xref: /openbmc/linux/drivers/mtd/nand/raw/nand_esmt.c (revision b23bf21f)
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 	nand_decode_ext_id(chip);
14 
15 	/* Extract ECC requirements from 5th id byte. */
16 	if (chip->id.len >= 5 && nand_is_slc(chip)) {
17 		chip->base.eccreq.step_size = 512;
18 		switch (chip->id.data[4] & 0x3) {
19 		case 0x0:
20 			chip->base.eccreq.strength = 4;
21 			break;
22 		case 0x1:
23 			chip->base.eccreq.strength = 2;
24 			break;
25 		case 0x2:
26 			chip->base.eccreq.strength = 1;
27 			break;
28 		default:
29 			WARN(1, "Could not get ECC info");
30 			chip->base.eccreq.step_size = 0;
31 			break;
32 		}
33 	}
34 }
35 
36 static int esmt_nand_init(struct nand_chip *chip)
37 {
38 	if (nand_is_slc(chip))
39 		/*
40 		 * It is known that some ESMT SLC NANDs have been shipped
41 		 * with the factory bad block markers in the first or last page
42 		 * of the block, instead of the first or second page. To be on
43 		 * the safe side, let's check all three locations.
44 		 */
45 		chip->options |= NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE |
46 				 NAND_BBM_LASTPAGE;
47 
48 	return 0;
49 }
50 
51 const struct nand_manufacturer_ops esmt_nand_manuf_ops = {
52 	.detect = esmt_nand_decode_id,
53 	.init = esmt_nand_init,
54 };
55