orion_nand.c

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/*
 * drivers/mtd/nand/orion_nand.c
 *
 * NAND support for Marvell Orion SoC platforms
 *
 * Tzachi Perelstein <[email protected]>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <asm/io.h>
#include <asm/sizes.h>
#include <linux/platform_data/mtd-orion_nand.h>

static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
    struct nand_chip *nc = mtd->priv;
    struct orion_nand_data *board = nc->priv;
    u32 offs;

    if (cmd == NAND_CMD_NONE)
        return;

    if (ctrl & NAND_CLE)
        offs = (1 << board->cle);
    else if (ctrl & NAND_ALE)
        offs = (1 << board->ale);
    else
        return;

    if (nc->options & NAND_BUSWIDTH_16)
        offs <<= 1;

    writeb(cmd, nc->IO_ADDR_W + offs);
}

static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
    struct nand_chip *chip = mtd->priv;
    void __iomem *io_base = chip->IO_ADDR_R;
    uint64_t *buf64;
    int i = 0;

    while (len && (unsigned long)buf & 7) {
        *buf++ = readb(io_base);
        len--;
    }
    buf64 = (uint64_t *)buf;
    while (i < len/8) {
        /*
         * Since GCC has no proper constraint (PR 43518)
         * force x variable to r2/r3 registers as ldrd instruction
         * requires first register to be even.
         */
        register uint64_t x asm ("r2");

        asm volatile ("ldrd\t%0, [%1]" : "=&r" (x) : "r" (io_base));
        buf64[i++] = x;
    }
    i *= 8;
    while (i < len)
        buf[i++] = readb(io_base);
}

static int __init orion_nand_probe(struct platform_device *pdev)
{
    struct mtd_info *mtd;
    struct mtd_part_parser_data ppdata = {};
    struct nand_chip *nc;
    struct orion_nand_data *board;
    struct resource *res;
    struct clk *clk;
    void __iomem *io_base;
    int ret = 0;
    u32 val = 0;

    nc = kzalloc(sizeof(struct nand_chip) + sizeof(struct mtd_info), GFP_KERNEL);
    if (!nc) {
        printk(KERN_ERR "orion_nand: failed to allocate device structure.\n");
        ret = -ENOMEM;
        goto no_res;
    }
    mtd = (struct mtd_info *)(nc + 1);

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        ret = -ENODEV;
        goto no_res;
    }

    io_base = ioremap(res->start, resource_size(res));
    if (!io_base) {
        printk(KERN_ERR "orion_nand: ioremap failed\n");
        ret = -EIO;
        goto no_res;
    }

    if (pdev->dev.of_node) {
        board = devm_kzalloc(&pdev->dev, sizeof(struct orion_nand_data),
                    GFP_KERNEL);
        if (!board) {
            printk(KERN_ERR "orion_nand: failed to allocate board structure.\n");
            ret = -ENOMEM;
            goto no_res;
        }
        if (!of_property_read_u32(pdev->dev.of_node, "cle", &val))
            board->cle = (u8)val;
        else
            board->cle = 0;
        if (!of_property_read_u32(pdev->dev.of_node, "ale", &val))
            board->ale = (u8)val;
        else
            board->ale = 1;
        if (!of_property_read_u32(pdev->dev.of_node,
                        "bank-width", &val))
            board->width = (u8)val * 8;
        else
            board->width = 8;
        if (!of_property_read_u32(pdev->dev.of_node,
                        "chip-delay", &val))
            board->chip_delay = (u8)val;
    } else
        board = pdev->dev.platform_data;

    mtd->priv = nc;
    mtd->owner = THIS_MODULE;

    nc->priv = board;
    nc->IO_ADDR_R = nc->IO_ADDR_W = io_base;
    nc->cmd_ctrl = orion_nand_cmd_ctrl;
    nc->read_buf = orion_nand_read_buf;
    nc->ecc.mode = NAND_ECC_SOFT;

    if (board->chip_delay)
        nc->chip_delay = board->chip_delay;

    WARN(board->width > 16,
        "%d bit bus width out of range",
        board->width);

    if (board->width == 16)
        nc->options |= NAND_BUSWIDTH_16;

    if (board->dev_ready)
        nc->dev_ready = board->dev_ready;

    platform_set_drvdata(pdev, mtd);

    /* Not all platforms can gate the clock, so it is not
       an error if the clock does not exists. */
    clk = clk_get(&pdev->dev, NULL);
    if (!IS_ERR(clk)) {
        clk_prepare_enable(clk);
        clk_put(clk);
    }

    if (nand_scan(mtd, 1)) {
        ret = -ENXIO;
        goto no_dev;
    }

    mtd->name = "orion_nand";
    ppdata.of_node = pdev->dev.of_node;
    ret = mtd_device_parse_register(mtd, NULL, &ppdata,
            board->parts, board->nr_parts);
    if (ret) {
        nand_release(mtd);
        goto no_dev;
    }

    return 0;

no_dev:
    if (!IS_ERR(clk)) {
        clk_disable_unprepare(clk);
        clk_put(clk);
    }
    platform_set_drvdata(pdev, NULL);
    iounmap(io_base);
no_res:
    kfree(nc);

    return ret;
}

static int __devexit orion_nand_remove(struct platform_device *pdev)
{
    struct mtd_info *mtd = platform_get_drvdata(pdev);
    struct nand_chip *nc = mtd->priv;
    struct clk *clk;

    nand_release(mtd);

    iounmap(nc->IO_ADDR_W);

    kfree(nc);

    clk = clk_get(&pdev->dev, NULL);
    if (!IS_ERR(clk)) {
        clk_disable_unprepare(clk);
        clk_put(clk);
    }

    return 0;
}

#ifdef CONFIG_OF
static struct of_device_id orion_nand_of_match_table[] = {
    { .compatible = "marvell,orion-nand", },
    {},
};
#endif

static struct platform_driver orion_nand_driver = {
    .remove     = __devexit_p(orion_nand_remove),
    .driver     = {
        .name   = "orion_nand",
        .owner  = THIS_MODULE,
        .of_match_table = of_match_ptr(orion_nand_of_match_table),
    },
};

static int __init orion_nand_init(void)
{
    return platform_driver_probe(&orion_nand_driver, orion_nand_probe);
}

static void __exit orion_nand_exit(void)
{
    platform_driver_unregister(&orion_nand_driver);
}

module_init(orion_nand_init);
module_exit(orion_nand_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Tzachi Perelstein");
MODULE_DESCRIPTION("NAND glue for Orion platforms");
MODULE_ALIAS("platform:orion_nand");