1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright © 2008 Ilya Yanok, Emcraft Systems 4 */ 5 6 #include <linux/slab.h> 7 #include <linux/module.h> 8 #include <linux/mtd/mtd.h> 9 #include <linux/mtd/rawnand.h> 10 #include <linux/mtd/partitions.h> 11 #include <linux/of.h> 12 #include <linux/of_address.h> 13 #include <linux/platform_device.h> 14 #include <linux/io.h> 15 16 #define FPGA_NAND_CMD_MASK (0x7 << 28) 17 #define FPGA_NAND_CMD_COMMAND (0x0 << 28) 18 #define FPGA_NAND_CMD_ADDR (0x1 << 28) 19 #define FPGA_NAND_CMD_READ (0x2 << 28) 20 #define FPGA_NAND_CMD_WRITE (0x3 << 28) 21 #define FPGA_NAND_BUSY (0x1 << 15) 22 #define FPGA_NAND_ENABLE (0x1 << 31) 23 #define FPGA_NAND_DATA_SHIFT 16 24 25 struct socrates_nand_host { 26 struct nand_controller controller; 27 struct nand_chip nand_chip; 28 void __iomem *io_base; 29 struct device *dev; 30 }; 31 32 /** 33 * socrates_nand_write_buf - write buffer to chip 34 * @this: NAND chip object 35 * @buf: data buffer 36 * @len: number of bytes to write 37 */ 38 static void socrates_nand_write_buf(struct nand_chip *this, const uint8_t *buf, 39 int len) 40 { 41 int i; 42 struct socrates_nand_host *host = nand_get_controller_data(this); 43 44 for (i = 0; i < len; i++) { 45 out_be32(host->io_base, FPGA_NAND_ENABLE | 46 FPGA_NAND_CMD_WRITE | 47 (buf[i] << FPGA_NAND_DATA_SHIFT)); 48 } 49 } 50 51 /** 52 * socrates_nand_read_buf - read chip data into buffer 53 * @this: NAND chip object 54 * @buf: buffer to store date 55 * @len: number of bytes to read 56 */ 57 static void socrates_nand_read_buf(struct nand_chip *this, uint8_t *buf, 58 int len) 59 { 60 int i; 61 struct socrates_nand_host *host = nand_get_controller_data(this); 62 uint32_t val; 63 64 val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ; 65 66 out_be32(host->io_base, val); 67 for (i = 0; i < len; i++) { 68 buf[i] = (in_be32(host->io_base) >> 69 FPGA_NAND_DATA_SHIFT) & 0xff; 70 } 71 } 72 73 /** 74 * socrates_nand_read_byte - read one byte from the chip 75 * @mtd: MTD device structure 76 */ 77 static uint8_t socrates_nand_read_byte(struct nand_chip *this) 78 { 79 uint8_t byte; 80 socrates_nand_read_buf(this, &byte, sizeof(byte)); 81 return byte; 82 } 83 84 /* 85 * Hardware specific access to control-lines 86 */ 87 static void socrates_nand_cmd_ctrl(struct nand_chip *nand_chip, int cmd, 88 unsigned int ctrl) 89 { 90 struct socrates_nand_host *host = nand_get_controller_data(nand_chip); 91 uint32_t val; 92 93 if (cmd == NAND_CMD_NONE) 94 return; 95 96 if (ctrl & NAND_CLE) 97 val = FPGA_NAND_CMD_COMMAND; 98 else 99 val = FPGA_NAND_CMD_ADDR; 100 101 if (ctrl & NAND_NCE) 102 val |= FPGA_NAND_ENABLE; 103 104 val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT; 105 106 out_be32(host->io_base, val); 107 } 108 109 /* 110 * Read the Device Ready pin. 111 */ 112 static int socrates_nand_device_ready(struct nand_chip *nand_chip) 113 { 114 struct socrates_nand_host *host = nand_get_controller_data(nand_chip); 115 116 if (in_be32(host->io_base) & FPGA_NAND_BUSY) 117 return 0; /* busy */ 118 return 1; 119 } 120 121 static int socrates_attach_chip(struct nand_chip *chip) 122 { 123 if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT && 124 chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN) 125 chip->ecc.algo = NAND_ECC_ALGO_HAMMING; 126 127 return 0; 128 } 129 130 static const struct nand_controller_ops socrates_ops = { 131 .attach_chip = socrates_attach_chip, 132 }; 133 134 /* 135 * Probe for the NAND device. 136 */ 137 static int socrates_nand_probe(struct platform_device *ofdev) 138 { 139 struct socrates_nand_host *host; 140 struct mtd_info *mtd; 141 struct nand_chip *nand_chip; 142 int res; 143 144 /* Allocate memory for the device structure (and zero it) */ 145 host = devm_kzalloc(&ofdev->dev, sizeof(*host), GFP_KERNEL); 146 if (!host) 147 return -ENOMEM; 148 149 host->io_base = of_iomap(ofdev->dev.of_node, 0); 150 if (host->io_base == NULL) { 151 dev_err(&ofdev->dev, "ioremap failed\n"); 152 return -EIO; 153 } 154 155 nand_chip = &host->nand_chip; 156 mtd = nand_to_mtd(nand_chip); 157 host->dev = &ofdev->dev; 158 159 nand_controller_init(&host->controller); 160 host->controller.ops = &socrates_ops; 161 nand_chip->controller = &host->controller; 162 163 /* link the private data structures */ 164 nand_set_controller_data(nand_chip, host); 165 nand_set_flash_node(nand_chip, ofdev->dev.of_node); 166 mtd->name = "socrates_nand"; 167 mtd->dev.parent = &ofdev->dev; 168 169 nand_chip->legacy.cmd_ctrl = socrates_nand_cmd_ctrl; 170 nand_chip->legacy.read_byte = socrates_nand_read_byte; 171 nand_chip->legacy.write_buf = socrates_nand_write_buf; 172 nand_chip->legacy.read_buf = socrates_nand_read_buf; 173 nand_chip->legacy.dev_ready = socrates_nand_device_ready; 174 175 /* TODO: I have no idea what real delay is. */ 176 nand_chip->legacy.chip_delay = 20; /* 20us command delay time */ 177 178 /* 179 * This driver assumes that the default ECC engine should be TYPE_SOFT. 180 * Set ->engine_type before registering the NAND devices in order to 181 * provide a driver specific default value. 182 */ 183 nand_chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT; 184 185 dev_set_drvdata(&ofdev->dev, host); 186 187 res = nand_scan(nand_chip, 1); 188 if (res) 189 goto out; 190 191 res = mtd_device_register(mtd, NULL, 0); 192 if (!res) 193 return res; 194 195 nand_cleanup(nand_chip); 196 197 out: 198 iounmap(host->io_base); 199 return res; 200 } 201 202 /* 203 * Remove a NAND device. 204 */ 205 static void socrates_nand_remove(struct platform_device *ofdev) 206 { 207 struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev); 208 struct nand_chip *chip = &host->nand_chip; 209 int ret; 210 211 ret = mtd_device_unregister(nand_to_mtd(chip)); 212 WARN_ON(ret); 213 nand_cleanup(chip); 214 215 iounmap(host->io_base); 216 } 217 218 static const struct of_device_id socrates_nand_match[] = 219 { 220 { 221 .compatible = "abb,socrates-nand", 222 }, 223 {}, 224 }; 225 226 MODULE_DEVICE_TABLE(of, socrates_nand_match); 227 228 static struct platform_driver socrates_nand_driver = { 229 .driver = { 230 .name = "socrates_nand", 231 .of_match_table = socrates_nand_match, 232 }, 233 .probe = socrates_nand_probe, 234 .remove = socrates_nand_remove, 235 }; 236 237 module_platform_driver(socrates_nand_driver); 238 239 MODULE_LICENSE("GPL"); 240 MODULE_AUTHOR("Ilya Yanok"); 241 MODULE_DESCRIPTION("NAND driver for Socrates board"); 242