1 /*
2 * Copyright 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
3 *
4 * OF helpers for mtd.
5 *
6 * This file is released under the GPLv2
7 *
8 */
9 #include <linux/kernel.h>
10 #include <linux/of_mtd.h>
11 #include <linux/mtd/nand.h>
12 #include <linux/export.h>
13
14 /**
15 * It maps 'enum nand_ecc_modes_t' found in include/linux/mtd/nand.h
16 * into the device tree binding of 'nand-ecc', so that MTD
17 * device driver can get nand ecc from device tree.
18 */
19 static const char *nand_ecc_modes[] = {
20 [NAND_ECC_NONE] = "none",
21 [NAND_ECC_SOFT] = "soft",
22 [NAND_ECC_HW] = "hw",
23 [NAND_ECC_HW_SYNDROME] = "hw_syndrome",
24 [NAND_ECC_HW_OOB_FIRST] = "hw_oob_first",
25 [NAND_ECC_SOFT_BCH] = "soft_bch",
26 };
27
28 /**
29 * of_get_nand_ecc_mode - Get nand ecc mode for given device_node
30 * @np: Pointer to the given device_node
31 *
32 * The function gets ecc mode string from property 'nand-ecc-mode',
33 * and return its index in nand_ecc_modes table, or errno in error case.
34 */
of_get_nand_ecc_mode(struct device_node * np)35 int of_get_nand_ecc_mode(struct device_node *np)
36 {
37 const char *pm;
38 int err, i;
39
40 err = of_property_read_string(np, "nand-ecc-mode", &pm);
41 if (err < 0)
42 return err;
43
44 for (i = 0; i < ARRAY_SIZE(nand_ecc_modes); i++)
45 if (!strcasecmp(pm, nand_ecc_modes[i]))
46 return i;
47
48 return -ENODEV;
49 }
50 EXPORT_SYMBOL_GPL(of_get_nand_ecc_mode);
51
52 /**
53 * of_get_nand_ecc_step_size - Get ECC step size associated to
54 * the required ECC strength (see below).
55 * @np: Pointer to the given device_node
56 *
57 * return the ECC step size, or errno in error case.
58 */
of_get_nand_ecc_step_size(struct device_node * np)59 int of_get_nand_ecc_step_size(struct device_node *np)
60 {
61 int ret;
62 u32 val;
63
64 ret = of_property_read_u32(np, "nand-ecc-step-size", &val);
65 return ret ? ret : val;
66 }
67 EXPORT_SYMBOL_GPL(of_get_nand_ecc_step_size);
68
69 /**
70 * of_get_nand_ecc_strength - Get required ECC strength over the
71 * correspnding step size as defined by 'nand-ecc-size'
72 * @np: Pointer to the given device_node
73 *
74 * return the ECC strength, or errno in error case.
75 */
of_get_nand_ecc_strength(struct device_node * np)76 int of_get_nand_ecc_strength(struct device_node *np)
77 {
78 int ret;
79 u32 val;
80
81 ret = of_property_read_u32(np, "nand-ecc-strength", &val);
82 return ret ? ret : val;
83 }
84 EXPORT_SYMBOL_GPL(of_get_nand_ecc_strength);
85
86 /**
87 * of_get_nand_bus_width - Get nand bus witdh for given device_node
88 * @np: Pointer to the given device_node
89 *
90 * return bus width option, or errno in error case.
91 */
of_get_nand_bus_width(struct device_node * np)92 int of_get_nand_bus_width(struct device_node *np)
93 {
94 u32 val;
95
96 if (of_property_read_u32(np, "nand-bus-width", &val))
97 return 8;
98
99 switch(val) {
100 case 8:
101 case 16:
102 return val;
103 default:
104 return -EIO;
105 }
106 }
107 EXPORT_SYMBOL_GPL(of_get_nand_bus_width);
108
109 /**
110 * of_get_nand_on_flash_bbt - Get nand on flash bbt for given device_node
111 * @np: Pointer to the given device_node
112 *
113 * return true if present false other wise
114 */
of_get_nand_on_flash_bbt(struct device_node * np)115 bool of_get_nand_on_flash_bbt(struct device_node *np)
116 {
117 return of_property_read_bool(np, "nand-on-flash-bbt");
118 }
119 EXPORT_SYMBOL_GPL(of_get_nand_on_flash_bbt);
120