drivers/mtd/nand/omap_elm.c

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