xref: /openbmc/linux/drivers/mtd/nand/raw/nand_esmt.c (revision 63705da3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2018 Toradex AG
4  *
5  * Author: Marcel Ziswiler <marcel.ziswiler@toradex.com>
6  */
7 
8 #include <linux/mtd/rawnand.h>
9 #include "internals.h"
10 
11 static void esmt_nand_decode_id(struct nand_chip *chip)
12 {
13 	struct nand_device *base = &chip->base;
14 	struct nand_ecc_props requirements = {};
15 
16 	nand_decode_ext_id(chip);
17 
18 	/* Extract ECC requirements from 5th id byte. */
19 	if (chip->id.len >= 5 && nand_is_slc(chip)) {
20 		requirements.step_size = 512;
21 		switch (chip->id.data[4] & 0x3) {
22 		case 0x0:
23 			requirements.strength = 4;
24 			break;
25 		case 0x1:
26 			requirements.strength = 2;
27 			break;
28 		case 0x2:
29 			requirements.strength = 1;
30 			break;
31 		default:
32 			WARN(1, "Could not get ECC info");
33 			requirements.step_size = 0;
34 			break;
35 		}
36 	}
37 
38 	nanddev_set_ecc_requirements(base, &requirements);
39 }
40 
41 static int esmt_nand_init(struct nand_chip *chip)
42 {
43 	if (nand_is_slc(chip))
44 		/*
45 		 * It is known that some ESMT SLC NANDs have been shipped
46 		 * with the factory bad block markers in the first or last page
47 		 * of the block, instead of the first or second page. To be on
48 		 * the safe side, let's check all three locations.
49 		 */
50 		chip->options |= NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE |
51 				 NAND_BBM_LASTPAGE;
52 
53 	return 0;
54 }
55 
56 const struct nand_manufacturer_ops esmt_nand_manuf_ops = {
57 	.detect = esmt_nand_decode_id,
58 	.init = esmt_nand_init,
59 };
60