drivers/mmc/host/dw_mmc-rockchip.c

   1 /*
   2  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/clk.h>
  13 #include <linux/mmc/host.h>
  14 #include <linux/mmc/dw_mmc.h>
  15 #include <linux/of_address.h>
  16 #include <linux/pm_runtime.h>
  17 #include <linux/slab.h>
  18
  19 #include "dw_mmc.h"
  20 #include "dw_mmc-pltfm.h"
  21
  22 #define RK3288_CLKGEN_DIV       2
  23
  24 struct dw_mci_rockchip_priv_data {
  25         struct clk              *drv_clk;
  26         struct clk              *sample_clk;
  27         int                     default_sample_phase;
  28 };
  29
  30 static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  31 {
  32         struct dw_mci_rockchip_priv_data *priv = host->priv;
  33         int ret;
  34         unsigned int cclkin;
  35         u32 bus_hz;
  36
  37         if (ios->clock == 0)
  38                 return;
  39
  40         /*
  41          * cclkin: source clock of mmc controller
  42          * bus_hz: card interface clock generated by CLKGEN
  43          * bus_hz = cclkin / RK3288_CLKGEN_DIV
  44          * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
  45          *
  46          * Note: div can only be 0 or 1
  47          *       if DDR50 8bit mode(only emmc work in 8bit mode),
  48          *       div must be set 1
  49          */
  50         if (ios->bus_width == MMC_BUS_WIDTH_8 &&
  51             ios->timing == MMC_TIMING_MMC_DDR52)
  52                 cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
  53         else
  54                 cclkin = ios->clock * RK3288_CLKGEN_DIV;
  55
  56         ret = clk_set_rate(host->ciu_clk, cclkin);
  57         if (ret)
  58                 dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
  59
  60         bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
  61         if (bus_hz != host->bus_hz) {
  62                 host->bus_hz = bus_hz;
  63                 /* force dw_mci_setup_bus() */
  64                 host->current_speed = 0;
  65         }
  66
  67         /* Make sure we use phases which we can enumerate with */
  68         if (!IS_ERR(priv->sample_clk))
  69                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
  70
  71         /*
  72          * Set the drive phase offset based on speed mode to achieve hold times.
  73          *
  74          * NOTE: this is _not_ a value that is dynamically tuned and is also
  75          * _not_ a value that will vary from board to board.  It is a value
  76          * that could vary between different SoC models if they had massively
  77          * different output clock delays inside their dw_mmc IP block (delay_o),
  78          * but since it's OK to overshoot a little we don't need to do complex
  79          * calculations and can pick values that will just work for everyone.
  80          *
  81          * When picking values we'll stick with picking 0/90/180/270 since
  82          * those can be made very accurately on all known Rockchip SoCs.
  83          *
  84          * Note that these values match values from the DesignWare Databook
  85          * tables for the most part except for SDR12 and "ID mode".  For those
  86          * two modes the databook calculations assume a clock in of 50MHz.  As
  87          * seen above, we always use a clock in rate that is exactly the
  88          * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
  89          * back out before the controller sees it).
  90          *
  91          * From measurement of a single device, it appears that delay_o is
  92          * about .5 ns.  Since we try to leave a bit of margin, it's expected
  93          * that numbers here will be fine even with much larger delay_o
  94          * (the 1.4 ns assumed by the DesignWare Databook would result in the
  95          * same results, for instance).
  96          */
  97         if (!IS_ERR(priv->drv_clk)) {
  98                 int phase;
  99
 100                 /*
 101                  * In almost all cases a 90 degree phase offset will provide
 102                  * sufficient hold times across all valid input clock rates
 103                  * assuming delay_o is not absurd for a given SoC.  We'll use
 104                  * that as a default.
 105                  */
 106                 phase = 90;
 107
 108                 switch (ios->timing) {
 109                 case MMC_TIMING_MMC_DDR52:
 110                         /*
 111                          * Since clock in rate with MMC_DDR52 is doubled when
 112                          * bus width is 8 we need to double the phase offset
 113                          * to get the same timings.
 114                          */
 115                         if (ios->bus_width == MMC_BUS_WIDTH_8)
 116                                 phase = 180;
 117                         break;
 118                 case MMC_TIMING_UHS_SDR104:
 119                 case MMC_TIMING_MMC_HS200:
 120                         /*
 121                          * In the case of 150 MHz clock (typical max for
 122                          * Rockchip SoCs), 90 degree offset will add a delay
 123                          * of 1.67 ns.  That will meet min hold time of .8 ns
 124                          * as long as clock output delay is < .87 ns.  On
 125                          * SoCs measured this seems to be OK, but it doesn't
 126                          * hurt to give margin here, so we use 180.
 127                          */
 128                         phase = 180;
 129                         break;
 130                 }
 131
 132                 clk_set_phase(priv->drv_clk, phase);
 133         }
 134 }
 135
 136 #define NUM_PHASES                      360
 137 #define TUNING_ITERATION_TO_PHASE(i)    (DIV_ROUND_UP((i) * 360, NUM_PHASES))
 138
 139 static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 140 {
 141         struct dw_mci *host = slot->host;
 142         struct dw_mci_rockchip_priv_data *priv = host->priv;
 143         struct mmc_host *mmc = slot->mmc;
 144         int ret = 0;
 145         int i;
 146         bool v, prev_v = 0, first_v;
 147         struct range_t {
 148                 int start;
 149                 int end; /* inclusive */
 150         };
 151         struct range_t *ranges;
 152         unsigned int range_count = 0;
 153         int longest_range_len = -1;
 154         int longest_range = -1;
 155         int middle_phase;
 156
 157         if (IS_ERR(priv->sample_clk)) {
 158                 dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
 159                 return -EIO;
 160         }
 161
 162         ranges = kmalloc_array(NUM_PHASES / 2 + 1, sizeof(*ranges), GFP_KERNEL);
 163         if (!ranges)
 164                 return -ENOMEM;
 165
 166         /* Try each phase and extract good ranges */
 167         for (i = 0; i < NUM_PHASES; ) {
 168                 clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i));
 169
 170                 v = !mmc_send_tuning(mmc, opcode, NULL);
 171
 172                 if (i == 0)
 173                         first_v = v;
 174
 175                 if ((!prev_v) && v) {
 176                         range_count++;
 177                         ranges[range_count-1].start = i;
 178                 }
 179                 if (v) {
 180                         ranges[range_count-1].end = i;
 181                         i++;
 182                 } else if (i == NUM_PHASES - 1) {
 183                         /* No extra skipping rules if we're at the end */
 184                         i++;
 185                 } else {
 186                         /*
 187                          * No need to check too close to an invalid
 188                          * one since testing bad phases is slow.  Skip
 189                          * 20 degrees.
 190                          */
 191                         i += DIV_ROUND_UP(20 * NUM_PHASES, 360);
 192
 193                         /* Always test the last one */
 194                         if (i >= NUM_PHASES)
 195                                 i = NUM_PHASES - 1;
 196                 }
 197
 198                 prev_v = v;
 199         }
 200
 201         if (range_count == 0) {
 202                 dev_warn(host->dev, "All phases bad!");
 203                 ret = -EIO;
 204                 goto free;
 205         }
 206
 207         /* wrap around case, merge the end points */
 208         if ((range_count > 1) && first_v && v) {
 209                 ranges[0].start = ranges[range_count-1].start;
 210                 range_count--;
 211         }
 212
 213         if (ranges[0].start == 0 && ranges[0].end == NUM_PHASES - 1) {
 214                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
 215                 dev_info(host->dev, "All phases work, using default phase %d.",
 216                          priv->default_sample_phase);
 217                 goto free;
 218         }
 219
 220         /* Find the longest range */
 221         for (i = 0; i < range_count; i++) {
 222                 int len = (ranges[i].end - ranges[i].start + 1);
 223
 224                 if (len < 0)
 225                         len += NUM_PHASES;
 226
 227                 if (longest_range_len < len) {
 228                         longest_range_len = len;
 229                         longest_range = i;
 230                 }
 231
 232                 dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
 233                         TUNING_ITERATION_TO_PHASE(ranges[i].start),
 234                         TUNING_ITERATION_TO_PHASE(ranges[i].end),
 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                 TUNING_ITERATION_TO_PHASE(ranges[longest_range].end),
 242                 longest_range_len
 243         );
 244
 245         middle_phase = ranges[longest_range].start + longest_range_len / 2;
 246         middle_phase %= NUM_PHASES;
 247         dev_info(host->dev, "Successfully tuned phase to %d\n",
 248                  TUNING_ITERATION_TO_PHASE(middle_phase));
 249
 250         clk_set_phase(priv->sample_clk,
 251                       TUNING_ITERATION_TO_PHASE(middle_phase));
 252
 253 free:
 254         kfree(ranges);
 255         return ret;
 256 }
 257
 258 static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 259 {
 260         struct device_node *np = host->dev->of_node;
 261         struct dw_mci_rockchip_priv_data *priv;
 262
 263         priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 264         if (!priv)
 265                 return -ENOMEM;
 266
 267         if (of_property_read_u32(np, "rockchip,default-sample-phase",
 268                                         &priv->default_sample_phase))
 269                 priv->default_sample_phase = 0;
 270
 271         priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
 272         if (IS_ERR(priv->drv_clk))
 273                 dev_dbg(host->dev, "ciu_drv not available\n");
 274
 275         priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
 276         if (IS_ERR(priv->sample_clk))
 277                 dev_dbg(host->dev, "ciu_sample not available\n");
 278
 279         host->priv = priv;
 280
 281         return 0;
 282 }
 283
 284 static int dw_mci_rockchip_init(struct dw_mci *host)
 285 {
 286         /* It is slot 8 on Rockchip SoCs */
 287         host->sdio_id0 = 8;
 288
 289         if (of_device_is_compatible(host->dev->of_node,
 290                                     "rockchip,rk3288-dw-mshc"))
 291                 host->bus_hz /= RK3288_CLKGEN_DIV;
 292
 293         return 0;
 294 }
 295
 296 /* Common capabilities of RK3288 SoC */
 297 static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
 298         MMC_CAP_CMD23,
 299         MMC_CAP_CMD23,
 300         MMC_CAP_CMD23,
 301         MMC_CAP_CMD23,
 302 };
 303
 304 static const struct dw_mci_drv_data rk2928_drv_data = {
 305         .init                   = dw_mci_rockchip_init,
 306 };
 307
 308 static const struct dw_mci_drv_data rk3288_drv_data = {
 309         .caps                   = dw_mci_rk3288_dwmmc_caps,
 310         .set_ios                = dw_mci_rk3288_set_ios,
 311         .execute_tuning         = dw_mci_rk3288_execute_tuning,
 312         .parse_dt               = dw_mci_rk3288_parse_dt,
 313         .init                   = dw_mci_rockchip_init,
 314 };
 315
 316 static const struct of_device_id dw_mci_rockchip_match[] = {
 317         { .compatible = "rockchip,rk2928-dw-mshc",
 318                 .data = &rk2928_drv_data },
 319         { .compatible = "rockchip,rk3288-dw-mshc",
 320                 .data = &rk3288_drv_data },
 321         {},
 322 };
 323 MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
 324
 325 static int dw_mci_rockchip_probe(struct platform_device *pdev)
 326 {
 327         const struct dw_mci_drv_data *drv_data;
 328         const struct of_device_id *match;
 329         int ret;
 330
 331         if (!pdev->dev.of_node)
 332                 return -ENODEV;
 333
 334         match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
 335         drv_data = match->data;
 336
 337         pm_runtime_get_noresume(&pdev->dev);
 338         pm_runtime_set_active(&pdev->dev);
 339         pm_runtime_enable(&pdev->dev);
 340         pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 341         pm_runtime_use_autosuspend(&pdev->dev);
 342
 343         ret = dw_mci_pltfm_register(pdev, drv_data);
 344         if (ret) {
 345                 pm_runtime_disable(&pdev->dev);
 346                 pm_runtime_set_suspended(&pdev->dev);
 347                 pm_runtime_put_noidle(&pdev->dev);
 348                 return ret;
 349         }
 350
 351         pm_runtime_put_autosuspend(&pdev->dev);
 352
 353         return 0;
 354 }
 355
 356 static int dw_mci_rockchip_remove(struct platform_device *pdev)
 357 {
 358         pm_runtime_get_sync(&pdev->dev);
 359         pm_runtime_disable(&pdev->dev);
 360         pm_runtime_put_noidle(&pdev->dev);
 361
 362         return dw_mci_pltfm_remove(pdev);
 363 }
 364
 365 static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
 366         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 367                                 pm_runtime_force_resume)
 368         SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
 369                            dw_mci_runtime_resume,
 370                            NULL)
 371 };
 372
 373 static struct platform_driver dw_mci_rockchip_pltfm_driver = {
 374         .probe          = dw_mci_rockchip_probe,
 375         .remove         = dw_mci_rockchip_remove,
 376         .driver         = {
 377                 .name           = "dwmmc_rockchip",
 378                 .of_match_table = dw_mci_rockchip_match,
 379                 .pm             = &dw_mci_rockchip_dev_pm_ops,
 380         },
 381 };
 382
 383 module_platform_driver(dw_mci_rockchip_pltfm_driver);
 384
 385 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
 386 MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
 387 MODULE_ALIAS("platform:dwmmc_rockchip");
 388 MODULE_LICENSE("GPL v2");