Commit 3f410690 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Brian Norris
Browse files

mtd: mxc-nand: Do the word to byte mangling in the read_byte callback 



When the hardware operates in 16 bit mode it always reads 16 bits even
for operations that only have the lower 8 bits defined. So the upper
bits must be discarded. Do this in the read_byte callback instead of
when reading the NAND id to support reading byte wise more than 5 bytes
and at other occations (like reading the ONFI parameter page).

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
parent 1f42adc8

drivers/mtd/nand/mxc_nand.c

+10 −24
Original line number Diff line number Diff line
@@ -552,30 +552,17 @@ static void send_page_v1(struct mtd_info *mtd, unsigned int ops) 


static void send_read_id_v3(struct mxc_nand_host *host)

{

	struct nand_chip *this = &host->nand;



	/* Read ID into main buffer */

	writel(NFC_ID, NFC_V3_LAUNCH);



	wait_op_done(host, true);



	memcpy32_fromio(host->data_buf, host->main_area0, 16);



	if (this->options & NAND_BUSWIDTH_16) {

		/* compress the ID info */

		host->data_buf[1] = host->data_buf[2];

		host->data_buf[2] = host->data_buf[4];

		host->data_buf[3] = host->data_buf[6];

		host->data_buf[4] = host->data_buf[8];

		host->data_buf[5] = host->data_buf[10];

	}

}



/* Request the NANDFC to perform a read of the NAND device ID. */

static void send_read_id_v1_v2(struct mxc_nand_host *host)

{

	struct nand_chip *this = &host->nand;



	/* NANDFC buffer 0 is used for device ID output */

	writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);
@@ -585,15 +572,6 @@ static void send_read_id_v1_v2(struct mxc_nand_host *host) 
	wait_op_done(host, true);



	memcpy32_fromio(host->data_buf, host->main_area0, 16);



	if (this->options & NAND_BUSWIDTH_16) {

		/* compress the ID info */

		host->data_buf[1] = host->data_buf[2];

		host->data_buf[2] = host->data_buf[4];

		host->data_buf[3] = host->data_buf[6];

		host->data_buf[4] = host->data_buf[8];

		host->data_buf[5] = host->data_buf[10];

	}

}



static uint16_t get_dev_status_v3(struct mxc_nand_host *host)
@@ -719,9 +697,17 @@ static u_char mxc_nand_read_byte(struct mtd_info *mtd) 
	if (host->status_request)

		return host->devtype_data->get_dev_status(host) & 0xFF;



	if (nand_chip->options & NAND_BUSWIDTH_16) {

		/* only take the lower byte of each word */

		ret = *(uint16_t *)(host->data_buf + host->buf_start);



		host->buf_start += 2;

	} else {

		ret = *(uint8_t *)(host->data_buf + host->buf_start);

		host->buf_start++;

	}



	pr_debug("%s: ret=0x%hhx (start=%u)\n", __func__, ret, host->buf_start);

	return ret;

}

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