mtd: add nand_ecc test module

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

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/tests/Makefile b/drivers/mtd/tests/Makefile
index c1d5013..b44dcab 100644 (file)
--- 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_TESTS) += mtd_nandecctest.o

diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
new file mode 100644 (file)
index 0000000..c1f3105
--- /dev/null
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -0,0 +1,87 @@
+#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>
+
+#if defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE)
+
+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 "mtd_nandecctest: ok - %s\n", testname);
+               return 0;
+       }
+
+       printk(KERN_ERR "mtd_nandecctest: 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("NAND ECC function test module");
+MODULE_AUTHOR("Akinobu Mita");
+MODULE_LICENSE("GPL");