1/*
2 * drivers/mtd/nand/socrates_nand.c
3 *
4 *  Copyright © 2008 Ilya Yanok, Emcraft Systems
5 *
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 */
12
13#include <linux/slab.h>
14#include <linux/module.h>
15#include <linux/mtd/mtd.h>
16#include <linux/mtd/nand.h>
17#include <linux/mtd/partitions.h>
18#include <linux/of_address.h>
19#include <linux/of_platform.h>
20#include <linux/io.h>
21
22#define FPGA_NAND_CMD_MASK		(0x7 << 28)
23#define FPGA_NAND_CMD_COMMAND		(0x0 << 28)
24#define FPGA_NAND_CMD_ADDR		(0x1 << 28)
25#define FPGA_NAND_CMD_READ		(0x2 << 28)
26#define FPGA_NAND_CMD_WRITE		(0x3 << 28)
27#define FPGA_NAND_BUSY			(0x1 << 15)
28#define FPGA_NAND_ENABLE		(0x1 << 31)
29#define FPGA_NAND_DATA_SHIFT		16
30
31struct socrates_nand_host {
32	struct nand_chip	nand_chip;
33	struct mtd_info		mtd;
34	void __iomem		*io_base;
35	struct device		*dev;
36};
37
38/**
39 * socrates_nand_write_buf -  write buffer to chip
40 * @mtd:	MTD device structure
41 * @buf:	data buffer
42 * @len:	number of bytes to write
43 */
44static void socrates_nand_write_buf(struct mtd_info *mtd,
45		const uint8_t *buf, int len)
46{
47	int i;
48	struct nand_chip *this = mtd->priv;
49	struct socrates_nand_host *host = this->priv;
50
51	for (i = 0; i < len; i++) {
52		out_be32(host->io_base, FPGA_NAND_ENABLE |
53				FPGA_NAND_CMD_WRITE |
54				(buf[i] << FPGA_NAND_DATA_SHIFT));
55	}
56}
57
58/**
59 * socrates_nand_read_buf -  read chip data into buffer
60 * @mtd:	MTD device structure
61 * @buf:	buffer to store date
62 * @len:	number of bytes to read
63 */
64static void socrates_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
65{
66	int i;
67	struct nand_chip *this = mtd->priv;
68	struct socrates_nand_host *host = this->priv;
69	uint32_t val;
70
71	val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
72
73	out_be32(host->io_base, val);
74	for (i = 0; i < len; i++) {
75		buf[i] = (in_be32(host->io_base) >>
76				FPGA_NAND_DATA_SHIFT) & 0xff;
77	}
78}
79
80/**
81 * socrates_nand_read_byte -  read one byte from the chip
82 * @mtd:	MTD device structure
83 */
84static uint8_t socrates_nand_read_byte(struct mtd_info *mtd)
85{
86	uint8_t byte;
87	socrates_nand_read_buf(mtd, &byte, sizeof(byte));
88	return byte;
89}
90
91/**
92 * socrates_nand_read_word -  read one word from the chip
93 * @mtd:	MTD device structure
94 */
95static uint16_t socrates_nand_read_word(struct mtd_info *mtd)
96{
97	uint16_t word;
98	socrates_nand_read_buf(mtd, (uint8_t *)&word, sizeof(word));
99	return word;
100}
101
102/*
103 * Hardware specific access to control-lines
104 */
105static void socrates_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
106		unsigned int ctrl)
107{
108	struct nand_chip *nand_chip = mtd->priv;
109	struct socrates_nand_host *host = nand_chip->priv;
110	uint32_t val;
111
112	if (cmd == NAND_CMD_NONE)
113		return;
114
115	if (ctrl & NAND_CLE)
116		val = FPGA_NAND_CMD_COMMAND;
117	else
118		val = FPGA_NAND_CMD_ADDR;
119
120	if (ctrl & NAND_NCE)
121		val |= FPGA_NAND_ENABLE;
122
123	val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
124
125	out_be32(host->io_base, val);
126}
127
128/*
129 * Read the Device Ready pin.
130 */
131static int socrates_nand_device_ready(struct mtd_info *mtd)
132{
133	struct nand_chip *nand_chip = mtd->priv;
134	struct socrates_nand_host *host = nand_chip->priv;
135
136	if (in_be32(host->io_base) & FPGA_NAND_BUSY)
137		return 0; /* busy */
138	return 1;
139}
140
141/*
142 * Probe for the NAND device.
143 */
144static int socrates_nand_probe(struct platform_device *ofdev)
145{
146	struct socrates_nand_host *host;
147	struct mtd_info *mtd;
148	struct nand_chip *nand_chip;
149	int res;
150	struct mtd_part_parser_data ppdata;
151
152	/* Allocate memory for the device structure (and zero it) */
153	host = devm_kzalloc(&ofdev->dev, sizeof(*host), GFP_KERNEL);
154	if (!host)
155		return -ENOMEM;
156
157	host->io_base = of_iomap(ofdev->dev.of_node, 0);
158	if (host->io_base == NULL) {
159		dev_err(&ofdev->dev, "ioremap failed\n");
160		return -EIO;
161	}
162
163	mtd = &host->mtd;
164	nand_chip = &host->nand_chip;
165	host->dev = &ofdev->dev;
166
167	nand_chip->priv = host;		/* link the private data structures */
168	mtd->priv = nand_chip;
169	mtd->name = "socrates_nand";
170	mtd->owner = THIS_MODULE;
171	mtd->dev.parent = &ofdev->dev;
172	ppdata.of_node = ofdev->dev.of_node;
173
174	/*should never be accessed directly */
175	nand_chip->IO_ADDR_R = (void *)0xdeadbeef;
176	nand_chip->IO_ADDR_W = (void *)0xdeadbeef;
177
178	nand_chip->cmd_ctrl = socrates_nand_cmd_ctrl;
179	nand_chip->read_byte = socrates_nand_read_byte;
180	nand_chip->read_word = socrates_nand_read_word;
181	nand_chip->write_buf = socrates_nand_write_buf;
182	nand_chip->read_buf = socrates_nand_read_buf;
183	nand_chip->dev_ready = socrates_nand_device_ready;
184
185	nand_chip->ecc.mode = NAND_ECC_SOFT;	/* enable ECC */
186
187	/* TODO: I have no idea what real delay is. */
188	nand_chip->chip_delay = 20;		/* 20us command delay time */
189
190	dev_set_drvdata(&ofdev->dev, host);
191
192	/* first scan to find the device and get the page size */
193	if (nand_scan_ident(mtd, 1, NULL)) {
194		res = -ENXIO;
195		goto out;
196	}
197
198	/* second phase scan */
199	if (nand_scan_tail(mtd)) {
200		res = -ENXIO;
201		goto out;
202	}
203
204	res = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
205	if (!res)
206		return res;
207
208	nand_release(mtd);
209
210out:
211	iounmap(host->io_base);
212	return res;
213}
214
215/*
216 * Remove a NAND device.
217 */
218static int socrates_nand_remove(struct platform_device *ofdev)
219{
220	struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
221	struct mtd_info *mtd = &host->mtd;
222
223	nand_release(mtd);
224
225	iounmap(host->io_base);
226
227	return 0;
228}
229
230static const struct of_device_id socrates_nand_match[] =
231{
232	{
233		.compatible   = "abb,socrates-nand",
234	},
235	{},
236};
237
238MODULE_DEVICE_TABLE(of, socrates_nand_match);
239
240static struct platform_driver socrates_nand_driver = {
241	.driver = {
242		.name = "socrates_nand",
243		.of_match_table = socrates_nand_match,
244	},
245	.probe		= socrates_nand_probe,
246	.remove		= socrates_nand_remove,
247};
248
249module_platform_driver(socrates_nand_driver);
250
251MODULE_LICENSE("GPL");
252MODULE_AUTHOR("Ilya Yanok");
253MODULE_DESCRIPTION("NAND driver for Socrates board");
254