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 <pe...@ti.com>
---
drivers/mtd/devices/elm.c | 13 ++++++++++++-
drivers/mtd/nand/omap2.c | 9 ++++++---
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 f160d2c..c51752a 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 ab9c472..6f9b339 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 bf0a83b..6e37156 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 */
--
1.8.5.1.163.gd7aced9
--
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