mtd: mtd_nandecctest: rewrite the test routine

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=6060fb42a0bf93015d05c1a857b94894936f40ee
Commit:     6060fb42a0bf93015d05c1a857b94894936f40ee
Parent:     c092b43906098a6879d0fa9f74e5141516b9b856
Author:     Akinobu Mita <akinobu.mita at gmail.com>
AuthorDate: Sat Sep 8 01:48:07 2012 +0900
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Sat Sep 29 15:47:37 2012 +0100

    mtd: mtd_nandecctest: rewrite the test routine
    
    This rewrites the entire test routine in order to make it easy to add more
    tests by later changes and minimize duplication of each tests as much as
    possible.
    
    Now that each test is described by the members of struct nand_ecc_test:
    - name: descriptive testname
    - prepare: function to prepare data block and ecc with artifical corruption
    - verify: function to verify the result of correcting data block
    
    Signed-off-by: Akinobu Mita <akinobu.mita at gmail.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/tests/mtd_nandecctest.c |   93 ++++++++++++++++++++++++++---------
 1 files changed, 70 insertions(+), 23 deletions(-)

diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
index d90daf8..204f796ed 100644
--- a/drivers/mtd/tests/mtd_nandecctest.c
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -7,8 +7,24 @@
 #include <linux/slab.h>
 #include <linux/mtd/nand_ecc.h>
 
+/*
+ * Test the implementation for software ECC
+ *
+ * No actual MTD device is needed, So we don't need to warry about losing
+ * important data by human error.
+ *
+ * This covers possible patterns of corruption which can be reliably corrected
+ * or detected.
+ */
+
 #if defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE)
 
+struct nand_ecc_test {
+	const char *name;
+	void (*prepare)(void *, void *, void *, void *, const size_t);
+	int (*verify)(void *, void *, void *, const size_t);
+};
+
 /*
  * The reason for this __change_bit_le() instead of __change_bit() is to inject
  * bit error properly within the region which is not a multiple of
@@ -23,13 +39,44 @@
 #error "Unknown byte order"
 #endif
 
-static void inject_single_bit_error(void *data, size_t size)
+static void single_bit_error_data(void *error_data, void *correct_data,
+				size_t size)
 {
 	unsigned int offset = random32() % (size * BITS_PER_BYTE);
 
-	__change_bit_le(offset, data);
+	memcpy(error_data, correct_data, size);
+	__change_bit_le(offset, error_data);
+}
+
+static void single_bit_error_in_data(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	single_bit_error_data(error_data, correct_data, size);
+	memcpy(error_ecc, correct_ecc, 3);
+}
+
+static int single_bit_error_correct(void *error_data, void *error_ecc,
+				void *correct_data, const size_t size)
+{
+	unsigned char calc_ecc[3];
+	int ret;
+
+	__nand_calculate_ecc(error_data, size, calc_ecc);
+	ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+	if (ret == 1 && !memcmp(correct_data, error_data, size))
+		return 0;
+
+	return -EINVAL;
 }
 
+static const struct nand_ecc_test nand_ecc_test[] = {
+	{
+		.name = "single-bit-error-in-data-correct",
+		.prepare = single_bit_error_in_data,
+		.verify = single_bit_error_correct,
+	},
+};
+
 static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,
 			void *correct_ecc, const size_t size)
 {
@@ -46,14 +93,14 @@ static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,
 			DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false);
 }
 
-static int nand_ecc_test(const size_t size)
+static int nand_ecc_test_run(const size_t size)
 {
+	int i;
 	int err = 0;
 	void *error_data;
 	void *error_ecc;
 	void *correct_data;
 	void *correct_ecc;
-	char testname[30];
 
 	error_data = kmalloc(size, GFP_KERNEL);
 	error_ecc = kmalloc(3, GFP_KERNEL);
@@ -65,25 +112,25 @@ static int nand_ecc_test(const size_t size)
 		goto error;
 	}
 
-	sprintf(testname, "nand-ecc-%zu", size);
-
 	get_random_bytes(correct_data, size);
-
-	memcpy(error_data, correct_data, size);
-	inject_single_bit_error(error_data, size);
-
 	__nand_calculate_ecc(correct_data, size, correct_ecc);
-	__nand_calculate_ecc(error_data, size, error_ecc);
-	__nand_correct_data(error_data, correct_ecc, error_ecc, size);
-
-	if (memcmp(correct_data, error_data, size)) {
-		pr_err("mtd_nandecctest: not ok - %s\n", testname);
-		dump_data_ecc(error_data, error_ecc, correct_data, correct_ecc,
-				size);
-		err = -EINVAL;
-		goto error;
+
+	for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
+		nand_ecc_test[i].prepare(error_data, error_ecc,
+				correct_data, correct_ecc, size);
+		err = nand_ecc_test[i].verify(error_data, error_ecc,
+						correct_data, size);
+
+		if (err) {
+			pr_err("mtd_nandecctest: not ok - %s-%zd\n",
+				nand_ecc_test[i].name, size);
+			dump_data_ecc(error_data, error_ecc,
+				correct_data, correct_ecc, size);
+			break;
+		}
+		pr_info("mtd_nandecctest: ok - %s-%zd\n",
+			nand_ecc_test[i].name, size);
 	}
-	pr_info("mtd_nandecctest: ok - %s\n", testname);
 error:
 	kfree(error_data);
 	kfree(error_ecc);
@@ -95,7 +142,7 @@ error:
 
 #else
 
-static int nand_ecc_test(const size_t size)
+static int nand_ecc_test_run(const size_t size)
 {
 	return 0;
 }
@@ -106,11 +153,11 @@ static int __init ecc_test_init(void)
 {
 	int err;
 
-	err = nand_ecc_test(256);
+	err = nand_ecc_test_run(256);
 	if (err)
 		return err;
 
-	return nand_ecc_test(512);
+	return nand_ecc_test_run(512);
 }
 
 static void __exit ecc_test_exit(void)