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