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authorPekon Gupta <pekon@ti.com>2014-03-20 18:48:34 +0530
committerBrian Norris <computersforpeace@gmail.com>2014-03-25 23:08:52 -0700
commit3f4eb14bdbe148fcc3a8e02f506ccc9b8c955ad4 (patch)
treeeff0b8120b1a9d7c21cb97bbde936fa3e829228d /drivers/mtd/devices
parentd9ba46d32c0edc5207fec424230dfa786a24a117 (diff)
downloadblackbird-op-linux-3f4eb14bdbe148fcc3a8e02f506ccc9b8c955ad4.tar.gz
blackbird-op-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>
Diffstat (limited to 'drivers/mtd/devices')
-rw-r--r--drivers/mtd/devices/elm.c13
1 files changed, 12 insertions, 1 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);
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