drivers/mtd/nand/gpio.c

   1 /*
   2  * drivers/mtd/nand/gpio.c
   3  *
   4  * Updated, and converted to generic GPIO based driver by Russell King.
   5  *
   6  * Written by Ben Dooks <ben@simtec.co.uk>
   7  *   Based on 2.4 version by Mark Whittaker
   8  *
   9  * © 2004 Simtec Electronics
  10  *
  11  * Device driver for NAND flash that uses a memory mapped interface to
  12  * read/write the NAND commands and data, and GPIO pins for control signals
  13  * (the DT binding refers to this as "GPIO assisted NAND flash")
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License version 2 as
  17  * published by the Free Software Foundation.
  18  *
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/err.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/gpio.h>
  27 #include <linux/io.h>
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/nand.h>
  30 #include <linux/mtd/partitions.h>
  31 #include <linux/mtd/nand-gpio.h>
  32 #include <linux/of.h>
  33 #include <linux/of_address.h>
  34 #include <linux/of_gpio.h>
  35
  36 struct gpiomtd {
  37         void __iomem            *io_sync;
  38         struct nand_chip        nand_chip;
  39         struct gpio_nand_platdata plat;
  40 };
  41
  42 static inline struct gpiomtd *gpio_nand_getpriv(struct mtd_info *mtd)
  43 {
  44         return container_of(mtd_to_nand(mtd), struct gpiomtd, nand_chip);
  45 }
  46
  47
  48 #ifdef CONFIG_ARM
  49 /* gpio_nand_dosync()
  50  *
  51  * Make sure the GPIO state changes occur in-order with writes to NAND
  52  * memory region.
  53  * Needed on PXA due to bus-reordering within the SoC itself (see section on
  54  * I/O ordering in PXA manual (section 2.3, p35)
  55  */
  56 static void gpio_nand_dosync(struct gpiomtd *gpiomtd)
  57 {
  58         unsigned long tmp;
  59
  60         if (gpiomtd->io_sync) {
  61                 /*
  62                  * Linux memory barriers don't cater for what's required here.
  63                  * What's required is what's here - a read from a separate
  64                  * region with a dependency on that read.
  65                  */
  66                 tmp = readl(gpiomtd->io_sync);
  67                 asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
  68         }
  69 }
  70 #else
  71 static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) {}
  72 #endif
  73
  74 static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
  75 {
  76         struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
  77
  78         gpio_nand_dosync(gpiomtd);
  79
  80         if (ctrl & NAND_CTRL_CHANGE) {
  81                 if (gpio_is_valid(gpiomtd->plat.gpio_nce))
  82                         gpio_set_value(gpiomtd->plat.gpio_nce,
  83                                        !(ctrl & NAND_NCE));
  84                 gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
  85                 gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
  86                 gpio_nand_dosync(gpiomtd);
  87         }
  88         if (cmd == NAND_CMD_NONE)
  89                 return;
  90
  91         writeb(cmd, gpiomtd->nand_chip.IO_ADDR_W);
  92         gpio_nand_dosync(gpiomtd);
  93 }
  94
  95 static int gpio_nand_devready(struct mtd_info *mtd)
  96 {
  97         struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
  98
  99         return gpio_get_value(gpiomtd->plat.gpio_rdy);
 100 }
 101
 102 #ifdef CONFIG_OF
 103 static const struct of_device_id gpio_nand_id_table[] = {
 104         { .compatible = "gpio-control-nand" },
 105         {}
 106 };
 107 MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
 108
 109 static int gpio_nand_get_config_of(const struct device *dev,
 110                                    struct gpio_nand_platdata *plat)
 111 {
 112         u32 val;
 113
 114         if (!dev->of_node)
 115                 return -ENODEV;
 116
 117         if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
 118                 if (val == 2) {
 119                         plat->options |= NAND_BUSWIDTH_16;
 120                 } else if (val != 1) {
 121                         dev_err(dev, "invalid bank-width %u\n", val);
 122                         return -EINVAL;
 123                 }
 124         }
 125
 126         plat->gpio_rdy = of_get_gpio(dev->of_node, 0);
 127         plat->gpio_nce = of_get_gpio(dev->of_node, 1);
 128         plat->gpio_ale = of_get_gpio(dev->of_node, 2);
 129         plat->gpio_cle = of_get_gpio(dev->of_node, 3);
 130         plat->gpio_nwp = of_get_gpio(dev->of_node, 4);
 131
 132         if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
 133                 plat->chip_delay = val;
 134
 135         return 0;
 136 }
 137
 138 static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
 139 {
 140         struct resource *r;
 141         u64 addr;
 142
 143         if (of_property_read_u64(pdev->dev.of_node,
 144                                        "gpio-control-nand,io-sync-reg", &addr))
 145                 return NULL;
 146
 147         r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
 148         if (!r)
 149                 return NULL;
 150
 151         r->start = addr;
 152         r->end = r->start + 0x3;
 153         r->flags = IORESOURCE_MEM;
 154
 155         return r;
 156 }
 157 #else /* CONFIG_OF */
 158 static inline int gpio_nand_get_config_of(const struct device *dev,
 159                                           struct gpio_nand_platdata *plat)
 160 {
 161         return -ENOSYS;
 162 }
 163
 164 static inline struct resource *
 165 gpio_nand_get_io_sync_of(struct platform_device *pdev)
 166 {
 167         return NULL;
 168 }
 169 #endif /* CONFIG_OF */
 170
 171 static inline int gpio_nand_get_config(const struct device *dev,
 172                                        struct gpio_nand_platdata *plat)
 173 {
 174         int ret = gpio_nand_get_config_of(dev, plat);
 175
 176         if (!ret)
 177                 return ret;
 178
 179         if (dev_get_platdata(dev)) {
 180                 memcpy(plat, dev_get_platdata(dev), sizeof(*plat));
 181                 return 0;
 182         }
 183
 184         return -EINVAL;
 185 }
 186
 187 static inline struct resource *
 188 gpio_nand_get_io_sync(struct platform_device *pdev)
 189 {
 190         struct resource *r = gpio_nand_get_io_sync_of(pdev);
 191
 192         if (r)
 193                 return r;
 194
 195         return platform_get_resource(pdev, IORESOURCE_MEM, 1);
 196 }
 197
 198 static int gpio_nand_remove(struct platform_device *pdev)
 199 {
 200         struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
 201
 202         nand_release(nand_to_mtd(&gpiomtd->nand_chip));
 203
 204         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 205                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 206         if (gpio_is_valid(gpiomtd->plat.gpio_nce))
 207                 gpio_set_value(gpiomtd->plat.gpio_nce, 1);
 208
 209         return 0;
 210 }
 211
 212 static int gpio_nand_probe(struct platform_device *pdev)
 213 {
 214         struct gpiomtd *gpiomtd;
 215         struct nand_chip *chip;
 216         struct mtd_info *mtd;
 217         struct resource *res;
 218         int ret = 0;
 219
 220         if (!pdev->dev.of_node && !dev_get_platdata(&pdev->dev))
 221                 return -EINVAL;
 222
 223         gpiomtd = devm_kzalloc(&pdev->dev, sizeof(*gpiomtd), GFP_KERNEL);
 224         if (!gpiomtd)
 225                 return -ENOMEM;
 226
 227         chip = &gpiomtd->nand_chip;
 228
 229         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 230         chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
 231         if (IS_ERR(chip->IO_ADDR_R))
 232                 return PTR_ERR(chip->IO_ADDR_R);
 233
 234         res = gpio_nand_get_io_sync(pdev);
 235         if (res) {
 236                 gpiomtd->io_sync = devm_ioremap_resource(&pdev->dev, res);
 237                 if (IS_ERR(gpiomtd->io_sync))
 238                         return PTR_ERR(gpiomtd->io_sync);
 239         }
 240
 241         ret = gpio_nand_get_config(&pdev->dev, &gpiomtd->plat);
 242         if (ret)
 243                 return ret;
 244
 245         if (gpio_is_valid(gpiomtd->plat.gpio_nce)) {
 246                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce,
 247                                         "NAND NCE");
 248                 if (ret)
 249                         return ret;
 250                 gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
 251         }
 252
 253         if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
 254                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nwp,
 255                                         "NAND NWP");
 256                 if (ret)
 257                         return ret;
 258         }
 259
 260         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_ale, "NAND ALE");
 261         if (ret)
 262                 return ret;
 263         gpio_direction_output(gpiomtd->plat.gpio_ale, 0);
 264
 265         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_cle, "NAND CLE");
 266         if (ret)
 267                 return ret;
 268         gpio_direction_output(gpiomtd->plat.gpio_cle, 0);
 269
 270         if (gpio_is_valid(gpiomtd->plat.gpio_rdy)) {
 271                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_rdy,
 272                                         "NAND RDY");
 273                 if (ret)
 274                         return ret;
 275                 gpio_direction_input(gpiomtd->plat.gpio_rdy);
 276                 chip->dev_ready = gpio_nand_devready;
 277         }
 278
 279         nand_set_flash_node(chip, pdev->dev.of_node);
 280         chip->IO_ADDR_W         = chip->IO_ADDR_R;
 281         chip->ecc.mode          = NAND_ECC_SOFT;
 282         chip->ecc.algo          = NAND_ECC_HAMMING;
 283         chip->options           = gpiomtd->plat.options;
 284         chip->chip_delay        = gpiomtd->plat.chip_delay;
 285         chip->cmd_ctrl          = gpio_nand_cmd_ctrl;
 286
 287         mtd                     = nand_to_mtd(chip);
 288         mtd->dev.parent         = &pdev->dev;
 289
 290         platform_set_drvdata(pdev, gpiomtd);
 291
 292         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 293                 gpio_direction_output(gpiomtd->plat.gpio_nwp, 1);
 294
 295         ret = nand_scan(mtd, 1);
 296         if (ret)
 297                 goto err_wp;
 298
 299         if (gpiomtd->plat.adjust_parts)
 300                 gpiomtd->plat.adjust_parts(&gpiomtd->plat, mtd->size);
 301
 302         ret = mtd_device_register(mtd, gpiomtd->plat.parts,
 303                                   gpiomtd->plat.num_parts);
 304         if (!ret)
 305                 return 0;
 306
 307 err_wp:
 308         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 309                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 310
 311         return ret;
 312 }
 313
 314 static struct platform_driver gpio_nand_driver = {
 315         .probe          = gpio_nand_probe,
 316         .remove         = gpio_nand_remove,
 317         .driver         = {
 318                 .name   = "gpio-nand",
 319                 .of_match_table = of_match_ptr(gpio_nand_id_table),
 320         },
 321 };
 322
 323 module_platform_driver(gpio_nand_driver);
 324
 325 MODULE_LICENSE("GPL");
 326 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 327 MODULE_DESCRIPTION("GPIO NAND Driver");