1 /*
2  * Copyright (C) 2017 Free Electrons
3  * Copyright (C) 2017 NextThing Co
4  *
5  * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17 
18 #include <linux/mtd/rawnand.h>
19 
20 static void toshiba_nand_decode_id(struct nand_chip *chip)
21 {
22 	struct mtd_info *mtd = nand_to_mtd(chip);
23 
24 	nand_decode_ext_id(chip);
25 
26 	/*
27 	 * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
28 	 * 512B page. For Toshiba SLC, we decode the 5th/6th byte as
29 	 * follows:
30 	 * - ID byte 6, bits[2:0]: 100b -> 43nm, 101b -> 32nm,
31 	 *                         110b -> 24nm
32 	 * - ID byte 5, bit[7]:    1 -> BENAND, 0 -> raw SLC
33 	 */
34 	if (chip->id.len >= 6 && nand_is_slc(chip) &&
35 	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
36 	    !(chip->id.data[4] & 0x80) /* !BENAND */)
37 		mtd->oobsize = 32 * mtd->writesize >> 9;
38 
39 	/*
40 	 * Extract ECC requirements from 6th id byte.
41 	 * For Toshiba SLC, ecc requrements are as follows:
42 	 *  - 43nm: 1 bit ECC for each 512Byte is required.
43 	 *  - 32nm: 4 bit ECC for each 512Byte is required.
44 	 *  - 24nm: 8 bit ECC for each 512Byte is required.
45 	 */
46 	if (chip->id.len >= 6 && nand_is_slc(chip)) {
47 		chip->ecc_step_ds = 512;
48 		switch (chip->id.data[5] & 0x7) {
49 		case 0x4:
50 			chip->ecc_strength_ds = 1;
51 			break;
52 		case 0x5:
53 			chip->ecc_strength_ds = 4;
54 			break;
55 		case 0x6:
56 			chip->ecc_strength_ds = 8;
57 			break;
58 		default:
59 			WARN(1, "Could not get ECC info");
60 			chip->ecc_step_ds = 0;
61 			break;
62 		}
63 	}
64 }
65 
66 static int toshiba_nand_init(struct nand_chip *chip)
67 {
68 	if (nand_is_slc(chip))
69 		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
70 
71 	return 0;
72 }
73 
74 const struct nand_manufacturer_ops toshiba_nand_manuf_ops = {
75 	.detect = toshiba_nand_decode_id,
76 	.init = toshiba_nand_init,
77 };
78