1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Jonathan McDowell <noodles@earth.li> 4 * 5 * Derived from drivers/mtd/nand/toto.c (removed in v2.6.28) 6 * Copyright (c) 2003 Texas Instruments 7 * Copyright (c) 2002 Thomas Gleixner <tgxl@linutronix.de> 8 * 9 * Converted to platform driver by Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> 10 * Partially stolen from plat_nand.c 11 * 12 * Overview: 13 * This is a device driver for the NAND flash device found on the 14 * Amstrad E3 (Delta). 15 */ 16 17 #include <linux/slab.h> 18 #include <linux/module.h> 19 #include <linux/delay.h> 20 #include <linux/gpio/consumer.h> 21 #include <linux/mtd/mtd.h> 22 #include <linux/mtd/nand-gpio.h> 23 #include <linux/mtd/rawnand.h> 24 #include <linux/mtd/partitions.h> 25 #include <linux/of_device.h> 26 #include <linux/platform_device.h> 27 #include <linux/sizes.h> 28 29 /* 30 * MTD structure for E3 (Delta) 31 */ 32 struct gpio_nand { 33 struct nand_controller base; 34 struct nand_chip nand_chip; 35 struct gpio_desc *gpiod_rdy; 36 struct gpio_desc *gpiod_nce; 37 struct gpio_desc *gpiod_nre; 38 struct gpio_desc *gpiod_nwp; 39 struct gpio_desc *gpiod_nwe; 40 struct gpio_desc *gpiod_ale; 41 struct gpio_desc *gpiod_cle; 42 struct gpio_descs *data_gpiods; 43 bool data_in; 44 unsigned int tRP; 45 unsigned int tWP; 46 u8 (*io_read)(struct gpio_nand *this); 47 void (*io_write)(struct gpio_nand *this, u8 byte); 48 }; 49 50 static void gpio_nand_write_commit(struct gpio_nand *priv) 51 { 52 gpiod_set_value(priv->gpiod_nwe, 1); 53 ndelay(priv->tWP); 54 gpiod_set_value(priv->gpiod_nwe, 0); 55 } 56 57 static void gpio_nand_io_write(struct gpio_nand *priv, u8 byte) 58 { 59 struct gpio_descs *data_gpiods = priv->data_gpiods; 60 DECLARE_BITMAP(values, BITS_PER_TYPE(byte)) = { byte, }; 61 62 gpiod_set_raw_array_value(data_gpiods->ndescs, data_gpiods->desc, 63 data_gpiods->info, values); 64 65 gpio_nand_write_commit(priv); 66 } 67 68 static void gpio_nand_dir_output(struct gpio_nand *priv, u8 byte) 69 { 70 struct gpio_descs *data_gpiods = priv->data_gpiods; 71 DECLARE_BITMAP(values, BITS_PER_TYPE(byte)) = { byte, }; 72 int i; 73 74 for (i = 0; i < data_gpiods->ndescs; i++) 75 gpiod_direction_output_raw(data_gpiods->desc[i], 76 test_bit(i, values)); 77 78 gpio_nand_write_commit(priv); 79 80 priv->data_in = false; 81 } 82 83 static u8 gpio_nand_io_read(struct gpio_nand *priv) 84 { 85 u8 res; 86 struct gpio_descs *data_gpiods = priv->data_gpiods; 87 DECLARE_BITMAP(values, BITS_PER_TYPE(res)) = { 0, }; 88 89 gpiod_set_value(priv->gpiod_nre, 1); 90 ndelay(priv->tRP); 91 92 gpiod_get_raw_array_value(data_gpiods->ndescs, data_gpiods->desc, 93 data_gpiods->info, values); 94 95 gpiod_set_value(priv->gpiod_nre, 0); 96 97 res = values[0]; 98 return res; 99 } 100 101 static void gpio_nand_dir_input(struct gpio_nand *priv) 102 { 103 struct gpio_descs *data_gpiods = priv->data_gpiods; 104 int i; 105 106 for (i = 0; i < data_gpiods->ndescs; i++) 107 gpiod_direction_input(data_gpiods->desc[i]); 108 109 priv->data_in = true; 110 } 111 112 static void gpio_nand_write_buf(struct gpio_nand *priv, const u8 *buf, int len) 113 { 114 int i = 0; 115 116 if (len > 0 && priv->data_in) 117 gpio_nand_dir_output(priv, buf[i++]); 118 119 while (i < len) 120 priv->io_write(priv, buf[i++]); 121 } 122 123 static void gpio_nand_read_buf(struct gpio_nand *priv, u8 *buf, int len) 124 { 125 int i; 126 127 if (priv->data_gpiods && !priv->data_in) 128 gpio_nand_dir_input(priv); 129 130 for (i = 0; i < len; i++) 131 buf[i] = priv->io_read(priv); 132 } 133 134 static void gpio_nand_ctrl_cs(struct gpio_nand *priv, bool assert) 135 { 136 gpiod_set_value(priv->gpiod_nce, assert); 137 } 138 139 static int gpio_nand_exec_op(struct nand_chip *this, 140 const struct nand_operation *op, bool check_only) 141 { 142 struct gpio_nand *priv = nand_get_controller_data(this); 143 const struct nand_op_instr *instr; 144 int ret = 0; 145 146 if (check_only) 147 return 0; 148 149 gpio_nand_ctrl_cs(priv, 1); 150 151 for (instr = op->instrs; instr < op->instrs + op->ninstrs; instr++) { 152 switch (instr->type) { 153 case NAND_OP_CMD_INSTR: 154 gpiod_set_value(priv->gpiod_cle, 1); 155 gpio_nand_write_buf(priv, &instr->ctx.cmd.opcode, 1); 156 gpiod_set_value(priv->gpiod_cle, 0); 157 break; 158 159 case NAND_OP_ADDR_INSTR: 160 gpiod_set_value(priv->gpiod_ale, 1); 161 gpio_nand_write_buf(priv, instr->ctx.addr.addrs, 162 instr->ctx.addr.naddrs); 163 gpiod_set_value(priv->gpiod_ale, 0); 164 break; 165 166 case NAND_OP_DATA_IN_INSTR: 167 gpio_nand_read_buf(priv, instr->ctx.data.buf.in, 168 instr->ctx.data.len); 169 break; 170 171 case NAND_OP_DATA_OUT_INSTR: 172 gpio_nand_write_buf(priv, instr->ctx.data.buf.out, 173 instr->ctx.data.len); 174 break; 175 176 case NAND_OP_WAITRDY_INSTR: 177 ret = priv->gpiod_rdy ? 178 nand_gpio_waitrdy(this, priv->gpiod_rdy, 179 instr->ctx.waitrdy.timeout_ms) : 180 nand_soft_waitrdy(this, 181 instr->ctx.waitrdy.timeout_ms); 182 break; 183 } 184 185 if (ret) 186 break; 187 } 188 189 gpio_nand_ctrl_cs(priv, 0); 190 191 return ret; 192 } 193 194 static int gpio_nand_setup_interface(struct nand_chip *this, int csline, 195 const struct nand_interface_config *cf) 196 { 197 struct gpio_nand *priv = nand_get_controller_data(this); 198 const struct nand_sdr_timings *sdr = nand_get_sdr_timings(cf); 199 struct device *dev = &nand_to_mtd(this)->dev; 200 201 if (IS_ERR(sdr)) 202 return PTR_ERR(sdr); 203 204 if (csline == NAND_DATA_IFACE_CHECK_ONLY) 205 return 0; 206 207 if (priv->gpiod_nre) { 208 priv->tRP = DIV_ROUND_UP(sdr->tRP_min, 1000); 209 dev_dbg(dev, "using %u ns read pulse width\n", priv->tRP); 210 } 211 212 priv->tWP = DIV_ROUND_UP(sdr->tWP_min, 1000); 213 dev_dbg(dev, "using %u ns write pulse width\n", priv->tWP); 214 215 return 0; 216 } 217 218 static const struct nand_controller_ops gpio_nand_ops = { 219 .exec_op = gpio_nand_exec_op, 220 .setup_interface = gpio_nand_setup_interface, 221 }; 222 223 /* 224 * Main initialization routine 225 */ 226 static int gpio_nand_probe(struct platform_device *pdev) 227 { 228 struct gpio_nand_platdata *pdata = dev_get_platdata(&pdev->dev); 229 const struct mtd_partition *partitions = NULL; 230 int num_partitions = 0; 231 struct gpio_nand *priv; 232 struct nand_chip *this; 233 struct mtd_info *mtd; 234 int (*probe)(struct platform_device *pdev, struct gpio_nand *priv); 235 int err = 0; 236 237 if (pdata) { 238 partitions = pdata->parts; 239 num_partitions = pdata->num_parts; 240 } 241 242 /* Allocate memory for MTD device structure and private data */ 243 priv = devm_kzalloc(&pdev->dev, sizeof(struct gpio_nand), 244 GFP_KERNEL); 245 if (!priv) 246 return -ENOMEM; 247 248 this = &priv->nand_chip; 249 250 mtd = nand_to_mtd(this); 251 mtd->dev.parent = &pdev->dev; 252 253 nand_set_controller_data(this, priv); 254 nand_set_flash_node(this, pdev->dev.of_node); 255 256 priv->gpiod_rdy = devm_gpiod_get_optional(&pdev->dev, "rdy", GPIOD_IN); 257 if (IS_ERR(priv->gpiod_rdy)) { 258 err = PTR_ERR(priv->gpiod_rdy); 259 dev_warn(&pdev->dev, "RDY GPIO request failed (%d)\n", err); 260 return err; 261 } 262 263 this->ecc.mode = NAND_ECC_SOFT; 264 this->ecc.algo = NAND_ECC_HAMMING; 265 266 platform_set_drvdata(pdev, priv); 267 268 /* Set chip enabled but write protected */ 269 priv->gpiod_nwp = devm_gpiod_get_optional(&pdev->dev, "nwp", 270 GPIOD_OUT_HIGH); 271 if (IS_ERR(priv->gpiod_nwp)) { 272 err = PTR_ERR(priv->gpiod_nwp); 273 dev_err(&pdev->dev, "NWP GPIO request failed (%d)\n", err); 274 return err; 275 } 276 277 priv->gpiod_nce = devm_gpiod_get_optional(&pdev->dev, "nce", 278 GPIOD_OUT_LOW); 279 if (IS_ERR(priv->gpiod_nce)) { 280 err = PTR_ERR(priv->gpiod_nce); 281 dev_err(&pdev->dev, "NCE GPIO request failed (%d)\n", err); 282 return err; 283 } 284 285 priv->gpiod_nre = devm_gpiod_get_optional(&pdev->dev, "nre", 286 GPIOD_OUT_LOW); 287 if (IS_ERR(priv->gpiod_nre)) { 288 err = PTR_ERR(priv->gpiod_nre); 289 dev_err(&pdev->dev, "NRE GPIO request failed (%d)\n", err); 290 return err; 291 } 292 293 priv->gpiod_nwe = devm_gpiod_get_optional(&pdev->dev, "nwe", 294 GPIOD_OUT_LOW); 295 if (IS_ERR(priv->gpiod_nwe)) { 296 err = PTR_ERR(priv->gpiod_nwe); 297 dev_err(&pdev->dev, "NWE GPIO request failed (%d)\n", err); 298 return err; 299 } 300 301 priv->gpiod_ale = devm_gpiod_get(&pdev->dev, "ale", GPIOD_OUT_LOW); 302 if (IS_ERR(priv->gpiod_ale)) { 303 err = PTR_ERR(priv->gpiod_ale); 304 dev_err(&pdev->dev, "ALE GPIO request failed (%d)\n", err); 305 return err; 306 } 307 308 priv->gpiod_cle = devm_gpiod_get(&pdev->dev, "cle", GPIOD_OUT_LOW); 309 if (IS_ERR(priv->gpiod_cle)) { 310 err = PTR_ERR(priv->gpiod_cle); 311 dev_err(&pdev->dev, "CLE GPIO request failed (%d)\n", err); 312 return err; 313 } 314 315 /* Request array of data pins, initialize them as input */ 316 priv->data_gpiods = devm_gpiod_get_array_optional(&pdev->dev, "data", 317 GPIOD_IN); 318 if (IS_ERR(priv->data_gpiods)) { 319 err = PTR_ERR(priv->data_gpiods); 320 dev_err(&pdev->dev, "data GPIO request failed: %d\n", err); 321 return err; 322 } 323 if (priv->data_gpiods) { 324 if (!priv->gpiod_nwe) { 325 dev_err(&pdev->dev, 326 "mandatory NWE pin not provided by platform\n"); 327 return -ENODEV; 328 } 329 330 priv->io_read = gpio_nand_io_read; 331 priv->io_write = gpio_nand_io_write; 332 priv->data_in = true; 333 } 334 335 if (pdev->id_entry) 336 probe = (void *) pdev->id_entry->driver_data; 337 else 338 probe = of_device_get_match_data(&pdev->dev); 339 if (probe) 340 err = probe(pdev, priv); 341 if (err) 342 return err; 343 344 if (!priv->io_read || !priv->io_write) { 345 dev_err(&pdev->dev, "incomplete device configuration\n"); 346 return -ENODEV; 347 } 348 349 /* Initialize the NAND controller object embedded in gpio_nand. */ 350 priv->base.ops = &gpio_nand_ops; 351 nand_controller_init(&priv->base); 352 this->controller = &priv->base; 353 354 /* 355 * FIXME: We should release write protection only after nand_scan() to 356 * be on the safe side but we can't do that until we have a generic way 357 * to assert/deassert WP from the core. Even if the core shouldn't 358 * write things in the nand_scan() path, it should have control on this 359 * pin just in case we ever need to disable write protection during 360 * chip detection/initialization. 361 */ 362 /* Release write protection */ 363 gpiod_set_value(priv->gpiod_nwp, 0); 364 365 /* Scan to find existence of the device */ 366 err = nand_scan(this, 1); 367 if (err) 368 return err; 369 370 /* Register the partitions */ 371 err = mtd_device_register(mtd, partitions, num_partitions); 372 if (err) 373 goto err_nand_cleanup; 374 375 return 0; 376 377 err_nand_cleanup: 378 nand_cleanup(this); 379 380 return err; 381 } 382 383 /* 384 * Clean up routine 385 */ 386 static int gpio_nand_remove(struct platform_device *pdev) 387 { 388 struct gpio_nand *priv = platform_get_drvdata(pdev); 389 struct mtd_info *mtd = nand_to_mtd(&priv->nand_chip); 390 int ret; 391 392 /* Apply write protection */ 393 gpiod_set_value(priv->gpiod_nwp, 1); 394 395 /* Unregister device */ 396 ret = mtd_device_unregister(mtd); 397 WARN_ON(ret); 398 nand_cleanup(mtd_to_nand(mtd)); 399 400 return 0; 401 } 402 403 static const struct of_device_id gpio_nand_of_id_table[] = { 404 { 405 /* sentinel */ 406 }, 407 }; 408 MODULE_DEVICE_TABLE(of, gpio_nand_of_id_table); 409 410 static const struct platform_device_id gpio_nand_plat_id_table[] = { 411 { 412 .name = "ams-delta-nand", 413 }, { 414 /* sentinel */ 415 }, 416 }; 417 MODULE_DEVICE_TABLE(platform, gpio_nand_plat_id_table); 418 419 static struct platform_driver gpio_nand_driver = { 420 .probe = gpio_nand_probe, 421 .remove = gpio_nand_remove, 422 .id_table = gpio_nand_plat_id_table, 423 .driver = { 424 .name = "ams-delta-nand", 425 .of_match_table = of_match_ptr(gpio_nand_of_id_table), 426 }, 427 }; 428 429 module_platform_driver(gpio_nand_driver); 430 431 MODULE_LICENSE("GPL v2"); 432 MODULE_AUTHOR("Jonathan McDowell <noodles@earth.li>"); 433 MODULE_DESCRIPTION("Glue layer for NAND flash on Amstrad E3 (Delta)"); 434