drivers/mtd/nand/raw/nand_samsung.c

Source file repositories/reference/linux-study-clean/drivers/mtd/nand/raw/nand_samsung.c

File Facts

System
Linux kernel
Corpus path
drivers/mtd/nand/raw/nand_samsung.c
Extension
.c
Size
3162 bytes
Lines
140
Domain
Driver Families
Bucket
drivers/mtd
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

switch (((extid >> 2) & 0x4) | (extid & 0x3)) {
		case 1:
			memorg->oobsize = 128;
			break;
		case 2:
			memorg->oobsize = 218;
			break;
		case 3:
			memorg->oobsize = 400;
			break;
		case 4:
			memorg->oobsize = 436;
			break;
		case 5:
			memorg->oobsize = 512;
			break;
		case 6:
			memorg->oobsize = 640;
			break;
		default:
			/*
			 * We should never reach this case, but if that
			 * happens, this probably means Samsung decided to use
			 * a different extended ID format, and we should find
			 * a way to support it.
			 */
			WARN(1, "Invalid OOB size value");
			break;
		}

		mtd->oobsize = memorg->oobsize;

		/* Get blocksize */
		extid >>= 2;
		memorg->pages_per_eraseblock = (128 * 1024) <<
					       (((extid >> 1) & 0x04) |
						(extid & 0x03)) /
					       memorg->pagesize;
		mtd->erasesize = (128 * 1024) <<
				 (((extid >> 1) & 0x04) | (extid & 0x03));

		/* Extract ECC requirements from 5th id byte*/
		extid = (chip->id.data[4] >> 4) & 0x07;
		if (extid < 5) {
			requirements.step_size = 512;
			requirements.strength = 1 << extid;
		} else {
			requirements.step_size = 1024;
			switch (extid) {
			case 5:
				requirements.strength = 24;
				break;
			case 6:
				requirements.strength = 40;
				break;
			case 7:
				requirements.strength = 60;
				break;
			default:
				WARN(1, "Could not decode ECC info");
				requirements.step_size = 0;
			}
		}
	} else {
		nand_decode_ext_id(chip);

		if (nand_is_slc(chip)) {
			switch (chip->id.data[1]) {
			/* K9F4G08U0D-S[I|C]B0(T00) */
			case 0xDC:
				requirements.step_size = 512;
				requirements.strength = 1;
				break;

			/* K9F1G08U0E 21nm chips do not support subpage write */
			case 0xF1:
				if (chip->id.len > 4 &&
				    (chip->id.data[4] & GENMASK(1, 0)) == 0x1)
					chip->options |= NAND_NO_SUBPAGE_WRITE;
				break;
			default:
				break;
			}
		}
	}

	nanddev_set_ecc_requirements(base, &requirements);
}

static int samsung_nand_init(struct nand_chip *chip)

Annotation

Implementation Notes