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| author | Pekon Gupta <pekon@ti.com> | 2014-03-20 14:18:34 +0100 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2014-03-26 07:08:52 +0100 |
| commit | 3f4eb14bdbe148fcc3a8e02f506ccc9b8c955ad4 (patch) | |
| tree | eff0b8120b1a9d7c21cb97bbde936fa3e829228d | |
| parent | mtd: st_spi_fsm: Succinctly reorganise .remove() (diff) | |
| download | linux-3f4eb14bdbe148fcc3a8e02f506ccc9b8c955ad4.tar.xz linux-3f4eb14bdbe148fcc3a8e02f506ccc9b8c955ad4.zip | |
mtd: devices: elm: check for hardware engine's design constraints
ELM hardware engine is used by BCH ecc-schemes for detecting and locating ECC
errors. This patch adds the following checks for ELM hardware engine:
- ELM internal buffers are of 1K,
so it cannot process data with ecc-step-size > 1K.
- ELM engine can execute upto maximum of 8 threads in parallel,
so in *page-mode* (when complete page is processed in single iteration),
ELM cannot support ecc-steps > 8.
Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
| -rw-r--r-- | drivers/mtd/devices/elm.c | 13 | ||||
| -rw-r--r-- | drivers/mtd/nand/omap2.c | 9 | ||||
| -rw-r--r-- | include/linux/platform_data/elm.h | 3 |
3 files changed, 20 insertions, 5 deletions
diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c index f160d2c6cd59..c51752ad072e 100644 --- a/drivers/mtd/devices/elm.c +++ b/drivers/mtd/devices/elm.c @@ -103,7 +103,8 @@ static u32 elm_read_reg(struct elm_info *info, int offset) * @dev: ELM device * @bch_type: Type of BCH ecc */ -int elm_config(struct device *dev, enum bch_ecc bch_type) +int elm_config(struct device *dev, enum bch_ecc bch_type, + int ecc_steps, int ecc_step_size, int ecc_syndrome_size) { u32 reg_val; struct elm_info *info = dev_get_drvdata(dev); @@ -112,6 +113,16 @@ int elm_config(struct device *dev, enum bch_ecc bch_type) dev_err(dev, "Unable to configure elm - device not probed?\n"); return -ENODEV; } + /* ELM cannot detect ECC errors for chunks > 1KB */ + if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) { + dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size); + return -EINVAL; + } + /* ELM support 8 error syndrome process */ + if (ecc_steps > ERROR_VECTOR_MAX) { + dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps); + return -EINVAL; + } reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index ab9c472456d9..6f9b339aed74 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -1540,6 +1540,8 @@ static int is_elm_present(struct omap_nand_info *info, struct device_node *elm_node, enum bch_ecc bch_type) { struct platform_device *pdev; + struct nand_ecc_ctrl *ecc = &info->nand.ecc; + int err; /* check whether elm-id is passed via DT */ if (!elm_node) { pr_err("nand: error: ELM DT node not found\n"); @@ -1553,9 +1555,10 @@ static int is_elm_present(struct omap_nand_info *info, } /* ELM module available, now configure it */ info->elm_dev = &pdev->dev; - if (elm_config(info->elm_dev, bch_type)) - return -ENODEV; - return 0; + err = elm_config(info->elm_dev, bch_type, + (info->mtd.writesize / ecc->size), ecc->size, ecc->bytes); + + return err; } #endif /* CONFIG_MTD_NAND_ECC_BCH */ diff --git a/include/linux/platform_data/elm.h b/include/linux/platform_data/elm.h index bf0a83b7ed9d..6e37156b0902 100644 --- a/include/linux/platform_data/elm.h +++ b/include/linux/platform_data/elm.h @@ -50,5 +50,6 @@ struct elm_errorvec { void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, struct elm_errorvec *err_vec); -int elm_config(struct device *dev, enum bch_ecc bch_type); +int elm_config(struct device *dev, enum bch_ecc bch_type, + int ecc_steps, int ecc_step_size, int ecc_syndrome_size); #endif /* __ELM_H */ |