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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Updated, and converted to generic GPIO based driver by Russell King.
4 *
5 * Written by Ben Dooks <ben@simtec.co.uk>
6 * Based on 2.4 version by Mark Whittaker
7 *
8 * © 2004 Simtec Electronics
9 *
10 * Device driver for NAND flash that uses a memory mapped interface to
11 * read/write the NAND commands and data, and GPIO pins for control signals
12 * (the DT binding refers to this as "GPIO assisted NAND flash")
13 */
14
15#include <linux/kernel.h>
16#include <linux/err.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/gpio/consumer.h>
21#include <linux/io.h>
22#include <linux/mtd/mtd.h>
23#include <linux/mtd/rawnand.h>
24#include <linux/mtd/partitions.h>
25#include <linux/mtd/nand-gpio.h>
26#include <linux/of.h>
27#include <linux/of_address.h>
28#include <linux/delay.h>
29
30struct gpiomtd {
31 struct nand_controller base;
32 void __iomem *io;
33 void __iomem *io_sync;
34 struct nand_chip nand_chip;
35 struct gpio_nand_platdata plat;
36 struct gpio_desc *nce; /* Optional chip enable */
37 struct gpio_desc *cle;
38 struct gpio_desc *ale;
39 struct gpio_desc *rdy;
40 struct gpio_desc *nwp; /* Optional write protection */
41};
42
43static inline struct gpiomtd *gpio_nand_getpriv(struct mtd_info *mtd)
44{
45 return container_of(mtd_to_nand(mtd), struct gpiomtd, nand_chip);
46}
47
48
49#ifdef CONFIG_ARM
50/* gpio_nand_dosync()
51 *
52 * Make sure the GPIO state changes occur in-order with writes to NAND
53 * memory region.
54 * Needed on PXA due to bus-reordering within the SoC itself (see section on
55 * I/O ordering in PXA manual (section 2.3, p35)
56 */
57static void gpio_nand_dosync(struct gpiomtd *gpiomtd)
58{
59 unsigned long tmp;
60
61 if (gpiomtd->io_sync) {
62 /*
63 * Linux memory barriers don't cater for what's required here.
64 * What's required is what's here - a read from a separate
65 * region with a dependency on that read.
66 */
67 tmp = readl(gpiomtd->io_sync);
68 asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
69 }
70}
71#else
72static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) {}
73#endif
74
75static int gpio_nand_exec_instr(struct nand_chip *chip,
76 const struct nand_op_instr *instr)
77{
78 struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
79 unsigned int i;
80
81 switch (instr->type) {
82 case NAND_OP_CMD_INSTR:
83 gpio_nand_dosync(gpiomtd);
84 gpiod_set_value(gpiomtd->cle, 1);
85 gpio_nand_dosync(gpiomtd);
86 writeb(instr->ctx.cmd.opcode, gpiomtd->io);
87 gpio_nand_dosync(gpiomtd);
88 gpiod_set_value(gpiomtd->cle, 0);
89 return 0;
90
91 case NAND_OP_ADDR_INSTR:
92 gpio_nand_dosync(gpiomtd);
93 gpiod_set_value(gpiomtd->ale, 1);
94 gpio_nand_dosync(gpiomtd);
95 for (i = 0; i < instr->ctx.addr.naddrs; i++)
96 writeb(instr->ctx.addr.addrs[i], gpiomtd->io);
97 gpio_nand_dosync(gpiomtd);
98 gpiod_set_value(gpiomtd->ale, 0);
99 return 0;
100
101 case NAND_OP_DATA_IN_INSTR:
102 gpio_nand_dosync(gpiomtd);
103 if ((chip->options & NAND_BUSWIDTH_16) &&
104 !instr->ctx.data.force_8bit)
105 ioread16_rep(gpiomtd->io, instr->ctx.data.buf.in,
106 instr->ctx.data.len / 2);
107 else
108 ioread8_rep(gpiomtd->io, instr->ctx.data.buf.in,
109 instr->ctx.data.len);
110 return 0;
111
112 case NAND_OP_DATA_OUT_INSTR:
113 gpio_nand_dosync(gpiomtd);
114 if ((chip->options & NAND_BUSWIDTH_16) &&
115 !instr->ctx.data.force_8bit)
116 iowrite16_rep(gpiomtd->io, instr->ctx.data.buf.out,
117 instr->ctx.data.len / 2);
118 else
119 iowrite8_rep(gpiomtd->io, instr->ctx.data.buf.out,
120 instr->ctx.data.len);
121 return 0;
122
123 case NAND_OP_WAITRDY_INSTR:
124 if (!gpiomtd->rdy)
125 return nand_soft_waitrdy(chip, instr->ctx.waitrdy.timeout_ms);
126
127 return nand_gpio_waitrdy(chip, gpiomtd->rdy,
128 instr->ctx.waitrdy.timeout_ms);
129
130 default:
131 return -EINVAL;
132 }
133
134 return 0;
135}
136
137static int gpio_nand_exec_op(struct nand_chip *chip,
138 const struct nand_operation *op,
139 bool check_only)
140{
141 struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
142 unsigned int i;
143 int ret = 0;
144
145 if (check_only)
146 return 0;
147
148 gpio_nand_dosync(gpiomtd);
149 gpiod_set_value(gpiomtd->nce, 0);
150 for (i = 0; i < op->ninstrs; i++) {
151 ret = gpio_nand_exec_instr(chip, &op->instrs[i]);
152 if (ret)
153 break;
154
155 if (op->instrs[i].delay_ns)
156 ndelay(op->instrs[i].delay_ns);
157 }
158 gpio_nand_dosync(gpiomtd);
159 gpiod_set_value(gpiomtd->nce, 1);
160
161 return ret;
162}
163
164static int gpio_nand_attach_chip(struct nand_chip *chip)
165{
166 if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT &&
167 chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
168 chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
169
170 return 0;
171}
172
173static const struct nand_controller_ops gpio_nand_ops = {
174 .exec_op = gpio_nand_exec_op,
175 .attach_chip = gpio_nand_attach_chip,
176};
177
178#ifdef CONFIG_OF
179static const struct of_device_id gpio_nand_id_table[] = {
180 { .compatible = "gpio-control-nand" },
181 {}
182};
183MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
184
185static int gpio_nand_get_config_of(const struct device *dev,
186 struct gpio_nand_platdata *plat)
187{
188 u32 val;
189
190 if (!dev->of_node)
191 return -ENODEV;
192
193 if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
194 if (val == 2) {
195 plat->options |= NAND_BUSWIDTH_16;
196 } else if (val != 1) {
197 dev_err(dev, "invalid bank-width %u\n", val);
198 return -EINVAL;
199 }
200 }
201
202 if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
203 plat->chip_delay = val;
204
205 return 0;
206}
207
208static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
209{
210 struct resource *r;
211 u64 addr;
212
213 if (of_property_read_u64(pdev->dev.of_node,
214 "gpio-control-nand,io-sync-reg", &addr))
215 return NULL;
216
217 r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
218 if (!r)
219 return NULL;
220
221 r->start = addr;
222 r->end = r->start + 0x3;
223 r->flags = IORESOURCE_MEM;
224
225 return r;
226}
227#else /* CONFIG_OF */
228static inline int gpio_nand_get_config_of(const struct device *dev,
229 struct gpio_nand_platdata *plat)
230{
231 return -ENOSYS;
232}
233
234static inline struct resource *
235gpio_nand_get_io_sync_of(struct platform_device *pdev)
236{
237 return NULL;
238}
239#endif /* CONFIG_OF */
240
241static inline int gpio_nand_get_config(const struct device *dev,
242 struct gpio_nand_platdata *plat)
243{
244 int ret = gpio_nand_get_config_of(dev, plat);
245
246 if (!ret)
247 return ret;
248
249 if (dev_get_platdata(dev)) {
250 memcpy(plat, dev_get_platdata(dev), sizeof(*plat));
251 return 0;
252 }
253
254 return -EINVAL;
255}
256
257static inline struct resource *
258gpio_nand_get_io_sync(struct platform_device *pdev)
259{
260 struct resource *r = gpio_nand_get_io_sync_of(pdev);
261
262 if (r)
263 return r;
264
265 return platform_get_resource(pdev, IORESOURCE_MEM, 1);
266}
267
268static void gpio_nand_remove(struct platform_device *pdev)
269{
270 struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
271 struct nand_chip *chip = &gpiomtd->nand_chip;
272 int ret;
273
274 ret = mtd_device_unregister(nand_to_mtd(chip));
275 WARN_ON(ret);
276 nand_cleanup(chip);
277
278 /* Enable write protection and disable the chip */
279 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
280 gpiod_set_value(gpiomtd->nwp, 0);
281 if (gpiomtd->nce && !IS_ERR(gpiomtd->nce))
282 gpiod_set_value(gpiomtd->nce, 0);
283}
284
285static int gpio_nand_probe(struct platform_device *pdev)
286{
287 struct gpiomtd *gpiomtd;
288 struct nand_chip *chip;
289 struct mtd_info *mtd;
290 struct resource *res;
291 struct device *dev = &pdev->dev;
292 int ret = 0;
293
294 if (!dev->of_node && !dev_get_platdata(dev))
295 return -EINVAL;
296
297 gpiomtd = devm_kzalloc(dev, sizeof(*gpiomtd), GFP_KERNEL);
298 if (!gpiomtd)
299 return -ENOMEM;
300
301 chip = &gpiomtd->nand_chip;
302
303 gpiomtd->io = devm_platform_ioremap_resource(pdev, 0);
304 if (IS_ERR(gpiomtd->io))
305 return PTR_ERR(gpiomtd->io);
306
307 res = gpio_nand_get_io_sync(pdev);
308 if (res) {
309 gpiomtd->io_sync = devm_ioremap_resource(dev, res);
310 if (IS_ERR(gpiomtd->io_sync))
311 return PTR_ERR(gpiomtd->io_sync);
312 }
313
314 ret = gpio_nand_get_config(dev, &gpiomtd->plat);
315 if (ret)
316 return ret;
317
318 /* Just enable the chip */
319 gpiomtd->nce = devm_gpiod_get_optional(dev, "nce", GPIOD_OUT_HIGH);
320 if (IS_ERR(gpiomtd->nce))
321 return PTR_ERR(gpiomtd->nce);
322
323 /* We disable write protection once we know probe() will succeed */
324 gpiomtd->nwp = devm_gpiod_get_optional(dev, "nwp", GPIOD_OUT_LOW);
325 if (IS_ERR(gpiomtd->nwp)) {
326 ret = PTR_ERR(gpiomtd->nwp);
327 goto out_ce;
328 }
329
330 gpiomtd->ale = devm_gpiod_get(dev, "ale", GPIOD_OUT_LOW);
331 if (IS_ERR(gpiomtd->ale)) {
332 ret = PTR_ERR(gpiomtd->ale);
333 goto out_ce;
334 }
335
336 gpiomtd->cle = devm_gpiod_get(dev, "cle", GPIOD_OUT_LOW);
337 if (IS_ERR(gpiomtd->cle)) {
338 ret = PTR_ERR(gpiomtd->cle);
339 goto out_ce;
340 }
341
342 gpiomtd->rdy = devm_gpiod_get_optional(dev, "rdy", GPIOD_IN);
343 if (IS_ERR(gpiomtd->rdy)) {
344 ret = PTR_ERR(gpiomtd->rdy);
345 goto out_ce;
346 }
347
348 nand_controller_init(&gpiomtd->base);
349 gpiomtd->base.ops = &gpio_nand_ops;
350
351 nand_set_flash_node(chip, pdev->dev.of_node);
352 chip->options = gpiomtd->plat.options;
353 chip->controller = &gpiomtd->base;
354
355 mtd = nand_to_mtd(chip);
356 mtd->dev.parent = dev;
357
358 platform_set_drvdata(pdev, gpiomtd);
359
360 /* Disable write protection, if wired up */
361 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
362 gpiod_direction_output(gpiomtd->nwp, 1);
363
364 /*
365 * This driver assumes that the default ECC engine should be TYPE_SOFT.
366 * Set ->engine_type before registering the NAND devices in order to
367 * provide a driver specific default value.
368 */
369 chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
370
371 ret = nand_scan(chip, 1);
372 if (ret)
373 goto err_wp;
374
375 if (gpiomtd->plat.adjust_parts)
376 gpiomtd->plat.adjust_parts(&gpiomtd->plat, mtd->size);
377
378 ret = mtd_device_register(mtd, gpiomtd->plat.parts,
379 gpiomtd->plat.num_parts);
380 if (!ret)
381 return 0;
382
383err_wp:
384 if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
385 gpiod_set_value(gpiomtd->nwp, 0);
386out_ce:
387 if (gpiomtd->nce && !IS_ERR(gpiomtd->nce))
388 gpiod_set_value(gpiomtd->nce, 0);
389
390 return ret;
391}
392
393static struct platform_driver gpio_nand_driver = {
394 .probe = gpio_nand_probe,
395 .remove_new = gpio_nand_remove,
396 .driver = {
397 .name = "gpio-nand",
398 .of_match_table = of_match_ptr(gpio_nand_id_table),
399 },
400};
401
402module_platform_driver(gpio_nand_driver);
403
404MODULE_LICENSE("GPL");
405MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
406MODULE_DESCRIPTION("GPIO NAND Driver");