alistair23-linux/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 struct resource gpmc_nand_resource[] = {
	{
		.flags		= IORESOURCE_MEM,
	},
	{
		.flags		= IORESOURCE_IRQ,
	},
	{
		.flags		= IORESOURCE_IRQ,
	},
};

static struct platform_device gpmc_nand_device = {
	.name		= "omap2-nand",
	.id		= 0,
	.num_resources	= ARRAY_SIZE(gpmc_nand_resource),
	.resource	= gpmc_nand_resource,
};

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;

	/* 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;

	/*
	 * For now, assume 4-bit mode is only supported on OMAP3630 ES1.x, x>=1
	 * and AM33xx derivates. Other chips may be added if confirmed to work.
	 */
	if ((ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW) &&
	    (!cpu_is_omap3630() || (GET_OMAP_REVISION() == 0)))
		return 0;

	/* legacy platforms support only HAM1 (1-bit Hamming) ECC scheme */
	if (ecc_opt == OMAP_ECC_HAM1_CODE_HW)
		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 device *dev = &gpmc_nand_device.dev;

	memset(&s, 0, sizeof(struct gpmc_settings));

	gpmc_nand_device.dev.platform_data = gpmc_nand_data;

	err = gpmc_cs_request(gpmc_nand_data->cs, NAND_IO_SIZE,
				(unsigned long *)&gpmc_nand_resource[0].start);
	if (err < 0) {
		dev_err(dev, "Cannot request GPMC CS %d, error %d\n",
			gpmc_nand_data->cs, err);
		return err;
	}

	gpmc_nand_resource[0].end = gpmc_nand_resource[0].start +
							NAND_IO_SIZE - 1;

	gpmc_nand_resource[1].start =
				gpmc_get_client_irq(GPMC_IRQ_FIFOEVENTENABLE);
	gpmc_nand_resource[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) {
			dev_err(dev, "Unable to set gpmc timings: %d\n", err);
			return err;
		}
	}

	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)) {
		dev_err(dev, "Unsupported NAND ECC scheme selected\n");
		return -EINVAL;
	}

	err = platform_device_register(&gpmc_nand_device);
	if (err < 0) {
		dev_err(dev, "Unable to register NAND device\n");
		goto out_free_cs;
	}

	return 0;

out_free_cs:
	gpmc_cs_free(gpmc_nand_data->cs);

	return err;
}