1 /* 2 * Updated, and converted to generic GPIO based driver by Russell King. 3 * 4 * Written by Ben Dooks <ben@simtec.co.uk> 5 * Based on 2.4 version by Mark Whittaker 6 * 7 * © 2004 Simtec Electronics 8 * 9 * Device driver for NAND flash that uses a memory mapped interface to 10 * read/write the NAND commands and data, and GPIO pins for control signals 11 * (the DT binding refers to this as "GPIO assisted NAND flash") 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License version 2 as 15 * published by the Free Software Foundation. 16 * 17 */ 18 19 #include <linux/kernel.h> 20 #include <linux/err.h> 21 #include <linux/slab.h> 22 #include <linux/module.h> 23 #include <linux/platform_device.h> 24 #include <linux/gpio/consumer.h> 25 #include <linux/io.h> 26 #include <linux/mtd/mtd.h> 27 #include <linux/mtd/rawnand.h> 28 #include <linux/mtd/partitions.h> 29 #include <linux/mtd/nand-gpio.h> 30 #include <linux/of.h> 31 #include <linux/of_address.h> 32 33 struct gpiomtd { 34 void __iomem *io_sync; 35 struct nand_chip nand_chip; 36 struct gpio_nand_platdata plat; 37 struct gpio_desc *nce; /* Optional chip enable */ 38 struct gpio_desc *cle; 39 struct gpio_desc *ale; 40 struct gpio_desc *rdy; 41 struct gpio_desc *nwp; /* Optional write protection */ 42 }; 43 44 static inline struct gpiomtd *gpio_nand_getpriv(struct mtd_info *mtd) 45 { 46 return container_of(mtd_to_nand(mtd), struct gpiomtd, nand_chip); 47 } 48 49 50 #ifdef CONFIG_ARM 51 /* gpio_nand_dosync() 52 * 53 * Make sure the GPIO state changes occur in-order with writes to NAND 54 * memory region. 55 * Needed on PXA due to bus-reordering within the SoC itself (see section on 56 * I/O ordering in PXA manual (section 2.3, p35) 57 */ 58 static void gpio_nand_dosync(struct gpiomtd *gpiomtd) 59 { 60 unsigned long tmp; 61 62 if (gpiomtd->io_sync) { 63 /* 64 * Linux memory barriers don't cater for what's required here. 65 * What's required is what's here - a read from a separate 66 * region with a dependency on that read. 67 */ 68 tmp = readl(gpiomtd->io_sync); 69 asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp)); 70 } 71 } 72 #else 73 static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) {} 74 #endif 75 76 static void gpio_nand_cmd_ctrl(struct nand_chip *chip, int cmd, 77 unsigned int ctrl) 78 { 79 struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip)); 80 81 gpio_nand_dosync(gpiomtd); 82 83 if (ctrl & NAND_CTRL_CHANGE) { 84 if (gpiomtd->nce) 85 gpiod_set_value(gpiomtd->nce, !(ctrl & NAND_NCE)); 86 gpiod_set_value(gpiomtd->cle, !!(ctrl & NAND_CLE)); 87 gpiod_set_value(gpiomtd->ale, !!(ctrl & NAND_ALE)); 88 gpio_nand_dosync(gpiomtd); 89 } 90 if (cmd == NAND_CMD_NONE) 91 return; 92 93 writeb(cmd, gpiomtd->nand_chip.legacy.IO_ADDR_W); 94 gpio_nand_dosync(gpiomtd); 95 } 96 97 static int gpio_nand_devready(struct nand_chip *chip) 98 { 99 struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip)); 100 101 return gpiod_get_value(gpiomtd->rdy); 102 } 103 104 #ifdef CONFIG_OF 105 static const struct of_device_id gpio_nand_id_table[] = { 106 { .compatible = "gpio-control-nand" }, 107 {} 108 }; 109 MODULE_DEVICE_TABLE(of, gpio_nand_id_table); 110 111 static int gpio_nand_get_config_of(const struct device *dev, 112 struct gpio_nand_platdata *plat) 113 { 114 u32 val; 115 116 if (!dev->of_node) 117 return -ENODEV; 118 119 if (!of_property_read_u32(dev->of_node, "bank-width", &val)) { 120 if (val == 2) { 121 plat->options |= NAND_BUSWIDTH_16; 122 } else if (val != 1) { 123 dev_err(dev, "invalid bank-width %u\n", val); 124 return -EINVAL; 125 } 126 } 127 128 if (!of_property_read_u32(dev->of_node, "chip-delay", &val)) 129 plat->chip_delay = val; 130 131 return 0; 132 } 133 134 static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev) 135 { 136 struct resource *r; 137 u64 addr; 138 139 if (of_property_read_u64(pdev->dev.of_node, 140 "gpio-control-nand,io-sync-reg", &addr)) 141 return NULL; 142 143 r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL); 144 if (!r) 145 return NULL; 146 147 r->start = addr; 148 r->end = r->start + 0x3; 149 r->flags = IORESOURCE_MEM; 150 151 return r; 152 } 153 #else /* CONFIG_OF */ 154 static inline int gpio_nand_get_config_of(const struct device *dev, 155 struct gpio_nand_platdata *plat) 156 { 157 return -ENOSYS; 158 } 159 160 static inline struct resource * 161 gpio_nand_get_io_sync_of(struct platform_device *pdev) 162 { 163 return NULL; 164 } 165 #endif /* CONFIG_OF */ 166 167 static inline int gpio_nand_get_config(const struct device *dev, 168 struct gpio_nand_platdata *plat) 169 { 170 int ret = gpio_nand_get_config_of(dev, plat); 171 172 if (!ret) 173 return ret; 174 175 if (dev_get_platdata(dev)) { 176 memcpy(plat, dev_get_platdata(dev), sizeof(*plat)); 177 return 0; 178 } 179 180 return -EINVAL; 181 } 182 183 static inline struct resource * 184 gpio_nand_get_io_sync(struct platform_device *pdev) 185 { 186 struct resource *r = gpio_nand_get_io_sync_of(pdev); 187 188 if (r) 189 return r; 190 191 return platform_get_resource(pdev, IORESOURCE_MEM, 1); 192 } 193 194 static int gpio_nand_remove(struct platform_device *pdev) 195 { 196 struct gpiomtd *gpiomtd = platform_get_drvdata(pdev); 197 198 nand_release(&gpiomtd->nand_chip); 199 200 /* Enable write protection and disable the chip */ 201 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp)) 202 gpiod_set_value(gpiomtd->nwp, 0); 203 if (gpiomtd->nce && !IS_ERR(gpiomtd->nce)) 204 gpiod_set_value(gpiomtd->nce, 0); 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 struct device *dev = &pdev->dev; 216 int ret = 0; 217 218 if (!dev->of_node && !dev_get_platdata(dev)) 219 return -EINVAL; 220 221 gpiomtd = devm_kzalloc(dev, sizeof(*gpiomtd), GFP_KERNEL); 222 if (!gpiomtd) 223 return -ENOMEM; 224 225 chip = &gpiomtd->nand_chip; 226 227 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 228 chip->legacy.IO_ADDR_R = devm_ioremap_resource(dev, res); 229 if (IS_ERR(chip->legacy.IO_ADDR_R)) 230 return PTR_ERR(chip->legacy.IO_ADDR_R); 231 232 res = gpio_nand_get_io_sync(pdev); 233 if (res) { 234 gpiomtd->io_sync = devm_ioremap_resource(dev, res); 235 if (IS_ERR(gpiomtd->io_sync)) 236 return PTR_ERR(gpiomtd->io_sync); 237 } 238 239 ret = gpio_nand_get_config(dev, &gpiomtd->plat); 240 if (ret) 241 return ret; 242 243 /* Just enable the chip */ 244 gpiomtd->nce = devm_gpiod_get_optional(dev, "nce", GPIOD_OUT_HIGH); 245 if (IS_ERR(gpiomtd->nce)) 246 return PTR_ERR(gpiomtd->nce); 247 248 /* We disable write protection once we know probe() will succeed */ 249 gpiomtd->nwp = devm_gpiod_get_optional(dev, "nwp", GPIOD_OUT_LOW); 250 if (IS_ERR(gpiomtd->nwp)) { 251 ret = PTR_ERR(gpiomtd->nwp); 252 goto out_ce; 253 } 254 255 gpiomtd->ale = devm_gpiod_get(dev, "ale", GPIOD_OUT_LOW); 256 if (IS_ERR(gpiomtd->ale)) { 257 ret = PTR_ERR(gpiomtd->ale); 258 goto out_ce; 259 } 260 261 gpiomtd->cle = devm_gpiod_get(dev, "cle", GPIOD_OUT_LOW); 262 if (IS_ERR(gpiomtd->cle)) { 263 ret = PTR_ERR(gpiomtd->cle); 264 goto out_ce; 265 } 266 267 gpiomtd->rdy = devm_gpiod_get_optional(dev, "rdy", GPIOD_IN); 268 if (IS_ERR(gpiomtd->rdy)) { 269 ret = PTR_ERR(gpiomtd->rdy); 270 goto out_ce; 271 } 272 /* Using RDY pin */ 273 if (gpiomtd->rdy) 274 chip->legacy.dev_ready = gpio_nand_devready; 275 276 nand_set_flash_node(chip, pdev->dev.of_node); 277 chip->legacy.IO_ADDR_W = chip->legacy.IO_ADDR_R; 278 chip->ecc.mode = NAND_ECC_SOFT; 279 chip->ecc.algo = NAND_ECC_HAMMING; 280 chip->options = gpiomtd->plat.options; 281 chip->legacy.chip_delay = gpiomtd->plat.chip_delay; 282 chip->legacy.cmd_ctrl = gpio_nand_cmd_ctrl; 283 284 mtd = nand_to_mtd(chip); 285 mtd->dev.parent = dev; 286 287 platform_set_drvdata(pdev, gpiomtd); 288 289 /* Disable write protection, if wired up */ 290 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp)) 291 gpiod_direction_output(gpiomtd->nwp, 1); 292 293 ret = nand_scan(chip, 1); 294 if (ret) 295 goto err_wp; 296 297 if (gpiomtd->plat.adjust_parts) 298 gpiomtd->plat.adjust_parts(&gpiomtd->plat, mtd->size); 299 300 ret = mtd_device_register(mtd, gpiomtd->plat.parts, 301 gpiomtd->plat.num_parts); 302 if (!ret) 303 return 0; 304 305 err_wp: 306 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp)) 307 gpiod_set_value(gpiomtd->nwp, 0); 308 out_ce: 309 if (gpiomtd->nce && !IS_ERR(gpiomtd->nce)) 310 gpiod_set_value(gpiomtd->nce, 0); 311 312 return ret; 313 } 314 315 static struct platform_driver gpio_nand_driver = { 316 .probe = gpio_nand_probe, 317 .remove = gpio_nand_remove, 318 .driver = { 319 .name = "gpio-nand", 320 .of_match_table = of_match_ptr(gpio_nand_id_table), 321 }, 322 }; 323 324 module_platform_driver(gpio_nand_driver); 325 326 MODULE_LICENSE("GPL"); 327 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 328 MODULE_DESCRIPTION("GPIO NAND Driver"); 329