drivers/mmc/host/dw_mmc-rockchip.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/platform_device.h>
   8 #include <linux/clk.h>
   9 #include <linux/mmc/host.h>
  10 #include <linux/of_address.h>
  11 #include <linux/mmc/slot-gpio.h>
  12 #include <linux/pm_runtime.h>
  13 #include <linux/slab.h>
  14
  15 #include "dw_mmc.h"
  16 #include "dw_mmc-pltfm.h"
  17
  18 #define RK3288_CLKGEN_DIV       2
  19
  20 struct dw_mci_rockchip_priv_data {
  21         struct clk              *drv_clk;
  22         struct clk              *sample_clk;
  23         int                     default_sample_phase;
  24         int                     num_phases;
  25 };
  26
  27 static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  28 {
  29         struct dw_mci_rockchip_priv_data *priv = host->priv;
  30         int ret;
  31         unsigned int cclkin;
  32         u32 bus_hz;
  33
  34         if (ios->clock == 0)
  35                 return;
  36
  37         /*
  38          * cclkin: source clock of mmc controller
  39          * bus_hz: card interface clock generated by CLKGEN
  40          * bus_hz = cclkin / RK3288_CLKGEN_DIV
  41          * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
  42          *
  43          * Note: div can only be 0 or 1, but div must be set to 1 for eMMC
  44          * DDR52 8-bit mode.
  45          */
  46         if (ios->bus_width == MMC_BUS_WIDTH_8 &&
  47             ios->timing == MMC_TIMING_MMC_DDR52)
  48                 cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
  49         else
  50                 cclkin = ios->clock * RK3288_CLKGEN_DIV;
  51
  52         ret = clk_set_rate(host->ciu_clk, cclkin);
  53         if (ret)
  54                 dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
  55
  56         bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
  57         if (bus_hz != host->bus_hz) {
  58                 host->bus_hz = bus_hz;
  59                 /* force dw_mci_setup_bus() */
  60                 host->current_speed = 0;
  61         }
  62
  63         /* Make sure we use phases which we can enumerate with */
  64         if (!IS_ERR(priv->sample_clk))
  65                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
  66
  67         /*
  68          * Set the drive phase offset based on speed mode to achieve hold times.
  69          *
  70          * NOTE: this is _not_ a value that is dynamically tuned and is also
  71          * _not_ a value that will vary from board to board.  It is a value
  72          * that could vary between different SoC models if they had massively
  73          * different output clock delays inside their dw_mmc IP block (delay_o),
  74          * but since it's OK to overshoot a little we don't need to do complex
  75          * calculations and can pick values that will just work for everyone.
  76          *
  77          * When picking values we'll stick with picking 0/90/180/270 since
  78          * those can be made very accurately on all known Rockchip SoCs.
  79          *
  80          * Note that these values match values from the DesignWare Databook
  81          * tables for the most part except for SDR12 and "ID mode".  For those
  82          * two modes the databook calculations assume a clock in of 50MHz.  As
  83          * seen above, we always use a clock in rate that is exactly the
  84          * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
  85          * back out before the controller sees it).
  86          *
  87          * From measurement of a single device, it appears that delay_o is
  88          * about .5 ns.  Since we try to leave a bit of margin, it's expected
  89          * that numbers here will be fine even with much larger delay_o
  90          * (the 1.4 ns assumed by the DesignWare Databook would result in the
  91          * same results, for instance).
  92          */
  93         if (!IS_ERR(priv->drv_clk)) {
  94                 int phase;
  95
  96                 /*
  97                  * In almost all cases a 90 degree phase offset will provide
  98                  * sufficient hold times across all valid input clock rates
  99                  * assuming delay_o is not absurd for a given SoC.  We'll use
 100                  * that as a default.
 101                  */
 102                 phase = 90;
 103
 104                 switch (ios->timing) {
 105                 case MMC_TIMING_MMC_DDR52:
 106                         /*
 107                          * Since clock in rate with MMC_DDR52 is doubled when
 108                          * bus width is 8 we need to double the phase offset
 109                          * to get the same timings.
 110                          */
 111                         if (ios->bus_width == MMC_BUS_WIDTH_8)
 112                                 phase = 180;
 113                         break;
 114                 case MMC_TIMING_UHS_SDR104:
 115                 case MMC_TIMING_MMC_HS200:
 116                         /*
 117                          * In the case of 150 MHz clock (typical max for
 118                          * Rockchip SoCs), 90 degree offset will add a delay
 119                          * of 1.67 ns.  That will meet min hold time of .8 ns
 120                          * as long as clock output delay is < .87 ns.  On
 121                          * SoCs measured this seems to be OK, but it doesn't
 122                          * hurt to give margin here, so we use 180.
 123                          */
 124                         phase = 180;
 125                         break;
 126                 }
 127
 128                 clk_set_phase(priv->drv_clk, phase);
 129         }
 130 }
 131
 132 #define TUNING_ITERATION_TO_PHASE(i, num_phases) \
 133                 (DIV_ROUND_UP((i) * 360, num_phases))
 134
 135 static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 136 {
 137         struct dw_mci *host = slot->host;
 138         struct dw_mci_rockchip_priv_data *priv = host->priv;
 139         struct mmc_host *mmc = slot->mmc;
 140         int ret = 0;
 141         int i;
 142         bool v, prev_v = 0, first_v;
 143         struct range_t {
 144                 int start;
 145                 int end; /* inclusive */
 146         };
 147         struct range_t *ranges;
 148         unsigned int range_count = 0;
 149         int longest_range_len = -1;
 150         int longest_range = -1;
 151         int middle_phase;
 152
 153         if (IS_ERR(priv->sample_clk)) {
 154                 dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
 155                 return -EIO;
 156         }
 157
 158         ranges = kmalloc_array(priv->num_phases / 2 + 1,
 159                                sizeof(*ranges), GFP_KERNEL);
 160         if (!ranges)
 161                 return -ENOMEM;
 162
 163         /* Try each phase and extract good ranges */
 164         for (i = 0; i < priv->num_phases; ) {
 165                 clk_set_phase(priv->sample_clk,
 166                               TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
 167
 168                 v = !mmc_send_tuning(mmc, opcode, NULL);
 169
 170                 if (i == 0)
 171                         first_v = v;
 172
 173                 if ((!prev_v) && v) {
 174                         range_count++;
 175                         ranges[range_count-1].start = i;
 176                 }
 177                 if (v) {
 178                         ranges[range_count-1].end = i;
 179                         i++;
 180                 } else if (i == priv->num_phases - 1) {
 181                         /* No extra skipping rules if we're at the end */
 182                         i++;
 183                 } else {
 184                         /*
 185                          * No need to check too close to an invalid
 186                          * one since testing bad phases is slow.  Skip
 187                          * 20 degrees.
 188                          */
 189                         i += DIV_ROUND_UP(20 * priv->num_phases, 360);
 190
 191                         /* Always test the last one */
 192                         if (i >= priv->num_phases)
 193                                 i = priv->num_phases - 1;
 194                 }
 195
 196                 prev_v = v;
 197         }
 198
 199         if (range_count == 0) {
 200                 dev_warn(host->dev, "All phases bad!");
 201                 ret = -EIO;
 202                 goto free;
 203         }
 204
 205         /* wrap around case, merge the end points */
 206         if ((range_count > 1) && first_v && v) {
 207                 ranges[0].start = ranges[range_count-1].start;
 208                 range_count--;
 209         }
 210
 211         if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
 212                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
 213                 dev_info(host->dev, "All phases work, using default phase %d.",
 214                          priv->default_sample_phase);
 215                 goto free;
 216         }
 217
 218         /* Find the longest range */
 219         for (i = 0; i < range_count; i++) {
 220                 int len = (ranges[i].end - ranges[i].start + 1);
 221
 222                 if (len < 0)
 223                         len += priv->num_phases;
 224
 225                 if (longest_range_len < len) {
 226                         longest_range_len = len;
 227                         longest_range = i;
 228                 }
 229
 230                 dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
 231                         TUNING_ITERATION_TO_PHASE(ranges[i].start,
 232                                                   priv->num_phases),
 233                         TUNING_ITERATION_TO_PHASE(ranges[i].end,
 234                                                   priv->num_phases),
 235                         len
 236                 );
 237         }
 238
 239         dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
 240                 TUNING_ITERATION_TO_PHASE(ranges[longest_range].start,
 241                                           priv->num_phases),
 242                 TUNING_ITERATION_TO_PHASE(ranges[longest_range].end,
 243                                           priv->num_phases),
 244                 longest_range_len
 245         );
 246
 247         middle_phase = ranges[longest_range].start + longest_range_len / 2;
 248         middle_phase %= priv->num_phases;
 249         dev_info(host->dev, "Successfully tuned phase to %d\n",
 250                  TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));
 251
 252         clk_set_phase(priv->sample_clk,
 253                       TUNING_ITERATION_TO_PHASE(middle_phase,
 254                                                 priv->num_phases));
 255
 256 free:
 257         kfree(ranges);
 258         return ret;
 259 }
 260
 261 static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 262 {
 263         struct device_node *np = host->dev->of_node;
 264         struct dw_mci_rockchip_priv_data *priv;
 265
 266         priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 267         if (!priv)
 268                 return -ENOMEM;
 269
 270         if (of_property_read_u32(np, "rockchip,desired-num-phases",
 271                                         &priv->num_phases))
 272                 priv->num_phases = 360;
 273
 274         if (of_property_read_u32(np, "rockchip,default-sample-phase",
 275                                         &priv->default_sample_phase))
 276                 priv->default_sample_phase = 0;
 277
 278         priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
 279         if (IS_ERR(priv->drv_clk))
 280                 dev_dbg(host->dev, "ciu-drive not available\n");
 281
 282         priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
 283         if (IS_ERR(priv->sample_clk))
 284                 dev_dbg(host->dev, "ciu-sample not available\n");
 285
 286         host->priv = priv;
 287
 288         return 0;
 289 }
 290
 291 static int dw_mci_rockchip_init(struct dw_mci *host)
 292 {
 293         /* It is slot 8 on Rockchip SoCs */
 294         host->sdio_id0 = 8;
 295
 296         if (of_device_is_compatible(host->dev->of_node,
 297                                     "rockchip,rk3288-dw-mshc"))
 298                 host->bus_hz /= RK3288_CLKGEN_DIV;
 299
 300         return 0;
 301 }
 302
 303 /* Common capabilities of RK3288 SoC */
 304 static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
 305         MMC_CAP_CMD23,
 306         MMC_CAP_CMD23,
 307         MMC_CAP_CMD23,
 308         MMC_CAP_CMD23,
 309 };
 310
 311 static const struct dw_mci_drv_data rk2928_drv_data = {
 312         .init                   = dw_mci_rockchip_init,
 313 };
 314
 315 static const struct dw_mci_drv_data rk3288_drv_data = {
 316         .caps                   = dw_mci_rk3288_dwmmc_caps,
 317         .num_caps               = ARRAY_SIZE(dw_mci_rk3288_dwmmc_caps),
 318         .set_ios                = dw_mci_rk3288_set_ios,
 319         .execute_tuning         = dw_mci_rk3288_execute_tuning,
 320         .parse_dt               = dw_mci_rk3288_parse_dt,
 321         .init                   = dw_mci_rockchip_init,
 322 };
 323
 324 static const struct of_device_id dw_mci_rockchip_match[] = {
 325         { .compatible = "rockchip,rk2928-dw-mshc",
 326                 .data = &rk2928_drv_data },
 327         { .compatible = "rockchip,rk3288-dw-mshc",
 328                 .data = &rk3288_drv_data },
 329         {},
 330 };
 331 MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
 332
 333 static int dw_mci_rockchip_probe(struct platform_device *pdev)
 334 {
 335         const struct dw_mci_drv_data *drv_data;
 336         const struct of_device_id *match;
 337         int ret;
 338
 339         if (!pdev->dev.of_node)
 340                 return -ENODEV;
 341
 342         match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
 343         drv_data = match->data;
 344
 345         pm_runtime_get_noresume(&pdev->dev);
 346         pm_runtime_set_active(&pdev->dev);
 347         pm_runtime_enable(&pdev->dev);
 348         pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 349         pm_runtime_use_autosuspend(&pdev->dev);
 350
 351         ret = dw_mci_pltfm_register(pdev, drv_data);
 352         if (ret) {
 353                 pm_runtime_disable(&pdev->dev);
 354                 pm_runtime_set_suspended(&pdev->dev);
 355                 pm_runtime_put_noidle(&pdev->dev);
 356                 return ret;
 357         }
 358
 359         pm_runtime_put_autosuspend(&pdev->dev);
 360
 361         return 0;
 362 }
 363
 364 static int dw_mci_rockchip_remove(struct platform_device *pdev)
 365 {
 366         pm_runtime_get_sync(&pdev->dev);
 367         pm_runtime_disable(&pdev->dev);
 368         pm_runtime_put_noidle(&pdev->dev);
 369
 370         return dw_mci_pltfm_remove(pdev);
 371 }
 372
 373 static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
 374         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 375                                 pm_runtime_force_resume)
 376         SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
 377                            dw_mci_runtime_resume,
 378                            NULL)
 379 };
 380
 381 static struct platform_driver dw_mci_rockchip_pltfm_driver = {
 382         .probe          = dw_mci_rockchip_probe,
 383         .remove         = dw_mci_rockchip_remove,
 384         .driver         = {
 385                 .name           = "dwmmc_rockchip",
 386                 .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
 387                 .of_match_table = dw_mci_rockchip_match,
 388                 .pm             = &dw_mci_rockchip_dev_pm_ops,
 389         },
 390 };
 391
 392 module_platform_driver(dw_mci_rockchip_pltfm_driver);
 393
 394 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
 395 MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
 396 MODULE_ALIAS("platform:dwmmc_rockchip");
 397 MODULE_LICENSE("GPL v2");