1 files changed, 70 insertions, 23 deletions

diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
index d90daf879c46..204f796ed3e7 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)