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mtd: nand: qcom: erased codeword detection configuration

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The NAND controller returns ECC failure during read of completely
erased codeword. The NAND controller has hardware functionality
to detect erased codeword in case of BCH ECC algorithm. The
NAND_ERASED_CW_DETECT_CFG register controls the erased
codeword/page detection controller. This register should be reset
before every page read by setting and clearing bit 0 of
NAND_ERASED_CW_DETECT_CFG.

Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Abhishek Sahu 2017-08-17 17:37:44 +05:30 committed by Boris Brezillon
parent 91af95c143
commit a86b9c4f57
1 changed files with 21 additions and 0 deletions
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21
drivers/mtd/nand/qcom_nandc.c
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@ -203,6 +203,11 @@ nandc_set_reg(nandc, NAND_READ_LOCATION_##reg, \
#define NAND_BAM_NWD BIT(1)
/* Finish writing in the current BAM sgl and start writing in another BAM sgl */
#define NAND_BAM_NEXT_SGL BIT(2)
/*
* Erased codeword status is being used two times in single transfer so this
* flag will determine the current value of erased codeword status register
*/
#define NAND_ERASED_CW_SET BIT(4)
/*
* This data type corresponds to the BAM transaction which will be used for all
@ -281,6 +286,8 @@ struct nandc_regs {
__le32 read_location2;
__le32 read_location3;
__le32 erased_cw_detect_cfg_clr;
__le32 erased_cw_detect_cfg_set;
};
/*
@ -810,6 +817,13 @@ static int write_reg_dma(struct qcom_nand_controller *nandc, int first,
if (first == NAND_FLASH_CMD)
flow_control = true;
if (first == NAND_ERASED_CW_DETECT_CFG) {
if (flags & NAND_ERASED_CW_SET)
vaddr = &regs->erased_cw_detect_cfg_set;
else
vaddr = &regs->erased_cw_detect_cfg_clr;
}
if (first == NAND_EXEC_CMD)
flags |= NAND_BAM_NWD;
@ -864,6 +878,9 @@ static void config_nand_page_read(struct qcom_nand_controller *nandc)
write_reg_dma(nandc, NAND_ADDR0, 2, 0);
write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1, 0);
write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1, 0);
write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1,
NAND_ERASED_CW_SET | NAND_BAM_NEXT_SGL);
}
/*
@ -2264,6 +2281,10 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
host->clrflashstatus = FS_READY_BSY_N;
host->clrreadstatus = 0xc0;
nandc->regs->erased_cw_detect_cfg_clr =
cpu_to_le32(CLR_ERASED_PAGE_DET);
nandc->regs->erased_cw_detect_cfg_set =
cpu_to_le32(SET_ERASED_PAGE_DET);
dev_dbg(nandc->dev,
"cfg0 %x cfg1 %x ecc_buf_cfg %x ecc_bch cfg %x cw_size %d cw_data %d strength %d parity_bytes %d steps %d\n",