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Linux/drivers/mtd/nand/socrates_nand.c

  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 
 31 struct 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  */
 44 static 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  */
 64 static 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  */
 84 static 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  */
 95 static 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  */
105 static 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  */
131 static 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  */
144 static 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 
210 out:
211         iounmap(host->io_base);
212         return res;
213 }
214 
215 /*
216  * Remove a NAND device.
217  */
218 static 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 
230 static const struct of_device_id socrates_nand_match[] =
231 {
232         {
233                 .compatible   = "abb,socrates-nand",
234         },
235         {},
236 };
237 
238 MODULE_DEVICE_TABLE(of, socrates_nand_match);
239 
240 static struct platform_driver socrates_nand_driver = {
241         .driver = {
242                 .name = "socrates_nand",
243                 .owner = THIS_MODULE,
244                 .of_match_table = socrates_nand_match,
245         },
246         .probe          = socrates_nand_probe,
247         .remove         = socrates_nand_remove,
248 };
249 
250 module_platform_driver(socrates_nand_driver);
251 
252 MODULE_LICENSE("GPL");
253 MODULE_AUTHOR("Ilya Yanok");
254 MODULE_DESCRIPTION("NAND driver for Socrates board");
255 

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