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1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2010-2011 Texas Instruments, <www.ti.com>
4  * Mansoor Ahamed <mansoor.ahamed@ti.com>
5  *
6  * BCH Error Location Module (ELM) support.
7  *
8  * NOTE:
9  * 1. Supports only continuous mode. Dont see need for page mode in uboot
10  * 2. Supports only syndrome polynomial 0. i.e. poly local variable is
11  *    always set to ELM_DEFAULT_POLY. Dont see need for other polynomial
12  *    sets in uboot
13  */
14 
15 #include <common.h>
16 #include <asm/io.h>
17 #include <linux/errno.h>
18 #include <linux/mtd/omap_elm.h>
19 #include <asm/arch/hardware.h>
20 
21 #define DRIVER_NAME		"omap-elm"
22 #define ELM_DEFAULT_POLY (0)
23 
24 struct elm *elm_cfg;
25 
26 /**
27  * elm_load_syndromes - Load BCH syndromes based on bch_type selection
28  * @syndrome: BCH syndrome
29  * @bch_type: BCH4/BCH8/BCH16
30  * @poly: Syndrome Polynomial set to use
31  */
elm_load_syndromes(u8 * syndrome,enum bch_level bch_type,u8 poly)32 static void elm_load_syndromes(u8 *syndrome, enum bch_level bch_type, u8 poly)
33 {
34 	u32 *ptr;
35 	u32 val;
36 
37 	/* reg 0 */
38 	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[0];
39 	val = syndrome[0] | (syndrome[1] << 8) | (syndrome[2] << 16) |
40 				(syndrome[3] << 24);
41 	writel(val, ptr);
42 	/* reg 1 */
43 	ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[1];
44 	val = syndrome[4] | (syndrome[5] << 8) | (syndrome[6] << 16) |
45 				(syndrome[7] << 24);
46 	writel(val, ptr);
47 
48 	if (bch_type == BCH_8_BIT || bch_type == BCH_16_BIT) {
49 		/* reg 2 */
50 		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[2];
51 		val = syndrome[8] | (syndrome[9] << 8) | (syndrome[10] << 16) |
52 				(syndrome[11] << 24);
53 		writel(val, ptr);
54 		/* reg 3 */
55 		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[3];
56 		val = syndrome[12] | (syndrome[13] << 8) |
57 			(syndrome[14] << 16) | (syndrome[15] << 24);
58 		writel(val, ptr);
59 	}
60 
61 	if (bch_type == BCH_16_BIT) {
62 		/* reg 4 */
63 		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[4];
64 		val = syndrome[16] | (syndrome[17] << 8) |
65 			(syndrome[18] << 16) | (syndrome[19] << 24);
66 		writel(val, ptr);
67 
68 		/* reg 5 */
69 		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[5];
70 		val = syndrome[20] | (syndrome[21] << 8) |
71 			(syndrome[22] << 16) | (syndrome[23] << 24);
72 		writel(val, ptr);
73 
74 		/* reg 6 */
75 		ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6];
76 		val = syndrome[24] | (syndrome[25] << 8) |
77 			(syndrome[26] << 16) | (syndrome[27] << 24);
78 		writel(val, ptr);
79 	}
80 }
81 
82 /**
83  * elm_check_errors - Check for BCH errors and return error locations
84  * @syndrome: BCH syndrome
85  * @bch_type: BCH4/BCH8/BCH16
86  * @error_count: Returns number of errrors in the syndrome
87  * @error_locations: Returns error locations (in decimal) in this array
88  *
89  * Check the provided syndrome for BCH errors and return error count
90  * and locations in the array passed. Returns -1 if error is not correctable,
91  * else returns 0
92  */
elm_check_error(u8 * syndrome,enum bch_level bch_type,u32 * error_count,u32 * error_locations)93 int elm_check_error(u8 *syndrome, enum bch_level bch_type, u32 *error_count,
94 		u32 *error_locations)
95 {
96 	u8 poly = ELM_DEFAULT_POLY;
97 	s8 i;
98 	u32 location_status;
99 
100 	elm_load_syndromes(syndrome, bch_type, poly);
101 
102 	/* start processing */
103 	writel((readl(&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6])
104 				| ELM_SYNDROME_FRAGMENT_6_SYNDROME_VALID),
105 		&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6]);
106 
107 	/* wait for processing to complete */
108 	while ((readl(&elm_cfg->irqstatus) & (0x1 << poly)) != 0x1)
109 		;
110 	/* clear status */
111 	writel((readl(&elm_cfg->irqstatus) | (0x1 << poly)),
112 			&elm_cfg->irqstatus);
113 
114 	/* check if correctable */
115 	location_status = readl(&elm_cfg->error_location[poly].location_status);
116 	if (!(location_status & ELM_LOCATION_STATUS_ECC_CORRECTABLE_MASK)) {
117 		printf("%s: uncorrectable ECC errors\n", DRIVER_NAME);
118 		return -EBADMSG;
119 	}
120 
121 	/* get error count */
122 	*error_count = readl(&elm_cfg->error_location[poly].location_status) &
123 					ELM_LOCATION_STATUS_ECC_NB_ERRORS_MASK;
124 
125 	for (i = 0; i < *error_count; i++) {
126 		error_locations[i] =
127 		     readl(&elm_cfg->error_location[poly].error_location_x[i]);
128 	}
129 
130 	return 0;
131 }
132 
133 
134 /**
135  * elm_config - Configure ELM module
136  * @level: 4 / 8 / 16 bit BCH
137  *
138  * Configure ELM module based on BCH level.
139  * Set mode as continuous mode.
140  * Currently we are using only syndrome 0 and syndromes 1 to 6 are not used.
141  * Also, the mode is set only for syndrome 0
142  */
elm_config(enum bch_level level)143 int elm_config(enum bch_level level)
144 {
145 	u32 val;
146 	u8 poly = ELM_DEFAULT_POLY;
147 	u32 buffer_size = 0x7FF;
148 
149 	/* config size and level */
150 	val = (u32)(level) & ELM_LOCATION_CONFIG_ECC_BCH_LEVEL_MASK;
151 	val |= ((buffer_size << ELM_LOCATION_CONFIG_ECC_SIZE_POS) &
152 				ELM_LOCATION_CONFIG_ECC_SIZE_MASK);
153 	writel(val, &elm_cfg->location_config);
154 
155 	/* config continous mode */
156 	/* enable interrupt generation for syndrome polynomial set */
157 	writel((readl(&elm_cfg->irqenable) | (0x1 << poly)),
158 			&elm_cfg->irqenable);
159 	/* set continuous mode for the syndrome polynomial set */
160 	writel((readl(&elm_cfg->page_ctrl) & ~(0x1 << poly)),
161 			&elm_cfg->page_ctrl);
162 
163 	return 0;
164 }
165 
166 /**
167  * elm_reset - Do a soft reset of ELM
168  *
169  * Perform a soft reset of ELM and return after reset is done.
170  */
elm_reset(void)171 void elm_reset(void)
172 {
173 	/* initiate reset */
174 	writel((readl(&elm_cfg->sysconfig) | ELM_SYSCONFIG_SOFTRESET),
175 			&elm_cfg->sysconfig);
176 
177 	/* wait for reset complete and normal operation */
178 	while ((readl(&elm_cfg->sysstatus) & ELM_SYSSTATUS_RESETDONE) !=
179 		ELM_SYSSTATUS_RESETDONE)
180 		;
181 }
182 
183 /**
184  * elm_init - Initialize ELM module
185  *
186  * Initialize ELM support. Currently it does only base address init
187  * and ELM reset.
188  */
elm_init(void)189 void elm_init(void)
190 {
191 	elm_cfg = (struct elm *)ELM_BASE;
192 	elm_reset();
193 }
194