mtd: nand: omap: Revert to using software ECC by default

[deliverable/linux.git] / arch / arm / mach-omap2 / gpmc-nand.c

/*
 * gpmc-nand.c
 *
 * Copyright (C) 2009 Texas Instruments
 * Vimal Singh <vimalsingh@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/mtd/nand.h>
#include <linux/platform_data/mtd-nand-omap2.h>

#include <asm/mach/flash.h>

#include "gpmc.h"
#include "soc.h"
#include "gpmc-nand.h"

/* minimum size for IO mapping */
#define	NAND_IO_SIZE	4

static bool gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt)
{
	/* platforms which support all ECC schemes */
	if (soc_is_am33xx() || soc_is_am43xx() || cpu_is_omap44xx() ||
		 soc_is_omap54xx() || soc_is_dra7xx())
		return 1;

	if (ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW ||
		 ecc_opt == OMAP_ECC_BCH8_CODE_HW_DETECTION_SW) {
		if (cpu_is_omap24xx())
			return 0;
		else if (cpu_is_omap3630() && (GET_OMAP_REVISION() == 0))
			return 0;
		else
			return 1;
	}

	/* OMAP3xxx do not have ELM engine, so cannot support ECC schemes
	 * which require H/W based ECC error detection */
	if ((cpu_is_omap34xx() || cpu_is_omap3630()) &&
	    ((ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
		 (ecc_opt == OMAP_ECC_BCH8_CODE_HW)))
		return 0;

	/* legacy platforms support only HAM1 (1-bit Hamming) ECC scheme */
	if (ecc_opt == OMAP_ECC_HAM1_CODE_HW ||
	    ecc_opt == OMAP_ECC_HAM1_CODE_SW)
		return 1;
	else
		return 0;
}

/* This function will go away once the device-tree convertion is complete */
static void gpmc_set_legacy(struct omap_nand_platform_data *gpmc_nand_data,
			    struct gpmc_settings *s)
{
	/* Enable RD PIN Monitoring Reg */
	if (gpmc_nand_data->dev_ready) {
		s->wait_on_read = true;
		s->wait_on_write = true;
	}

	if (gpmc_nand_data->devsize == NAND_BUSWIDTH_16)
		s->device_width = GPMC_DEVWIDTH_16BIT;
	else
		s->device_width = GPMC_DEVWIDTH_8BIT;
}

int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
		   struct gpmc_timings *gpmc_t)
{
	int err	= 0;
	struct gpmc_settings s;
	struct platform_device *pdev;
	struct resource gpmc_nand_res[] = {
		{ .flags = IORESOURCE_MEM, },
		{ .flags = IORESOURCE_IRQ, },
		{ .flags = IORESOURCE_IRQ, },
	};

	BUG_ON(gpmc_nand_data->cs >= GPMC_CS_NUM);

	err = gpmc_cs_request(gpmc_nand_data->cs, NAND_IO_SIZE,
			      (unsigned long *)&gpmc_nand_res[0].start);
	if (err < 0) {
		pr_err("omap2-gpmc: Cannot request GPMC CS %d, error %d\n",
		       gpmc_nand_data->cs, err);
		return err;
	}
	gpmc_nand_res[0].end = gpmc_nand_res[0].start + NAND_IO_SIZE - 1;
	gpmc_nand_res[1].start = gpmc_get_client_irq(GPMC_IRQ_FIFOEVENTENABLE);
	gpmc_nand_res[2].start = gpmc_get_client_irq(GPMC_IRQ_COUNT_EVENT);

	if (gpmc_t) {
		err = gpmc_cs_set_timings(gpmc_nand_data->cs, gpmc_t);
		if (err < 0) {
			pr_err("omap2-gpmc: Unable to set gpmc timings: %d\n", err);
			return err;
		}
	}

	memset(&s, 0, sizeof(struct gpmc_settings));
	if (gpmc_nand_data->of_node)
		gpmc_read_settings_dt(gpmc_nand_data->of_node, &s);
	else
		gpmc_set_legacy(gpmc_nand_data, &s);

	s.device_nand = true;
	err = gpmc_cs_program_settings(gpmc_nand_data->cs, &s);
	if (err < 0)
		goto out_free_cs;

	err = gpmc_configure(GPMC_CONFIG_WP, 0);
	if (err < 0)
		goto out_free_cs;

	gpmc_update_nand_reg(&gpmc_nand_data->reg, gpmc_nand_data->cs);

	if (!gpmc_hwecc_bch_capable(gpmc_nand_data->ecc_opt)) {
		pr_err("omap2-nand: Unsupported NAND ECC scheme selected\n");
		err = -EINVAL;
		goto out_free_cs;
	}


	pdev = platform_device_alloc("omap2-nand", gpmc_nand_data->cs);
	if (pdev) {
		err = platform_device_add_resources(pdev, gpmc_nand_res,
						    ARRAY_SIZE(gpmc_nand_res));
		if (!err)
			pdev->dev.platform_data = gpmc_nand_data;
	} else {
		err = -ENOMEM;
	}
	if (err)
		goto out_free_pdev;

	err = platform_device_add(pdev);
	if (err) {
		dev_err(&pdev->dev, "Unable to register NAND device\n");
		goto out_free_pdev;
	}

	return 0;

out_free_pdev:
	platform_device_put(pdev);
out_free_cs:
	gpmc_cs_free(gpmc_nand_data->cs);

	return err;
}