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/slab.h>
  17
  18 #include "dw_mmc.h"
  19 #include "dw_mmc-pltfm.h"
  20
  21 #define RK3288_CLKGEN_DIV       2
  22
  23 struct dw_mci_rockchip_priv_data {
  24         struct clk              *drv_clk;
  25         struct clk              *sample_clk;
  26         int                     default_sample_phase;
  27 };
  28
  29 static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  30 {
  31         struct dw_mci_rockchip_priv_data *priv = host->priv;
  32         int ret;
  33         unsigned int cclkin;
  34         u32 bus_hz;
  35
  36         if (ios->clock == 0)
  37                 return;
  38
  39         /*
  40          * cclkin: source clock of mmc controller
  41          * bus_hz: card interface clock generated by CLKGEN
  42          * bus_hz = cclkin / RK3288_CLKGEN_DIV
  43          * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
  44          *
  45          * Note: div can only be 0 or 1
  46          *       if DDR50 8bit mode(only emmc work in 8bit mode),
  47          *       div must be set 1
  48          */
  49         if (ios->bus_width == MMC_BUS_WIDTH_8 &&
  50             ios->timing == MMC_TIMING_MMC_DDR52)
  51                 cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
  52         else
  53                 cclkin = ios->clock * RK3288_CLKGEN_DIV;
  54
  55         ret = clk_set_rate(host->ciu_clk, cclkin);
  56         if (ret)
  57                 dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
  58
  59         bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
  60         if (bus_hz != host->bus_hz) {
  61                 host->bus_hz = bus_hz;
  62                 /* force dw_mci_setup_bus() */
  63                 host->current_speed = 0;
  64         }
  65
  66         /* Make sure we use phases which we can enumerate with */
  67         if (!IS_ERR(priv->sample_clk))
  68                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
  69
  70         /*
  71          * Set the drive phase offset based on speed mode to achieve hold times.
  72          *
  73          * NOTE: this is _not_ a value that is dynamically tuned and is also
  74          * _not_ a value that will vary from board to board.  It is a value
  75          * that could vary between different SoC models if they had massively
  76          * different output clock delays inside their dw_mmc IP block (delay_o),
  77          * but since it's OK to overshoot a little we don't need to do complex
  78          * calculations and can pick values that will just work for everyone.
  79          *
  80          * When picking values we'll stick with picking 0/90/180/270 since
  81          * those can be made very accurately on all known Rockchip SoCs.
  82          *
  83          * Note that these values match values from the DesignWare Databook
  84          * tables for the most part except for SDR12 and "ID mode".  For those
  85          * two modes the databook calculations assume a clock in of 50MHz.  As
  86          * seen above, we always use a clock in rate that is exactly the
  87          * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
  88          * back out before the controller sees it).
  89          *
  90          * From measurement of a single device, it appears that delay_o is
  91          * about .5 ns.  Since we try to leave a bit of margin, it's expected
  92          * that numbers here will be fine even with much larger delay_o
  93          * (the 1.4 ns assumed by the DesignWare Databook would result in the
  94          * same results, for instance).
  95          */
  96         if (!IS_ERR(priv->drv_clk)) {
  97                 int phase;
  98
  99                 /*
 100                  * In almost all cases a 90 degree phase offset will provide
 101                  * sufficient hold times across all valid input clock rates
 102                  * assuming delay_o is not absurd for a given SoC.  We'll use
 103                  * that as a default.
 104                  */
 105                 phase = 90;
 106
 107                 switch (ios->timing) {
 108                 case MMC_TIMING_MMC_DDR52:
 109                         /*
 110                          * Since clock in rate with MMC_DDR52 is doubled when
 111                          * bus width is 8 we need to double the phase offset
 112                          * to get the same timings.
 113                          */
 114                         if (ios->bus_width == MMC_BUS_WIDTH_8)
 115                                 phase = 180;
 116                         break;
 117                 case MMC_TIMING_UHS_SDR104:
 118                 case MMC_TIMING_MMC_HS200:
 119                         /*
 120                          * In the case of 150 MHz clock (typical max for
 121                          * Rockchip SoCs), 90 degree offset will add a delay
 122                          * of 1.67 ns.  That will meet min hold time of .8 ns
 123                          * as long as clock output delay is < .87 ns.  On
 124                          * SoCs measured this seems to be OK, but it doesn't
 125                          * hurt to give margin here, so we use 180.
 126                          */
 127                         phase = 180;
 128                         break;
 129                 }
 130
 131                 clk_set_phase(priv->drv_clk, phase);
 132         }
 133 }
 134
 135 #define NUM_PHASES                      360
 136 #define TUNING_ITERATION_TO_PHASE(i)    (DIV_ROUND_UP((i) * 360, NUM_PHASES))
 137
 138 static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 139 {
 140         struct dw_mci *host = slot->host;
 141         struct dw_mci_rockchip_priv_data *priv = host->priv;
 142         struct mmc_host *mmc = slot->mmc;
 143         int ret = 0;
 144         int i;
 145         bool v, prev_v = 0, first_v;
 146         struct range_t {
 147                 int start;
 148                 int end; /* inclusive */
 149         };
 150         struct range_t *ranges;
 151         unsigned int range_count = 0;
 152         int longest_range_len = -1;
 153         int longest_range = -1;
 154         int middle_phase;
 155
 156         if (IS_ERR(priv->sample_clk)) {
 157                 dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
 158                 return -EIO;
 159         }
 160
 161         ranges = kmalloc_array(NUM_PHASES / 2 + 1, sizeof(*ranges), GFP_KERNEL);
 162         if (!ranges)
 163                 return -ENOMEM;
 164
 165         /* Try each phase and extract good ranges */
 166         for (i = 0; i < NUM_PHASES; ) {
 167                 clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i));
 168
 169                 v = !mmc_send_tuning(mmc, opcode, NULL);
 170
 171                 if (i == 0)
 172                         first_v = v;
 173
 174                 if ((!prev_v) && v) {
 175                         range_count++;
 176                         ranges[range_count-1].start = i;
 177                 }
 178                 if (v) {
 179                         ranges[range_count-1].end = i;
 180                         i++;
 181                 } else if (i == NUM_PHASES - 1) {
 182                         /* No extra skipping rules if we're at the end */
 183                         i++;
 184                 } else {
 185                         /*
 186                          * No need to check too close to an invalid
 187                          * one since testing bad phases is slow.  Skip
 188                          * 20 degrees.
 189                          */
 190                         i += DIV_ROUND_UP(20 * NUM_PHASES, 360);
 191
 192                         /* Always test the last one */
 193                         if (i >= NUM_PHASES)
 194                                 i = NUM_PHASES - 1;
 195                 }
 196
 197                 prev_v = v;
 198         }
 199
 200         if (range_count == 0) {
 201                 dev_warn(host->dev, "All phases bad!");
 202                 ret = -EIO;
 203                 goto free;
 204         }
 205
 206         /* wrap around case, merge the end points */
 207         if ((range_count > 1) && first_v && v) {
 208                 ranges[0].start = ranges[range_count-1].start;
 209                 range_count--;
 210         }
 211
 212         if (ranges[0].start == 0 && ranges[0].end == NUM_PHASES - 1) {
 213                 clk_set_phase(priv->sample_clk, priv->default_sample_phase);
 214                 dev_info(host->dev, "All phases work, using default phase %d.",
 215                          priv->default_sample_phase);
 216                 goto free;
 217         }
 218
 219         /* Find the longest range */
 220         for (i = 0; i < range_count; i++) {
 221                 int len = (ranges[i].end - ranges[i].start + 1);
 222
 223                 if (len < 0)
 224                         len += NUM_PHASES;
 225
 226                 if (longest_range_len < len) {
 227                         longest_range_len = len;
 228                         longest_range = i;
 229                 }
 230
 231                 dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
 232                         TUNING_ITERATION_TO_PHASE(ranges[i].start),
 233                         TUNING_ITERATION_TO_PHASE(ranges[i].end),
 234                         len
 235                 );
 236         }
 237
 238         dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
 239                 TUNING_ITERATION_TO_PHASE(ranges[longest_range].start),
 240                 TUNING_ITERATION_TO_PHASE(ranges[longest_range].end),
 241                 longest_range_len
 242         );
 243
 244         middle_phase = ranges[longest_range].start + longest_range_len / 2;
 245         middle_phase %= NUM_PHASES;
 246         dev_info(host->dev, "Successfully tuned phase to %d\n",
 247                  TUNING_ITERATION_TO_PHASE(middle_phase));
 248
 249         clk_set_phase(priv->sample_clk,
 250                       TUNING_ITERATION_TO_PHASE(middle_phase));
 251
 252 free:
 253         kfree(ranges);
 254         return ret;
 255 }
 256
 257 static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 258 {
 259         struct device_node *np = host->dev->of_node;
 260         struct dw_mci_rockchip_priv_data *priv;
 261
 262         priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 263         if (!priv)
 264                 return -ENOMEM;
 265
 266         if (of_property_read_u32(np, "rockchip,default-sample-phase",
 267                                         &priv->default_sample_phase))
 268                 priv->default_sample_phase = 0;
 269
 270         priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
 271         if (IS_ERR(priv->drv_clk))
 272                 dev_dbg(host->dev, "ciu_drv not available\n");
 273
 274         priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
 275         if (IS_ERR(priv->sample_clk))
 276                 dev_dbg(host->dev, "ciu_sample not available\n");
 277
 278         host->priv = priv;
 279
 280         return 0;
 281 }
 282
 283 static int dw_mci_rockchip_init(struct dw_mci *host)
 284 {
 285         /* It is slot 8 on Rockchip SoCs */
 286         host->sdio_id0 = 8;
 287
 288         if (of_device_is_compatible(host->dev->of_node,
 289                                     "rockchip,rk3288-dw-mshc"))
 290                 host->bus_hz /= RK3288_CLKGEN_DIV;
 291
 292         return 0;
 293 }
 294
 295 /* Common capabilities of RK3288 SoC */
 296 static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
 297         MMC_CAP_CMD23,
 298         MMC_CAP_CMD23,
 299         MMC_CAP_CMD23,
 300         MMC_CAP_CMD23,
 301 };
 302
 303 static const struct dw_mci_drv_data rk2928_drv_data = {
 304         .init                   = dw_mci_rockchip_init,
 305 };
 306
 307 static const struct dw_mci_drv_data rk3288_drv_data = {
 308         .caps                   = dw_mci_rk3288_dwmmc_caps,
 309         .set_ios                = dw_mci_rk3288_set_ios,
 310         .execute_tuning         = dw_mci_rk3288_execute_tuning,
 311         .parse_dt               = dw_mci_rk3288_parse_dt,
 312         .init                   = dw_mci_rockchip_init,
 313 };
 314
 315 static const struct of_device_id dw_mci_rockchip_match[] = {
 316         { .compatible = "rockchip,rk2928-dw-mshc",
 317                 .data = &rk2928_drv_data },
 318         { .compatible = "rockchip,rk3288-dw-mshc",
 319                 .data = &rk3288_drv_data },
 320         {},
 321 };
 322 MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
 323
 324 static int dw_mci_rockchip_probe(struct platform_device *pdev)
 325 {
 326         const struct dw_mci_drv_data *drv_data;
 327         const struct of_device_id *match;
 328
 329         if (!pdev->dev.of_node)
 330                 return -ENODEV;
 331
 332         match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
 333         drv_data = match->data;
 334
 335         return dw_mci_pltfm_register(pdev, drv_data);
 336 }
 337
 338 static struct platform_driver dw_mci_rockchip_pltfm_driver = {
 339         .probe          = dw_mci_rockchip_probe,
 340         .remove         = dw_mci_pltfm_remove,
 341         .driver         = {
 342                 .name           = "dwmmc_rockchip",
 343                 .of_match_table = dw_mci_rockchip_match,
 344                 .pm             = &dw_mci_pltfm_pmops,
 345         },
 346 };
 347
 348 module_platform_driver(dw_mci_rockchip_pltfm_driver);
 349
 350 MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
 351 MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
 352 MODULE_ALIAS("platform:dwmmc_rockchip");
 353 MODULE_LICENSE("GPL v2");