From: Stefan Agner stefan.agner@toradex.com
Calculate BCH geometry at start and store the information in a structure. This avoids recalculation on every page access and allows to calculate ECC relevant information in one place. This patch does not change ECC layout or driver behavior in any way.
The patch aligns the driver somewhat with the Linux GPMI NAND driver which drives the same IP.
Signed-off-by: Stefan Agner stefan.agner@toradex.com ---
drivers/mtd/nand/mxs_nand.c | 182 +++++++++++++++++++++++--------------------- 1 file changed, 95 insertions(+), 87 deletions(-)
diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c index 1fe7a712d2..5b9398bd98 100644 --- a/drivers/mtd/nand/mxs_nand.c +++ b/drivers/mtd/nand/mxs_nand.c @@ -30,7 +30,6 @@
#define MXS_NAND_DMA_DESCRIPTOR_COUNT 4
-#define MXS_NAND_CHUNK_DATA_CHUNK_SIZE 512 #if (defined(CONFIG_MX6) || defined(CONFIG_MX7)) #define MXS_NAND_CHUNK_DATA_CHUNK_SIZE_SHIFT 2 #else @@ -47,12 +46,35 @@
#define MXS_NAND_BCH_TIMEOUT 10000
+/** + * @gf_len: The length of Galois Field. (e.g., 13 or 14) + * @ecc_strength: A number that describes the strength of the ECC + * algorithm. + * @ecc_chunk_size: The size, in bytes, of a single ECC chunk. Note + * the first chunk in the page includes both data and + * metadata, so it's a bit larger than this value. + * @ecc_chunk_count: The number of ECC chunks in the page, + * @block_mark_byte_offset: The byte offset in the ECC-based page view at + * which the underlying physical block mark appears. + * @block_mark_bit_offset: The bit offset into the ECC-based page view at + * which the underlying physical block mark appears. + */ +struct bch_geometry { + unsigned int gf_len; + unsigned int ecc_strength; + unsigned int ecc_chunk_size; + unsigned int ecc_chunk_count; + unsigned int block_mark_byte_offset; + unsigned int block_mark_bit_offset; +}; + struct mxs_nand_info { struct nand_chip chip; int cur_chip;
uint32_t cmd_queue_len; uint32_t data_buf_size; + struct bch_geometry bch_geometry;
uint8_t *cmd_buf; uint8_t *data_buf; @@ -75,8 +97,6 @@ struct mxs_nand_info { };
struct nand_ecclayout fake_ecc_layout; -static int chunk_data_size = MXS_NAND_CHUNK_DATA_CHUNK_SIZE; -static int galois_field = 13;
/* * Cache management functions @@ -137,61 +157,21 @@ static void mxs_nand_return_dma_descs(struct mxs_nand_info *info) info->desc_index = 0; }
-static uint32_t mxs_nand_ecc_chunk_cnt(uint32_t page_data_size) -{ - return page_data_size / chunk_data_size; -} - -static uint32_t mxs_nand_ecc_size_in_bits(uint32_t ecc_strength) -{ - return ecc_strength * galois_field; -} - static uint32_t mxs_nand_aux_status_offset(void) { return (MXS_NAND_METADATA_SIZE + 0x3) & ~0x3; }
-static inline uint32_t mxs_nand_get_ecc_strength(uint32_t page_data_size, - uint32_t page_oob_size) +static inline int mxs_nand_calc_mark_offset(struct bch_geometry *geo, + uint32_t page_data_size) { - int ecc_strength; - int max_ecc_strength_supported; - - /* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */ - if (is_mx6sx() || is_mx7()) - max_ecc_strength_supported = 62; - else - max_ecc_strength_supported = 40; - - /* - * Determine the ECC layout with the formula: - * ECC bits per chunk = (total page spare data bits) / - * (bits per ECC level) / (chunks per page) - * where: - * total page spare data bits = - * (page oob size - meta data size) * (bits per byte) - */ - ecc_strength = ((page_oob_size - MXS_NAND_METADATA_SIZE) * 8) - / (galois_field * - mxs_nand_ecc_chunk_cnt(page_data_size)); - - return min(round_down(ecc_strength, 2), max_ecc_strength_supported); -} - -static inline uint32_t mxs_nand_get_mark_offset(uint32_t page_data_size, - uint32_t ecc_strength) -{ - uint32_t chunk_data_size_in_bits; - uint32_t chunk_ecc_size_in_bits; + uint32_t chunk_data_size_in_bits = geo->ecc_chunk_size * 8; + uint32_t chunk_ecc_size_in_bits = geo->ecc_strength * geo->gf_len; uint32_t chunk_total_size_in_bits; uint32_t block_mark_chunk_number; uint32_t block_mark_chunk_bit_offset; uint32_t block_mark_bit_offset;
- chunk_data_size_in_bits = chunk_data_size * 8; - chunk_ecc_size_in_bits = mxs_nand_ecc_size_in_bits(ecc_strength); - chunk_total_size_in_bits = chunk_data_size_in_bits + chunk_ecc_size_in_bits;
@@ -216,7 +196,7 @@ static inline uint32_t mxs_nand_get_mark_offset(uint32_t page_data_size, (block_mark_chunk_number * chunk_total_size_in_bits);
if (block_mark_chunk_bit_offset > chunk_data_size_in_bits) - return 1; + return -EINVAL;
/* * Now that we know the chunk number in which the block mark appears, @@ -225,21 +205,59 @@ static inline uint32_t mxs_nand_get_mark_offset(uint32_t page_data_size, block_mark_bit_offset -= block_mark_chunk_number * chunk_ecc_size_in_bits;
- return block_mark_bit_offset; -} + geo->block_mark_byte_offset = block_mark_bit_offset >> 3; + geo->block_mark_bit_offset = block_mark_bit_offset & 0x7;
-static uint32_t mxs_nand_mark_byte_offset(struct mtd_info *mtd) -{ - uint32_t ecc_strength; - ecc_strength = mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize); - return mxs_nand_get_mark_offset(mtd->writesize, ecc_strength) >> 3; + return 0; }
-static uint32_t mxs_nand_mark_bit_offset(struct mtd_info *mtd) +static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo, + struct mtd_info *mtd) { - uint32_t ecc_strength; - ecc_strength = mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize); - return mxs_nand_get_mark_offset(mtd->writesize, ecc_strength) & 0x7; + unsigned int max_ecc_strength_supported; + + /* The default for the length of Galois Field. */ + geo->gf_len = 13; + + /* The default for chunk size. */ + geo->ecc_chunk_size = 512; + + if (geo->ecc_chunk_size < mtd->oobsize) { + geo->gf_len = 14; + geo->ecc_chunk_size *= 2; + } + + if (mtd->oobsize > geo->ecc_chunk_size) { + printf("Not support the NAND chips whose oob size is larger then %d bytes!\n", + geo->ecc_chunk_size); + return -EINVAL; + } + + geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size; + + /* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */ + if (is_mx6sx() || is_mx7()) + max_ecc_strength_supported = 62; + else + max_ecc_strength_supported = 40; + + /* + * Determine the ECC layout with the formula: + * ECC bits per chunk = (total page spare data bits) / + * (bits per ECC level) / (chunks per page) + * where: + * total page spare data bits = + * (page oob size - meta data size) * (bits per byte) + */ + geo->ecc_strength = ((mtd->oobsize - MXS_NAND_METADATA_SIZE) * 8) + / (geo->gf_len * geo->ecc_chunk_count); + + geo->ecc_strength = min(round_down(geo->ecc_strength, 2), max_ecc_strength_supported); + + if (mxs_nand_calc_mark_offset(geo, mtd->writesize) < 0) + return -EINVAL; + + return 0; }
/* @@ -380,18 +398,15 @@ static void mxs_nand_select_chip(struct mtd_info *mtd, int chip) * swapping the block mark, or swapping it *back* -- but it doesn't matter * because the the operation is the same. */ -static void mxs_nand_swap_block_mark(struct mtd_info *mtd, - uint8_t *data_buf, uint8_t *oob_buf) +static void mxs_nand_swap_block_mark(struct bch_geometry *geo, + uint8_t *data_buf, uint8_t *oob_buf) { - uint32_t bit_offset; - uint32_t buf_offset; + uint32_t bit_offset = geo->block_mark_bit_offset; + uint32_t buf_offset = geo->block_mark_byte_offset;
uint32_t src; uint32_t dst;
- bit_offset = mxs_nand_mark_bit_offset(mtd); - buf_offset = mxs_nand_mark_byte_offset(mtd); - /* * Get the byte from the data area that overlays the block mark. Since * the ECC engine applies its own view to the bits in the page, the @@ -567,6 +582,7 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand, int page) { struct mxs_nand_info *nand_info = nand_get_controller_data(nand); + struct bch_geometry *geo = &nand_info->bch_geometry; struct mxs_dma_desc *d; uint32_t channel = MXS_DMA_CHANNEL_AHB_APBH_GPMI0 + nand_info->cur_chip; uint32_t corrected = 0, failed = 0; @@ -665,11 +681,11 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand, mxs_nand_inval_data_buf(nand_info);
/* Read DMA completed, now do the mark swapping. */ - mxs_nand_swap_block_mark(mtd, nand_info->data_buf, nand_info->oob_buf); + mxs_nand_swap_block_mark(geo, nand_info->data_buf, nand_info->oob_buf);
/* Loop over status bytes, accumulating ECC status. */ status = nand_info->oob_buf + mxs_nand_aux_status_offset(); - for (i = 0; i < mxs_nand_ecc_chunk_cnt(mtd->writesize); i++) { + for (i = 0; i < geo->ecc_chunk_count; i++) { if (status[i] == 0x00) continue;
@@ -717,6 +733,7 @@ static int mxs_nand_ecc_write_page(struct mtd_info *mtd, int oob_required, int page) { struct mxs_nand_info *nand_info = nand_get_controller_data(nand); + struct bch_geometry *geo = &nand_info->bch_geometry; struct mxs_dma_desc *d; uint32_t channel = MXS_DMA_CHANNEL_AHB_APBH_GPMI0 + nand_info->cur_chip; int ret; @@ -725,7 +742,7 @@ static int mxs_nand_ecc_write_page(struct mtd_info *mtd, memcpy(nand_info->oob_buf, nand->oob_poi, mtd->oobsize);
/* Handle block mark swapping. */ - mxs_nand_swap_block_mark(mtd, nand_info->data_buf, nand_info->oob_buf); + mxs_nand_swap_block_mark(geo, nand_info->data_buf, nand_info->oob_buf);
/* Compile the DMA descriptor - write data. */ d = mxs_nand_get_dma_desc(nand_info); @@ -986,39 +1003,30 @@ static int mxs_nand_setup_ecc(struct mtd_info *mtd) { struct nand_chip *nand = mtd_to_nand(mtd); struct mxs_nand_info *nand_info = nand_get_controller_data(nand); + struct bch_geometry *geo = &nand_info->bch_geometry; struct mxs_bch_regs *bch_regs = (struct mxs_bch_regs *)MXS_BCH_BASE; uint32_t tmp;
- if (mtd->oobsize > MXS_NAND_CHUNK_DATA_CHUNK_SIZE) { - galois_field = 14; - chunk_data_size = MXS_NAND_CHUNK_DATA_CHUNK_SIZE * 2; - } - - if (mtd->oobsize > chunk_data_size) { - printf("Not support the NAND chips whose oob size is larger then %d bytes!\n", chunk_data_size); + if (mxs_nand_calc_ecc_layout(geo, mtd)) return -EINVAL; - }
/* Configure BCH and set NFC geometry */ mxs_reset_block(&bch_regs->hw_bch_ctrl_reg);
/* Configure layout 0 */ - tmp = (mxs_nand_ecc_chunk_cnt(mtd->writesize) - 1) - << BCH_FLASHLAYOUT0_NBLOCKS_OFFSET; + tmp = (geo->ecc_chunk_count - 1) << BCH_FLASHLAYOUT0_NBLOCKS_OFFSET; tmp |= MXS_NAND_METADATA_SIZE << BCH_FLASHLAYOUT0_META_SIZE_OFFSET; - tmp |= (mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize) >> 1) - << BCH_FLASHLAYOUT0_ECC0_OFFSET; - tmp |= chunk_data_size >> MXS_NAND_CHUNK_DATA_CHUNK_SIZE_SHIFT; - tmp |= (14 == galois_field ? 1 : 0) << + tmp |= (geo->ecc_strength >> 1) << BCH_FLASHLAYOUT0_ECC0_OFFSET; + tmp |= geo->ecc_chunk_size >> MXS_NAND_CHUNK_DATA_CHUNK_SIZE_SHIFT; + tmp |= (geo->gf_len == 14 ? 1 : 0) << BCH_FLASHLAYOUT0_GF13_0_GF14_1_OFFSET; writel(tmp, &bch_regs->hw_bch_flash0layout0);
tmp = (mtd->writesize + mtd->oobsize) << BCH_FLASHLAYOUT1_PAGE_SIZE_OFFSET; - tmp |= (mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize) >> 1) - << BCH_FLASHLAYOUT1_ECCN_OFFSET; - tmp |= chunk_data_size >> MXS_NAND_CHUNK_DATA_CHUNK_SIZE_SHIFT; - tmp |= (14 == galois_field ? 1 : 0) << + tmp |= (geo->ecc_strength >> 1) << BCH_FLASHLAYOUT1_ECCN_OFFSET; + tmp |= geo->ecc_chunk_size >> MXS_NAND_CHUNK_DATA_CHUNK_SIZE_SHIFT; + tmp |= (geo->gf_len == 14 ? 1 : 0) << BCH_FLASHLAYOUT1_GF13_0_GF14_1_OFFSET; writel(tmp, &bch_regs->hw_bch_flash0layout1);