mtd: nand: set ECC algorithm to Hamming on fallback
[deliverable/linux.git] / drivers / mtd / nand / nand_base.c
index feb1448e9dd6a14b0c1dd6bd2a77b8016bd5dbbd..2a049576ab31f0f025e68f4b89037935938ec531 100644 (file)
 #include <linux/bitops.h>
 #include <linux/io.h>
 #include <linux/mtd/partitions.h>
-#include <linux/of_mtd.h>
+#include <linux/of.h>
+
+static int nand_get_device(struct mtd_info *mtd, int new_state);
+
+static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
+                            struct mtd_oob_ops *ops);
 
 /* Define default oob placement schemes for large and small page devices */
-static struct nand_ecclayout nand_oob_8 = {
-       .eccbytes = 3,
-       .eccpos = {0, 1, 2},
-       .oobfree = {
-               {.offset = 3,
-                .length = 2},
-               {.offset = 6,
-                .length = 2} }
-};
+static int nand_ooblayout_ecc_sp(struct mtd_info *mtd, int section,
+                                struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
 
-static struct nand_ecclayout nand_oob_16 = {
-       .eccbytes = 6,
-       .eccpos = {0, 1, 2, 3, 6, 7},
-       .oobfree = {
-               {.offset = 8,
-                . length = 8} }
-};
+       if (section > 1)
+               return -ERANGE;
 
-static struct nand_ecclayout nand_oob_64 = {
-       .eccbytes = 24,
-       .eccpos = {
-                  40, 41, 42, 43, 44, 45, 46, 47,
-                  48, 49, 50, 51, 52, 53, 54, 55,
-                  56, 57, 58, 59, 60, 61, 62, 63},
-       .oobfree = {
-               {.offset = 2,
-                .length = 38} }
-};
+       if (!section) {
+               oobregion->offset = 0;
+               oobregion->length = 4;
+       } else {
+               oobregion->offset = 6;
+               oobregion->length = ecc->total - 4;
+       }
 
-static struct nand_ecclayout nand_oob_128 = {
-       .eccbytes = 48,
-       .eccpos = {
-                  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},
-       .oobfree = {
-               {.offset = 2,
-                .length = 78} }
+       return 0;
+}
+
+static int nand_ooblayout_free_sp(struct mtd_info *mtd, int section,
+                                 struct mtd_oob_region *oobregion)
+{
+       if (section > 1)
+               return -ERANGE;
+
+       if (mtd->oobsize == 16) {
+               if (section)
+                       return -ERANGE;
+
+               oobregion->length = 8;
+               oobregion->offset = 8;
+       } else {
+               oobregion->length = 2;
+               if (!section)
+                       oobregion->offset = 3;
+               else
+                       oobregion->offset = 6;
+       }
+
+       return 0;
+}
+
+const struct mtd_ooblayout_ops nand_ooblayout_sp_ops = {
+       .ecc = nand_ooblayout_ecc_sp,
+       .free = nand_ooblayout_free_sp,
 };
+EXPORT_SYMBOL_GPL(nand_ooblayout_sp_ops);
 
-static int nand_get_device(struct mtd_info *mtd, int new_state);
+static int nand_ooblayout_ecc_lp(struct mtd_info *mtd, int section,
+                                struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
 
-static int nand_do_write_oob(struct mtd_info *mtd, loff_t to,
-                            struct mtd_oob_ops *ops);
+       if (section)
+               return -ERANGE;
+
+       oobregion->length = ecc->total;
+       oobregion->offset = mtd->oobsize - oobregion->length;
+
+       return 0;
+}
+
+static int nand_ooblayout_free_lp(struct mtd_info *mtd, int section,
+                                 struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+       if (section)
+               return -ERANGE;
+
+       oobregion->length = mtd->oobsize - ecc->total - 2;
+       oobregion->offset = 2;
+
+       return 0;
+}
+
+const struct mtd_ooblayout_ops nand_ooblayout_lp_ops = {
+       .ecc = nand_ooblayout_ecc_lp,
+       .free = nand_ooblayout_free_lp,
+};
+EXPORT_SYMBOL_GPL(nand_ooblayout_lp_ops);
 
 static int check_offs_len(struct mtd_info *mtd,
                                        loff_t ofs, uint64_t len)
@@ -3929,6 +3971,98 @@ ident_done:
        return type;
 }
 
+static const char * const nand_ecc_modes[] = {
+       [NAND_ECC_NONE]         = "none",
+       [NAND_ECC_SOFT]         = "soft",
+       [NAND_ECC_HW]           = "hw",
+       [NAND_ECC_HW_SYNDROME]  = "hw_syndrome",
+       [NAND_ECC_HW_OOB_FIRST] = "hw_oob_first",
+       [NAND_ECC_SOFT_BCH]     = "soft_bch",
+};
+
+static int of_get_nand_ecc_mode(struct device_node *np)
+{
+       const char *pm;
+       int err, i;
+
+       err = of_property_read_string(np, "nand-ecc-mode", &pm);
+       if (err < 0)
+               return err;
+
+       for (i = 0; i < ARRAY_SIZE(nand_ecc_modes); i++)
+               if (!strcasecmp(pm, nand_ecc_modes[i]))
+                       return i;
+
+       return -ENODEV;
+}
+
+static int of_get_nand_ecc_algo(struct device_node *np)
+{
+       const char *pm;
+       int err;
+
+       /*
+        * TODO: Read ECC algo OF property and map it to enum nand_ecc_algo.
+        * It's not implemented yet as currently NAND subsystem ignores
+        * algorithm explicitly set this way. Once it's handled we should
+        * document & support new property.
+        */
+
+       /*
+        * For backward compatibility we also read "nand-ecc-mode" checking
+        * for some obsoleted values that were specifying ECC algorithm.
+        */
+       err = of_property_read_string(np, "nand-ecc-mode", &pm);
+       if (err < 0)
+               return err;
+
+       if (!strcasecmp(pm, "soft"))
+               return NAND_ECC_HAMMING;
+       else if (!strcasecmp(pm, "soft_bch"))
+               return NAND_ECC_BCH;
+
+       return -ENODEV;
+}
+
+static int of_get_nand_ecc_step_size(struct device_node *np)
+{
+       int ret;
+       u32 val;
+
+       ret = of_property_read_u32(np, "nand-ecc-step-size", &val);
+       return ret ? ret : val;
+}
+
+static int of_get_nand_ecc_strength(struct device_node *np)
+{
+       int ret;
+       u32 val;
+
+       ret = of_property_read_u32(np, "nand-ecc-strength", &val);
+       return ret ? ret : val;
+}
+
+static int of_get_nand_bus_width(struct device_node *np)
+{
+       u32 val;
+
+       if (of_property_read_u32(np, "nand-bus-width", &val))
+               return 8;
+
+       switch (val) {
+       case 8:
+       case 16:
+               return val;
+       default:
+               return -EIO;
+       }
+}
+
+static bool of_get_nand_on_flash_bbt(struct device_node *np)
+{
+       return of_property_read_bool(np, "nand-on-flash-bbt");
+}
+
 static int nand_dt_init(struct nand_chip *chip)
 {
        struct device_node *dn = nand_get_flash_node(chip);
@@ -4112,19 +4246,15 @@ int nand_scan_tail(struct mtd_info *mtd)
        /*
         * If no default placement scheme is given, select an appropriate one.
         */
-       if (!ecc->layout && (ecc->mode != NAND_ECC_SOFT_BCH)) {
+       if (!mtd->ooblayout && (ecc->mode != NAND_ECC_SOFT_BCH)) {
                switch (mtd->oobsize) {
                case 8:
-                       ecc->layout = &nand_oob_8;
-                       break;
                case 16:
-                       ecc->layout = &nand_oob_16;
+                       mtd_set_ooblayout(mtd, &nand_ooblayout_sp_ops);
                        break;
                case 64:
-                       ecc->layout = &nand_oob_64;
-                       break;
                case 128:
-                       ecc->layout = &nand_oob_128;
+                       mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
                        break;
                default:
                        WARN(1, "No oob scheme defined for oobsize %d\n",
@@ -4207,6 +4337,7 @@ int nand_scan_tail(struct mtd_info *mtd)
                pr_warn("%d byte HW ECC not possible on %d byte page size, fallback to SW ECC\n",
                        ecc->size, mtd->writesize);
                ecc->mode = NAND_ECC_SOFT;
+               ecc->algo = NAND_ECC_HAMMING;
 
        case NAND_ECC_SOFT:
                ecc->calculate = nand_calculate_ecc;
@@ -4249,6 +4380,21 @@ int nand_scan_tail(struct mtd_info *mtd)
                        ecc->strength = 4;
                }
 
+               /*
+                * if no ecc placement scheme was provided pickup the default
+                * large page one.
+                */
+               if (!mtd->ooblayout) {
+                       /* handle large page devices only */
+                       if (mtd->oobsize < 64) {
+                               WARN(1, "OOB layout is required when using software BCH on small pages\n");
+                               ret = -EINVAL;
+                               goto err_free;
+                       }
+
+                       mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+               }
+
                /* See nand_bch_init() for details. */
                ecc->bytes = 0;
                ecc->priv = nand_bch_init(mtd);
@@ -4285,7 +4431,6 @@ int nand_scan_tail(struct mtd_info *mtd)
                ecc->write_oob_raw = ecc->write_oob;
 
        /* propagate ecc info to mtd_info */
-       mtd_set_ecclayout(mtd, ecc->layout);
        mtd->ecc_strength = ecc->strength;
        mtd->ecc_step_size = ecc->size;
 
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