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/*
* Copyright 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
*
* OF helpers for mtd.
*
* This file is released under the GPLv2
*
*/
#include <linux/kernel.h>
#include <linux/of_mtd.h>
#include <linux/mtd/nand.h>
#include <linux/export.h>
/**
* It maps 'enum nand_ecc_modes_t' found in include/linux/mtd/nand.h
* into the device tree binding of 'nand-ecc', so that MTD
* device driver can get nand ecc from device tree.
*/
static const char *nand_ecc_modes[] = {
[NAND_ECC_NONE] = "none",
[NAND_ECC_SOFT] = "soft",
[NAND_ECC_HW] = "hw",
[NAND_ECC_HW_SYNDROME] = "hw_syndrome",
[NAND_ECC_HW_OOB_FIRST] = "hw_oob_first",
[NAND_ECC_SOFT_BCH] = "soft_bch",
};
/**
* of_get_nand_ecc_mode - Get nand ecc mode for given device_node
* @np: Pointer to the given device_node
*
* The function gets ecc mode string from property 'nand-ecc-mode',
* and return its index in nand_ecc_modes table, or errno in error case.
*/
int of_get_nand_ecc_mode(struct device_node *np)
{
const char *pm;
int err, i;
err = of_property_read_string(np, "nand-ecc-mode", &pm);
if (err < 0)
return err;
for (i = 0; i < ARRAY_SIZE(nand_ecc_modes); i++)
if (!strcasecmp(pm, nand_ecc_modes[i]))
return i;
return -ENODEV;
}
EXPORT_SYMBOL_GPL(of_get_nand_ecc_mode);
/**
* of_get_nand_ecc_algo - Get nand ecc algorithm for given device_node
* @np: Pointer to the given device_node
*
* The function gets ecc algorithm and returns its enum value, or errno in error
* case.
*/
int of_get_nand_ecc_algo(struct device_node *np)
{
const char *pm;
int err;
/*
* TODO: Read ECC algo OF property and map it to enum nand_ecc_algo.
* It's not implemented yet as currently NAND subsystem ignores
* algorithm explicitly set this way. Once it's handled we should
* document & support new property.
*/
/*
* For backward compatibility we also read "nand-ecc-mode" checking
* for some obsoleted values that were specifying ECC algorithm.
*/
err = of_property_read_string(np, "nand-ecc-mode", &pm);
if (err < 0)
return err;
if (!strcasecmp(pm, "soft"))
return NAND_ECC_HAMMING;
else if (!strcasecmp(pm, "soft_bch"))
return NAND_ECC_BCH;
return -ENODEV;
}
EXPORT_SYMBOL_GPL(of_get_nand_ecc_algo);
/**
* of_get_nand_ecc_step_size - Get ECC step size associated to
* the required ECC strength (see below).
* @np: Pointer to the given device_node
*
* return the ECC step size, or errno in error case.
*/
int of_get_nand_ecc_step_size(struct device_node *np)
{
int ret;
u32 val;
ret = of_property_read_u32(np, "nand-ecc-step-size", &val);
return ret ? ret : val;
}
EXPORT_SYMBOL_GPL(of_get_nand_ecc_step_size);
/**
* of_get_nand_ecc_strength - Get required ECC strength over the
* correspnding step size as defined by 'nand-ecc-size'
* @np: Pointer to the given device_node
*
* return the ECC strength, or errno in error case.
*/
int of_get_nand_ecc_strength(struct device_node *np)
{
int ret;
u32 val;
ret = of_property_read_u32(np, "nand-ecc-strength", &val);
return ret ? ret : val;
}
EXPORT_SYMBOL_GPL(of_get_nand_ecc_strength);
/**
* of_get_nand_bus_width - Get nand bus witdh for given device_node
* @np: Pointer to the given device_node
*
* return bus width option, or errno in error case.
*/
int of_get_nand_bus_width(struct device_node *np)
{
u32 val;
if (of_property_read_u32(np, "nand-bus-width", &val))
return 8;
switch(val) {
case 8:
case 16:
return val;
default:
return -EIO;
}
}
EXPORT_SYMBOL_GPL(of_get_nand_bus_width);
/**
* of_get_nand_on_flash_bbt - Get nand on flash bbt for given device_node
* @np: Pointer to the given device_node
*
* return true if present false other wise
*/
bool of_get_nand_on_flash_bbt(struct device_node *np)
{
return of_property_read_bool(np, "nand-on-flash-bbt");
}
EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);
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