[PATCH master] mtd: nand: reinstate raw NAND IS_ENABLED(CONFIG_MTD_WRITE) checks

[PATCH master] mtd: nand: reinstate raw NAND IS_ENABLED(CONFIG_MTD_WRITE) checks

[Ahmad Fatoum]

Some barebox configurations like OMAP MLO require no MTD write support
to chainload the bigger second stage barebox. As these configurations
are often size limited by On-Chip SRAM, drivers are expected to guard
write-related code behind CONFIG_MTD_WRITE. This got lost with the
recent NAND sync leading to multiple kilobytes in increased code size.

Reinstate the IS_ENABLED(CONFIG_MTD_WRITE) checks to counteract this
somewhat. There's likely more opportunity to slim down nand_base as we
are still above the original size, but this here is the lowest hanging
fruit.

Fixes: 78c57f8acd69 ("mtd: nand: update to Linux-6.9-rc2")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/mtd/nand/raw/nand_base.c | 45 ++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 0e214edac876..69451b87d19e 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -3695,6 +3695,9 @@ int nand_write_oob_std(struct nand_chip *chip, int page)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	return nand_prog_page_op(chip, page, mtd->writesize, chip->oob_poi,
 				 mtd->oobsize);
 }
@@ -3714,6 +3717,9 @@ static int nand_write_oob_syndrome(struct nand_chip *chip, int page)
 	int ret, i, len, pos, sndcmd = 0, steps = chip->ecc.steps;
 	const uint8_t *bufpoi = chip->oob_poi;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	/*
 	 * data-ecc-data-ecc ... ecc-oob
 	 * or
@@ -3916,6 +3922,9 @@ int nand_write_page_raw(struct nand_chip *chip, const uint8_t *buf,
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_prog_page_begin_op(chip, page, 0, buf, mtd->writesize);
 	if (ret)
 		return ret;
@@ -3954,6 +3963,9 @@ int nand_monolithic_write_page_raw(struct nand_chip *chip, const u8 *buf,
 	unsigned int size = mtd->writesize;
 	u8 *write_buf = (u8 *)buf;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	if (oob_required) {
 		size += mtd->oobsize;
 
@@ -3986,6 +3998,9 @@ static int nand_write_page_raw_syndrome(struct nand_chip *chip,
 	uint8_t *oob = chip->oob_poi;
 	int steps, size, ret;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 	if (ret)
 		return ret;
@@ -4048,6 +4063,9 @@ static int nand_write_page_swecc(struct nand_chip *chip, const uint8_t *buf,
 	uint8_t *ecc_calc = chip->ecc.calc_buf;
 	const uint8_t *p = buf;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	/* Software ECC calculation */
 	for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
 		chip->ecc.calculate(chip, p, &ecc_calc[i]);
@@ -4077,6 +4095,9 @@ static int nand_write_page_hwecc(struct nand_chip *chip, const uint8_t *buf,
 	uint8_t *ecc_calc = chip->ecc.calc_buf;
 	const uint8_t *p = buf;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 	if (ret)
 		return ret;
@@ -4128,6 +4149,9 @@ static int nand_write_subpage_hwecc(struct nand_chip *chip, uint32_t offset,
 	int oob_bytes       = mtd->oobsize / ecc_steps;
 	int step, ret;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 	if (ret)
 		return ret;
@@ -4195,6 +4219,9 @@ static int nand_write_page_syndrome(struct nand_chip *chip, const uint8_t *buf,
 	uint8_t *oob = chip->oob_poi;
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_prog_page_begin_op(chip, page, 0, NULL, 0);
 	if (ret)
 		return ret;
@@ -4261,6 +4288,9 @@ static int nand_write_page(struct nand_chip *chip, uint32_t offset,
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	int status, subpage;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	if (!(chip->options & NAND_NO_SUBPAGE_WRITE) &&
 		chip->ecc.write_subpage)
 		subpage = offset || (data_len < mtd->writesize);
@@ -4307,6 +4337,9 @@ static int nand_do_write_ops(struct nand_chip *chip, loff_t to,
 	int ret;
 	int oob_required = oob ? 1 : 0;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ops->retlen = 0;
 	if (!writelen)
 		return 0;
@@ -4424,6 +4457,9 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to,
 	struct nand_chip *chip = mtd_to_nand(mtd);
 	int ret = 0;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ops->retlen = 0;
 
 	nand_get_device(chip);
@@ -4457,6 +4493,9 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to,
  */
 static int nand_erase(struct mtd_info *mtd, struct erase_info *instr)
 {
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	return nand_erase_nand(mtd_to_nand(mtd), instr, 0);
 }
 
@@ -4475,6 +4514,9 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr,
 	int page, pages_per_block, ret, chipnr;
 	loff_t len;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	pr_debug("%s: start = 0x%012llx, len = %llu\n",
 			__func__, (unsigned long long)instr->addr,
 			(unsigned long long)instr->len);
@@ -4610,6 +4652,9 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs)
 {
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_MTD_WRITE))
+		return -ENOTSUPP;
+
 	ret = nand_block_isbad(mtd, ofs);
 	if (ret) {
 		/* If it was bad already, return success and do nothing */
-- 
2.39.2

Re: [PATCH master] mtd: nand: reinstate raw NAND IS_ENABLED(CONFIG_MTD_WRITE) checks

[Sascha Hauer]

On Tue, 28 May 2024 13:51:41 +0200, Ahmad Fatoum wrote:
> Some barebox configurations like OMAP MLO require no MTD write support
> to chainload the bigger second stage barebox. As these configurations
> are often size limited by On-Chip SRAM, drivers are expected to guard
> write-related code behind CONFIG_MTD_WRITE. This got lost with the
> recent NAND sync leading to multiple kilobytes in increased code size.
> 
> Reinstate the IS_ENABLED(CONFIG_MTD_WRITE) checks to counteract this
> somewhat. There's likely more opportunity to slim down nand_base as we
> are still above the original size, but this here is the lowest hanging
> fruit.
> 
> [...]

Applied, thanks!

[1/1] mtd: nand: reinstate raw NAND IS_ENABLED(CONFIG_MTD_WRITE) checks
      https://git.pengutronix.de/cgit/barebox/commit/?id=55cf43c442c2 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>