[PATCH v2 12/14] mtd: rawnand: qcom: check for operation errors in case of raw read

Abhishek Sahu
2018-05-03T12:22:20Z

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>
---
* Changes from v1:

1. Removed the code for copy_last_cw.

drivers/mtd/nand/raw/qcom_nandc.c | 58 +++++++++++++++++++++++++++------------
1 file changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index 10bdc6c..d828115 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/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.
@@ -1731,7 +1755,7 @@ 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,
@@ -1841,7 +1865,7 @@ 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;
@@ -1860,12 +1884,13 @@ static int qcom_nandc_read_page_raw(struct mtd_info *mtd,
}

ret = submit_descs(nandc);
- if (ret)
+ free_descs(nandc);
+ if (ret) {
dev_err(nandc->dev, "failure to read raw page\n");
+ return ret;
+ }

- free_descs(nandc);
-
- return ret;
+ return check_flash_errors(host, ecc->steps);
}

/* implements ecc->read_oob() */
@@ -2085,7 +2110,6 @@ static int qcom_nandc_block_bad(struct mtd_info *mtd, loff_t ofs)
struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
struct nand_ecc_ctrl *ecc = &chip->ecc;
int page, ret, bbpos, bad = 0;
- u32 flash_status;
u8 *bbm_bytes_buf = chip->data_buf;

page = (int)(ofs >> chip->page_shift) & chip->pagemask;
@@ -2112,7 +2136,7 @@ static int qcom_nandc_block_bad(struct mtd_info *mtd, loff_t ofs)
* bbpos offset.
*/
nandc_set_read_loc(nandc, 0, bbpos, host->bbm_size, 1);
- config_nand_single_cw_page_read(nandc);
+ config_nand_single_cw_page_read(nandc, host->use_ecc);
read_data_dma(nandc, FLASH_BUF_ACC + bbpos, bbm_bytes_buf,
host->bbm_size, 0);

@@ -2123,9 +2147,7 @@ static int qcom_nandc_block_bad(struct mtd_info *mtd, loff_t ofs)
goto err;
}

- flash_status = le32_to_cpu(nandc->reg_read_buf[0]);
-
- if (flash_status & (FS_OP_ERR | FS_MPU_ERR)) {
+ if (check_flash_errors(host, 1)) {
dev_warn(nandc->dev, "error when trying to read BBM\n");
goto err;
}
--
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