LXR linux/drivers/mtd/nand/oxnas

   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
  34struct 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
  41static 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
  49static 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
  57static 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 */
  66static 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 */
  81static 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(struct nand_chip),
  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
 163static 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
 175static const struct of_device_id oxnas_nand_match[] = {
 176        { .compatible = "oxsemi,ox820-nand" },
 177        {},
 178};
 179MODULE_DEVICE_TABLE(of, oxnas_nand_match);
 180
 181static 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
 190module_platform_driver(oxnas_nand_driver);
 191
 192MODULE_LICENSE("GPL");
 193MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 194MODULE_DESCRIPTION("Oxnas NAND driver");
 195MODULE_ALIAS("platform:oxnas_nand");
 196