current implementation in omap3_init_bch() has some redundant code like:
(1) omap3_init_bch() re-probes the DT-binding to detect presence of ELM h/w
engine on SoC. And based on that it selects implemetation of ecc-scheme.
However, this is already done as part of GPMC DT parsing.
(2) As omap3_init_bch() serves as common function for configuring all types of
BCHx ecc-schemes, so there are multiple levels of redudant if..then..else
checks while populating nand_chip->ecc.
This patch make following changes to OMAP NAND driver:
(1) removes omap3_init_bch(): each ecc-scheme is individually configured in
omap_nand_probe() there by removing redundant if..then..else checks.
(2) adds is_elm_present(): re-probing of ELM device via DT is not required as
it's done in GPMC driver probe. Thus is_elm_present() just initializes ELM
driver with NAND probe data, when ecc-scheme with h/w based error-detection
is used.
(3) separates out configuration of different flavours of "BCH4" and "BCH8"
ecc-schemes as given in below table
(4) conditionally compiles callbacks implementations of ecc.hwctl(),
ecc.calculate(), ecc.correct() to avoid warning of un-used functions.
+---------------------------------------+---------------+---------------+
| ECC scheme |ECC calculation|Error detection|
+---------------------------------------+---------------+---------------+
|OMAP_ECC_HAM1_CODE_HW |H/W (GPMC) |S/W |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH4_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.c)|
| (needs CONFIG_MTD_NAND_ECC_BCH) | | |
| | | |
|OMAP_ECC_BCH4_CODE_HW |H/W (GPMC) |H/W (ELM) |
| (needs CONFIG_MTD_NAND_OMAP_BCH && | | |
| ti,elm-id) | | |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH8_CODE_HW_DETECTION_SW |H/W (GPMC) |S/W (lib/bch.c)|
| (needs CONFIG_MTD_NAND_ECC_BCH) | | |
| | | |
|OMAP_ECC_BCH8_CODE_HW |H/W (GPMC) |H/W (ELM) |
| (needs CONFIG_MTD_NAND_OMAP_BCH && | | |
| ti,elm-id) | | |
+---------------------------------------+---------------+---------------+
- 'CONFIG_MTD_NAND_ECC_BCH' is generic KConfig required to build lib/bch.c
which is required for ECC error detection done in software.
(mainly used for legacy platforms which do not have on-chip ELM engine)
- 'CONFIG_MTD_NAND_OMAP_BCH' is OMAP specific Kconfig to detemine presence
on ELM h/w engine on SoC.
Signed-off-by: Pekon Gupta <pekon@xxxxxx>
---
drivers/mtd/nand/omap2.c | 281 ++++++++++++++++++++++++++---------------------
1 file changed, 158 insertions(+), 123 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index f464321..86ce48b 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -25,10 +25,8 @@
#include <linux/of.h>
#include <linux/of_device.h>
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
#include <linux/bch.h>
#include <linux/platform_data/elm.h>
-#endif
#include <linux/platform_data/mtd-nand-omap2.h>
@@ -141,6 +139,8 @@
#define BCH_ECC_SIZE0 0x0 /* ecc_size0 = 0, no oob protection */
#define BCH_ECC_SIZE1 0x20 /* ecc_size1 = 32 */
+#define OMAP_ECC_BCH8_POLYNOMIAL 0x201b
+
#ifdef CONFIG_MTD_NAND_OMAP_BCH
static u_char bch8_vector[] = {0xf3, 0xdb, 0x14, 0x16, 0x8b, 0xd2, 0xbe, 0xcc,
0xac, 0x6b, 0xff, 0x99, 0x7b};
@@ -182,14 +182,12 @@ struct omap_nand_info {
u_char *buf;
int buf_len;
struct gpmc_nand_regs reg;
-
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
+ /* fields specific for BCHx_HW ECC scheme */
struct bch_control *bch;
struct nand_ecclayout ecclayout;
bool is_elm_used;
struct device *elm_dev;
struct device_node *of_node;
-#endif
};
/**
@@ -1058,8 +1056,7 @@ static int omap_dev_ready(struct mtd_info *mtd)
}
}
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
-
+#if defined(CONFIG_MTD_NAND_ECC_BCH) || defined(CONFIG_MTD_NAND_OMAP_BCH)
/**
* omap3_enable_hwecc_bch - Program OMAP3 GPMC to perform BCH ECC correction
* @mtd: MTD device structure
@@ -1140,7 +1137,9 @@ static void omap3_enable_hwecc_bch(struct mtd_info *mtd, int mode)
/* Clear ecc and enable bits */
writel(ECCCLEAR | ECC1, info->reg.gpmc_ecc_control);
}
+#endif
+#ifdef CONFIG_MTD_NAND_ECC_BCH
/**
* omap3_calculate_ecc_bch4 - Generate 7 bytes of ECC bytes
* @mtd: MTD device structure
@@ -1225,7 +1224,9 @@ static int omap3_calculate_ecc_bch8(struct mtd_info *mtd, const u_char *dat,
return 0;
}
+#endif /* CONFIG_MTD_NAND_ECC_BCH */
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
/**
* omap3_calculate_ecc_bch - Generate bytes of ECC bytes
* @mtd: MTD device structure
@@ -1517,7 +1518,9 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
return stat;
}
+#endif /* CONFIG_MTD_NAND_OMAP_BCH */
+#ifdef CONFIG_MTD_NAND_ECC_BCH
/**
* omap3_correct_data_bch - Decode received data and correct errors
* @mtd: MTD device structure
@@ -1549,7 +1552,9 @@ static int omap3_correct_data_bch(struct mtd_info *mtd, u_char *data,
}
return count;
}
+#endif /* CONFIG_MTD_NAND_ECC_BCH */
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
/**
* omap_write_page_bch - BCH ecc based write page function for entire page
* @mtd: mtd info structure
@@ -1637,118 +1642,48 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
}
/**
- * omap3_free_bch - Release BCH ecc resources
- * @mtd: MTD device structure
+ * is_elm_present - checks for presence of ELM module by scanning DT nodes
+ * @omap_nand_info: NAND device structure containing platform data
+ * @bch_type: 0x0=BCH4, 0x1=BCH8, 0x2=BCH16
*/
-static void omap3_free_bch(struct mtd_info *mtd)
+static int is_elm_present(struct omap_nand_info *info,
+ struct device_node *elm_node, enum bch_ecc bch_type)
{
- struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
- mtd);
- if (info->bch) {
- free_bch(info->bch);
- info->bch = NULL;
+ struct platform_device *pdev;
+ info->is_elm_used = false;
+ /* check whether elm-id is passed via DT */
+ if (!elm_node) {
+ pr_err("nand: error: ELM DT node not found\n");
+ return -ENODEV;
+ }
+ pdev = of_find_device_by_node(elm_node);
+ /* check whether ELM device is registered */
+ if (!pdev) {
+ pr_err("nand: error: ELM device not found\n");
+ return -ENODEV;
}
+ /* ELM module available, now configure it */
+ info->elm_dev = &pdev->dev;
+ if (elm_config(info->elm_dev, bch_type))
+ return -ENODEV;
+ info->is_elm_used = true;
+ return 0;
}
+#endif /* CONFIG_MTD_NAND_ECC_BCH */
+#ifdef CONFIG_MTD_NAND_ECC_BCH
/**
- * omap3_init_bch - Initialize BCH ECC
+ * omap3_free_bch - Release BCH ecc resources
* @mtd: MTD device structure
- * @ecc_opt: OMAP ECC mode (OMAP_ECC_BCH4_CODE_HW or OMAP_ECC_BCH8_CODE_HW)
*/
-static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
+static void omap3_free_bch(struct mtd_info *mtd)
{
- int max_errors;
struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd);
-#ifdef CONFIG_MTD_NAND_OMAP_BCH8
- const int hw_errors = BCH8_MAX_ERROR;
-#else
- const int hw_errors = BCH4_MAX_ERROR;
-#endif
- enum bch_ecc bch_type;
- const __be32 *parp;
- int lenp;
- struct device_node *elm_node;
-
- info->bch = NULL;
-
- max_errors = (ecc_opt == OMAP_ECC_BCH8_CODE_HW) ?
- BCH8_MAX_ERROR : BCH4_MAX_ERROR;
- if (max_errors != hw_errors) {
- pr_err("cannot configure %d-bit BCH ecc, only %d-bit supported",
- max_errors, hw_errors);
- goto fail;
- }
-
- info->nand.ecc.size = 512;
- info->nand.ecc.hwctl = omap3_enable_hwecc_bch;
- info->nand.ecc.mode = NAND_ECC_HW;
- info->nand.ecc.strength = max_errors;
-
- if (hw_errors == BCH8_MAX_ERROR)
- bch_type = BCH8_ECC;
- else
- bch_type = BCH4_ECC;
-
- /* Detect availability of ELM module */
- parp = of_get_property(info->of_node, "elm_id", &lenp);
- if ((parp == NULL) && (lenp != (sizeof(void *) * 2))) {
- pr_err("Missing elm_id property, fall back to Software BCH\n");
- info->is_elm_used = false;
- } else {
- struct platform_device *pdev;
-
- elm_node = of_find_node_by_phandle(be32_to_cpup(parp));
- pdev = of_find_device_by_node(elm_node);
- info->elm_dev = &pdev->dev;
-
- if (elm_config(info->elm_dev, bch_type) == 0)
- info->is_elm_used = true;
- }
-
- if (info->is_elm_used && (mtd->writesize <= 4096)) {
-
- if (hw_errors == BCH8_MAX_ERROR)
- info->nand.ecc.bytes = BCH8_SIZE;
- else
- info->nand.ecc.bytes = BCH4_SIZE;
-
- info->nand.ecc.correct = omap_elm_correct_data;
- info->nand.ecc.calculate = omap3_calculate_ecc_bch;
- info->nand.ecc.read_page = omap_read_page_bch;
- info->nand.ecc.write_page = omap_write_page_bch;
- } else {
- /*
- * software bch library is only used to detect and
- * locate errors
- */
- info->bch = init_bch(13, max_errors,
- 0x201b /* hw polynomial */);
- if (!info->bch)
- goto fail;
-
- info->nand.ecc.correct = omap3_correct_data_bch;
-
- /*
- * The number of corrected errors in an ecc block that will
- * trigger block scrubbing defaults to the ecc strength (4 or 8)
- * Set mtd->bitflip_threshold here to define a custom threshold.
- */
-
- if (max_errors == 8) {
- info->nand.ecc.bytes = 13;
- info->nand.ecc.calculate = omap3_calculate_ecc_bch8;
- } else {
- info->nand.ecc.bytes = 7;
- info->nand.ecc.calculate = omap3_calculate_ecc_bch4;
- }
+ if (info->bch) {
+ free_bch(info->bch);
+ info->bch = NULL;
}
-
- pr_info("enabling NAND BCH ecc with %d-bit correction\n", max_errors);
- return 0;
-fail:
- omap3_free_bch(mtd);
- return -1;
}
/**
@@ -1806,11 +1741,6 @@ fail:
}
#else
-static int omap3_init_bch(struct mtd_info *mtd, int ecc_opt)
-{
- pr_err("CONFIG_MTD_NAND_OMAP_BCH is not enabled\n");
- return -1;
-}
static int omap3_init_bch_tail(struct mtd_info *mtd)
{
return -1;
@@ -1818,7 +1748,7 @@ static int omap3_init_bch_tail(struct mtd_info *mtd)
static void omap3_free_bch(struct mtd_info *mtd)
{
}
-#endif /* CONFIG_MTD_NAND_OMAP_BCH */
+#endif /* CONFIG_MTD_NAND_ECC_BCH */
static int omap_nand_probe(struct platform_device *pdev)
{
@@ -1851,15 +1781,14 @@ static int omap_nand_probe(struct platform_device *pdev)
info->pdev = pdev;
info->gpmc_cs = pdata->cs;
info->reg = pdata->reg;
+ info->bch = NULL;
+ info->of_node = pdata->of_node;
mtd = &info->mtd;
mtd->priv = &info->nand;
mtd->name = dev_name(&pdev->dev);
mtd->owner = THIS_MODULE;
nand_chip = &info->nand;
nand_chip->options |= NAND_SKIP_BBTSCAN;
-#ifdef CONFIG_MTD_NAND_OMAP_BCH
- info->of_node = pdata->of_node;
-#endif
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
@@ -2001,22 +1930,125 @@ static int omap_nand_probe(struct platform_device *pdev)
goto out_release_mem_region;
}
- /* select the ecc type */
- if (pdata->ecc_opt == OMAP_ECC_HAM1_CODE_HW) {
+ /* populate MTD interface based on ECC scheme */
+ switch (pdata->ecc_opt) {
+ case OMAP_ECC_HAM1_CODE_HW:
+ pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n");
+ nand_chip->ecc.mode = NAND_ECC_HW;
nand_chip->ecc.bytes = 3;
nand_chip->ecc.size = 512;
nand_chip->ecc.strength = 1;
nand_chip->ecc.calculate = omap_calculate_ecc;
nand_chip->ecc.hwctl = omap_enable_hwecc;
nand_chip->ecc.correct = omap_correct_data;
- nand_chip->ecc.mode = NAND_ECC_HW;
- } else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
- (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {
- err = omap3_init_bch(mtd, pdata->ecc_opt);
- if (err) {
+ break;
+
+ case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
+#ifdef CONFIG_MTD_NAND_ECC_BCH
+ pr_info("nand: using OMAP_ECC_BCH4_CODE_HW_DETECTION_SW\n");
+ nand_chip->ecc.mode = NAND_ECC_HW;
+ nand_chip->ecc.size = 512;
+ nand_chip->ecc.bytes = 7;
+ nand_chip->ecc.strength = 4;
+ nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
+ nand_chip->ecc.correct = omap3_correct_data_bch;
+ nand_chip->ecc.calculate = omap3_calculate_ecc_bch4;
+ /* software bch library is used for locating errors */
+ info->bch = init_bch(nand_chip->ecc.bytes,
+ nand_chip->ecc.strength,
+ OMAP_ECC_BCH8_POLYNOMIAL);
+ if (!info->bch) {
+ pr_err("nand: error: unable to use s/w BCH library\n");
err = -EINVAL;
+ }
+ break;
+#else
+ pr_err("nand: error: CONFIG_MTD_NAND_ECC_BCH not enabled\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+#endif
+
+ case OMAP_ECC_BCH4_CODE_HW:
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
+ pr_info("nand: using OMAP_ECC_BCH4_CODE_HW ECC scheme\n");
+ nand_chip->ecc.mode = NAND_ECC_HW;
+ nand_chip->ecc.size = 512;
+ /* 14th bit is kept reserved for ROM-code compatibility */
+ nand_chip->ecc.bytes = 7 + 1;
+ nand_chip->ecc.strength = 4;
+ nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
+ nand_chip->ecc.correct = omap_elm_correct_data;
+ nand_chip->ecc.calculate = omap3_calculate_ecc_bch;
+ nand_chip->ecc.read_page = omap_read_page_bch;
+ nand_chip->ecc.write_page = omap_write_page_bch;
+ /* This ECC scheme requires ELM H/W block */
+ if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {
+ pr_err("nand: error: could not initialize ELM\n");
+ err = -ENODEV;
goto out_release_mem_region;
}
+ break;
+#else
+ pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+#endif
+
+ case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+#ifdef CONFIG_MTD_NAND_ECC_BCH
+ pr_info("nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW\n");
+ nand_chip->ecc.mode = NAND_ECC_HW;
+ nand_chip->ecc.size = 512;
+ nand_chip->ecc.bytes = 13;
+ nand_chip->ecc.strength = 8;
+ nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
+ nand_chip->ecc.correct = omap3_correct_data_bch;
+ nand_chip->ecc.calculate = omap3_calculate_ecc_bch8;
+ /* software bch library is used for locating errors */
+ info->bch = init_bch(nand_chip->ecc.bytes,
+ nand_chip->ecc.strength,
+ OMAP_ECC_BCH8_POLYNOMIAL);
+ if (!info->bch) {
+ pr_err("nand: error: unable to use s/w BCH library\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+ }
+ break;
+#else
+ pr_err("nand: error: CONFIG_MTD_NAND_ECC_BCH not enabled\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+#endif
+
+ case OMAP_ECC_BCH8_CODE_HW:
+#ifdef CONFIG_MTD_NAND_OMAP_BCH
+ pr_info("nand: using OMAP_ECC_BCH8_CODE_HW ECC scheme\n");
+ nand_chip->ecc.mode = NAND_ECC_HW;
+ nand_chip->ecc.size = 512;
+ /* 14th bit is kept reserved for ROM-code compatibility */
+ nand_chip->ecc.bytes = 13 + 1;
+ nand_chip->ecc.strength = 8;
+ nand_chip->ecc.hwctl = omap3_enable_hwecc_bch;
+ nand_chip->ecc.correct = omap_elm_correct_data;
+ nand_chip->ecc.calculate = omap3_calculate_ecc_bch;
+ nand_chip->ecc.read_page = omap_read_page_bch;
+ nand_chip->ecc.write_page = omap_write_page_bch;
+ /* This ECC scheme requires ELM H/W block */
+ if (is_elm_present(info, pdata->elm_of_node, BCH8_ECC) < 0) {
+ pr_err("nand: error: could not initialize ELM\n");
+ goto out_release_mem_region;
+ }
+ break;
+#else
+ pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
+#endif
+
+ default:
+ pr_err("nand: error: invalid or unsupported ECC scheme\n");
+ err = -EINVAL;
+ goto out_release_mem_region;
}
/* rom code layout */
@@ -2038,6 +2070,8 @@ static int omap_nand_probe(struct platform_device *pdev)
nand_chip->ecc.layout = &omap_oobinfo;
} else if ((pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW) ||
+ (pdata->ecc_opt == OMAP_ECC_BCH4_CODE_HW_DETECTION_SW) ||
+ (pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW_DETECTION_SW) ||
(pdata->ecc_opt == OMAP_ECC_BCH8_CODE_HW)) {
/* build OOB layout for BCH ECC correction */
err = omap3_init_bch_tail(mtd);
@@ -2070,6 +2104,7 @@ out_release_mem_region:
free_irq(info->gpmc_irq_fifo, info);
release_mem_region(info->phys_base, info->mem_size);
out_free_info:
+ omap3_free_bch(mtd);
kfree(info);
return err;
--
1.8.1
--
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