mtd: nand: omap: use drivers/mtd/nand/nand_bch.c wrapper for BCH ECC instead of lib/bch.c

generic frame-work in mtd/nand/nand_bch.c is a wrapper above lib/bch.h which
encapsulates all control information specific to BCH ecc algorithm in software.
Thus this patch:
(1) replace omap specific implementations with equivalent wrapper in nand_bch.c
    so that generic code from nand_bch.c is re-used. like;
        omap3_correct_data_bch() -> nand_bch_correct_data()
        omap3_free_bch() -> nand_bch_free()
(2) replace direct calls to lib/bch.c with wrapper functions defined in nand_bch.c
	init_bch() -> nand_bch_init()

Signed-off-by: Pekon Gupta <pekon@ti.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 22 insertions, 74 deletions

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index b6a08b23853b..93aa35c8260c 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -25,7 +25,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 
-#include <linux/bch.h>
+#include <linux/mtd/nand_bch.h>
 #include <linux/platform_data/elm.h>
 
 #include <linux/platform_data/mtd-nand-omap2.h>
@@ -140,7 +140,6 @@
 #define BCH_ECC_SIZE1           0x20    /* ecc_size1 = 32 */
 
 #define BADBLOCK_MARKER_LENGTH          2
-#define OMAP_ECC_BCH8_POLYNOMIAL        0x201b
 
 #ifdef CONFIG_MTD_NAND_OMAP_BCH
 static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
@@ -173,7 +172,6 @@ struct omap_nand_info {
         int                                     buf_len;
         struct gpmc_nand_regs           reg;
         /* fields specific for BCHx_HW ECC scheme */
-        struct bch_control             *bch;
         bool                            is_elm_used;
         struct device                   *elm_dev;
         struct device_node              *of_node;
@@ -1507,43 +1505,7 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
 
         return stat;
 }
-#endif /* CONFIG_MTD_NAND_OMAP_BCH */
 
-#ifdef CONFIG_MTD_NAND_ECC_BCH
-/**
- * omap3_correct_data_bch - Decode received data and correct errors
- * @mtd: MTD device structure
- * @data: page data
- * @read_ecc: ecc read from nand flash
- * @calc_ecc: ecc read from HW ECC registers
- */
-static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data,
-                                  u_char *read_ecc, u_char *calc_ecc)
-{
-        int i, count;
-        /* cannot correct more than 8 errors */
-        unsigned int errloc[8];
-        struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
-                                                   mtd);
-
-        count = decode_bch(info->bch, NULL, 512, read_ecc, calc_ecc, NULL,
-                           errloc);
-        if (count > 0) {
-                /* correct errors */
-                for (i = 0; i < count; i++) {
-                        /* correct data only, not ecc bytes */
-                        if (errloc[i] < 8*512)
-                                data[errloc[i]/8] ^= 1 << (errloc[i] & 7);
-                        pr_debug("corrected bitflip %u\n", errloc[i]);
-                }
-        } else if (count < 0) {
-                pr_err("ecc unrecoverable error\n");
-        }
-        return count;
-}
-#endif /* CONFIG_MTD_NAND_ECC_BCH */
-
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
 /**
  * omap_write_page_bch - BCH ecc based write page function for entire page
  * @mtd:                mtd info structure
@@ -1660,28 +1622,6 @@ static int is_elm_present(struct omap_nand_info *info,
 }
 #endif /* CONFIG_MTD_NAND_ECC_BCH */
 
-#ifdef CONFIG_MTD_NAND_ECC_BCH
-/**
- * omap3_free_bch - Release BCH ecc resources
- * @mtd: MTD device structure
- */
-static void omap3_free_bch(struct mtd_info *mtd)
-{
-        struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
-                                                   mtd);
-        if (info->bch) {
-                free_bch(info->bch);
-                info->bch = NULL;
-        }
-}
-
-#else
-
-static void omap3_free_bch(struct mtd_info *mtd)
-{
-}
-#endif /* CONFIG_MTD_NAND_ECC_BCH */
-
 static int omap_nand_probe(struct platform_device *pdev)
 {
         struct omap_nand_info           *info;
@@ -1714,13 +1654,13 @@ static int omap_nand_probe(struct platform_device *pdev)
         info->pdev              = pdev;
         info->gpmc_cs           = pdata->cs;
         info->reg               = pdata->reg;
-        info->bch               = NULL;
         info->of_node           = pdata->of_node;
         mtd                     = &info->mtd;
         mtd->priv               = &info->nand;
         mtd->name               = dev_name(&pdev->dev);
         mtd->owner              = THIS_MODULE;
         nand_chip               = &info->nand;
+        nand_chip->ecc.priv     = NULL;
         nand_chip->options      |= NAND_SKIP_BBTSCAN;
 
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1903,7 +1843,7 @@ static int omap_nand_probe(struct platform_device *pdev)
                 nand_chip->ecc.bytes            = 7;
                 nand_chip->ecc.strength         = 4;
                 nand_chip->ecc.hwctl            = omap3_enable_hwecc_bch;
-                nand_chip->ecc.correct          = omap3_correct_data_bch;
+                nand_chip->ecc.correct          = nand_bch_correct_data;
                 nand_chip->ecc.calculate        = omap3_calculate_ecc_bch4;
                 /* define ECC layout */
                 ecclayout->eccbytes             = nand_chip->ecc.bytes *
@@ -1913,10 +1853,11 @@ static int omap_nand_probe(struct platform_device *pdev)
                 ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
                                                         ecclayout->eccbytes;
                 /* software bch library is used for locating errors */
-                info->bch = init_bch(nand_chip->ecc.bytes,
-                                        nand_chip->ecc.strength,
-                                        OMAP_ECC_BCH8_POLYNOMIAL);
-                if (!info->bch) {
+                nand_chip->ecc.priv             = nand_bch_init(mtd,
+                                                        nand_chip->ecc.size,
+                                                        nand_chip->ecc.bytes,
+                                                        &nand_chip->ecc.layout);
+                if (!nand_chip->ecc.priv) {
                         pr_err("nand: error: unable to use s/w BCH library\n");
                         err = -EINVAL;
                 }
@@ -1968,7 +1909,7 @@ static int omap_nand_probe(struct platform_device *pdev)
                 nand_chip->ecc.bytes            = 13;
                 nand_chip->ecc.strength         = 8;
                 nand_chip->ecc.hwctl            = omap3_enable_hwecc_bch;
-                nand_chip->ecc.correct          = omap3_correct_data_bch;
+                nand_chip->ecc.correct          = nand_bch_correct_data;
                 nand_chip->ecc.calculate        = omap3_calculate_ecc_bch8;
                 /* define ECC layout */
                 ecclayout->eccbytes             = nand_chip->ecc.bytes *
@@ -1978,10 +1919,11 @@ static int omap_nand_probe(struct platform_device *pdev)
                 ecclayout->oobfree->offset      = ecclayout->eccpos[0] +
                                                         ecclayout->eccbytes;
                 /* software bch library is used for locating errors */
-                info->bch = init_bch(nand_chip->ecc.bytes,
-                                        nand_chip->ecc.strength,
-                                        OMAP_ECC_BCH8_POLYNOMIAL);
-                if (!info->bch) {
+                nand_chip->ecc.priv             = nand_bch_init(mtd,
+                                                        nand_chip->ecc.size,
+                                                        nand_chip->ecc.bytes,
+                                                        &nand_chip->ecc.layout);
+                if (!nand_chip->ecc.priv) {
                         pr_err("nand: error: unable to use s/w BCH library\n");
                         err = -EINVAL;
                         goto out_release_mem_region;
@@ -2067,7 +2009,10 @@ out_release_mem_region:
                 free_irq(info->gpmc_irq_fifo, info);
         release_mem_region(info->phys_base, info->mem_size);
 out_free_info:
-        omap3_free_bch(mtd);
+        if (nand_chip->ecc.priv) {
+                nand_bch_free(nand_chip->ecc.priv);
+                nand_chip->ecc.priv = NULL;
+        }
         kfree(info);
 
         return err;
@@ -2079,7 +2024,10 @@ static int omap_nand_remove(struct platform_device *pdev)
         struct nand_chip *nand_chip = mtd->priv;
         struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
                                                         mtd);
-        omap3_free_bch(mtd);
+        if (nand_chip->ecc.priv) {
+                nand_bch_free(nand_chip->ecc.priv);
+                nand_chip->ecc.priv = NULL;
+        }
 
         if (info->dma)
                 dma_release_channel(info->dma);