* [PATCH v8 1/4] mtd: devices: elm: check for hardware engine's design constraints
2014-03-20 13:13 [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Pekon Gupta
@ 2014-03-20 13:13 ` Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 2/4] mtd: devices: elm: clean elm_load_syndrome Pekon Gupta
` (3 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Pekon Gupta @ 2014-03-20 13:13 UTC (permalink / raw)
To: Tony Lindgren; +Cc: linux-omap, Ezequiel Garcia, Stefan Roese, Pekon Gupta
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>
---
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
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v8 2/4] mtd: devices: elm: clean elm_load_syndrome
2014-03-20 13:13 [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 1/4] mtd: devices: elm: check for hardware engine's design constraints Pekon Gupta
@ 2014-03-20 13:13 ` Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 3/4] mtd: devices: elm: configure parallel channels based on ecc_steps Pekon Gupta
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Pekon Gupta @ 2014-03-20 13:13 UTC (permalink / raw)
To: Tony Lindgren; +Cc: linux-omap, Ezequiel Garcia, Stefan Roese, Pekon Gupta
This patch refactors elm_load_syndrome() to make it scalable for newer
ECC schemes by removing scheme specific macros (like ECC_BYTES*xx),
and instead using ECC control information passed during elm_config.
Signed-off-by: Pekon Gupta <pekon@ti.com>
---
drivers/mtd/devices/elm.c | 18 +++++++++++-------
include/linux/platform_data/elm.h | 7 -------
2 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c
index c51752a..4fbfaf6 100644
--- a/drivers/mtd/devices/elm.c
+++ b/drivers/mtd/devices/elm.c
@@ -84,6 +84,7 @@ struct elm_info {
struct list_head list;
enum bch_ecc bch_type;
struct elm_registers elm_regs;
+ int ecc_syndrome_size;
};
static LIST_HEAD(elm_devices);
@@ -126,7 +127,8 @@ int elm_config(struct device *dev, enum bch_ecc bch_type,
reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
- info->bch_type = bch_type;
+ info->bch_type = bch_type;
+ info->ecc_syndrome_size = ecc_syndrome_size;
return 0;
}
@@ -175,10 +177,8 @@ static void elm_load_syndrome(struct elm_info *info,
elm_configure_page_mode(info, i, true);
offset = ELM_SYNDROME_FRAGMENT_0 +
SYNDROME_FRAGMENT_REG_SIZE * i;
-
- /* BCH8 */
- if (info->bch_type) {
-
+ switch (info->bch_type) {
+ case BCH8_ECC:
/* syndrome fragment 0 = ecc[9-12B] */
val = cpu_to_be32(*(u32 *) &ecc[9]);
elm_write_reg(info, offset, val);
@@ -197,7 +197,8 @@ static void elm_load_syndrome(struct elm_info *info,
offset += 4;
val = ecc[0];
elm_write_reg(info, offset, val);
- } else {
+ break;
+ case BCH4_ECC:
/* syndrome fragment 0 = ecc[20-52b] bits */
val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
((ecc[2] & 0xf) << 28);
@@ -207,11 +208,14 @@ static void elm_load_syndrome(struct elm_info *info,
offset += 4;
val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
elm_write_reg(info, offset, val);
+ break;
+ default:
+ pr_err("invalid config bch_type\n");
}
}
/* Update ecc pointer with ecc byte size */
- ecc += info->bch_type ? BCH8_SIZE : BCH4_SIZE;
+ ecc += info->ecc_syndrome_size;
}
}
diff --git a/include/linux/platform_data/elm.h b/include/linux/platform_data/elm.h
index 6e37156..4edb406 100644
--- a/include/linux/platform_data/elm.h
+++ b/include/linux/platform_data/elm.h
@@ -26,13 +26,6 @@ enum bch_ecc {
/* ELM support 8 error syndrome process */
#define ERROR_VECTOR_MAX 8
-#define BCH8_ECC_OOB_BYTES 13
-#define BCH4_ECC_OOB_BYTES 7
-/* RBL requires 14 byte even though BCH8 uses only 13 byte */
-#define BCH8_SIZE (BCH8_ECC_OOB_BYTES + 1)
-/* Uses 1 extra byte to handle erased pages */
-#define BCH4_SIZE (BCH4_ECC_OOB_BYTES + 1)
-
/**
* struct elm_errorvec - error vector for elm
* @error_reported: set true for vectors error is reported
--
1.8.5.1.163.gd7aced9
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v8 3/4] mtd: devices: elm: configure parallel channels based on ecc_steps
2014-03-20 13:13 [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 1/4] mtd: devices: elm: check for hardware engine's design constraints Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 2/4] mtd: devices: elm: clean elm_load_syndrome Pekon Gupta
@ 2014-03-20 13:13 ` Pekon Gupta
2014-03-20 13:13 ` [PATCH v8 4/4] mtd: devices: elm: update DRIVER_NAME as "omap-elm" Pekon Gupta
2014-03-20 13:17 ` [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Gupta, Pekon
4 siblings, 0 replies; 9+ messages in thread
From: Pekon Gupta @ 2014-03-20 13:13 UTC (permalink / raw)
To: Tony Lindgren; +Cc: linux-omap, Ezequiel Garcia, Stefan Roese, Pekon Gupta
ELM hardware can process up to maximum of 8 hannels in parallel for
ECC error detection. Currently the number of channels getting configured for
processing is static determined by macro ERROR_VECTOR_MAX. However, the actual
number of channels that need to be processed is the ECC step number.
This patch just avoids configuring extra unused channels.
Signed-off-by: Pekon Gupta <pekon@ti.com>
---
drivers/mtd/devices/elm.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c
index 4fbfaf6..26df41f 100644
--- a/drivers/mtd/devices/elm.c
+++ b/drivers/mtd/devices/elm.c
@@ -84,6 +84,7 @@ struct elm_info {
struct list_head list;
enum bch_ecc bch_type;
struct elm_registers elm_regs;
+ int ecc_steps;
int ecc_syndrome_size;
};
@@ -128,6 +129,7 @@ int elm_config(struct device *dev, enum bch_ecc bch_type,
reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
info->bch_type = bch_type;
+ info->ecc_steps = ecc_steps;
info->ecc_syndrome_size = ecc_syndrome_size;
return 0;
@@ -170,7 +172,7 @@ static void elm_load_syndrome(struct elm_info *info,
int i, offset;
u32 val;
- for (i = 0; i < ERROR_VECTOR_MAX; i++) {
+ for (i = 0; i < info->ecc_steps; i++) {
/* Check error reported */
if (err_vec[i].error_reported) {
@@ -238,7 +240,7 @@ static void elm_start_processing(struct elm_info *info,
* Set syndrome vector valid, so that ELM module
* will process it for vectors error is reported
*/
- for (i = 0; i < ERROR_VECTOR_MAX; i++) {
+ for (i = 0; i < info->ecc_steps; i++) {
if (err_vec[i].error_reported) {
offset = ELM_SYNDROME_FRAGMENT_6 +
SYNDROME_FRAGMENT_REG_SIZE * i;
@@ -267,7 +269,7 @@ static void elm_error_correction(struct elm_info *info,
int offset;
u32 reg_val;
- for (i = 0; i < ERROR_VECTOR_MAX; i++) {
+ for (i = 0; i < info->ecc_steps; i++) {
/* Check error reported */
if (err_vec[i].error_reported) {
--
1.8.5.1.163.gd7aced9
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v8 4/4] mtd: devices: elm: update DRIVER_NAME as "omap-elm"
2014-03-20 13:13 [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Pekon Gupta
` (2 preceding siblings ...)
2014-03-20 13:13 ` [PATCH v8 3/4] mtd: devices: elm: configure parallel channels based on ecc_steps Pekon Gupta
@ 2014-03-20 13:13 ` Pekon Gupta
2014-03-20 13:17 ` [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Gupta, Pekon
4 siblings, 0 replies; 9+ messages in thread
From: Pekon Gupta @ 2014-03-20 13:13 UTC (permalink / raw)
To: Tony Lindgren; +Cc: linux-omap, Ezequiel Garcia, Stefan Roese, Pekon Gupta
use "omap-elm" as DRIVER_NAME
Signed-off-by: Pekon Gupta <pekon@ti.com>
---
drivers/mtd/devices/elm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c
index 26df41f..1fd4a0f 100644
--- a/drivers/mtd/devices/elm.c
+++ b/drivers/mtd/devices/elm.c
@@ -15,6 +15,8 @@
*
*/
+#define DRIVER_NAME "omap-elm"
+
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
@@ -520,7 +522,7 @@ MODULE_DEVICE_TABLE(of, elm_of_match);
static struct platform_driver elm_driver = {
.driver = {
- .name = "elm",
+ .name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(elm_of_match),
.pm = &elm_pm_ops,
--
1.8.5.1.163.gd7aced9
^ permalink raw reply related [flat|nested] 9+ messages in thread* RE: [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup
2014-03-20 13:13 [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup Pekon Gupta
` (3 preceding siblings ...)
2014-03-20 13:13 ` [PATCH v8 4/4] mtd: devices: elm: update DRIVER_NAME as "omap-elm" Pekon Gupta
@ 2014-03-20 13:17 ` Gupta, Pekon
4 siblings, 0 replies; 9+ messages in thread
From: Gupta, Pekon @ 2014-03-20 13:17 UTC (permalink / raw)
To: Tony Lindgren; +Cc: linux-omap, Ezequiel Garcia, Stefan Roese
>From: Gupta, Pekon
>Subject: [PATCH v8 0/4] mtd: devices: elm: add checks ELM H/W constrains, driver code cleanup
>
Sorry, sent to the wrong list.. was intended for linux-mtd list
Please ignore the whole series.
with regards, pekon
^ permalink raw reply [flat|nested] 9+ messages in thread