drivers/mtd/nand/oxnas_nand.c

   1 /*
   2  * Oxford Semiconductor OXNAS NAND driver
   3
   4  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
   5  * Heavily based on plat_nand.c :
   6  * Author: Vitaly Wool <vitalywool@gmail.com>
   7  * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
   8  * Copyright (C) 2012 John Crispin <blogic@openwrt.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21 #include <linux/clk.h>
  22 #include <linux/reset.h>
  23 #include <linux/mtd/mtd.h>
  24 #include <linux/mtd/nand.h>
  25 #include <linux/mtd/partitions.h>
  26 #include <linux/of.h>
  27
  28 /* Nand commands */
  29 #define OXNAS_NAND_CMD_ALE              BIT(18)
  30 #define OXNAS_NAND_CMD_CLE              BIT(19)
  31
  32 #define OXNAS_NAND_MAX_CHIPS    1
  33
  34 struct oxnas_nand_ctrl {
  35         struct nand_hw_control base;
  36         void __iomem *io_base;
  37         struct clk *clk;
  38         struct nand_chip *chips[OXNAS_NAND_MAX_CHIPS];
  39 };
  40
  41 static uint8_t oxnas_nand_read_byte(struct mtd_info *mtd)
  42 {
  43         struct nand_chip *chip = mtd_to_nand(mtd);
  44         struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
  45
  46         return readb(oxnas->io_base);
  47 }
  48
  49 static void oxnas_nand_read_buf(struct mtd_info *mtd, u8 *buf, int len)
  50 {
  51         struct nand_chip *chip = mtd_to_nand(mtd);
  52         struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
  53
  54         ioread8_rep(oxnas->io_base, buf, len);
  55 }
  56
  57 static void oxnas_nand_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
  58 {
  59         struct nand_chip *chip = mtd_to_nand(mtd);
  60         struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
  61
  62         iowrite8_rep(oxnas->io_base, buf, len);
  63 }
  64
  65 /* Single CS command control */
  66 static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
  67                                 unsigned int ctrl)
  68 {
  69         struct nand_chip *chip = mtd_to_nand(mtd);
  70         struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
  71
  72         if (ctrl & NAND_CLE)
  73                 writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_CLE);
  74         else if (ctrl & NAND_ALE)
  75                 writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_ALE);
  76 }
  77
  78 /*
  79  * Probe for the NAND device.
  80  */
  81 static int oxnas_nand_probe(struct platform_device *pdev)
  82 {
  83         struct device_node *np = pdev->dev.of_node;
  84         struct device_node *nand_np;
  85         struct oxnas_nand_ctrl *oxnas;
  86         struct nand_chip *chip;
  87         struct mtd_info *mtd;
  88         struct resource *res;
  89         int nchips = 0;
  90         int count = 0;
  91         int err = 0;
  92
  93         /* Allocate memory for the device structure (and zero it) */
  94         oxnas = devm_kzalloc(&pdev->dev, sizeof(*oxnas),
  95                              GFP_KERNEL);
  96         if (!oxnas)
  97                 return -ENOMEM;
  98
  99         nand_hw_control_init(&oxnas->base);
 100
 101         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 102         oxnas->io_base = devm_ioremap_resource(&pdev->dev, res);
 103         if (IS_ERR(oxnas->io_base))
 104                 return PTR_ERR(oxnas->io_base);
 105
 106         oxnas->clk = devm_clk_get(&pdev->dev, NULL);
 107         if (IS_ERR(oxnas->clk))
 108                 oxnas->clk = NULL;
 109
 110         /* Only a single chip node is supported */
 111         count = of_get_child_count(np);
 112         if (count > 1)
 113                 return -EINVAL;
 114
 115         clk_prepare_enable(oxnas->clk);
 116         device_reset_optional(&pdev->dev);
 117
 118         for_each_child_of_node(np, nand_np) {
 119                 chip = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
 120                                     GFP_KERNEL);
 121                 if (!chip)
 122                         return -ENOMEM;
 123
 124                 chip->controller = &oxnas->base;
 125
 126                 nand_set_flash_node(chip, nand_np);
 127                 nand_set_controller_data(chip, oxnas);
 128
 129                 mtd = nand_to_mtd(chip);
 130                 mtd->dev.parent = &pdev->dev;
 131                 mtd->priv = chip;
 132
 133                 chip->cmd_ctrl = oxnas_nand_cmd_ctrl;
 134                 chip->read_buf = oxnas_nand_read_buf;
 135                 chip->read_byte = oxnas_nand_read_byte;
 136                 chip->write_buf = oxnas_nand_write_buf;
 137                 chip->chip_delay = 30;
 138
 139                 /* Scan to find existence of the device */
 140                 err = nand_scan(mtd, 1);
 141                 if (err)
 142                         return err;
 143
 144                 err = mtd_device_register(mtd, NULL, 0);
 145                 if (err) {
 146                         nand_release(mtd);
 147                         return err;
 148                 }
 149
 150                 oxnas->chips[nchips] = chip;
 151                 ++nchips;
 152         }
 153
 154         /* Exit if no chips found */
 155         if (!nchips)
 156                 return -ENODEV;
 157
 158         platform_set_drvdata(pdev, oxnas);
 159
 160         return 0;
 161 }
 162
 163 static int oxnas_nand_remove(struct platform_device *pdev)
 164 {
 165         struct oxnas_nand_ctrl *oxnas = platform_get_drvdata(pdev);
 166
 167         if (oxnas->chips[0])
 168                 nand_release(nand_to_mtd(oxnas->chips[0]));
 169
 170         clk_disable_unprepare(oxnas->clk);
 171
 172         return 0;
 173 }
 174
 175 static const struct of_device_id oxnas_nand_match[] = {
 176         { .compatible = "oxsemi,ox820-nand" },
 177         {},
 178 };
 179 MODULE_DEVICE_TABLE(of, oxnas_nand_match);
 180
 181 static struct platform_driver oxnas_nand_driver = {
 182         .probe  = oxnas_nand_probe,
 183         .remove = oxnas_nand_remove,
 184         .driver = {
 185                 .name           = "oxnas_nand",
 186                 .of_match_table = oxnas_nand_match,
 187         },
 188 };
 189
 190 module_platform_driver(oxnas_nand_driver);
 191
 192 MODULE_LICENSE("GPL");
 193 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 194 MODULE_DESCRIPTION("Oxnas NAND driver");
 195 MODULE_ALIAS("platform:oxnas_nand");