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 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  */
  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  */
  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                 return -1;
 118
 119         /* get error count */
 120         *error_count = readl(&elm_cfg->error_location[poly].location_status) &
 121                                         ELM_LOCATION_STATUS_ECC_NB_ERRORS_MASK;
 122
 123         for (i = 0; i < *error_count; i++) {
 124                 error_locations[i] =
 125                      readl(&elm_cfg->error_location[poly].error_location_x[i]);
 126         }
 127
 128         return 0;
 129 }
 130
 131
 132 /**
 133  * elm_config - Configure ELM module
 134  * @level: 4 / 8 / 16 bit BCH
 135  *
 136  * Configure ELM module based on BCH level.
 137  * Set mode as continuous mode.
 138  * Currently we are using only syndrome 0 and syndromes 1 to 6 are not used.
 139  * Also, the mode is set only for syndrome 0
 140  */
 141 int elm_config(enum bch_level level)
 142 {
 143         u32 val;
 144         u8 poly = ELM_DEFAULT_POLY;
 145         u32 buffer_size = 0x7FF;
 146
 147         /* config size and level */
 148         val = (u32)(level) & ELM_LOCATION_CONFIG_ECC_BCH_LEVEL_MASK;
 149         val |= ((buffer_size << ELM_LOCATION_CONFIG_ECC_SIZE_POS) &
 150                                 ELM_LOCATION_CONFIG_ECC_SIZE_MASK);
 151         writel(val, &elm_cfg->location_config);
 152
 153         /* config continous mode */
 154         /* enable interrupt generation for syndrome polynomial set */
 155         writel((readl(&elm_cfg->irqenable) | (0x1 << poly)),
 156                         &elm_cfg->irqenable);
 157         /* set continuous mode for the syndrome polynomial set */
 158         writel((readl(&elm_cfg->page_ctrl) & ~(0x1 << poly)),
 159                         &elm_cfg->page_ctrl);
 160
 161         return 0;
 162 }
 163
 164 /**
 165  * elm_reset - Do a soft reset of ELM
 166  *
 167  * Perform a soft reset of ELM and return after reset is done.
 168  */
 169 void elm_reset(void)
 170 {
 171         /* initiate reset */
 172         writel((readl(&elm_cfg->sysconfig) | ELM_SYSCONFIG_SOFTRESET),
 173                         &elm_cfg->sysconfig);
 174
 175         /* wait for reset complete and normal operation */
 176         while ((readl(&elm_cfg->sysstatus) & ELM_SYSSTATUS_RESETDONE) !=
 177                 ELM_SYSSTATUS_RESETDONE)
 178                 ;
 179 }
 180
 181 /**
 182  * elm_init - Initialize ELM module
 183  *
 184  * Initialize ELM support. Currently it does only base address init
 185  * and ELM reset.
 186  */
 187 void elm_init(void)
 188 {
 189         elm_cfg = (struct elm *)ELM_BASE;
 190         elm_reset();
 191 }