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From:   Abhishek Sahu <absahu@codeaurora.org>
To:     Boris Brezillon <boris.brezillon@bootlin.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>
Cc:     David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mtd@lists.infradead.org, Andy Gross <andy.gross@linaro.org>,
        Abhishek Sahu <absahu@codeaurora.org>
Subject: [PATCH 2/5] mtd: rawnand: qcom: remove driver specific block_markbad function
Date:   Fri,  6 Jul 2018 13:21:56 +0530
Message-Id: <1530863519-5564-3-git-send-email-absahu@codeaurora.org>
In-Reply-To: <1530863519-5564-1-git-send-email-absahu@codeaurora.org>
References: <1530863519-5564-1-git-send-email-absahu@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The NAND base layer calls write_oob() by setting bytes at
chip->badblockpos with value non 0xFF for updating bad block status.
The QCOM NAND controller skips the bad block bytes while doing normal
write with ECC enabled. When initial support for this driver was
added, the driver specific function was added temporarily for
block_markbad() with assumption to change for raw read in NAND base
layer. Moving to raw read for block_markbad() seems to take more time
so this patch removes driver specific block_markbad() function by
using following HACK in write_oob() function.

Check for BBM bytes in OOB and accordingly do raw write for updating
BBM bytes in NAND flash or normal write for updating available OOB
bytes.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
---
 drivers/mtd/nand/raw/qcom_nandc.c | 103 +++++++++++++++-----------------------
 1 file changed, 40 insertions(+), 63 deletions(-)

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index ea253ac..df12cf3 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -2138,28 +2138,57 @@ static int qcom_nandc_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
 	struct qcom_nand_host *host = to_qcom_nand_host(chip);
 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
 	struct nand_ecc_ctrl *ecc = &chip->ecc;
-	u8 *oob = chip->oob_poi;
-	int data_size, oob_size;
+	u8 *oob = chip->oob_poi, bbm_byte;
+	int data_size, oob_size, bbm_offset, write_size;
 	int ret;
 
-	host->use_ecc = true;
 	clear_bam_transaction(nandc);
 
-	/* calculate the data and oob size for the last codeword/step */
-	data_size = ecc->size - ((ecc->steps - 1) << 2);
-	oob_size = mtd->oobavail;
+	/*
+	 * The NAND base layer calls ecc->write_oob() by setting bytes at
+	 * chip->badblockpos (chip->badblockpos will be 0 for QCOM NAND
+	 * controller layout) in OOB buffer with value other that 0xFF
+	 * for updating bad block status. QCOM NAND controller skips
+	 * BBM bytes while writing with ECC, so following HACK has been
+	 * added in this function for using generic block_markbad() function.
+	 *
+	 * Check for BBM bytes in OOB and accordingly do raw write for
+	 * updating BBM bytes in NAND flash or normal write with ECC for
+	 * updating available OOB bytes.
+	 */
+	bbm_byte = oob[0];
+	if (chip->options & NAND_BUSWIDTH_16)
+		bbm_byte &= oob[1];
 
-	memset(nandc->data_buffer, 0xff, host->cw_data);
-	/* override new oob content to last codeword */
-	mtd_ooblayout_get_databytes(mtd, nandc->data_buffer + data_size, oob,
-				    0, mtd->oobavail);
+	/* Write BBM bytes by doing raw write. */
+	if (bbm_byte != 0xff) {
+		host->use_ecc = false;
+		memset(nandc->data_buffer, 0xff, host->cw_size);
+		/* Determine the BBM bytes position and update the same */
+		bbm_offset = mtd->writesize - host->cw_size * (ecc->steps - 1);
+		memcpy(nandc->data_buffer + bbm_offset, oob, host->bbm_size);
+		write_size = host->cw_size;
+	/* Write OOB bytes by doing normal write with ECC */
+	} else {
+		host->use_ecc = true;
+		/* calculate the data and oob size for the last codeword/step */
+		data_size = ecc->size - ((ecc->steps - 1) << 2);
+		oob_size = mtd->oobavail;
+
+		memset(nandc->data_buffer, 0xff, host->cw_data);
+		/* override new oob content to last codeword */
+		mtd_ooblayout_get_databytes(mtd, nandc->data_buffer + data_size,
+					    oob, 0, mtd->oobavail);
+
+		write_size = data_size + oob_size;
+	}
 
 	set_address(host, host->cw_size * (ecc->steps - 1), page);
 	update_rw_regs(host, 1, false);
 
 	config_nand_page_write(nandc);
 	write_data_dma(nandc, FLASH_BUF_ACC,
-		       nandc->data_buffer, data_size + oob_size, 0);
+		       nandc->data_buffer, write_size, 0);
 	config_nand_cw_write(nandc);
 
 	ret = submit_descs(nandc);
@@ -2174,48 +2203,6 @@ static int qcom_nandc_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
 	return nand_prog_page_end_op(chip);
 }
 
-static int qcom_nandc_block_markbad(struct mtd_info *mtd, loff_t ofs)
-{
-	struct nand_chip *chip = mtd_to_nand(mtd);
-	struct qcom_nand_host *host = to_qcom_nand_host(chip);
-	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
-	struct nand_ecc_ctrl *ecc = &chip->ecc;
-	int page, ret;
-
-	clear_read_regs(nandc);
-	clear_bam_transaction(nandc);
-
-	/*
-	 * to mark the BBM as bad, we flash the entire last codeword with 0s.
-	 * we don't care about the rest of the content in the codeword since
-	 * we aren't going to use this block again
-	 */
-	memset(nandc->data_buffer, 0x00, host->cw_size);
-
-	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
-
-	/* prepare write */
-	host->use_ecc = false;
-	set_address(host, host->cw_size * (ecc->steps - 1), page);
-	update_rw_regs(host, 1, false);
-
-	config_nand_page_write(nandc);
-	write_data_dma(nandc, FLASH_BUF_ACC,
-		       nandc->data_buffer, host->cw_size, 0);
-	config_nand_cw_write(nandc);
-
-	ret = submit_descs(nandc);
-
-	free_descs(nandc);
-
-	if (ret) {
-		dev_err(nandc->dev, "failure to update BBM\n");
-		return -EIO;
-	}
-
-	return nand_prog_page_end_op(chip);
-}
-
 /*
  * the three functions below implement chip->read_byte(), chip->read_buf()
  * and chip->write_buf() respectively. these aren't used for
@@ -2757,16 +2744,6 @@ static int qcom_nand_host_init(struct qcom_nand_controller *nandc,
 	chip->set_features	= nand_get_set_features_notsupp;
 	chip->get_features	= nand_get_set_features_notsupp;
 
-	/*
-	 * the bad block marker is writable only when we write the last codeword
-	 * of a page with ECC disabled. currently, the nand_base and nand_bbt
-	 * helpers don't allow us to write BB from a nand chip with ECC
-	 * disabled (MTD_OPS_PLACE_OOB is set by default). use the block_markbad
-	 * helpers until we permanently switch to using
-	 * MTD_OPS_RAW for all drivers (with the help of badblockbits)
-	 */
-	chip->block_markbad	= qcom_nandc_block_markbad;
-
 	chip->controller = &nandc->controller;
 	chip->options |= NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER |
 			 NAND_SKIP_BBTSCAN;
-- 
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