drivers/mmc/host/sdhci-bcm-kona.c

   1 /*
   2  * Copyright (C) 2013 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/delay.h>
  17 #include <linux/highmem.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/mmc/host.h>
  20 #include <linux/io.h>
  21 #include <linux/clk.h>
  22 #include <linux/regulator/consumer.h>
  23 #include <linux/of.h>
  24 #include <linux/of_device.h>
  25 #include <linux/mmc/slot-gpio.h>
  26
  27 #include "sdhci-pltfm.h"
  28 #include "sdhci.h"
  29
  30 #define SDHCI_SOFT_RESET                        0x01000000
  31 #define KONA_SDHOST_CORECTRL                    0x8000
  32 #define KONA_SDHOST_CD_PINCTRL                  0x00000008
  33 #define KONA_SDHOST_STOP_HCLK                   0x00000004
  34 #define KONA_SDHOST_RESET                       0x00000002
  35 #define KONA_SDHOST_EN                          0x00000001
  36
  37 #define KONA_SDHOST_CORESTAT                    0x8004
  38 #define KONA_SDHOST_WP                          0x00000002
  39 #define KONA_SDHOST_CD_SW                       0x00000001
  40
  41 #define KONA_SDHOST_COREIMR                     0x8008
  42 #define KONA_SDHOST_IP                          0x00000001
  43
  44 #define KONA_SDHOST_COREISR                     0x800C
  45 #define KONA_SDHOST_COREIMSR                    0x8010
  46 #define KONA_SDHOST_COREDBG1                    0x8014
  47 #define KONA_SDHOST_COREGPO_MASK                0x8018
  48
  49 #define SD_DETECT_GPIO_DEBOUNCE_128MS           128
  50
  51 #define KONA_MMC_AUTOSUSPEND_DELAY              (50)
  52
  53 struct sdhci_bcm_kona_dev {
  54         struct mutex    write_lock; /* protect back to back writes */
  55 };
  56
  57
  58 static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
  59 {
  60         unsigned int val;
  61         unsigned long timeout;
  62
  63         /* This timeout should be sufficent for core to reset */
  64         timeout = jiffies + msecs_to_jiffies(100);
  65
  66         /* reset the host using the top level reset */
  67         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
  68         val |= KONA_SDHOST_RESET;
  69         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
  70
  71         while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
  72                 if (time_is_before_jiffies(timeout)) {
  73                         pr_err("Error: sd host is stuck in reset!!!\n");
  74                         return -EFAULT;
  75                 }
  76         }
  77
  78         /* bring the host out of reset */
  79         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
  80         val &= ~KONA_SDHOST_RESET;
  81
  82         /*
  83          * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
  84          * Back-to-Back writes to same register needs delay when SD bus clock
  85          * is very low w.r.t AHB clock, mainly during boot-time and during card
  86          * insert-removal.
  87          */
  88         usleep_range(1000, 5000);
  89         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
  90
  91         return 0;
  92 }
  93
  94 static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
  95 {
  96         unsigned int val;
  97
  98         /* enable the interrupt from the IP core */
  99         val = sdhci_readl(host, KONA_SDHOST_COREIMR);
 100         val |= KONA_SDHOST_IP;
 101         sdhci_writel(host, val, KONA_SDHOST_COREIMR);
 102
 103         /* Enable the AHB clock gating module to the host */
 104         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
 105         val |= KONA_SDHOST_EN;
 106
 107         /*
 108          * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
 109          * Back-to-Back writes to same register needs delay when SD bus clock
 110          * is very low w.r.t AHB clock, mainly during boot-time and during card
 111          * insert-removal.
 112          */
 113         usleep_range(1000, 5000);
 114         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
 115 }
 116
 117 /*
 118  * Software emulation of the SD card insertion/removal. Set insert=1 for insert
 119  * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
 120  * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
 121  * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
 122  */
 123 static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
 124 {
 125         struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
 126         struct sdhci_bcm_kona_dev *kona_dev = sdhci_pltfm_priv(pltfm_priv);
 127         u32 val;
 128
 129         /*
 130          * Back-to-Back register write needs a delay of min 10uS.
 131          * Back-to-Back writes to same register needs delay when SD bus clock
 132          * is very low w.r.t AHB clock, mainly during boot-time and during card
 133          * insert-removal.
 134          * We keep 20uS
 135          */
 136         mutex_lock(&kona_dev->write_lock);
 137         udelay(20);
 138         val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
 139
 140         if (insert) {
 141                 int ret;
 142
 143                 ret = mmc_gpio_get_ro(host->mmc);
 144                 if (ret >= 0)
 145                         val = (val & ~KONA_SDHOST_WP) |
 146                                 ((ret) ? KONA_SDHOST_WP : 0);
 147
 148                 val |= KONA_SDHOST_CD_SW;
 149                 sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
 150         } else {
 151                 val &= ~KONA_SDHOST_CD_SW;
 152                 sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
 153         }
 154         mutex_unlock(&kona_dev->write_lock);
 155
 156         return 0;
 157 }
 158
 159 /*
 160  * SD card interrupt event callback
 161  */
 162 static void sdhci_bcm_kona_card_event(struct sdhci_host *host)
 163 {
 164         if (mmc_gpio_get_cd(host->mmc) > 0) {
 165                 dev_dbg(mmc_dev(host->mmc),
 166                         "card inserted\n");
 167                 sdhci_bcm_kona_sd_card_emulate(host, 1);
 168         } else {
 169                 dev_dbg(mmc_dev(host->mmc),
 170                         "card removed\n");
 171                 sdhci_bcm_kona_sd_card_emulate(host, 0);
 172         }
 173 }
 174
 175 static void sdhci_bcm_kona_init_74_clocks(struct sdhci_host *host,
 176                                 u8 power_mode)
 177 {
 178         /*
 179          *  JEDEC and SD spec specify supplying 74 continuous clocks to
 180          * device after power up. With minimum bus (100KHz) that
 181          * that translates to 740us
 182          */
 183         if (power_mode != MMC_POWER_OFF)
 184                 udelay(740);
 185 }
 186
 187 static const struct sdhci_ops sdhci_bcm_kona_ops = {
 188         .set_clock = sdhci_set_clock,
 189         .get_max_clock = sdhci_pltfm_clk_get_max_clock,
 190         .get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
 191         .platform_send_init_74_clocks = sdhci_bcm_kona_init_74_clocks,
 192         .set_bus_width = sdhci_set_bus_width,
 193         .reset = sdhci_reset,
 194         .set_uhs_signaling = sdhci_set_uhs_signaling,
 195         .card_event = sdhci_bcm_kona_card_event,
 196 };
 197
 198 static const struct sdhci_pltfm_data sdhci_pltfm_data_kona = {
 199         .ops    = &sdhci_bcm_kona_ops,
 200         .quirks = SDHCI_QUIRK_NO_CARD_NO_RESET |
 201                 SDHCI_QUIRK_BROKEN_TIMEOUT_VAL | SDHCI_QUIRK_32BIT_DMA_ADDR |
 202                 SDHCI_QUIRK_32BIT_DMA_SIZE | SDHCI_QUIRK_32BIT_ADMA_SIZE |
 203                 SDHCI_QUIRK_FORCE_BLK_SZ_2048 |
 204                 SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
 205 };
 206
 207 static const struct of_device_id sdhci_bcm_kona_of_match[] = {
 208         { .compatible = "brcm,kona-sdhci"},
 209         { .compatible = "bcm,kona-sdhci"}, /* deprecated name */
 210         {}
 211 };
 212 MODULE_DEVICE_TABLE(of, sdhci_bcm_kona_of_match);
 213
 214 static int sdhci_bcm_kona_probe(struct platform_device *pdev)
 215 {
 216         struct sdhci_bcm_kona_dev *kona_dev = NULL;
 217         struct sdhci_pltfm_host *pltfm_priv;
 218         struct device *dev = &pdev->dev;
 219         struct sdhci_host *host;
 220         int ret;
 221
 222         ret = 0;
 223
 224         host = sdhci_pltfm_init(pdev, &sdhci_pltfm_data_kona,
 225                         sizeof(*kona_dev));
 226         if (IS_ERR(host))
 227                 return PTR_ERR(host);
 228
 229         dev_dbg(dev, "%s: inited. IOADDR=%p\n", __func__, host->ioaddr);
 230
 231         pltfm_priv = sdhci_priv(host);
 232
 233         kona_dev = sdhci_pltfm_priv(pltfm_priv);
 234         mutex_init(&kona_dev->write_lock);
 235
 236         ret = mmc_of_parse(host->mmc);
 237         if (ret)
 238                 goto err_pltfm_free;
 239
 240         if (!host->mmc->f_max) {
 241                 dev_err(&pdev->dev, "Missing max-freq for SDHCI cfg\n");
 242                 ret = -ENXIO;
 243                 goto err_pltfm_free;
 244         }
 245
 246         /* Get and enable the core clock */
 247         pltfm_priv->clk = devm_clk_get(dev, NULL);
 248         if (IS_ERR(pltfm_priv->clk)) {
 249                 dev_err(dev, "Failed to get core clock\n");
 250                 ret = PTR_ERR(pltfm_priv->clk);
 251                 goto err_pltfm_free;
 252         }
 253
 254         ret = clk_set_rate(pltfm_priv->clk, host->mmc->f_max);
 255         if (ret) {
 256                 dev_err(dev, "Failed to set rate core clock\n");
 257                 goto err_pltfm_free;
 258         }
 259
 260         ret = clk_prepare_enable(pltfm_priv->clk);
 261         if (ret) {
 262                 dev_err(dev, "Failed to enable core clock\n");
 263                 goto err_pltfm_free;
 264         }
 265
 266         dev_dbg(dev, "non-removable=%c\n",
 267                 mmc_card_is_removable(host->mmc) ? 'N' : 'Y');
 268         dev_dbg(dev, "cd_gpio %c, wp_gpio %c\n",
 269                 (mmc_gpio_get_cd(host->mmc) != -ENOSYS) ? 'Y' : 'N',
 270                 (mmc_gpio_get_ro(host->mmc) != -ENOSYS) ? 'Y' : 'N');
 271
 272         if (!mmc_card_is_removable(host->mmc))
 273                 host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
 274
 275         dev_dbg(dev, "is_8bit=%c\n",
 276                 (host->mmc->caps & MMC_CAP_8_BIT_DATA) ? 'Y' : 'N');
 277
 278         ret = sdhci_bcm_kona_sd_reset(host);
 279         if (ret)
 280                 goto err_clk_disable;
 281
 282         sdhci_bcm_kona_sd_init(host);
 283
 284         ret = sdhci_add_host(host);
 285         if (ret)
 286                 goto err_reset;
 287
 288         /* if device is eMMC, emulate card insert right here */
 289         if (!mmc_card_is_removable(host->mmc)) {
 290                 ret = sdhci_bcm_kona_sd_card_emulate(host, 1);
 291                 if (ret) {
 292                         dev_err(dev,
 293                                 "unable to emulate card insertion\n");
 294                         goto err_remove_host;
 295                 }
 296         }
 297         /*
 298          * Since the card detection GPIO interrupt is configured to be
 299          * edge sensitive, check the initial GPIO value here, emulate
 300          * only if the card is present
 301          */
 302         if (mmc_gpio_get_cd(host->mmc) > 0)
 303                 sdhci_bcm_kona_sd_card_emulate(host, 1);
 304
 305         dev_dbg(dev, "initialized properly\n");
 306         return 0;
 307
 308 err_remove_host:
 309         sdhci_remove_host(host, 0);
 310
 311 err_reset:
 312         sdhci_bcm_kona_sd_reset(host);
 313
 314 err_clk_disable:
 315         clk_disable_unprepare(pltfm_priv->clk);
 316
 317 err_pltfm_free:
 318         sdhci_pltfm_free(pdev);
 319
 320         dev_err(dev, "Probing of sdhci-pltfm failed: %d\n", ret);
 321         return ret;
 322 }
 323
 324 static struct platform_driver sdhci_bcm_kona_driver = {
 325         .driver         = {
 326                 .name   = "sdhci-kona",
 327                 .pm     = &sdhci_pltfm_pmops,
 328                 .of_match_table = sdhci_bcm_kona_of_match,
 329         },
 330         .probe          = sdhci_bcm_kona_probe,
 331         .remove         = sdhci_pltfm_unregister,
 332 };
 333 module_platform_driver(sdhci_bcm_kona_driver);
 334
 335 MODULE_DESCRIPTION("SDHCI driver for Broadcom Kona platform");
 336 MODULE_AUTHOR("Broadcom");
 337 MODULE_LICENSE("GPL v2");