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Commit 2febcdf8 authored by Huang Shijie's avatar Huang Shijie Committed by David Woodhouse
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mtd: gpmi: set the BCH's geometry with the ecc info 



If the nand chip provides us the ECC info, we can use it firstly.
The set_geometry_by_ecc_info() will use the ECC info, and
calculate the parameters we need.

Rename the old code to legacy_set_geometry() which will takes effect
when there is no ECC info from the nand chip or we fails in the ECC info case.

Signed-off-by: default avatarHuang Shijie <b32955@freescale.com>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent d1048aaf

drivers/mtd/nand/gpmi-nand/gpmi-nand.c

+131 −1
Original line number Diff line number Diff line
@@ -111,7 +111,132 @@ static inline bool gpmi_check_ecc(struct gpmi_nand_data *this) 
	return true;

}



int common_nfc_set_geometry(struct gpmi_nand_data *this)

/*

 * If we can get the ECC information from the nand chip, we do not

 * need to calculate them ourselves.

 *

 * We may have available oob space in this case.

 */

static bool set_geometry_by_ecc_info(struct gpmi_nand_data *this)

{

	struct bch_geometry *geo = &this->bch_geometry;

	struct mtd_info *mtd = &this->mtd;

	struct nand_chip *chip = mtd->priv;

	struct nand_oobfree *of = gpmi_hw_ecclayout.oobfree;

	unsigned int block_mark_bit_offset;



	if (!(chip->ecc_strength_ds > 0 && chip->ecc_step_ds > 0))

		return false;



	switch (chip->ecc_step_ds) {

	case SZ_512:

		geo->gf_len = 13;

		break;

	case SZ_1K:

		geo->gf_len = 14;

		break;

	default:

		dev_err(this->dev,

			"unsupported nand chip. ecc bits : %d, ecc size : %d\n",

			chip->ecc_strength_ds, chip->ecc_step_ds);

		return false;

	}

	geo->ecc_chunk_size = chip->ecc_step_ds;

	geo->ecc_strength = round_up(chip->ecc_strength_ds, 2);

	if (!gpmi_check_ecc(this))

		return false;



	/* Keep the C >= O */

	if (geo->ecc_chunk_size < mtd->oobsize) {

		dev_err(this->dev,

			"unsupported nand chip. ecc size: %d, oob size : %d\n",

			chip->ecc_step_ds, mtd->oobsize);

		return false;

	}



	/* The default value, see comment in the legacy_set_geometry(). */

	geo->metadata_size = 10;



	geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size;



	/*

	 * Now, the NAND chip with 2K page(data chunk is 512byte) shows below:

	 *

	 *    |                          P                            |

	 *    |<----------------------------------------------------->|

	 *    |                                                       |

	 *    |                                        (Block Mark)   |

	 *    |                      P'                      |      | |     |

	 *    |<-------------------------------------------->|  D   | |  O' |

	 *    |                                              |<---->| |<--->|

	 *    V                                              V      V V     V

	 *    +---+----------+-+----------+-+----------+-+----------+-+-----+

	 *    | M |   data   |E|   data   |E|   data   |E|   data   |E|     |

	 *    +---+----------+-+----------+-+----------+-+----------+-+-----+

	 *                                                   ^              ^

	 *                                                   |      O       |

	 *                                                   |<------------>|

	 *                                                   |              |

	 *

	 *	P : the page size for BCH module.

	 *	E : The ECC strength.

	 *	G : the length of Galois Field.

	 *	N : The chunk count of per page.

	 *	M : the metasize of per page.

	 *	C : the ecc chunk size, aka the "data" above.

	 *	P': the nand chip's page size.

	 *	O : the nand chip's oob size.

	 *	O': the free oob.

	 *

	 *	The formula for P is :

	 *

	 *	            E * G * N

	 *	       P = ------------ + P' + M

	 *                      8

	 *

	 * The position of block mark moves forward in the ECC-based view

	 * of page, and the delta is:

	 *

	 *                   E * G * (N - 1)

	 *             D = (---------------- + M)

	 *                          8

	 *

	 * Please see the comment in legacy_set_geometry().

	 * With the condition C >= O , we still can get same result.

	 * So the bit position of the physical block mark within the ECC-based

	 * view of the page is :

	 *             (P' - D) * 8

	 */

	geo->page_size = mtd->writesize + geo->metadata_size +

		(geo->gf_len * geo->ecc_strength * geo->ecc_chunk_count) / 8;



	/* The available oob size we have. */

	if (geo->page_size < mtd->writesize + mtd->oobsize) {

		of->offset = geo->page_size - mtd->writesize;

		of->length = mtd->oobsize - of->offset;

		mtd->oobavail = gpmi_hw_ecclayout.oobavail = of->length;

	}



	geo->payload_size = mtd->writesize;



	geo->auxiliary_status_offset = ALIGN(geo->metadata_size, 4);

	geo->auxiliary_size = ALIGN(geo->metadata_size, 4)

				+ ALIGN(geo->ecc_chunk_count, 4);



	if (!this->swap_block_mark)

		return true;



	/* For bit swap. */

	block_mark_bit_offset = mtd->writesize * 8 -

		(geo->ecc_strength * geo->gf_len * (geo->ecc_chunk_count - 1)

				+ geo->metadata_size * 8);



	geo->block_mark_byte_offset = block_mark_bit_offset / 8;

	geo->block_mark_bit_offset  = block_mark_bit_offset % 8;

	return true;

}



static int legacy_set_geometry(struct gpmi_nand_data *this)

{

	struct bch_geometry *geo = &this->bch_geometry;

	struct mtd_info *mtd = &this->mtd;
@@ -223,6 +348,11 @@ int common_nfc_set_geometry(struct gpmi_nand_data *this) 
	return 0;

}



int common_nfc_set_geometry(struct gpmi_nand_data *this)

{

	return set_geometry_by_ecc_info(this) ? 0 : legacy_set_geometry(this);

}



struct dma_chan *get_dma_chan(struct gpmi_nand_data *this)

{

	int chipnr = this->current_chip;