1 // SPDX-License-Identifier: GPL-2.0-only
6  * Test for multi-bit error recovery on a NAND page This mostly tests the
11  *	0 - artificially inserting bit errors until the ECC fails
15  *	1 - re-writing the same pattern repeatedly until the ECC fails.
17  *	    generate '0' bits if '1' has been written sufficient times.
55 MODULE_PARM_DESC(mode, "0=incremental errors, 1=overwrite test");
85 	c = (c & 0x55) << 1 | (c & 0xAA) >> 1;  in hash()
95 	return mtdtest_write(mtd, offset, mtd->writesize, wbuffer);  in write_page()
98 /* Re-writes the data area while leaving the OOB alone. */
108 	ops.len       = mtd->writesize;  in rewrite_page()
117 	if (err || ops.retlen != mtd->writesize) {  in rewrite_page()
118 		pr_err("error: write_oob failed (%d)\n", err);  in rewrite_page()
120 			err = -EIO;  in rewrite_page()
138 	memcpy(&oldstats, &mtd->ecc_stats, sizeof(oldstats));  in read_page()
140 	err = mtd_read(mtd, offset, mtd->writesize, &read, rbuffer);  in read_page()
141 	if (!err || err == -EUCLEAN)  in read_page()
142 		err = mtd->ecc_stats.corrected - oldstats.corrected;  in read_page()
144 	if (err < 0 || read != mtd->writesize) {  in read_page()
147 			err = -EIO;  in read_page()
161 	for (i = 0; i < mtd->writesize; i++) {  in verify_page()
170 		return -EIO;  in verify_page()
175 #define CBIT(v, n) ((v) & (1 << (n)))
176 #define BCLR(v, n) ((v) = (v) & ~(1 << (n)))
178 /* Finds the first '1' bit in wbuffer starting at offset 'byte'
184 	while (byte < mtd->writesize) {  in insert_biterror()
185 		for (bit = 7; bit >= 0; bit--) {  in insert_biterror()
194 	pr_err("biterror: Failed to find a '1' bit\n");  in insert_biterror()
195 	return -EIO;  in insert_biterror()
208 	for (i = 0; i < mtd->writesize; i++)  in incremental_errors_test()
211 	err = write_page(1);  in incremental_errors_test()
215 	while (1) {  in incremental_errors_test()
217 		err = rewrite_page(1);  in incremental_errors_test()
221 		err = read_page(1);  in incremental_errors_test()
223 			pr_info("Read reported %d corrected bit errors\n", err);  in incremental_errors_test()
225 			pr_err("After %d biterrors per subpage, read reported error %d\n",  in incremental_errors_test()
231 		err = verify_page(1);  in incremental_errors_test()
237 		pr_info("Successfully corrected %d bit errors per subpage\n",  in incremental_errors_test()
253 /* Writes 'random' data to page and then re-writes that same data repeatedly.
254    This eventually develops bit errors (bits written as '1' will slowly become
265 	static unsigned bitstats[MAXBITS]; /* bit error histogram. */  in overwrite_test()
271 	for (i = 0; i < mtd->writesize; i++)  in overwrite_test()
274 	err = write_page(1);  in overwrite_test()
288 				err = -EIO;  in overwrite_test()
294 				pr_info("Read reported %d corrected bit errors\n",  in overwrite_test()
298 			pr_info("Read reported error %d\n", err);  in overwrite_test()
318 	 * errors, bitstats[1] the number of ops with 1 bit error, etc. */  in overwrite_test()
319 	pr_info("Bit error histogram (%d operations total):\n", opno);  in overwrite_test()
321 		pr_info("Page reads with %3d corrected bit errors: %d\n",  in overwrite_test()
334 	pr_info("MTD device: %d\n", dev);  in mtd_nandbiterrs_init()
345 		err = -ENODEV;  in mtd_nandbiterrs_init()
350 		(unsigned long long)mtd->size, mtd->erasesize,  in mtd_nandbiterrs_init()
351 		mtd->writesize, mtd->oobsize);  in mtd_nandbiterrs_init()
353 	subsize  = mtd->writesize >> mtd->subpage_sft;  in mtd_nandbiterrs_init()
354 	subcount = mtd->writesize / subsize;  in mtd_nandbiterrs_init()
356 	pr_info("Device uses %d subpages of %d bytes\n", subcount, subsize);  in mtd_nandbiterrs_init()
358 	offset     = (loff_t)page_offset * mtd->writesize;  in mtd_nandbiterrs_init()
364 	wbuffer = kmalloc(mtd->writesize, GFP_KERNEL);  in mtd_nandbiterrs_init()
366 		err = -ENOMEM;  in mtd_nandbiterrs_init()
370 	rbuffer = kmalloc(mtd->writesize, GFP_KERNEL);  in mtd_nandbiterrs_init()
372 		err = -ENOMEM;  in mtd_nandbiterrs_init()
388 	/* We leave the block un-erased in case of test failure. */  in mtd_nandbiterrs_init()
393 	err = -EIO;  in mtd_nandbiterrs_init()