linux/drivers/memory/tegra/tegra20-emc.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Tegra20 External Memory Controller driver
   4 *
   5 * Author: Dmitry Osipenko <digetx@gmail.com>
   6 */
   7
   8#include <linux/bitfield.h>
   9#include <linux/clk.h>
  10#include <linux/clk/tegra.h>
  11#include <linux/debugfs.h>
  12#include <linux/devfreq.h>
  13#include <linux/err.h>
  14#include <linux/interconnect-provider.h>
  15#include <linux/interrupt.h>
  16#include <linux/io.h>
  17#include <linux/iopoll.h>
  18#include <linux/kernel.h>
  19#include <linux/module.h>
  20#include <linux/mutex.h>
  21#include <linux/of.h>
  22#include <linux/platform_device.h>
  23#include <linux/pm_opp.h>
  24#include <linux/slab.h>
  25#include <linux/sort.h>
  26#include <linux/types.h>
  27
  28#include <soc/tegra/common.h>
  29#include <soc/tegra/fuse.h>
  30
  31#include "../jedec_ddr.h"
  32#include "../of_memory.h"
  33
  34#include "mc.h"
  35
  36#define EMC_INTSTATUS                           0x000
  37#define EMC_INTMASK                             0x004
  38#define EMC_DBG                                 0x008
  39#define EMC_ADR_CFG_0                           0x010
  40#define EMC_TIMING_CONTROL                      0x028
  41#define EMC_RC                                  0x02c
  42#define EMC_RFC                                 0x030
  43#define EMC_RAS                                 0x034
  44#define EMC_RP                                  0x038
  45#define EMC_R2W                                 0x03c
  46#define EMC_W2R                                 0x040
  47#define EMC_R2P                                 0x044
  48#define EMC_W2P                                 0x048
  49#define EMC_RD_RCD                              0x04c
  50#define EMC_WR_RCD                              0x050
  51#define EMC_RRD                                 0x054
  52#define EMC_REXT                                0x058
  53#define EMC_WDV                                 0x05c
  54#define EMC_QUSE                                0x060
  55#define EMC_QRST                                0x064
  56#define EMC_QSAFE                               0x068
  57#define EMC_RDV                                 0x06c
  58#define EMC_REFRESH                             0x070
  59#define EMC_BURST_REFRESH_NUM                   0x074
  60#define EMC_PDEX2WR                             0x078
  61#define EMC_PDEX2RD                             0x07c
  62#define EMC_PCHG2PDEN                           0x080
  63#define EMC_ACT2PDEN                            0x084
  64#define EMC_AR2PDEN                             0x088
  65#define EMC_RW2PDEN                             0x08c
  66#define EMC_TXSR                                0x090
  67#define EMC_TCKE                                0x094
  68#define EMC_TFAW                                0x098
  69#define EMC_TRPAB                               0x09c
  70#define EMC_TCLKSTABLE                          0x0a0
  71#define EMC_TCLKSTOP                            0x0a4
  72#define EMC_TREFBW                              0x0a8
  73#define EMC_QUSE_EXTRA                          0x0ac
  74#define EMC_ODT_WRITE                           0x0b0
  75#define EMC_ODT_READ                            0x0b4
  76#define EMC_MRR                                 0x0ec
  77#define EMC_FBIO_CFG5                           0x104
  78#define EMC_FBIO_CFG6                           0x114
  79#define EMC_STAT_CONTROL                        0x160
  80#define EMC_STAT_LLMC_CONTROL                   0x178
  81#define EMC_STAT_PWR_CLOCK_LIMIT                0x198
  82#define EMC_STAT_PWR_CLOCKS                     0x19c
  83#define EMC_STAT_PWR_COUNT                      0x1a0
  84#define EMC_AUTO_CAL_INTERVAL                   0x2a8
  85#define EMC_CFG_2                               0x2b8
  86#define EMC_CFG_DIG_DLL                         0x2bc
  87#define EMC_DLL_XFORM_DQS                       0x2c0
  88#define EMC_DLL_XFORM_QUSE                      0x2c4
  89#define EMC_ZCAL_REF_CNT                        0x2e0
  90#define EMC_ZCAL_WAIT_CNT                       0x2e4
  91#define EMC_CFG_CLKTRIM_0                       0x2d0
  92#define EMC_CFG_CLKTRIM_1                       0x2d4
  93#define EMC_CFG_CLKTRIM_2                       0x2d8
  94
  95#define EMC_CLKCHANGE_REQ_ENABLE                BIT(0)
  96#define EMC_CLKCHANGE_PD_ENABLE                 BIT(1)
  97#define EMC_CLKCHANGE_SR_ENABLE                 BIT(2)
  98
  99#define EMC_TIMING_UPDATE                       BIT(0)
 100
 101#define EMC_REFRESH_OVERFLOW_INT                BIT(3)
 102#define EMC_CLKCHANGE_COMPLETE_INT              BIT(4)
 103#define EMC_MRR_DIVLD_INT                       BIT(5)
 104
 105#define EMC_DBG_READ_MUX_ASSEMBLY               BIT(0)
 106#define EMC_DBG_WRITE_MUX_ACTIVE                BIT(1)
 107#define EMC_DBG_FORCE_UPDATE                    BIT(2)
 108#define EMC_DBG_READ_DQM_CTRL                   BIT(9)
 109#define EMC_DBG_CFG_PRIORITY                    BIT(24)
 110
 111#define EMC_FBIO_CFG5_DRAM_WIDTH_X16            BIT(4)
 112#define EMC_FBIO_CFG5_DRAM_TYPE                 GENMASK(1, 0)
 113
 114#define EMC_MRR_DEV_SELECTN                     GENMASK(31, 30)
 115#define EMC_MRR_MRR_MA                          GENMASK(23, 16)
 116#define EMC_MRR_MRR_DATA                        GENMASK(15, 0)
 117
 118#define EMC_ADR_CFG_0_EMEM_NUMDEV               GENMASK(25, 24)
 119
 120#define EMC_PWR_GATHER_CLEAR                    (1 << 8)
 121#define EMC_PWR_GATHER_DISABLE                  (2 << 8)
 122#define EMC_PWR_GATHER_ENABLE                   (3 << 8)
 123
 124enum emc_dram_type {
 125        DRAM_TYPE_RESERVED,
 126        DRAM_TYPE_DDR1,
 127        DRAM_TYPE_LPDDR2,
 128        DRAM_TYPE_DDR2,
 129};
 130
 131static const u16 emc_timing_registers[] = {
 132        EMC_RC,
 133        EMC_RFC,
 134        EMC_RAS,
 135        EMC_RP,
 136        EMC_R2W,
 137        EMC_W2R,
 138        EMC_R2P,
 139        EMC_W2P,
 140        EMC_RD_RCD,
 141        EMC_WR_RCD,
 142        EMC_RRD,
 143        EMC_REXT,
 144        EMC_WDV,
 145        EMC_QUSE,
 146        EMC_QRST,
 147        EMC_QSAFE,
 148        EMC_RDV,
 149        EMC_REFRESH,
 150        EMC_BURST_REFRESH_NUM,
 151        EMC_PDEX2WR,
 152        EMC_PDEX2RD,
 153        EMC_PCHG2PDEN,
 154        EMC_ACT2PDEN,
 155        EMC_AR2PDEN,
 156        EMC_RW2PDEN,
 157        EMC_TXSR,
 158        EMC_TCKE,
 159        EMC_TFAW,
 160        EMC_TRPAB,
 161        EMC_TCLKSTABLE,
 162        EMC_TCLKSTOP,
 163        EMC_TREFBW,
 164        EMC_QUSE_EXTRA,
 165        EMC_FBIO_CFG6,
 166        EMC_ODT_WRITE,
 167        EMC_ODT_READ,
 168        EMC_FBIO_CFG5,
 169        EMC_CFG_DIG_DLL,
 170        EMC_DLL_XFORM_DQS,
 171        EMC_DLL_XFORM_QUSE,
 172        EMC_ZCAL_REF_CNT,
 173        EMC_ZCAL_WAIT_CNT,
 174        EMC_AUTO_CAL_INTERVAL,
 175        EMC_CFG_CLKTRIM_0,
 176        EMC_CFG_CLKTRIM_1,
 177        EMC_CFG_CLKTRIM_2,
 178};
 179
 180struct emc_timing {
 181        unsigned long rate;
 182        u32 data[ARRAY_SIZE(emc_timing_registers)];
 183};
 184
 185enum emc_rate_request_type {
 186        EMC_RATE_DEVFREQ,
 187        EMC_RATE_DEBUG,
 188        EMC_RATE_ICC,
 189        EMC_RATE_TYPE_MAX,
 190};
 191
 192struct emc_rate_request {
 193        unsigned long min_rate;
 194        unsigned long max_rate;
 195};
 196
 197struct tegra_emc {
 198        struct device *dev;
 199        struct tegra_mc *mc;
 200        struct icc_provider provider;
 201        struct notifier_block clk_nb;
 202        struct clk *clk;
 203        void __iomem *regs;
 204        unsigned int dram_bus_width;
 205
 206        struct emc_timing *timings;
 207        unsigned int num_timings;
 208
 209        struct {
 210                struct dentry *root;
 211                unsigned long min_rate;
 212                unsigned long max_rate;
 213        } debugfs;
 214
 215        /*
 216         * There are multiple sources in the EMC driver which could request
 217         * a min/max clock rate, these rates are contained in this array.
 218         */
 219        struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];
 220
 221        /* protect shared rate-change code path */
 222        struct mutex rate_lock;
 223
 224        struct devfreq_simple_ondemand_data ondemand_data;
 225
 226        /* memory chip identity information */
 227        union lpddr2_basic_config4 basic_conf4;
 228        unsigned int manufacturer_id;
 229        unsigned int revision_id1;
 230        unsigned int revision_id2;
 231
 232        bool mrr_error;
 233};
 234
 235static irqreturn_t tegra_emc_isr(int irq, void *data)
 236{
 237        struct tegra_emc *emc = data;
 238        u32 intmask = EMC_REFRESH_OVERFLOW_INT;
 239        u32 status;
 240
 241        status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
 242        if (!status)
 243                return IRQ_NONE;
 244
 245        /* notify about HW problem */
 246        if (status & EMC_REFRESH_OVERFLOW_INT)
 247                dev_err_ratelimited(emc->dev,
 248                                    "refresh request overflow timeout\n");
 249
 250        /* clear interrupts */
 251        writel_relaxed(status, emc->regs + EMC_INTSTATUS);
 252
 253        return IRQ_HANDLED;
 254}
 255
 256static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc,
 257                                                unsigned long rate)
 258{
 259        struct emc_timing *timing = NULL;
 260        unsigned int i;
 261
 262        for (i = 0; i < emc->num_timings; i++) {
 263                if (emc->timings[i].rate >= rate) {
 264                        timing = &emc->timings[i];
 265                        break;
 266                }
 267        }
 268
 269        if (!timing) {
 270                dev_err(emc->dev, "no timing for rate %lu\n", rate);
 271                return NULL;
 272        }
 273
 274        return timing;
 275}
 276
 277static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
 278{
 279        struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
 280        unsigned int i;
 281
 282        if (!timing)
 283                return -EINVAL;
 284
 285        dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
 286                __func__, timing->rate, rate);
 287
 288        /* program shadow registers */
 289        for (i = 0; i < ARRAY_SIZE(timing->data); i++)
 290                writel_relaxed(timing->data[i],
 291                               emc->regs + emc_timing_registers[i]);
 292
 293        /* wait until programming has settled */
 294        readl_relaxed(emc->regs + emc_timing_registers[i - 1]);
 295
 296        return 0;
 297}
 298
 299static int emc_complete_timing_change(struct tegra_emc *emc, bool flush)
 300{
 301        int err;
 302        u32 v;
 303
 304        dev_dbg(emc->dev, "%s: flush %d\n", __func__, flush);
 305
 306        if (flush) {
 307                /* manually initiate memory timing update */
 308                writel_relaxed(EMC_TIMING_UPDATE,
 309                               emc->regs + EMC_TIMING_CONTROL);
 310                return 0;
 311        }
 312
 313        err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, v,
 314                                                v & EMC_CLKCHANGE_COMPLETE_INT,
 315                                                1, 100);
 316        if (err) {
 317                dev_err(emc->dev, "emc-car handshake timeout: %d\n", err);
 318                return err;
 319        }
 320
 321        return 0;
 322}
 323
 324static int tegra_emc_clk_change_notify(struct notifier_block *nb,
 325                                       unsigned long msg, void *data)
 326{
 327        struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
 328        struct clk_notifier_data *cnd = data;
 329        int err;
 330
 331        switch (msg) {
 332        case PRE_RATE_CHANGE:
 333                err = emc_prepare_timing_change(emc, cnd->new_rate);
 334                break;
 335
 336        case ABORT_RATE_CHANGE:
 337                err = emc_prepare_timing_change(emc, cnd->old_rate);
 338                if (err)
 339                        break;
 340
 341                err = emc_complete_timing_change(emc, true);
 342                break;
 343
 344        case POST_RATE_CHANGE:
 345                err = emc_complete_timing_change(emc, false);
 346                break;
 347
 348        default:
 349                return NOTIFY_DONE;
 350        }
 351
 352        return notifier_from_errno(err);
 353}
 354
 355static int load_one_timing_from_dt(struct tegra_emc *emc,
 356                                   struct emc_timing *timing,
 357                                   struct device_node *node)
 358{
 359        u32 rate;
 360        int err;
 361
 362        if (!of_device_is_compatible(node, "nvidia,tegra20-emc-table")) {
 363                dev_err(emc->dev, "incompatible DT node: %pOF\n", node);
 364                return -EINVAL;
 365        }
 366
 367        err = of_property_read_u32(node, "clock-frequency", &rate);
 368        if (err) {
 369                dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n",
 370                        node, err);
 371                return err;
 372        }
 373
 374        err = of_property_read_u32_array(node, "nvidia,emc-registers",
 375                                         timing->data,
 376                                         ARRAY_SIZE(emc_timing_registers));
 377        if (err) {
 378                dev_err(emc->dev,
 379                        "timing %pOF: failed to read emc timing data: %d\n",
 380                        node, err);
 381                return err;
 382        }
 383
 384        /*
 385         * The EMC clock rate is twice the bus rate, and the bus rate is
 386         * measured in kHz.
 387         */
 388        timing->rate = rate * 2 * 1000;
 389
 390        dev_dbg(emc->dev, "%s: %pOF: EMC rate %lu\n",
 391                __func__, node, timing->rate);
 392
 393        return 0;
 394}
 395
 396static int cmp_timings(const void *_a, const void *_b)
 397{
 398        const struct emc_timing *a = _a;
 399        const struct emc_timing *b = _b;
 400
 401        if (a->rate < b->rate)
 402                return -1;
 403
 404        if (a->rate > b->rate)
 405                return 1;
 406
 407        return 0;
 408}
 409
 410static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc,
 411                                          struct device_node *node)
 412{
 413        struct device_node *child;
 414        struct emc_timing *timing;
 415        int child_count;
 416        int err;
 417
 418        child_count = of_get_child_count(node);
 419        if (!child_count) {
 420                dev_err(emc->dev, "no memory timings in DT node: %pOF\n", node);
 421                return -EINVAL;
 422        }
 423
 424        emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
 425                                    GFP_KERNEL);
 426        if (!emc->timings)
 427                return -ENOMEM;
 428
 429        timing = emc->timings;
 430
 431        for_each_child_of_node(node, child) {
 432                if (of_node_name_eq(child, "lpddr2"))
 433                        continue;
 434
 435                err = load_one_timing_from_dt(emc, timing++, child);
 436                if (err) {
 437                        of_node_put(child);
 438                        return err;
 439                }
 440
 441                emc->num_timings++;
 442        }
 443
 444        sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
 445             NULL);
 446
 447        dev_info_once(emc->dev,
 448                      "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
 449                      emc->num_timings,
 450                      tegra_read_ram_code(),
 451                      emc->timings[0].rate / 1000000,
 452                      emc->timings[emc->num_timings - 1].rate / 1000000);
 453
 454        return 0;
 455}
 456
 457static struct device_node *
 458tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
 459{
 460        struct device *dev = emc->dev;
 461        struct device_node *np;
 462        u32 value, ram_code;
 463        int err;
 464
 465        if (emc->mrr_error) {
 466                dev_warn(dev, "memory timings skipped due to MRR error\n");
 467                return NULL;
 468        }
 469
 470        if (of_get_child_count(dev->of_node) == 0) {
 471                dev_info_once(dev, "device-tree doesn't have memory timings\n");
 472                return NULL;
 473        }
 474
 475        if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
 476                return of_node_get(dev->of_node);
 477
 478        ram_code = tegra_read_ram_code();
 479
 480        for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
 481             np = of_find_node_by_name(np, "emc-tables")) {
 482                err = of_property_read_u32(np, "nvidia,ram-code", &value);
 483                if (err || value != ram_code) {
 484                        struct device_node *lpddr2_np;
 485                        bool cfg_mismatches = false;
 486
 487                        lpddr2_np = of_find_node_by_name(np, "lpddr2");
 488                        if (lpddr2_np) {
 489                                const struct lpddr2_info *info;
 490
 491                                info = of_lpddr2_get_info(lpddr2_np, dev);
 492                                if (info) {
 493                                        if (info->manufacturer_id >= 0 &&
 494                                            info->manufacturer_id != emc->manufacturer_id)
 495                                                cfg_mismatches = true;
 496
 497                                        if (info->revision_id1 >= 0 &&
 498                                            info->revision_id1 != emc->revision_id1)
 499                                                cfg_mismatches = true;
 500
 501                                        if (info->revision_id2 >= 0 &&
 502                                            info->revision_id2 != emc->revision_id2)
 503                                                cfg_mismatches = true;
 504
 505                                        if (info->density != emc->basic_conf4.density)
 506                                                cfg_mismatches = true;
 507
 508                                        if (info->io_width != emc->basic_conf4.io_width)
 509                                                cfg_mismatches = true;
 510
 511                                        if (info->arch_type != emc->basic_conf4.arch_type)
 512                                                cfg_mismatches = true;
 513                                } else {
 514                                        dev_err(dev, "failed to parse %pOF\n", lpddr2_np);
 515                                        cfg_mismatches = true;
 516                                }
 517
 518                                of_node_put(lpddr2_np);
 519                        } else {
 520                                cfg_mismatches = true;
 521                        }
 522
 523                        if (cfg_mismatches) {
 524                                of_node_put(np);
 525                                continue;
 526                        }
 527                }
 528
 529                return np;
 530        }
 531
 532        dev_err(dev, "no memory timings for RAM code %u found in device tree\n",
 533                ram_code);
 534
 535        return NULL;
 536}
 537
 538static int emc_read_lpddr_mode_register(struct tegra_emc *emc,
 539                                        unsigned int emem_dev,
 540                                        unsigned int register_addr,
 541                                        unsigned int *register_data)
 542{
 543        u32 memory_dev = emem_dev + 1;
 544        u32 val, mr_mask = 0xff;
 545        int err;
 546
 547        /* clear data-valid interrupt status */
 548        writel_relaxed(EMC_MRR_DIVLD_INT, emc->regs + EMC_INTSTATUS);
 549
 550        /* issue mode register read request */
 551        val  = FIELD_PREP(EMC_MRR_DEV_SELECTN, memory_dev);
 552        val |= FIELD_PREP(EMC_MRR_MRR_MA, register_addr);
 553
 554        writel_relaxed(val, emc->regs + EMC_MRR);
 555
 556        /* wait for the LPDDR2 data-valid interrupt */
 557        err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, val,
 558                                                val & EMC_MRR_DIVLD_INT,
 559                                                1, 100);
 560        if (err) {
 561                dev_err(emc->dev, "mode register %u read failed: %d\n",
 562                        register_addr, err);
 563                emc->mrr_error = true;
 564                return err;
 565        }
 566
 567        /* read out mode register data */
 568        val = readl_relaxed(emc->regs + EMC_MRR);
 569        *register_data = FIELD_GET(EMC_MRR_MRR_DATA, val) & mr_mask;
 570
 571        return 0;
 572}
 573
 574static void emc_read_lpddr_sdram_info(struct tegra_emc *emc,
 575                                      unsigned int emem_dev,
 576                                      bool print_out)
 577{
 578        /* these registers are standard for all LPDDR JEDEC memory chips */
 579        emc_read_lpddr_mode_register(emc, emem_dev, 5, &emc->manufacturer_id);
 580        emc_read_lpddr_mode_register(emc, emem_dev, 6, &emc->revision_id1);
 581        emc_read_lpddr_mode_register(emc, emem_dev, 7, &emc->revision_id2);
 582        emc_read_lpddr_mode_register(emc, emem_dev, 8, &emc->basic_conf4.value);
 583
 584        if (!print_out)
 585                return;
 586
 587        dev_info(emc->dev, "SDRAM[dev%u]: manufacturer: 0x%x (%s) rev1: 0x%x rev2: 0x%x prefetch: S%u density: %uMbit iowidth: %ubit\n",
 588                 emem_dev, emc->manufacturer_id,
 589                 lpddr2_jedec_manufacturer(emc->manufacturer_id),
 590                 emc->revision_id1, emc->revision_id2,
 591                 4 >> emc->basic_conf4.arch_type,
 592                 64 << emc->basic_conf4.density,
 593                 32 >> emc->basic_conf4.io_width);
 594}
 595
 596static int emc_setup_hw(struct tegra_emc *emc)
 597{
 598        u32 emc_cfg, emc_dbg, emc_fbio, emc_adr_cfg;
 599        u32 intmask = EMC_REFRESH_OVERFLOW_INT;
 600        static bool print_sdram_info_once;
 601        enum emc_dram_type dram_type;
 602        const char *dram_type_str;
 603        unsigned int emem_numdev;
 604
 605        emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
 606
 607        /*
 608         * Depending on a memory type, DRAM should enter either self-refresh
 609         * or power-down state on EMC clock change.
 610         */
 611        if (!(emc_cfg & EMC_CLKCHANGE_PD_ENABLE) &&
 612            !(emc_cfg & EMC_CLKCHANGE_SR_ENABLE)) {
 613                dev_err(emc->dev,
 614                        "bootloader didn't specify DRAM auto-suspend mode\n");
 615                return -EINVAL;
 616        }
 617
 618        /* enable EMC and CAR to handshake on PLL divider/source changes */
 619        emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
 620        writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);
 621
 622        /* initialize interrupt */
 623        writel_relaxed(intmask, emc->regs + EMC_INTMASK);
 624        writel_relaxed(intmask, emc->regs + EMC_INTSTATUS);
 625
 626        /* ensure that unwanted debug features are disabled */
 627        emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
 628        emc_dbg |= EMC_DBG_CFG_PRIORITY;
 629        emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
 630        emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
 631        emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
 632        writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
 633
 634        emc_fbio = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
 635
 636        if (emc_fbio & EMC_FBIO_CFG5_DRAM_WIDTH_X16)
 637                emc->dram_bus_width = 16;
 638        else
 639                emc->dram_bus_width = 32;
 640
 641        dram_type = FIELD_GET(EMC_FBIO_CFG5_DRAM_TYPE, emc_fbio);
 642
 643        switch (dram_type) {
 644        case DRAM_TYPE_RESERVED:
 645                dram_type_str = "INVALID";
 646                break;
 647        case DRAM_TYPE_DDR1:
 648                dram_type_str = "DDR1";
 649                break;
 650        case DRAM_TYPE_LPDDR2:
 651                dram_type_str = "LPDDR2";
 652                break;
 653        case DRAM_TYPE_DDR2:
 654                dram_type_str = "DDR2";
 655                break;
 656        }
 657
 658        emc_adr_cfg = readl_relaxed(emc->regs + EMC_ADR_CFG_0);
 659        emem_numdev = FIELD_GET(EMC_ADR_CFG_0_EMEM_NUMDEV, emc_adr_cfg) + 1;
 660
 661        dev_info_once(emc->dev, "%ubit DRAM bus, %u %s %s attached\n",
 662                      emc->dram_bus_width, emem_numdev, dram_type_str,
 663                      emem_numdev == 2 ? "devices" : "device");
 664
 665        if (dram_type == DRAM_TYPE_LPDDR2) {
 666                while (emem_numdev--)
 667                        emc_read_lpddr_sdram_info(emc, emem_numdev,
 668                                                  !print_sdram_info_once);
 669                print_sdram_info_once = true;
 670        }
 671
 672        return 0;
 673}
 674
 675static long emc_round_rate(unsigned long rate,
 676                           unsigned long min_rate,
 677                           unsigned long max_rate,
 678                           void *arg)
 679{
 680        struct emc_timing *timing = NULL;
 681        struct tegra_emc *emc = arg;
 682        unsigned int i;
 683
 684        if (!emc->num_timings)
 685                return clk_get_rate(emc->clk);
 686
 687        min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
 688
 689        for (i = 0; i < emc->num_timings; i++) {
 690                if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
 691                        continue;
 692
 693                if (emc->timings[i].rate > max_rate) {
 694                        i = max(i, 1u) - 1;
 695
 696                        if (emc->timings[i].rate < min_rate)
 697                                break;
 698                }
 699
 700                if (emc->timings[i].rate < min_rate)
 701                        continue;
 702
 703                timing = &emc->timings[i];
 704                break;
 705        }
 706
 707        if (!timing) {
 708                dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
 709                        rate, min_rate, max_rate);
 710                return -EINVAL;
 711        }
 712
 713        return timing->rate;
 714}
 715
 716static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
 717{
 718        unsigned int i;
 719
 720        for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
 721                emc->requested_rate[i].min_rate = 0;
 722                emc->requested_rate[i].max_rate = ULONG_MAX;
 723        }
 724}
 725
 726static int emc_request_rate(struct tegra_emc *emc,
 727                            unsigned long new_min_rate,
 728                            unsigned long new_max_rate,
 729                            enum emc_rate_request_type type)
 730{
 731        struct emc_rate_request *req = emc->requested_rate;
 732        unsigned long min_rate = 0, max_rate = ULONG_MAX;
 733        unsigned int i;
 734        int err;
 735
 736        /* select minimum and maximum rates among the requested rates */
 737        for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
 738                if (i == type) {
 739                        min_rate = max(new_min_rate, min_rate);
 740                        max_rate = min(new_max_rate, max_rate);
 741                } else {
 742                        min_rate = max(req->min_rate, min_rate);
 743                        max_rate = min(req->max_rate, max_rate);
 744                }
 745        }
 746
 747        if (min_rate > max_rate) {
 748                dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
 749                                    __func__, type, min_rate, max_rate);
 750                return -ERANGE;
 751        }
 752
 753        /*
 754         * EMC rate-changes should go via OPP API because it manages voltage
 755         * changes.
 756         */
 757        err = dev_pm_opp_set_rate(emc->dev, min_rate);
 758        if (err)
 759                return err;
 760
 761        emc->requested_rate[type].min_rate = new_min_rate;
 762        emc->requested_rate[type].max_rate = new_max_rate;
 763
 764        return 0;
 765}
 766
 767static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
 768                            enum emc_rate_request_type type)
 769{
 770        struct emc_rate_request *req = &emc->requested_rate[type];
 771        int ret;
 772
 773        mutex_lock(&emc->rate_lock);
 774        ret = emc_request_rate(emc, rate, req->max_rate, type);
 775        mutex_unlock(&emc->rate_lock);
 776
 777        return ret;
 778}
 779
 780static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
 781                            enum emc_rate_request_type type)
 782{
 783        struct emc_rate_request *req = &emc->requested_rate[type];
 784        int ret;
 785
 786        mutex_lock(&emc->rate_lock);
 787        ret = emc_request_rate(emc, req->min_rate, rate, type);
 788        mutex_unlock(&emc->rate_lock);
 789
 790        return ret;
 791}
 792
 793/*
 794 * debugfs interface
 795 *
 796 * The memory controller driver exposes some files in debugfs that can be used
 797 * to control the EMC frequency. The top-level directory can be found here:
 798 *
 799 *   /sys/kernel/debug/emc
 800 *
 801 * It contains the following files:
 802 *
 803 *   - available_rates: This file contains a list of valid, space-separated
 804 *     EMC frequencies.
 805 *
 806 *   - min_rate: Writing a value to this file sets the given frequency as the
 807 *       floor of the permitted range. If this is higher than the currently
 808 *       configured EMC frequency, this will cause the frequency to be
 809 *       increased so that it stays within the valid range.
 810 *
 811 *   - max_rate: Similarily to the min_rate file, writing a value to this file
 812 *       sets the given frequency as the ceiling of the permitted range. If
 813 *       the value is lower than the currently configured EMC frequency, this
 814 *       will cause the frequency to be decreased so that it stays within the
 815 *       valid range.
 816 */
 817
 818static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate)
 819{
 820        unsigned int i;
 821
 822        for (i = 0; i < emc->num_timings; i++)
 823                if (rate == emc->timings[i].rate)
 824                        return true;
 825
 826        return false;
 827}
 828
 829static int tegra_emc_debug_available_rates_show(struct seq_file *s, void *data)
 830{
 831        struct tegra_emc *emc = s->private;
 832        const char *prefix = "";
 833        unsigned int i;
 834
 835        for (i = 0; i < emc->num_timings; i++) {
 836                seq_printf(s, "%s%lu", prefix, emc->timings[i].rate);
 837                prefix = " ";
 838        }
 839
 840        seq_puts(s, "\n");
 841
 842        return 0;
 843}
 844
 845static int tegra_emc_debug_available_rates_open(struct inode *inode,
 846                                                struct file *file)
 847{
 848        return single_open(file, tegra_emc_debug_available_rates_show,
 849                           inode->i_private);
 850}
 851
 852static const struct file_operations tegra_emc_debug_available_rates_fops = {
 853        .open = tegra_emc_debug_available_rates_open,
 854        .read = seq_read,
 855        .llseek = seq_lseek,
 856        .release = single_release,
 857};
 858
 859static int tegra_emc_debug_min_rate_get(void *data, u64 *rate)
 860{
 861        struct tegra_emc *emc = data;
 862
 863        *rate = emc->debugfs.min_rate;
 864
 865        return 0;
 866}
 867
 868static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
 869{
 870        struct tegra_emc *emc = data;
 871        int err;
 872
 873        if (!tegra_emc_validate_rate(emc, rate))
 874                return -EINVAL;
 875
 876        err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
 877        if (err < 0)
 878                return err;
 879
 880        emc->debugfs.min_rate = rate;
 881
 882        return 0;
 883}
 884
 885DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
 886                        tegra_emc_debug_min_rate_get,
 887                        tegra_emc_debug_min_rate_set, "%llu\n");
 888
 889static int tegra_emc_debug_max_rate_get(void *data, u64 *rate)
 890{
 891        struct tegra_emc *emc = data;
 892
 893        *rate = emc->debugfs.max_rate;
 894
 895        return 0;
 896}
 897
 898static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
 899{
 900        struct tegra_emc *emc = data;
 901        int err;
 902
 903        if (!tegra_emc_validate_rate(emc, rate))
 904                return -EINVAL;
 905
 906        err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
 907        if (err < 0)
 908                return err;
 909
 910        emc->debugfs.max_rate = rate;
 911
 912        return 0;
 913}
 914
 915DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
 916                        tegra_emc_debug_max_rate_get,
 917                        tegra_emc_debug_max_rate_set, "%llu\n");
 918
 919static void tegra_emc_debugfs_init(struct tegra_emc *emc)
 920{
 921        struct device *dev = emc->dev;
 922        unsigned int i;
 923        int err;
 924
 925        emc->debugfs.min_rate = ULONG_MAX;
 926        emc->debugfs.max_rate = 0;
 927
 928        for (i = 0; i < emc->num_timings; i++) {
 929                if (emc->timings[i].rate < emc->debugfs.min_rate)
 930                        emc->debugfs.min_rate = emc->timings[i].rate;
 931
 932                if (emc->timings[i].rate > emc->debugfs.max_rate)
 933                        emc->debugfs.max_rate = emc->timings[i].rate;
 934        }
 935
 936        if (!emc->num_timings) {
 937                emc->debugfs.min_rate = clk_get_rate(emc->clk);
 938                emc->debugfs.max_rate = emc->debugfs.min_rate;
 939        }
 940
 941        err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate,
 942                                 emc->debugfs.max_rate);
 943        if (err < 0) {
 944                dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n",
 945                        emc->debugfs.min_rate, emc->debugfs.max_rate,
 946                        emc->clk);
 947        }
 948
 949        emc->debugfs.root = debugfs_create_dir("emc", NULL);
 950
 951        debugfs_create_file("available_rates", 0444, emc->debugfs.root,
 952                            emc, &tegra_emc_debug_available_rates_fops);
 953        debugfs_create_file("min_rate", 0644, emc->debugfs.root,
 954                            emc, &tegra_emc_debug_min_rate_fops);
 955        debugfs_create_file("max_rate", 0644, emc->debugfs.root,
 956                            emc, &tegra_emc_debug_max_rate_fops);
 957}
 958
 959static inline struct tegra_emc *
 960to_tegra_emc_provider(struct icc_provider *provider)
 961{
 962        return container_of(provider, struct tegra_emc, provider);
 963}
 964
 965static struct icc_node_data *
 966emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
 967{
 968        struct icc_provider *provider = data;
 969        struct icc_node_data *ndata;
 970        struct icc_node *node;
 971
 972        /* External Memory is the only possible ICC route */
 973        list_for_each_entry(node, &provider->nodes, node_list) {
 974                if (node->id != TEGRA_ICC_EMEM)
 975                        continue;
 976
 977                ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
 978                if (!ndata)
 979                        return ERR_PTR(-ENOMEM);
 980
 981                /*
 982                 * SRC and DST nodes should have matching TAG in order to have
 983                 * it set by default for a requested path.
 984                 */
 985                ndata->tag = TEGRA_MC_ICC_TAG_ISO;
 986                ndata->node = node;
 987
 988                return ndata;
 989        }
 990
 991        return ERR_PTR(-EPROBE_DEFER);
 992}
 993
 994static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
 995{
 996        struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
 997        unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
 998        unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
 999        unsigned long long rate = max(avg_bw, peak_bw);
1000        unsigned int dram_data_bus_width_bytes;
1001        int err;
1002
1003        /*
1004         * Tegra20 EMC runs on x2 clock rate of SDRAM bus because DDR data
1005         * is sampled on both clock edges.  This means that EMC clock rate
1006         * equals to the peak data-rate.
1007         */
1008        dram_data_bus_width_bytes = emc->dram_bus_width / 8;
1009        do_div(rate, dram_data_bus_width_bytes);
1010        rate = min_t(u64, rate, U32_MAX);
1011
1012        err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
1013        if (err)
1014                return err;
1015
1016        return 0;
1017}
1018
1019static int tegra_emc_interconnect_init(struct tegra_emc *emc)
1020{
1021        const struct tegra_mc_soc *soc;
1022        struct icc_node *node;
1023        int err;
1024
1025        emc->mc = devm_tegra_memory_controller_get(emc->dev);
1026        if (IS_ERR(emc->mc))
1027                return PTR_ERR(emc->mc);
1028
1029        soc = emc->mc->soc;
1030
1031        emc->provider.dev = emc->dev;
1032        emc->provider.set = emc_icc_set;
1033        emc->provider.data = &emc->provider;
1034        emc->provider.aggregate = soc->icc_ops->aggregate;
1035        emc->provider.xlate_extended = emc_of_icc_xlate_extended;
1036
1037        err = icc_provider_add(&emc->provider);
1038        if (err)
1039                goto err_msg;
1040
1041        /* create External Memory Controller node */
1042        node = icc_node_create(TEGRA_ICC_EMC);
1043        if (IS_ERR(node)) {
1044                err = PTR_ERR(node);
1045                goto del_provider;
1046        }
1047
1048        node->name = "External Memory Controller";
1049        icc_node_add(node, &emc->provider);
1050
1051        /* link External Memory Controller to External Memory (DRAM) */
1052        err = icc_link_create(node, TEGRA_ICC_EMEM);
1053        if (err)
1054                goto remove_nodes;
1055
1056        /* create External Memory node */
1057        node = icc_node_create(TEGRA_ICC_EMEM);
1058        if (IS_ERR(node)) {
1059                err = PTR_ERR(node);
1060                goto remove_nodes;
1061        }
1062
1063        node->name = "External Memory (DRAM)";
1064        icc_node_add(node, &emc->provider);
1065
1066        return 0;
1067
1068remove_nodes:
1069        icc_nodes_remove(&emc->provider);
1070del_provider:
1071        icc_provider_del(&emc->provider);
1072err_msg:
1073        dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
1074
1075        return err;
1076}
1077
1078static void devm_tegra_emc_unset_callback(void *data)
1079{
1080        tegra20_clk_set_emc_round_callback(NULL, NULL);
1081}
1082
1083static void devm_tegra_emc_unreg_clk_notifier(void *data)
1084{
1085        struct tegra_emc *emc = data;
1086
1087        clk_notifier_unregister(emc->clk, &emc->clk_nb);
1088}
1089
1090static int tegra_emc_init_clk(struct tegra_emc *emc)
1091{
1092        int err;
1093
1094        tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
1095
1096        err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
1097                                       NULL);
1098        if (err)
1099                return err;
1100
1101        emc->clk = devm_clk_get(emc->dev, NULL);
1102        if (IS_ERR(emc->clk)) {
1103                dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
1104                return PTR_ERR(emc->clk);
1105        }
1106
1107        err = clk_notifier_register(emc->clk, &emc->clk_nb);
1108        if (err) {
1109                dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
1110                return err;
1111        }
1112
1113        err = devm_add_action_or_reset(emc->dev,
1114                                       devm_tegra_emc_unreg_clk_notifier, emc);
1115        if (err)
1116                return err;
1117
1118        return 0;
1119}
1120
1121static int tegra_emc_devfreq_target(struct device *dev, unsigned long *freq,
1122                                    u32 flags)
1123{
1124        struct tegra_emc *emc = dev_get_drvdata(dev);
1125        struct dev_pm_opp *opp;
1126        unsigned long rate;
1127
1128        opp = devfreq_recommended_opp(dev, freq, flags);
1129        if (IS_ERR(opp)) {
1130                dev_err(dev, "failed to find opp for %lu Hz\n", *freq);
1131                return PTR_ERR(opp);
1132        }
1133
1134        rate = dev_pm_opp_get_freq(opp);
1135        dev_pm_opp_put(opp);
1136
1137        return emc_set_min_rate(emc, rate, EMC_RATE_DEVFREQ);
1138}
1139
1140static int tegra_emc_devfreq_get_dev_status(struct device *dev,
1141                                            struct devfreq_dev_status *stat)
1142{
1143        struct tegra_emc *emc = dev_get_drvdata(dev);
1144
1145        /* freeze counters */
1146        writel_relaxed(EMC_PWR_GATHER_DISABLE, emc->regs + EMC_STAT_CONTROL);
1147
1148        /*
1149         *  busy_time: number of clocks EMC request was accepted
1150         * total_time: number of clocks PWR_GATHER control was set to ENABLE
1151         */
1152        stat->busy_time = readl_relaxed(emc->regs + EMC_STAT_PWR_COUNT);
1153        stat->total_time = readl_relaxed(emc->regs + EMC_STAT_PWR_CLOCKS);
1154        stat->current_frequency = clk_get_rate(emc->clk);
1155
1156        /* clear counters and restart */
1157        writel_relaxed(EMC_PWR_GATHER_CLEAR, emc->regs + EMC_STAT_CONTROL);
1158        writel_relaxed(EMC_PWR_GATHER_ENABLE, emc->regs + EMC_STAT_CONTROL);
1159
1160        return 0;
1161}
1162
1163static struct devfreq_dev_profile tegra_emc_devfreq_profile = {
1164        .polling_ms = 30,
1165        .target = tegra_emc_devfreq_target,
1166        .get_dev_status = tegra_emc_devfreq_get_dev_status,
1167};
1168
1169static int tegra_emc_devfreq_init(struct tegra_emc *emc)
1170{
1171        struct devfreq *devfreq;
1172
1173        /*
1174         * PWR_COUNT is 1/2 of PWR_CLOCKS at max, and thus, the up-threshold
1175         * should be less than 50.  Secondly, multiple active memory clients
1176         * may cause over 20% of lost clock cycles due to stalls caused by
1177         * competing memory accesses.  This means that threshold should be
1178         * set to a less than 30 in order to have a properly working governor.
1179         */
1180        emc->ondemand_data.upthreshold = 20;
1181
1182        /*
1183         * Reset statistic gathers state, select global bandwidth for the
1184         * statistics collection mode and set clocks counter saturation
1185         * limit to maximum.
1186         */
1187        writel_relaxed(0x00000000, emc->regs + EMC_STAT_CONTROL);
1188        writel_relaxed(0x00000000, emc->regs + EMC_STAT_LLMC_CONTROL);
1189        writel_relaxed(0xffffffff, emc->regs + EMC_STAT_PWR_CLOCK_LIMIT);
1190
1191        devfreq = devm_devfreq_add_device(emc->dev, &tegra_emc_devfreq_profile,
1192                                          DEVFREQ_GOV_SIMPLE_ONDEMAND,
1193                                          &emc->ondemand_data);
1194        if (IS_ERR(devfreq)) {
1195                dev_err(emc->dev, "failed to initialize devfreq: %pe", devfreq);
1196                return PTR_ERR(devfreq);
1197        }
1198
1199        return 0;
1200}
1201
1202static int tegra_emc_probe(struct platform_device *pdev)
1203{
1204        struct tegra_core_opp_params opp_params = {};
1205        struct device_node *np;
1206        struct tegra_emc *emc;
1207        int irq, err;
1208
1209        irq = platform_get_irq(pdev, 0);
1210        if (irq < 0) {
1211                dev_err(&pdev->dev, "please update your device tree\n");
1212                return irq;
1213        }
1214
1215        emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
1216        if (!emc)
1217                return -ENOMEM;
1218
1219        mutex_init(&emc->rate_lock);
1220        emc->clk_nb.notifier_call = tegra_emc_clk_change_notify;
1221        emc->dev = &pdev->dev;
1222
1223        emc->regs = devm_platform_ioremap_resource(pdev, 0);
1224        if (IS_ERR(emc->regs))
1225                return PTR_ERR(emc->regs);
1226
1227        err = emc_setup_hw(emc);
1228        if (err)
1229                return err;
1230
1231        np = tegra_emc_find_node_by_ram_code(emc);
1232        if (np) {
1233                err = tegra_emc_load_timings_from_dt(emc, np);
1234                of_node_put(np);
1235                if (err)
1236                        return err;
1237        }
1238
1239        err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0,
1240                               dev_name(&pdev->dev), emc);
1241        if (err) {
1242                dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
1243                return err;
1244        }
1245
1246        err = tegra_emc_init_clk(emc);
1247        if (err)
1248                return err;
1249
1250        opp_params.init_state = true;
1251
1252        err = devm_tegra_core_dev_init_opp_table(&pdev->dev, &opp_params);
1253        if (err)
1254                return err;
1255
1256        platform_set_drvdata(pdev, emc);
1257        tegra_emc_rate_requests_init(emc);
1258        tegra_emc_debugfs_init(emc);
1259        tegra_emc_interconnect_init(emc);
1260        tegra_emc_devfreq_init(emc);
1261
1262        /*
1263         * Don't allow the kernel module to be unloaded. Unloading adds some
1264         * extra complexity which doesn't really worth the effort in a case of
1265         * this driver.
1266         */
1267        try_module_get(THIS_MODULE);
1268
1269        return 0;
1270}
1271
1272static const struct of_device_id tegra_emc_of_match[] = {
1273        { .compatible = "nvidia,tegra20-emc", },
1274        {},
1275};
1276MODULE_DEVICE_TABLE(of, tegra_emc_of_match);
1277
1278static struct platform_driver tegra_emc_driver = {
1279        .probe = tegra_emc_probe,
1280        .driver = {
1281                .name = "tegra20-emc",
1282                .of_match_table = tegra_emc_of_match,
1283                .suppress_bind_attrs = true,
1284                .sync_state = icc_sync_state,
1285        },
1286};
1287module_platform_driver(tegra_emc_driver);
1288
1289MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
1290MODULE_DESCRIPTION("NVIDIA Tegra20 EMC driver");
1291MODULE_SOFTDEP("pre: governor_simpleondemand");
1292MODULE_LICENSE("GPL v2");
1293