mtd: nand: don't use read_buf for 8-bit ONFI transfers (bd9c6e99) · Commits · 戴 / test

Use a repeated read_byte() instead of read_buf(), since for x16 buswidth devices, we need to avoid the upper I/O[16:9] bits. See the following commit for reference: commit Author: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Date: Thu Dec 5 22:22:04 2013 +0100 mtd: nand: don't use {read,write}_buf for 8-bit transfers Now, I think that all barriers to probing ONFI on x16 devices are removed, so remove the check from nand_flash_detect_onfi(). Tested on 8-bit ONFI NAND (Micron MT29F32G08CBADAWP). Signed-off-by:

Brian Norris <computersforpeace@gmail.com> Tested-by:

Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Tested-By:

Pekon Gupta <pekon@ti.com>

drivers/mtd/nand/nand_base.c

+3 −11

Original line number	Diff line number	Diff line
		@@ -3065,7 +3065,7 @@ static int nand_flash_detect_onfi(struct mtd_info mtd, struct nand_chip chip,
		int *busw)
		{
		struct nand_onfi_params *p = &chip->onfi_params;
		int i;
		int i, j;
		int val;

		/* Try ONFI for unknown chip or LP */
		@@ -3074,18 +3074,10 @@ static int nand_flash_detect_onfi(struct mtd_info mtd, struct nand_chip chip,
		chip->read_byte(mtd) != 'F' \|\| chip->read_byte(mtd) != 'I')
		return 0;

		/*
		* ONFI must be probed in 8-bit mode or with NAND_BUSWIDTH_AUTO, not
		* with NAND_BUSWIDTH_16
		*/
		if (chip->options & NAND_BUSWIDTH_16) {
		pr_err("ONFI cannot be probed in 16-bit mode; aborting\n");
		return 0;
		}

		chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1);
		for (i = 0; i < 3; i++) {
		chip->read_buf(mtd, (uint8_t )p, sizeof(p));
		for (j = 0; j < sizeof(*p); j++)
		((uint8_t *)p)[j] = chip->read_byte(mtd);
		if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) ==
		le16_to_cpu(p->crc)) {
		break;

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