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                 gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
  82                 gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
  83                 gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
  84                 gpio_nand_dosync(gpiomtd);
  85         }
  86         if (cmd == NAND_CMD_NONE)
  87                 return;
  88
  89         writeb(cmd, gpiomtd->nand_chip.IO_ADDR_W);
  90         gpio_nand_dosync(gpiomtd);
  91 }
  92
  93 static int gpio_nand_devready(struct mtd_info *mtd)
  94 {
  95         struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
  96
  97         return gpio_get_value(gpiomtd->plat.gpio_rdy);
  98 }
  99
 100 #ifdef CONFIG_OF
 101 static const struct of_device_id gpio_nand_id_table[] = {
 102         { .compatible = "gpio-control-nand" },
 103         {}
 104 };
 105 MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
 106
 107 static int gpio_nand_get_config_of(const struct device *dev,
 108                                    struct gpio_nand_platdata *plat)
 109 {
 110         u32 val;
 111
 112         if (!dev->of_node)
 113                 return -ENODEV;
 114
 115         if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
 116                 if (val == 2) {
 117                         plat->options |= NAND_BUSWIDTH_16;
 118                 } else if (val != 1) {
 119                         dev_err(dev, "invalid bank-width %u\n", val);
 120                         return -EINVAL;
 121                 }
 122         }
 123
 124         plat->gpio_rdy = of_get_gpio(dev->of_node, 0);
 125         plat->gpio_nce = of_get_gpio(dev->of_node, 1);
 126         plat->gpio_ale = of_get_gpio(dev->of_node, 2);
 127         plat->gpio_cle = of_get_gpio(dev->of_node, 3);
 128         plat->gpio_nwp = of_get_gpio(dev->of_node, 4);
 129
 130         if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
 131                 plat->chip_delay = val;
 132
 133         return 0;
 134 }
 135
 136 static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
 137 {
 138         struct resource *r;
 139         u64 addr;
 140
 141         if (of_property_read_u64(pdev->dev.of_node,
 142                                        "gpio-control-nand,io-sync-reg", &addr))
 143                 return NULL;
 144
 145         r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
 146         if (!r)
 147                 return NULL;
 148
 149         r->start = addr;
 150         r->end = r->start + 0x3;
 151         r->flags = IORESOURCE_MEM;
 152
 153         return r;
 154 }
 155 #else /* CONFIG_OF */
 156 static inline int gpio_nand_get_config_of(const struct device *dev,
 157                                           struct gpio_nand_platdata *plat)
 158 {
 159         return -ENOSYS;
 160 }
 161
 162 static inline struct resource *
 163 gpio_nand_get_io_sync_of(struct platform_device *pdev)
 164 {
 165         return NULL;
 166 }
 167 #endif /* CONFIG_OF */
 168
 169 static inline int gpio_nand_get_config(const struct device *dev,
 170                                        struct gpio_nand_platdata *plat)
 171 {
 172         int ret = gpio_nand_get_config_of(dev, plat);
 173
 174         if (!ret)
 175                 return ret;
 176
 177         if (dev_get_platdata(dev)) {
 178                 memcpy(plat, dev_get_platdata(dev), sizeof(*plat));
 179                 return 0;
 180         }
 181
 182         return -EINVAL;
 183 }
 184
 185 static inline struct resource *
 186 gpio_nand_get_io_sync(struct platform_device *pdev)
 187 {
 188         struct resource *r = gpio_nand_get_io_sync_of(pdev);
 189
 190         if (r)
 191                 return r;
 192
 193         return platform_get_resource(pdev, IORESOURCE_MEM, 1);
 194 }
 195
 196 static int gpio_nand_remove(struct platform_device *pdev)
 197 {
 198         struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
 199
 200         nand_release(nand_to_mtd(&gpiomtd->nand_chip));
 201
 202         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 203                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 204         gpio_set_value(gpiomtd->plat.gpio_nce, 1);
 205
 206         return 0;
 207 }
 208
 209 static int gpio_nand_probe(struct platform_device *pdev)
 210 {
 211         struct gpiomtd *gpiomtd;
 212         struct nand_chip *chip;
 213         struct mtd_info *mtd;
 214         struct resource *res;
 215         int ret = 0;
 216
 217         if (!pdev->dev.of_node && !dev_get_platdata(&pdev->dev))
 218                 return -EINVAL;
 219
 220         gpiomtd = devm_kzalloc(&pdev->dev, sizeof(*gpiomtd), GFP_KERNEL);
 221         if (!gpiomtd)
 222                 return -ENOMEM;
 223
 224         chip = &gpiomtd->nand_chip;
 225
 226         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 227         chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
 228         if (IS_ERR(chip->IO_ADDR_R))
 229                 return PTR_ERR(chip->IO_ADDR_R);
 230
 231         res = gpio_nand_get_io_sync(pdev);
 232         if (res) {
 233                 gpiomtd->io_sync = devm_ioremap_resource(&pdev->dev, res);
 234                 if (IS_ERR(gpiomtd->io_sync))
 235                         return PTR_ERR(gpiomtd->io_sync);
 236         }
 237
 238         ret = gpio_nand_get_config(&pdev->dev, &gpiomtd->plat);
 239         if (ret)
 240                 return ret;
 241
 242         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce, "NAND NCE");
 243         if (ret)
 244                 return ret;
 245         gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
 246
 247         if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
 248                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nwp,
 249                                         "NAND NWP");
 250                 if (ret)
 251                         return ret;
 252         }
 253
 254         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_ale, "NAND ALE");
 255         if (ret)
 256                 return ret;
 257         gpio_direction_output(gpiomtd->plat.gpio_ale, 0);
 258
 259         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_cle, "NAND CLE");
 260         if (ret)
 261                 return ret;
 262         gpio_direction_output(gpiomtd->plat.gpio_cle, 0);
 263
 264         if (gpio_is_valid(gpiomtd->plat.gpio_rdy)) {
 265                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_rdy,
 266                                         "NAND RDY");
 267                 if (ret)
 268                         return ret;
 269                 gpio_direction_input(gpiomtd->plat.gpio_rdy);
 270                 chip->dev_ready = gpio_nand_devready;
 271         }
 272
 273         nand_set_flash_node(chip, pdev->dev.of_node);
 274         chip->IO_ADDR_W         = chip->IO_ADDR_R;
 275         chip->ecc.mode          = NAND_ECC_SOFT;
 276         chip->options           = gpiomtd->plat.options;
 277         chip->chip_delay        = gpiomtd->plat.chip_delay;
 278         chip->cmd_ctrl          = gpio_nand_cmd_ctrl;
 279
 280         mtd                     = nand_to_mtd(chip);
 281         mtd->dev.parent         = &pdev->dev;
 282
 283         platform_set_drvdata(pdev, gpiomtd);
 284
 285         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 286                 gpio_direction_output(gpiomtd->plat.gpio_nwp, 1);
 287
 288         if (nand_scan(mtd, 1)) {
 289                 ret = -ENXIO;
 290                 goto err_wp;
 291         }
 292
 293         if (gpiomtd->plat.adjust_parts)
 294                 gpiomtd->plat.adjust_parts(&gpiomtd->plat, mtd->size);
 295
 296         ret = mtd_device_register(mtd, gpiomtd->plat.parts,
 297                                   gpiomtd->plat.num_parts);
 298         if (!ret)
 299                 return 0;
 300
 301 err_wp:
 302         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 303                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 304
 305         return ret;
 306 }
 307
 308 static struct platform_driver gpio_nand_driver = {
 309         .probe          = gpio_nand_probe,
 310         .remove         = gpio_nand_remove,
 311         .driver         = {
 312                 .name   = "gpio-nand",
 313                 .of_match_table = of_match_ptr(gpio_nand_id_table),
 314         },
 315 };
 316
 317 module_platform_driver(gpio_nand_driver);
 318
 319 MODULE_LICENSE("GPL");
 320 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 321 MODULE_DESCRIPTION("GPIO NAND Driver");