[PATCH 1/2] mtd: Add __nand_calculate_ecc() to NAND ECC functions

[PATCH 1/2] mtd: Add __nand_calculate_ecc() to NAND ECC functions

[Akinobu Mita]

Add __nand_calculate_ecc() which does not take struct mtd_info.
The built-in 256/512 software ECC calculation and correction tester
will use it.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/nand/nand_ecc.c  |   25 ++++++++++++++++++++-----
 include/linux/mtd/nand_ecc.h |    6 ++++++
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/nand_ecc.c b/drivers/mtd/nand/nand_ecc.c
index db7ae9d..809fb53 100644
--- a/drivers/mtd/nand/nand_ecc.c
+++ b/drivers/mtd/nand/nand_ecc.c
@@ -150,20 +150,19 @@ static const char addressbits[256] = {
 };
 
 /**
- * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
+ * __nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
  *			 block
- * @mtd:	MTD block structure
  * @buf:	input buffer with raw data
+ * @eccsize:	data bytes per ecc step (256 or 512)
  * @code:	output buffer with ECC
  */
-int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
+void __nand_calculate_ecc(const unsigned char *buf, unsigned int eccsize,
 		       unsigned char *code)
 {
 	int i;
 	const uint32_t *bp = (uint32_t *)buf;
 	/* 256 or 512 bytes/ecc  */
-	const uint32_t eccsize_mult =
-			(((struct nand_chip *)mtd->priv)->ecc.size) >> 8;
+	const uint32_t eccsize_mult = eccsize >> 8;
 	uint32_t cur;		/* current value in buffer */
 	/* rp0..rp15..rp17 are the various accumulated parities (per byte) */
 	uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7;
@@ -412,6 +411,22 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
 		    (invparity[par & 0x55] << 2) |
 		    (invparity[rp17] << 1) |
 		    (invparity[rp16] << 0);
+}
+EXPORT_SYMBOL(__nand_calculate_ecc);
+
+/**
+ * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
+ *			 block
+ * @mtd:	MTD block structure
+ * @buf:	input buffer with raw data
+ * @code:	output buffer with ECC
+ */
+int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
+		       unsigned char *code)
+{
+	__nand_calculate_ecc(buf,
+			((struct nand_chip *)mtd->priv)->ecc.size, code);
+
 	return 0;
 }
 EXPORT_SYMBOL(nand_calculate_ecc);
diff --git a/include/linux/mtd/nand_ecc.h b/include/linux/mtd/nand_ecc.h
index 052ea8c..9cb10ff 100644
--- a/include/linux/mtd/nand_ecc.h
+++ b/include/linux/mtd/nand_ecc.h
@@ -16,6 +16,12 @@
 struct mtd_info;
 
 /*
+ * Calculate 3 byte ECC code for eccsize byte block
+ */
+void __nand_calculate_ecc(const u_char *dat, unsigned int eccsize,
+				u_char *ecc_code);
+
+/*
  * Calculate 3 byte ECC code for 256 byte block
  */
 int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code);
-- 
1.5.4.3

[PATCH 2/2] MTD: Add nand_ecc test module

[Akinobu Mita]

This module tests NAND ECC functions.

The test is simple.

1. Create a 256 or 512 bytes block of data filled with random bytes (data)
2. Duplicate the data block and inject single bit error (error_data)
3. Try to correct error_data
4. Compare data and error_data

This test is added into new MTD test group called MTD NAND test
which requires MTD NAND device support.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
---
 drivers/mtd/Kconfig               |    6 +++
 drivers/mtd/tests/Makefile        |    1 +
 drivers/mtd/tests/nand_ecc-test.c |   88 +++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/tests/nand_ecc-test.c

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index ecf90f5..abe5c7f 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -33,6 +33,12 @@ config MTD_TESTS
 	  should normally be compiled as kernel modules. The modules perform
 	  various checks and verifications when loaded.
 
+config MTD_NAND_TESTS
+	tristate "MTD NAND tests support"
+	depends on MTD_TESTS && MTD_NAND
+	help
+	  This option enables MTD tests which require NAND Device support.
+
 config MTD_CONCAT
 	tristate "MTD concatenating support"
 	help
diff --git a/drivers/mtd/tests/Makefile b/drivers/mtd/tests/Makefile
index c1d5013..3994d5a 100644
--- a/drivers/mtd/tests/Makefile
+++ b/drivers/mtd/tests/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_MTD_TESTS) += mtd_speedtest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_stresstest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_subpagetest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_torturetest.o
+obj-$(CONFIG_MTD_NAND_TESTS) += nand_ecc-test.o
diff --git a/drivers/mtd/tests/nand_ecc-test.c b/drivers/mtd/tests/nand_ecc-test.c
new file mode 100644
index 0000000..54bbb4a
--- /dev/null
+++ b/drivers/mtd/tests/nand_ecc-test.c
@@ -0,0 +1,88 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/string.h>
+#include <linux/bitops.h>
+#include <linux/jiffies.h>
+
+void inject_single_bit_error(void *data, size_t size)
+{
+	unsigned long offset = random32() % (size * BITS_PER_BYTE);
+
+	__change_bit(offset, data);
+}
+
+#if defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE)
+
+#include <linux/mtd/nand_ecc.h>
+
+static unsigned char data[512];
+static unsigned char error_data[512];
+
+static int nand_ecc_test(const size_t size)
+{
+	unsigned char code[3];
+	unsigned char error_code[3];
+	char testname[30];
+
+	BUG_ON(sizeof(data) < size);
+
+	sprintf(testname, "nand-ecc-%zu", size);
+
+	get_random_bytes(data, size);
+
+	memcpy(error_data, data, size);
+	inject_single_bit_error(error_data, size);
+
+	__nand_calculate_ecc(data, size, code);
+	__nand_calculate_ecc(error_data, size, error_code);
+	__nand_correct_data(error_data, code, error_code, size);
+
+	if (!memcmp(data, error_data, size)) {
+		printk(KERN_INFO "nand_ecc-test: ok - %s\n", testname);
+		return 0;
+	}
+
+	printk(KERN_ERR "nand_ecc-test: not ok - %s\n", testname);
+
+	printk(KERN_DEBUG "hexdump of data:\n");
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
+			data, size, false);
+	printk(KERN_DEBUG "hexdump of error data:\n");
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
+			error_data, size, false);
+
+	return -1;
+}
+
+#else
+
+static int nand_ecc_test(const size_t size)
+{
+	return 0;
+}
+
+#endif
+
+static int __init ecc_test_init(void)
+{
+	srandom32(jiffies);
+
+	nand_ecc_test(256);
+	nand_ecc_test(512);
+
+	return 0;
+}
+
+static void __exit ecc_test_exit(void)
+{
+}
+
+module_init(ecc_test_init);
+module_exit(ecc_test_exit);
+
+MODULE_DESCRIPTION("ECC test module");
+MODULE_AUTHOR("Akinobu Mita");
+MODULE_LICENSE("GPL");
-- 
1.5.4.3

Re: [PATCH 2/2] MTD: Add nand_ecc test module

[Akinobu Mita]

On Mon, Oct 19, 2009 at 03:11:46PM +0900, Akinobu Mita wrote:
> This module tests NAND ECC functions.
> 
> The test is simple.
> 
> 1. Create a 256 or 512 bytes block of data filled with random bytes (data)
> 2. Duplicate the data block and inject single bit error (error_data)
> 3. Try to correct error_data
> 4. Compare data and error_data
> 
> This test is added into new MTD test group called MTD NAND test
> which requires MTD NAND device support.
> 

...

> +
> +#if defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE)
> +

Oops. I forgot to remove this ifdefs.

[PATCH 2/2 -v2] MTD: Add nand_ecc test module

[Akinobu Mita]

* v2 changes
- remove ifdef
- make inject_single_bit_error static

This module tests NAND ECC functions.

The test is simple.

1. Create a 256 or 512 bytes block of data filled with random bytes (data)
2. Duplicate the data block and inject single bit error (error_data)
3. Try to correct error_data
4. Compare data and error_data

This test is added into new MTD test group called MTD NAND test
which requires MTD NAND device support.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
---
 drivers/mtd/Kconfig               |    6 +++
 drivers/mtd/tests/Makefile        |    1 +
 drivers/mtd/tests/nand_ecc-test.c |   76 +++++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mtd/tests/nand_ecc-test.c

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index ecf90f5..abe5c7f 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -33,6 +33,12 @@ config MTD_TESTS
 	  should normally be compiled as kernel modules. The modules perform
 	  various checks and verifications when loaded.
 
+config MTD_NAND_TESTS
+	tristate "MTD NAND tests support"
+	depends on MTD_TESTS && MTD_NAND
+	help
+	  This option enables MTD tests which require NAND Device support.
+
 config MTD_CONCAT
 	tristate "MTD concatenating support"
 	help
diff --git a/drivers/mtd/tests/Makefile b/drivers/mtd/tests/Makefile
index c1d5013..3994d5a 100644
--- a/drivers/mtd/tests/Makefile
+++ b/drivers/mtd/tests/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_MTD_TESTS) += mtd_speedtest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_stresstest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_subpagetest.o
 obj-$(CONFIG_MTD_TESTS) += mtd_torturetest.o
+obj-$(CONFIG_MTD_NAND_TESTS) += nand_ecc-test.o
diff --git a/drivers/mtd/tests/nand_ecc-test.c b/drivers/mtd/tests/nand_ecc-test.c
new file mode 100644
index 0000000..6244f80
--- /dev/null
+++ b/drivers/mtd/tests/nand_ecc-test.c
@@ -0,0 +1,76 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/string.h>
+#include <linux/bitops.h>
+#include <linux/jiffies.h>
+#include <linux/mtd/nand_ecc.h>
+
+static void inject_single_bit_error(void *data, size_t size)
+{
+	unsigned long offset = random32() % (size * BITS_PER_BYTE);
+
+	__change_bit(offset, data);
+}
+
+static unsigned char data[512];
+static unsigned char error_data[512];
+
+static int nand_ecc_test(const size_t size)
+{
+	unsigned char code[3];
+	unsigned char error_code[3];
+	char testname[30];
+
+	BUG_ON(sizeof(data) < size);
+
+	sprintf(testname, "nand-ecc-%zu", size);
+
+	get_random_bytes(data, size);
+
+	memcpy(error_data, data, size);
+	inject_single_bit_error(error_data, size);
+
+	__nand_calculate_ecc(data, size, code);
+	__nand_calculate_ecc(error_data, size, error_code);
+	__nand_correct_data(error_data, code, error_code, size);
+
+	if (!memcmp(data, error_data, size)) {
+		printk(KERN_INFO "nand_ecc-test: ok - %s\n", testname);
+		return 0;
+	}
+
+	printk(KERN_ERR "nand_ecc-test: not ok - %s\n", testname);
+
+	printk(KERN_DEBUG "hexdump of data:\n");
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
+			data, size, false);
+	printk(KERN_DEBUG "hexdump of error data:\n");
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
+			error_data, size, false);
+
+	return -1;
+}
+
+static int __init ecc_test_init(void)
+{
+	srandom32(jiffies);
+
+	nand_ecc_test(256);
+	nand_ecc_test(512);
+
+	return 0;
+}
+
+static void __exit ecc_test_exit(void)
+{
+}
+
+module_init(ecc_test_init);
+module_exit(ecc_test_exit);
+
+MODULE_DESCRIPTION("ECC test module");
+MODULE_AUTHOR("Akinobu Mita");
+MODULE_LICENSE("GPL");
-- 
1.5.4.3

Re: [PATCH 2/2] MTD: Add nand_ecc test module

[Artem Bityutskiy]

On Mon, 2009-10-19 at 15:11 +0900, Akinobu Mita wrote:
> This module tests NAND ECC functions.
> 
> The test is simple.
> 
> 1. Create a 256 or 512 bytes block of data filled with random bytes (data)
> 2. Duplicate the data block and inject single bit error (error_data)
> 3. Try to correct error_data
> 4. Compare data and error_data
> 
> This test is added into new MTD test group called MTD NAND test
> which requires MTD NAND device support.
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: linux-mtd@lists.infradead.org
> Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> ---
>  drivers/mtd/Kconfig               |    6 +++
>  drivers/mtd/tests/Makefile        |    1 +
>  drivers/mtd/tests/nand_ecc-test.c |   88 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 95 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/mtd/tests/nand_ecc-test.c
> 
> diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
> index ecf90f5..abe5c7f 100644
> --- a/drivers/mtd/Kconfig
> +++ b/drivers/mtd/Kconfig
> @@ -33,6 +33,12 @@ config MTD_TESTS
>  	  should normally be compiled as kernel modules. The modules perform
>  	  various checks and verifications when loaded.
>  
> +config MTD_NAND_TESTS
> +	tristate "MTD NAND tests support"
> +	depends on MTD_TESTS && MTD_NAND
> +	help
> +	  This option enables MTD tests which require NAND Device support.
> +
>  config MTD_CONCAT
>  	tristate "MTD concatenating support"
>  	help

Could this please be a separate patch? Also, some of the existing tests
are NAND only as well, so could do corresponding Makefile changes in the
same patch and move the to the MTD_NAND_TESTS set? The tests are:

mtd_oobtest.c
mtd_pagetest.c
mtd_subpagetest.c

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: [PATCH 2/2] MTD: Add nand_ecc test module

[Artem Bityutskiy]

On Tue, 2009-10-20 at 14:50 +0300, Artem Bityutskiy wrote:
> On Mon, 2009-10-19 at 15:11 +0900, Akinobu Mita wrote:
> > This module tests NAND ECC functions.
> > 
> > The test is simple.
> > 
> > 1. Create a 256 or 512 bytes block of data filled with random bytes (data)
> > 2. Duplicate the data block and inject single bit error (error_data)
> > 3. Try to correct error_data
> > 4. Compare data and error_data
> > 
> > This test is added into new MTD test group called MTD NAND test
> > which requires MTD NAND device support.
> > 
> > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> > Cc: David Woodhouse <dwmw2@infradead.org>
> > Cc: linux-mtd@lists.infradead.org
> > Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> > ---
> >  drivers/mtd/Kconfig               |    6 +++
> >  drivers/mtd/tests/Makefile        |    1 +
> >  drivers/mtd/tests/nand_ecc-test.c |   88 +++++++++++++++++++++++++++++++++++++
> >  3 files changed, 95 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/mtd/tests/nand_ecc-test.c
> > 
> > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
> > index ecf90f5..abe5c7f 100644
> > --- a/drivers/mtd/Kconfig
> > +++ b/drivers/mtd/Kconfig
> > @@ -33,6 +33,12 @@ config MTD_TESTS
> >  	  should normally be compiled as kernel modules. The modules perform
> >  	  various checks and verifications when loaded.
> >  
> > +config MTD_NAND_TESTS
> > +	tristate "MTD NAND tests support"
> > +	depends on MTD_TESTS && MTD_NAND
> > +	help
> > +	  This option enables MTD tests which require NAND Device support.
> > +
> >  config MTD_CONCAT
> >  	tristate "MTD concatenating support"
> >  	help
> 
> Could this please be a separate patch? Also, some of the existing tests
> are NAND only as well, so could do corresponding Makefile changes in the
> same patch and move the to the MTD_NAND_TESTS set? The tests are:
> 
> mtd_oobtest.c
> mtd_pagetest.c
> mtd_subpagetest.c

Err, and of course this patch has to be the _last_ in the series, to
preserve bisectability.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: [PATCH 2/2] MTD: Add nand_ecc test module

[Akinobu Mita]

On Tue, Oct 20, 2009 at 02:50:01PM +0300, Artem Bityutskiy wrote:
> > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
> > index ecf90f5..abe5c7f 100644
> > --- a/drivers/mtd/Kconfig
> > +++ b/drivers/mtd/Kconfig
> > @@ -33,6 +33,12 @@ config MTD_TESTS
> >  	  should normally be compiled as kernel modules. The modules perform
> >  	  various checks and verifications when loaded.
> >  
> > +config MTD_NAND_TESTS
> > +	tristate "MTD NAND tests support"
> > +	depends on MTD_TESTS && MTD_NAND
> > +	help
> > +	  This option enables MTD tests which require NAND Device support.
> > +
> >  config MTD_CONCAT
> >  	tristate "MTD concatenating support"
> >  	help
> 
> Could this please be a separate patch? Also, some of the existing tests
> are NAND only as well, so could do corresponding Makefile changes in the
> same patch and move the to the MTD_NAND_TESTS set? The tests are:
> 
> mtd_oobtest.c
> mtd_pagetest.c
> mtd_subpagetest.c

Should these MTD NAND tests support OneNAND device, too?

If so, the config with !CONFIG_MTD_NAND && MTD_ONENAND=m cannot select
this new MTD_NAND_TESTS. So Kconfig dependency should be:

config MTD_NAND_TESTS
        tristate "MTD NAND tests support"
        depends on MTD_TEST
        depends on MTD_NAND || MTD_ONENAND

But nand_ecc-test obviously needs CONFIG_MTD_NAND and cannot exist
in the same group.

Re: [PATCH 2/2] MTD: Add nand_ecc test module

[Artem Bityutskiy]

On Wed, 2009-10-21 at 06:46 +0200, ext Akinobu Mita wrote:
> On Tue, Oct 20, 2009 at 02:50:01PM +0300, Artem Bityutskiy wrote:
> > > diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
> > > index ecf90f5..abe5c7f 100644
> > > --- a/drivers/mtd/Kconfig
> > > +++ b/drivers/mtd/Kconfig
> > > @@ -33,6 +33,12 @@ config MTD_TESTS
> > >  	  should normally be compiled as kernel modules. The modules perform
> > >  	  various checks and verifications when loaded.
> > >  
> > > +config MTD_NAND_TESTS
> > > +	tristate "MTD NAND tests support"
> > > +	depends on MTD_TESTS && MTD_NAND
> > > +	help
> > > +	  This option enables MTD tests which require NAND Device support.
> > > +
> > >  config MTD_CONCAT
> > >  	tristate "MTD concatenating support"
> > >  	help
> > 
> > Could this please be a separate patch? Also, some of the existing tests
> > are NAND only as well, so could do corresponding Makefile changes in the
> > same patch and move the to the MTD_NAND_TESTS set? The tests are:
> > 
> > mtd_oobtest.c
> > mtd_pagetest.c
> > mtd_subpagetest.c
> 
> Should these MTD NAND tests support OneNAND device, too?
> 
> If so, the config with !CONFIG_MTD_NAND && MTD_ONENAND=m cannot select
> this new MTD_NAND_TESTS. So Kconfig dependency should be:
> 
> config MTD_NAND_TESTS
>         tristate "MTD NAND tests support"
>         depends on MTD_TEST
>         depends on MTD_NAND || MTD_ONENAND
> 
> But nand_ecc-test obviously needs CONFIG_MTD_NAND and cannot exist
> in the same group.

Oh, I see. May be your original idea with ifdefs in the code was not
bad at all :-) ?

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

Re: [PATCH 1/2] mtd: Add __nand_calculate_ecc() to NAND ECC functions

[vimal singh]

On Mon, Oct 19, 2009 at 11:41 AM, Akinobu Mita <akinobu.mita@gmail.com> wrote:
> Add __nand_calculate_ecc() which does not take struct mtd_info.
> The built-in 256/512 software ECC calculation and correction tester
> will use it.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> Cc: linux-mtd@lists.infradead.org
> ---
>  drivers/mtd/nand/nand_ecc.c  |   25 ++++++++++++++++++++-----
>  include/linux/mtd/nand_ecc.h |    6 ++++++
>  2 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mtd/nand/nand_ecc.c b/drivers/mtd/nand/nand_ecc.c
> index db7ae9d..809fb53 100644
> --- a/drivers/mtd/nand/nand_ecc.c
> +++ b/drivers/mtd/nand/nand_ecc.c
> @@ -150,20 +150,19 @@ static const char addressbits[256] = {
>  };
>
>  /**
> - * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
> + * __nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
>  *                      block
> - * @mtd:       MTD block structure
>  * @buf:       input buffer with raw data
> + * @eccsize:   data bytes per ecc step (256 or 512)
>  * @code:      output buffer with ECC
>  */
> -int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
> +void __nand_calculate_ecc(const unsigned char *buf, unsigned int eccsize,
>                       unsigned char *code)
>  {
>        int i;
>        const uint32_t *bp = (uint32_t *)buf;
>        /* 256 or 512 bytes/ecc  */
> -       const uint32_t eccsize_mult =
> -                       (((struct nand_chip *)mtd->priv)->ecc.size) >> 8;
> +       const uint32_t eccsize_mult = eccsize >> 8;
>        uint32_t cur;           /* current value in buffer */
>        /* rp0..rp15..rp17 are the various accumulated parities (per byte) */
>        uint32_t rp0, rp1, rp2, rp3, rp4, rp5, rp6, rp7;
> @@ -412,6 +411,22 @@ int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
>                    (invparity[par & 0x55] << 2) |
>                    (invparity[rp17] << 1) |
>                    (invparity[rp16] << 0);
> +}
> +EXPORT_SYMBOL(__nand_calculate_ecc);
> +
> +/**
> + * nand_calculate_ecc - [NAND Interface] Calculate 3-byte ECC for 256/512-byte
> + *                      block
> + * @mtd:       MTD block structure
> + * @buf:       input buffer with raw data
> + * @code:      output buffer with ECC
> + */
> +int nand_calculate_ecc(struct mtd_info *mtd, const unsigned char *buf,
> +                      unsigned char *code)
> +{
> +       __nand_calculate_ecc(buf,
> +                       ((struct nand_chip *)mtd->priv)->ecc.size, code);
> +
>        return 0;
>  }
>  EXPORT_SYMBOL(nand_calculate_ecc);
> diff --git a/include/linux/mtd/nand_ecc.h b/include/linux/mtd/nand_ecc.h
> index 052ea8c..9cb10ff 100644
> --- a/include/linux/mtd/nand_ecc.h
> +++ b/include/linux/mtd/nand_ecc.h
> @@ -16,6 +16,12 @@
>  struct mtd_info;
>
>  /*
> + * Calculate 3 byte ECC code for eccsize byte block
> + */
> +void __nand_calculate_ecc(const u_char *dat, unsigned int eccsize,
> +                               u_char *ecc_code);
> +
> +/*
>  * Calculate 3 byte ECC code for 256 byte block
>  */
Could you please correct above comment too?

-- 
Regards,
Vimal Singh


>  int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code);
> --
> 1.5.4.3
>
>
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