summaryrefslogtreecommitdiff
path: root/drivers/mtd/nand/omap_elm.c
blob: 35c6dd1f1bcc3a9dc45dcf568d42efcb2e85a798 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2010-2011 Texas Instruments, <www.ti.com>
 * Mansoor Ahamed <mansoor.ahamed@ti.com>
 *
 * BCH Error Location Module (ELM) support.
 *
 * NOTE:
 * 1. Supports only continuous mode. Dont see need for page mode in uboot
 * 2. Supports only syndrome polynomial 0. i.e. poly local variable is
 *    always set to ELM_DEFAULT_POLY. Dont see need for other polynomial
 *    sets in uboot
 */

#include <common.h>
#include <asm/io.h>
#include <linux/errno.h>
#include <linux/mtd/omap_elm.h>
#include <asm/arch/hardware.h>

#define DRIVER_NAME		"omap-elm"
#define ELM_DEFAULT_POLY (0)

struct elm *elm_cfg;

/**
 * elm_load_syndromes - Load BCH syndromes based on bch_type selection
 * @syndrome: BCH syndrome
 * @bch_type: BCH4/BCH8/BCH16
 * @poly: Syndrome Polynomial set to use
 */
static void elm_load_syndromes(u8 *syndrome, enum bch_level bch_type, u8 poly)
{
	u32 *ptr;
	u32 val;

	/* reg 0 */
	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[0];
	val = syndrome[0] | (syndrome[1] << 8) | (syndrome[2] << 16) |
				(syndrome[3] << 24);
	writel(val, ptr);
	/* reg 1 */
	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[1];
	val = syndrome[4] | (syndrome[5] << 8) | (syndrome[6] << 16) |
				(syndrome[7] << 24);
	writel(val, ptr);

	if (bch_type == BCH_8_BIT || bch_type == BCH_16_BIT) {
		/* reg 2 */
		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[2];
		val = syndrome[8] | (syndrome[9] << 8) | (syndrome[10] << 16) |
				(syndrome[11] << 24);
		writel(val, ptr);
		/* reg 3 */
		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[3];
		val = syndrome[12] | (syndrome[13] << 8) |
			(syndrome[14] << 16) | (syndrome[15] << 24);
		writel(val, ptr);
	}

	if (bch_type == BCH_16_BIT) {
		/* reg 4 */
		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[4];
		val = syndrome[16] | (syndrome[17] << 8) |
			(syndrome[18] << 16) | (syndrome[19] << 24);
		writel(val, ptr);

		/* reg 5 */
		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[5];
		val = syndrome[20] | (syndrome[21] << 8) |
			(syndrome[22] << 16) | (syndrome[23] << 24);
		writel(val, ptr);

		/* reg 6 */
		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6];
		val = syndrome[24] | (syndrome[25] << 8) |
			(syndrome[26] << 16) | (syndrome[27] << 24);
		writel(val, ptr);
	}
}

/**
 * elm_check_errors - Check for BCH errors and return error locations
 * @syndrome: BCH syndrome
 * @bch_type: BCH4/BCH8/BCH16
 * @error_count: Returns number of errrors in the syndrome
 * @error_locations: Returns error locations (in decimal) in this array
 *
 * Check the provided syndrome for BCH errors and return error count
 * and locations in the array passed. Returns -1 if error is not correctable,
 * else returns 0
 */
int elm_check_error(u8 *syndrome, enum bch_level bch_type, u32 *error_count,
		u32 *error_locations)
{
	u8 poly = ELM_DEFAULT_POLY;
	s8 i;
	u32 location_status;

	elm_load_syndromes(syndrome, bch_type, poly);

	/* start processing */
	writel((readl(&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6])
				| ELM_SYNDROME_FRAGMENT_6_SYNDROME_VALID),
		&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6]);

	/* wait for processing to complete */
	while ((readl(&elm_cfg->irqstatus) & (0x1 << poly)) != 0x1)
		;
	/* clear status */
	writel((readl(&elm_cfg->irqstatus) | (0x1 << poly)),
			&elm_cfg->irqstatus);

	/* check if correctable */
	location_status = readl(&elm_cfg->error_location[poly].location_status);
	if (!(location_status & ELM_LOCATION_STATUS_ECC_CORRECTABLE_MASK)) {
		printf("%s: uncorrectable ECC errors\n", DRIVER_NAME);
		return -EBADMSG;
	}

	/* get error count */
	*error_count = readl(&elm_cfg->error_location[poly].location_status) &
					ELM_LOCATION_STATUS_ECC_NB_ERRORS_MASK;

	for (i = 0; i < *error_count; i++) {
		error_locations[i] =
		     readl(&elm_cfg->error_location[poly].error_location_x[i]);
	}

	return 0;
}


/**
 * elm_config - Configure ELM module
 * @level: 4 / 8 / 16 bit BCH
 *
 * Configure ELM module based on BCH level.
 * Set mode as continuous mode.
 * Currently we are using only syndrome 0 and syndromes 1 to 6 are not used.
 * Also, the mode is set only for syndrome 0
 */
int elm_config(enum bch_level level)
{
	u32 val;
	u8 poly = ELM_DEFAULT_POLY;
	u32 buffer_size = 0x7FF;

	/* config size and level */
	val = (u32)(level) & ELM_LOCATION_CONFIG_ECC_BCH_LEVEL_MASK;
	val |= ((buffer_size << ELM_LOCATION_CONFIG_ECC_SIZE_POS) &
				ELM_LOCATION_CONFIG_ECC_SIZE_MASK);
	writel(val, &elm_cfg->location_config);

	/* config continous mode */
	/* enable interrupt generation for syndrome polynomial set */
	writel((readl(&elm_cfg->irqenable) | (0x1 << poly)),
			&elm_cfg->irqenable);
	/* set continuous mode for the syndrome polynomial set */
	writel((readl(&elm_cfg->page_ctrl) & ~(0x1 << poly)),
			&elm_cfg->page_ctrl);

	return 0;
}

/**
 * elm_reset - Do a soft reset of ELM
 *
 * Perform a soft reset of ELM and return after reset is done.
 */
void elm_reset(void)
{
	/* initiate reset */
	writel((readl(&elm_cfg->sysconfig) | ELM_SYSCONFIG_SOFTRESET),
			&elm_cfg->sysconfig);

	/* wait for reset complete and normal operation */
	while ((readl(&elm_cfg->sysstatus) & ELM_SYSSTATUS_RESETDONE) !=
		ELM_SYSSTATUS_RESETDONE)
		;
}

/**
 * elm_init - Initialize ELM module
 *
 * Initialize ELM support. Currently it does only base address init
 * and ELM reset.
 */
void elm_init(void)
{
	elm_cfg = (struct elm *)ELM_BASE;
	elm_reset();
}