mtd: rawnand: omap_gpmc: Fix BCH6/16 HW based correction
authorRoger Quadros <rogerq@kernel.org>
Tue, 20 Dec 2022 10:21:56 +0000 (12:21 +0200)
committerDario Binacchi <dario.binacchi@amarulasolutions.com>
Sun, 8 Jan 2023 09:33:20 +0000 (10:33 +0100)
The BCH detection hardware can generate ECC bytes for multiple
sectors in one go. Use that feature.

correct() only corrects one sector at a time so we need to call it
repeatedly for each sector.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Link: https://lore.kernel.org/all/20221220102203.52398-2-rogerq@kernel.org
drivers/mtd/nand/raw/omap_gpmc.c

index be3cb3c601b0b3735a147de0d188243728ea65b5..feaa739e786777996f5f95fe5f3ca67bb3151f26 100644 (file)
@@ -27,6 +27,9 @@
 
 #define BADBLOCK_MARKER_LENGTH 2
 #define SECTOR_BYTES           512
+#define ECCSIZE0_SHIFT         12
+#define ECCSIZE1_SHIFT         22
+#define ECC1RESULTSIZE         0x1
 #define ECCCLEAR               (0x1 << 8)
 #define ECCRESULTREG1          (0x1 << 0)
 /* 4 bit padding to make byte aligned, 56 = 52 + 4 */
@@ -186,72 +189,35 @@ static int __maybe_unused omap_correct_data(struct mtd_info *mtd, uint8_t *dat,
 __maybe_unused
 static void omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
 {
-       struct nand_chip        *nand   = mtd_to_nand(mtd);
-       struct omap_nand_info   *info   = nand_get_controller_data(nand);
+       struct nand_chip *nand = mtd_to_nand(mtd);
+       struct omap_nand_info *info = nand_get_controller_data(nand);
        unsigned int dev_width = (nand->options & NAND_BUSWIDTH_16) ? 1 : 0;
-       unsigned int ecc_algo = 0;
-       unsigned int bch_type = 0;
-       unsigned int eccsize1 = 0x00, eccsize0 = 0x00, bch_wrapmode = 0x00;
-       u32 ecc_size_config_val = 0;
-       u32 ecc_config_val = 0;
-       int cs = info->cs;
+       u32 val;
 
-       /* configure GPMC for specific ecc-scheme */
-       switch (info->ecc_scheme) {
-       case OMAP_ECC_HAM1_CODE_SW:
-               return;
-       case OMAP_ECC_HAM1_CODE_HW:
-               ecc_algo = 0x0;
-               bch_type = 0x0;
-               bch_wrapmode = 0x00;
-               eccsize0 = 0xFF;
-               eccsize1 = 0xFF;
+       /* Clear ecc and enable bits */
+       writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
+
+       /* program ecc and result sizes */
+       val = ((((nand->ecc.size >> 1) - 1) << ECCSIZE1_SHIFT) |
+                       ECC1RESULTSIZE);
+       writel(val, &gpmc_cfg->ecc_size_config);
+
+       switch (mode) {
+       case NAND_ECC_READ:
+       case NAND_ECC_WRITE:
+               writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
                break;
-       case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
-       case OMAP_ECC_BCH8_CODE_HW:
-               ecc_algo = 0x1;
-               bch_type = 0x1;
-               if (mode == NAND_ECC_WRITE) {
-                       bch_wrapmode = 0x01;
-                       eccsize0 = 0;  /* extra bits in nibbles per sector */
-                       eccsize1 = 28; /* OOB bits in nibbles per sector */
-               } else {
-                       bch_wrapmode = 0x01;
-                       eccsize0 = 26; /* ECC bits in nibbles per sector */
-                       eccsize1 = 2;  /* non-ECC bits in nibbles per sector */
-               }
-               break;
-       case OMAP_ECC_BCH16_CODE_HW:
-               ecc_algo = 0x1;
-               bch_type = 0x2;
-               if (mode == NAND_ECC_WRITE) {
-                       bch_wrapmode = 0x01;
-                       eccsize0 = 0;  /* extra bits in nibbles per sector */
-                       eccsize1 = 52; /* OOB bits in nibbles per sector */
-               } else {
-                       bch_wrapmode = 0x01;
-                       eccsize0 = 52; /* ECC bits in nibbles per sector */
-                       eccsize1 = 0;  /* non-ECC bits in nibbles per sector */
-               }
+       case NAND_ECC_READSYN:
+               writel(ECCCLEAR, &gpmc_cfg->ecc_control);
                break;
        default:
-               return;
+               printf("%s: error: unrecognized Mode[%d]!\n", __func__, mode);
+               break;
        }
-       /* Clear ecc and enable bits */
-       writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
-       /* Configure ecc size for BCH */
-       ecc_size_config_val = (eccsize1 << 22) | (eccsize0 << 12);
-       writel(ecc_size_config_val, &gpmc_cfg->ecc_size_config);
-
-       /* Configure device details for BCH engine */
-       ecc_config_val = ((ecc_algo << 16)      | /* HAM1 | BCHx */
-                       (bch_type << 12)        | /* BCH4/BCH8/BCH16 */
-                       (bch_wrapmode << 8)     | /* wrap mode */
-                       (dev_width << 7)        | /* bus width */
-                       (0x0 << 4)              | /* number of sectors */
-                       (cs <<  1)              | /* ECC CS */
-                       (0x1));                   /* enable ECC */
-       writel(ecc_config_val, &gpmc_cfg->ecc_config);
+
+       /* (ECC 16 or 8 bit col) | ( CS  )  | ECC Enable */
+       val = (dev_width << 7) | (info->cs << 1) | (0x1);
+       writel(val, &gpmc_cfg->ecc_config);
 }
 
 /*
@@ -270,6 +236,124 @@ static void omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
  */
 static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
                                uint8_t *ecc_code)
+{
+       u32 val;
+
+       val = readl(&gpmc_cfg->ecc1_result);
+       ecc_code[0] = val & 0xFF;
+       ecc_code[1] = (val >> 16) & 0xFF;
+       ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
+
+       return 0;
+}
+
+/* GPMC ecc engine settings for read */
+#define BCH_WRAPMODE_1          1       /* BCH wrap mode 1 */
+#define BCH8R_ECC_SIZE0         0x1a    /* ecc_size0 = 26 */
+#define BCH8R_ECC_SIZE1         0x2     /* ecc_size1 = 2 */
+#define BCH4R_ECC_SIZE0         0xd     /* ecc_size0 = 13 */
+#define BCH4R_ECC_SIZE1         0x3     /* ecc_size1 = 3 */
+
+/* GPMC ecc engine settings for write */
+#define BCH_WRAPMODE_6          6       /* BCH wrap mode 6 */
+#define BCH_ECC_SIZE0           0x0     /* ecc_size0 = 0, no oob protection */
+#define BCH_ECC_SIZE1           0x20    /* ecc_size1 = 32 */
+
+/**
+ * omap_enable_hwecc_bch - Program GPMC to perform BCH ECC calculation
+ * @mtd: MTD device structure
+ * @mode: Read/Write mode
+ *
+ * When using BCH with SW correction (i.e. no ELM), sector size is set
+ * to 512 bytes and we use BCH_WRAPMODE_6 wrapping mode
+ * for both reading and writing with:
+ * eccsize0 = 0  (no additional protected byte in spare area)
+ * eccsize1 = 32 (skip 32 nibbles = 16 bytes per sector in spare area)
+ */
+static void __maybe_unused omap_enable_hwecc_bch(struct mtd_info *mtd,
+                                                int mode)
+{
+       unsigned int bch_type;
+       unsigned int dev_width, nsectors;
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct omap_nand_info *info = nand_get_controller_data(chip);
+       u32 val, wr_mode;
+       unsigned int ecc_size1, ecc_size0;
+
+       /* GPMC configurations for calculating ECC */
+       switch (info->ecc_scheme) {
+       case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+               bch_type = 1;
+               nsectors = 1;
+               wr_mode   = BCH_WRAPMODE_6;
+               ecc_size0 = BCH_ECC_SIZE0;
+               ecc_size1 = BCH_ECC_SIZE1;
+               break;
+       case OMAP_ECC_BCH8_CODE_HW:
+               bch_type = 1;
+               nsectors = chip->ecc.steps;
+               if (mode == NAND_ECC_READ) {
+                       wr_mode   = BCH_WRAPMODE_1;
+                       ecc_size0 = BCH8R_ECC_SIZE0;
+                       ecc_size1 = BCH8R_ECC_SIZE1;
+               } else {
+                       wr_mode   = BCH_WRAPMODE_6;
+                       ecc_size0 = BCH_ECC_SIZE0;
+                       ecc_size1 = BCH_ECC_SIZE1;
+               }
+               break;
+       case OMAP_ECC_BCH16_CODE_HW:
+               bch_type = 0x2;
+               nsectors = chip->ecc.steps;
+               if (mode == NAND_ECC_READ) {
+                       wr_mode   = 0x01;
+                       ecc_size0 = 52; /* ECC bits in nibbles per sector */
+                       ecc_size1 = 0;  /* non-ECC bits in nibbles per sector */
+               } else {
+                       wr_mode   = 0x01;
+                       ecc_size0 = 0;  /* extra bits in nibbles per sector */
+                       ecc_size1 = 52; /* OOB bits in nibbles per sector */
+               }
+               break;
+       default:
+               return;
+       }
+
+       writel(ECCRESULTREG1, &gpmc_cfg->ecc_control);
+
+       /* Configure ecc size for BCH */
+       val = (ecc_size1 << ECCSIZE1_SHIFT) | (ecc_size0 << ECCSIZE0_SHIFT);
+       writel(val, &gpmc_cfg->ecc_size_config);
+
+       dev_width = (chip->options & NAND_BUSWIDTH_16) ? 1 : 0;
+
+       /* BCH configuration */
+       val = ((1                       << 16) | /* enable BCH */
+              (bch_type                << 12) | /* BCH4/BCH8/BCH16 */
+              (wr_mode                 <<  8) | /* wrap mode */
+              (dev_width               <<  7) | /* bus width */
+              (((nsectors - 1) & 0x7)  <<  4) | /* number of sectors */
+              (info->cs                <<  1) | /* ECC CS */
+              (0x1));                           /* enable ECC */
+
+       writel(val, &gpmc_cfg->ecc_config);
+
+       /* Clear ecc and enable bits */
+       writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
+}
+
+/**
+ * _omap_calculate_ecc_bch - Generate BCH ECC bytes for one sector
+ * @mtd:        MTD device structure
+ * @dat:        The pointer to data on which ecc is computed
+ * @ecc_code:   The ecc_code buffer
+ * @sector:     The sector number (for a multi sector page)
+ *
+ * Support calculating of BCH4/8/16 ECC vectors for one sector
+ * within a page. Sector number is in @sector.
+ */
+static int _omap_calculate_ecc_bch(struct mtd_info *mtd, const u8 *dat,
+                                  u8 *ecc_code, int sector)
 {
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct omap_nand_info *info = nand_get_controller_data(chip);
@@ -278,17 +362,11 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
        int8_t i = 0, j;
 
        switch (info->ecc_scheme) {
-       case OMAP_ECC_HAM1_CODE_HW:
-               val = readl(&gpmc_cfg->ecc1_result);
-               ecc_code[0] = val & 0xFF;
-               ecc_code[1] = (val >> 16) & 0xFF;
-               ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
-               break;
 #ifdef CONFIG_BCH
        case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
 #endif
        case OMAP_ECC_BCH8_CODE_HW:
-               ptr = &gpmc_cfg->bch_result_0_3[0].bch_result_x[3];
+               ptr = &gpmc_cfg->bch_result_0_3[sector].bch_result_x[3];
                val = readl(ptr);
                ecc_code[i++] = (val >>  0) & 0xFF;
                ptr--;
@@ -300,23 +378,24 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
                        ecc_code[i++] = (val >>  0) & 0xFF;
                        ptr--;
                }
+
                break;
        case OMAP_ECC_BCH16_CODE_HW:
-               val = readl(&gpmc_cfg->bch_result_4_6[0].bch_result_x[2]);
+               val = readl(&gpmc_cfg->bch_result_4_6[sector].bch_result_x[2]);
                ecc_code[i++] = (val >>  8) & 0xFF;
                ecc_code[i++] = (val >>  0) & 0xFF;
-               val = readl(&gpmc_cfg->bch_result_4_6[0].bch_result_x[1]);
+               val = readl(&gpmc_cfg->bch_result_4_6[sector].bch_result_x[1]);
                ecc_code[i++] = (val >> 24) & 0xFF;
                ecc_code[i++] = (val >> 16) & 0xFF;
                ecc_code[i++] = (val >>  8) & 0xFF;
                ecc_code[i++] = (val >>  0) & 0xFF;
-               val = readl(&gpmc_cfg->bch_result_4_6[0].bch_result_x[0]);
+               val = readl(&gpmc_cfg->bch_result_4_6[sector].bch_result_x[0]);
                ecc_code[i++] = (val >> 24) & 0xFF;
                ecc_code[i++] = (val >> 16) & 0xFF;
                ecc_code[i++] = (val >>  8) & 0xFF;
                ecc_code[i++] = (val >>  0) & 0xFF;
                for (j = 3; j >= 0; j--) {
-                       val = readl(&gpmc_cfg->bch_result_0_3[0].bch_result_x[j]
+                       val = readl(&gpmc_cfg->bch_result_0_3[sector].bch_result_x[j]
                                                                        );
                        ecc_code[i++] = (val >> 24) & 0xFF;
                        ecc_code[i++] = (val >> 16) & 0xFF;
@@ -329,18 +408,18 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
        }
        /* ECC scheme specific syndrome customizations */
        switch (info->ecc_scheme) {
-       case OMAP_ECC_HAM1_CODE_HW:
-               break;
 #ifdef CONFIG_BCH
        case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
-
+               /* Add constant polynomial to remainder, so that
+                * ECC of blank pages results in 0x0 on reading back
+                */
                for (i = 0; i < chip->ecc.bytes; i++)
-                       *(ecc_code + i) = *(ecc_code + i) ^
-                                               bch8_polynomial[i];
+                       ecc_code[i] ^= bch8_polynomial[i];
                break;
 #endif
        case OMAP_ECC_BCH8_CODE_HW:
-               ecc_code[chip->ecc.bytes - 1] = 0x00;
+               /* Set 14th ECC byte as 0x0 for ROM compatibility */
+               ecc_code[chip->ecc.bytes - 1] = 0x0;
                break;
        case OMAP_ECC_BCH16_CODE_HW:
                break;
@@ -350,6 +429,22 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
        return 0;
 }
 
+/**
+ * omap_calculate_ecc_bch - ECC generator for 1 sector
+ * @mtd:        MTD device structure
+ * @dat:       The pointer to data on which ecc is computed
+ * @ecc_code:  The ecc_code buffer
+ *
+ * Support calculating of BCH4/8/16 ECC vectors for one sector. This is used
+ * when SW based correction is required as ECC is required for one sector
+ * at a time.
+ */
+static int __maybe_unused omap_calculate_ecc_bch(struct mtd_info *mtd,
+                                 const u_char *dat, u_char *ecc_calc)
+{
+       return _omap_calculate_ecc_bch(mtd, dat, ecc_calc, 0);
+}
+
 static inline void omap_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
 {
        struct nand_chip *chip = mtd_to_nand(mtd);
@@ -474,6 +569,35 @@ static void omap_nand_read_prefetch(struct mtd_info *mtd, uint8_t *buf, int len)
 #endif /* CONFIG_NAND_OMAP_GPMC_PREFETCH */
 
 #ifdef CONFIG_NAND_OMAP_ELM
+
+/**
+ * omap_calculate_ecc_bch_multi - Generate ECC for multiple sectors
+ * @mtd:       MTD device structure
+ * @dat:       The pointer to data on which ecc is computed
+ * @ecc_code:  The ecc_code buffer
+ *
+ * Support calculating of BCH4/8/16 ecc vectors for the entire page in one go.
+ */
+static int omap_calculate_ecc_bch_multi(struct mtd_info *mtd,
+                                       const u_char *dat, u_char *ecc_calc)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       int eccbytes = chip->ecc.bytes;
+       unsigned long nsectors;
+       int i, ret;
+
+       nsectors = ((readl(&gpmc_cfg->ecc_config) >> 4) & 0x7) + 1;
+       for (i = 0; i < nsectors; i++) {
+               ret = _omap_calculate_ecc_bch(mtd, dat, ecc_calc, i);
+               if (ret)
+                       return ret;
+
+               ecc_calc += eccbytes;
+       }
+
+       return 0;
+}
+
 /*
  * omap_reverse_list - re-orders list elements in reverse order [internal]
  * @list:      pointer to start of list
@@ -626,52 +750,49 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
 {
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
+       int ecctotal = chip->ecc.total;
        int eccsteps = chip->ecc.steps;
        uint8_t *p = buf;
        uint8_t *ecc_calc = chip->buffers->ecccalc;
        uint8_t *ecc_code = chip->buffers->ecccode;
        uint32_t *eccpos = chip->ecc.layout->eccpos;
        uint8_t *oob = chip->oob_poi;
-       uint32_t data_pos;
        uint32_t oob_pos;
 
-       data_pos = 0;
        /* oob area start */
        oob_pos = (eccsize * eccsteps) + chip->ecc.layout->eccpos[0];
        oob += chip->ecc.layout->eccpos[0];
 
-       for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize,
-                               oob += eccbytes) {
-               chip->ecc.hwctl(mtd, NAND_ECC_READ);
-               /* read data */
-               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_pos, -1);
-               chip->read_buf(mtd, p, eccsize);
-
-               /* read respective ecc from oob area */
-               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, oob_pos, -1);
-               chip->read_buf(mtd, oob, eccbytes);
-               /* read syndrome */
-               chip->ecc.calculate(mtd, p, &ecc_calc[i]);
-
-               data_pos += eccsize;
-               oob_pos += eccbytes;
-       }
+       /* Enable ECC engine */
+       chip->ecc.hwctl(mtd, NAND_ECC_READ);
+
+       /* read entire page */
+       chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
+       chip->read_buf(mtd, buf, mtd->writesize);
+
+       /* read all ecc bytes from oob area */
+       chip->cmdfunc(mtd, NAND_CMD_RNDOUT, oob_pos, -1);
+       chip->read_buf(mtd, oob, ecctotal);
+
+       /* Calculate ecc bytes */
+       omap_calculate_ecc_bch_multi(mtd, buf, ecc_calc);
 
        for (i = 0; i < chip->ecc.total; i++)
                ecc_code[i] = chip->oob_poi[eccpos[i]];
 
+       /* error detect & correct */
        eccsteps = chip->ecc.steps;
        p = buf;
 
        for (i = 0 ; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                int stat;
-
                stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
                if (stat < 0)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;
        }
+
        return 0;
 }
 #endif /* CONFIG_NAND_OMAP_ELM */
@@ -819,9 +940,9 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
                nand->ecc.strength      = 8;
                nand->ecc.size          = SECTOR_BYTES;
                nand->ecc.bytes         = 13;
-               nand->ecc.hwctl         = omap_enable_hwecc;
+               nand->ecc.hwctl         = omap_enable_hwecc_bch;
                nand->ecc.correct       = omap_correct_data_bch_sw;
-               nand->ecc.calculate     = omap_calculate_ecc;
+               nand->ecc.calculate     = omap_calculate_ecc_bch;
                /* define ecc-layout */
                ecclayout->eccbytes     = nand->ecc.bytes * eccsteps;
                ecclayout->eccpos[0]    = BADBLOCK_MARKER_LENGTH;
@@ -860,9 +981,9 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
                nand->ecc.strength      = 8;
                nand->ecc.size          = SECTOR_BYTES;
                nand->ecc.bytes         = 14;
-               nand->ecc.hwctl         = omap_enable_hwecc;
+               nand->ecc.hwctl         = omap_enable_hwecc_bch;
                nand->ecc.correct       = omap_correct_data_bch;
-               nand->ecc.calculate     = omap_calculate_ecc;
+               nand->ecc.calculate     = omap_calculate_ecc_bch;
                nand->ecc.read_page     = omap_read_page_bch;
                /* define ecc-layout */
                ecclayout->eccbytes     = nand->ecc.bytes * eccsteps;
@@ -893,9 +1014,9 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
                nand->ecc.size          = SECTOR_BYTES;
                nand->ecc.bytes         = 26;
                nand->ecc.strength      = 16;
-               nand->ecc.hwctl         = omap_enable_hwecc;
+               nand->ecc.hwctl         = omap_enable_hwecc_bch;
                nand->ecc.correct       = omap_correct_data_bch;
-               nand->ecc.calculate     = omap_calculate_ecc;
+               nand->ecc.calculate     = omap_calculate_ecc_bch;
                nand->ecc.read_page     = omap_read_page_bch;
                /* define ecc-layout */
                ecclayout->eccbytes     = nand->ecc.bytes * eccsteps;