV_MIN, 377 CCU_DIV_CLKDIV_MAX(div->mask)); 378 data = ccu_div_prep(div->mask, val); 379 380 spin_lock_irqsave(&div->lock, flags); 381 regmap_update_bits(div->sys_regs, div->reg_ctl, div->mask, data); 382 spin_unlock_irqrestore(&div->lock, flags); 383 384 return 0; 385} 386 387#define ccu_div_dbgfs_mode 0644 388 389#else /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */ 390 391#define ccu_div_dbgfs_bit_set NULL 392#define ccu_div_dbgfs_var_clkdiv_set NULL 393#define ccu_div_dbgfs_mode 0444 394 395#endif /* !CCU_DIV_ALLOW_WRITE_DEBUGFS */ 396 397static int ccu_div_dbgfs_bit_get(void *priv, u64 *val) 398{ 399 const struct ccu_div_dbgfs_bit *bit = priv; 400 struct ccu_div *div = bit->div; 401 u32 data = 0; 402 403 regmap_read(div->sys_regs, div->reg_ctl, &data); 404 *val = !!(data & bit->mask); 405 406 return 0; 407} 408DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_bit_fops, 409 ccu_div_dbgfs_bit_get, ccu_div_dbgfs_bit_set, "%llu\n"); 410 411static int ccu_div_dbgfs_var_clkdiv_get(void *priv, u64 *val) 412{ 413 struct ccu_div *div = priv; 414 u32 data = 0; 415 416 regmap_read(div->sys_regs, div->reg_ctl, &data); 417 *val = ccu_div_get(div->mask, data); 418 419 return 0; 420} 421DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_var_clkdiv_fops, 422 ccu_div_dbgfs_var_clkdiv_get, ccu_div_dbgfs_var_clkdiv_set, "%llu\n"); 423 424static int ccu_div_dbgfs_fixed_clkdiv_get(void *priv, u64 *val) 425{ 426 struct ccu_div *div = priv; 427 428 *val = div->divider; 429 430 return 0; 431} 432DEFINE_DEBUGFS_ATTRIBUTE(ccu_div_dbgfs_fixed_clkdiv_fops, 433 ccu_div_dbgfs_fixed_clkdiv_get, NULL, "%llu\n"); 434 435static void ccu_div_var_debug_init(struct clk_hw *hw, struct dentry *dentry) 436{ 437 struct ccu_div *div = to_ccu_div(hw); 438 struct ccu_div_dbgfs_bit *bits; 439 int didx, bidx, num = 2; 440 const char *name; 441 442 num += !!(div->flags & CLK_SET_RATE_GATE) + 443 !!(div->features & CCU_DIV_RESET_DOMAIN); 444 445 bits = kcalloc(num, sizeof(*bits), GFP_KERNEL); 446 if (!bits) 447 return; 448 449 for (didx = 0, bidx = 0; bidx < CCU_DIV_DBGFS_BIT_NUM; ++bidx) { 450 name = ccu_div_bits[bidx].name; 451 if (!(div->flags & CLK_SET_RATE_GATE) && 452 !strcmp("div_en", name)) { 453 continue; 454 } 455 456 if (!(div->features & CCU_DIV_RESET_DOMAIN) && 457 !strcmp("div_rst", name)) { 458 continue; 459 } 460 461 if (!strcmp("div_buf", name)) 462 continue; 463 464 bits[didx] = ccu_div_bits[bidx]; 465 bits[didx].div = div; 466 467 if (div->features & CCU_DIV_LOCK_SHIFTED && 468 !strcmp("div_lock", name)) { 469 bits[didx].mask = CCU_DIV_CTL_LOCK_SHIFTED; 470 } 471 472 debugfs_create_file_unsafe(bits[didx].name, ccu_div_dbgfs_mode, 473 dentry, &bits[didx], 474 &ccu_div_dbgfs_bit_fops); 475 ++didx; 476 } 477 478 debugfs_create_file_unsafe("div_clkdiv", ccu_div_dbgfs_mode, dentry, 479 div, &ccu_div_dbgfs_var_clkdiv_fops); 480} 481 482static void ccu_div_gate_debug_init(struct clk_hw *hw, struct dentry *dentry) 483{ 484 struct ccu_div *div = to_ccu_div(hw); 485 struct ccu_div_dbgfs_bit *bit; 486 487 bit = kmalloc(sizeof(*bit), GFP_KERNEL); 488 if (!bit) 489 return; 490 491 *bit = ccu_div_bits[0]; 492 bit->div = div; 493 debugfs_create_file_unsafe(bit->name, ccu_div_dbgfs_mode, dentry, bit, 494 &ccu_div_dbgfs_bit_fops); 495 496 debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div, 497 &ccu_div_dbgfs_fixed_clkdiv_fops); 498} 499 500static void ccu_div_buf_debug_init(struct clk_hw *hw, struct dentry *dentry) 501{ 502 struct ccu_div *div = to_ccu_div(hw); 503 struct ccu_div_dbgfs_bit *bit; 504 505 bit = kmalloc(sizeof(*bit), GFP_KERNEL); 506 if (!bit) 507 return; 508 509 *bit = ccu_div_bits[3]; 510 bit->div = div; 511 debugfs_create_file_unsafe(bit->name, ccu_div_dbgfs_mode, dentry, bit, 512 &ccu_div_dbgfs_bit_fops); 513} 514 515static void ccu_div_fixed_debug_init(struct clk_hw *hw, struct dentry *dentry) 516{ 517 struct ccu_div *div = to_ccu_div(hw); 518 519 debugfs_create_file_unsafe("div_clkdiv", 0400, dentry, div, 520 &ccu_div_dbgfs_fixed_clkdiv_fops); 521} 522 523#else /* !CONFIG_DEBUG_FS */ 524 525#define ccu_div_var_debug_init NULL 526#define ccu_div_gate_debug_init NULL 527#define ccu_div_buf_debug_init NULL 528#define ccu_div_fixed_debug_init NULL 529 530#endif /* !CONFIG_DEBUG_FS */ 531 532static const struct clk_ops ccu_div_var_gate_to_set_ops = { 533 .enable = ccu_div_var_enable, 534 .disable = ccu_div_gate_disable, 535 .is_enabled = ccu_div_gate_is_enabled, 536 .recalc_rate = ccu_div_var_recalc_rate, 537 .round_rate = ccu_div_var_round_rate, 538 .set_rate = ccu_div_var_set_rate_fast, 539 .debug_init = ccu_div_var_debug_init 540}; 541 542static const struct clk_ops ccu_div_var_nogate_ops = { 543 .recalc_rate = ccu_div_var_recalc_rate, 544 .round_rate = ccu_div_var_round_rate, 545 .set_rate = ccu_div_var_set_rate_slow, 546 .debug_init = ccu_div_var_debug_init 547}; 548 549static const struct clk_ops ccu_div_gate_ops = { 550 .enable = ccu_div_gate_enable, 551 .disable = ccu_div_gate_disable, 552 .is_enabled = ccu_div_gate_is_enabled, 553 .recalc_rate = ccu_div_fixed_recalc_rate, 554 .round_rate = ccu_div_fixed_round_rate, 555 .set_rate = ccu_div_fixed_set_rate, 556 .debug_init = ccu_div_gate_debug_init 557}; 558 559static const struct clk_ops ccu_div_buf_ops = { 560 .enable = ccu_div_buf_enable, 561 .disable = ccu_div_buf_disable, 562 .is_enabled = ccu_div_buf_is_enabled, 563 .debug_init = ccu_div_buf_debug_init 564}; 565 566static const struct clk_ops ccu_div_fixed_ops = { 567 .recalc_rate = ccu_div_fixed_recalc_rate, 568 .round_rate = ccu_div_fixed_round_rate, 569 .set_rate = ccu_div_fixed_set_rate, 570 .debug_init = ccu_div_fixed_debug_init 571}; 572 573struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *div_init) 574{ 575 struct clk_parent_data parent_data = { }; 576 struct clk_init_data hw_init = { }; 577 struct ccu_div *div; 578 int ret; 579 580 if (!div_init) 581 return ERR_PTR(-EINVAL); 582 583 div = kzalloc(sizeof(*div), GFP_KERNEL); 584 if (!div) 585 return ERR_PTR(-ENOMEM); 586 587 /* 588 * Note since Baikal-T1 System Controller registers are MMIO-backed 589 * we won't check the regmap IO operations return status, because it 590 * must be zero anyway. 591 */ 592 div->hw.init = &hw_init; 593 div->id = div_init->id; 594 div->reg_ctl = div_init->base + CCU_DIV_CTL; 595 div->sys_regs = div_init->sys_regs; 596 div->flags = div_init->flags; 597 div->features = div_init->features; 598 spin_lock_init(&div->lock); 599 600 hw_init.name = div_init->name; 601 hw_init.flags = div_init->flags; 602 603 if (div_init->type == CCU_DIV_VAR) { 604 if (hw_init.flags & CLK_SET_RATE_GATE) 605 hw_init.ops = &ccu_div_var_gate_to_set_ops; 606 else 607 hw_init.ops = &ccu_div_var_nogate_ops; 608 div->mask = CCU_DIV_CTL_CLKDIV_MASK(div_init->width); 609 } else if (div_init->type == CCU_DIV_GATE) { 610 hw_init.ops = &ccu_div_gate_ops; 611 div->divider = div_init->divider; 612 } else if (div_init->type == CCU_DIV_BUF) { 613 hw_init.ops = &ccu_div_buf_ops; 614 } else if (div_init->type == CCU_DIV_FIXED) { 615 hw_init.ops = &ccu_div_fixed_ops; 616 div->divider = div_init->divider; 617 } else { 618 ret = -EINVAL; 619 goto err_free_div; 620 } 621 622 if (!div_init->parent_name) { 623 ret = -EINVAL; 624 goto err_free_div; 625 } 626 parent_data.fw_name = div_init->parent_name; 627 parent_data.name = div_init->parent_name; 628 hw_init.parent_data = &parent_data; 629 hw_init.num_parents = 1; 630 631 ret = of_clk_hw_register(div_init->np, &div->hw); 632 if (ret) 633 goto err_free_div; 634 635 return div; 636 637err_free_div: 638 kfree(div); 639 640 return ERR_PTR(ret); 641} 642 643void ccu_div_hw_unregister(struct ccu_div *div) 644{ 645 clk_hw_unregister(&div->hw); 646 647 kfree(div); 648} 649