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Subject[PATCH 7/9] mtd: nand: qcom: check for operation errors in case of raw read
Date
Currently there is no error checking for raw read. For raw
reads, there won’t be any ECC failure but the operational
failures are possible so schedule the NAND_FLASH_STATUS read
after each codeword.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
---
drivers/mtd/nand/qcom_nandc.c | 56 +++++++++++++++++++++++++++++++++++--------
1 file changed, 46 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/qcom_nandc.c b/drivers/mtd/nand/qcom_nandc.c
index dce97e8..40c790e 100644
--- a/drivers/mtd/nand/qcom_nandc.c
+++ b/drivers/mtd/nand/qcom_nandc.c
@@ -1099,7 +1099,8 @@ static void config_nand_page_read(struct qcom_nand_controller *nandc)
* Helper to prepare DMA descriptors for configuring registers
* before reading each codeword in NAND page.
*/
-static void config_nand_cw_read(struct qcom_nand_controller *nandc)
+static void
+config_nand_cw_read(struct qcom_nand_controller *nandc, bool use_ecc)
{
if (nandc->props->is_bam)
write_reg_dma(nandc, NAND_READ_LOCATION_0, 4,
@@ -1108,19 +1109,25 @@ static void config_nand_cw_read(struct qcom_nand_controller *nandc)
write_reg_dma(nandc, NAND_FLASH_CMD, 1, NAND_BAM_NEXT_SGL);
write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);

- read_reg_dma(nandc, NAND_FLASH_STATUS, 2, 0);
- read_reg_dma(nandc, NAND_ERASED_CW_DETECT_STATUS, 1,
- NAND_BAM_NEXT_SGL);
+ if (use_ecc) {
+ read_reg_dma(nandc, NAND_FLASH_STATUS, 2, 0);
+ read_reg_dma(nandc, NAND_ERASED_CW_DETECT_STATUS, 1,
+ NAND_BAM_NEXT_SGL);
+ } else {
+ read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
+ }
}

/*
* Helper to prepare dma descriptors to configure registers needed for reading a
* single codeword in page
*/
-static void config_nand_single_cw_page_read(struct qcom_nand_controller *nandc)
+static void
+config_nand_single_cw_page_read(struct qcom_nand_controller *nandc,
+ bool use_ecc)
{
config_nand_page_read(nandc);
- config_nand_cw_read(nandc);
+ config_nand_cw_read(nandc, use_ecc);
}

/*
@@ -1201,7 +1208,7 @@ static int nandc_param(struct qcom_nand_host *host)
nandc->buf_count = 512;
memset(nandc->data_buffer, 0xff, nandc->buf_count);

- config_nand_single_cw_page_read(nandc);
+ config_nand_single_cw_page_read(nandc, false);

read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer,
nandc->buf_count, 0);
@@ -1565,6 +1572,23 @@ struct read_stats {
__le32 erased_cw;
};

+/* reads back FLASH_STATUS register set by the controller */
+static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
+{
+ struct nand_chip *chip = &host->chip;
+ struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
+ int i;
+
+ for (i = 0; i < cw_cnt; i++) {
+ u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);
+
+ if (flash & (FS_OP_ERR | FS_MPU_ERR))
+ return -EIO;
+ }
+
+ return 0;
+}
+
/*
* reads back status registers set by the controller to notify page read
* errors. this is equivalent to what 'ecc->correct()' would do.
@@ -1707,7 +1731,7 @@ static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
}
}

- config_nand_cw_read(nandc);
+ config_nand_cw_read(nandc, true);

if (data_buf)
read_data_dma(nandc, FLASH_BUF_ACC, data_buf,
@@ -1771,7 +1795,7 @@ static int copy_last_cw(struct qcom_nand_host *host, int page)
set_address(host, host->cw_size * (ecc->steps - 1), page);
update_rw_regs(host, 1, true);

- config_nand_single_cw_page_read(nandc);
+ config_nand_single_cw_page_read(nandc, host->use_ecc);

read_data_dma(nandc, FLASH_BUF_ACC, nandc->data_buffer, size, 0);

@@ -1781,6 +1805,15 @@ static int copy_last_cw(struct qcom_nand_host *host, int page)

free_descs(nandc);

+ if (!ret) {
+ if (host->use_ecc)
+ ret = parse_read_errors(host, nandc->data_buffer,
+ nandc->data_buffer + size,
+ true);
+ else
+ ret = check_flash_errors(host, 1);
+ }
+
return ret;
}

@@ -1854,7 +1887,7 @@ static int qcom_nandc_read_page_raw(struct mtd_info *mtd,
nandc_set_read_loc(nandc, 3, read_loc, oob_size2, 1);
}

- config_nand_cw_read(nandc);
+ config_nand_cw_read(nandc, false);

read_data_dma(nandc, reg_off, data_buf, data_size1, 0);
reg_off += data_size1;
@@ -1878,6 +1911,9 @@ static int qcom_nandc_read_page_raw(struct mtd_info *mtd,

free_descs(nandc);

+ if (!ret)
+ ret = check_flash_errors(host, ecc->steps);
+
return 0;
}

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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