Re: [PATCH v2] mtd: rawnand: mark expected switch fall-throughs

Miquel Raynal
2019-02-05T12:55:50Z

Hi Gustavo,

"Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote on Mon, 28 Jan
2019 12:15:20 -0600:

> In preparation to enabling -Wimplicit-fallthrough, mark switch
> cases where we are expecting to fall through.
>
> This patch fixes the following warning:
>
> drivers/mtd/nand/onenand/onenand_base.c:3264:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/onenand/onenand_base.c:3288:17: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nand_base.c:5538:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nand_base.c:5557:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nand_base.c:5595:13: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nand_legacy.c:332:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nand_legacy.c:483:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nandsim.c:2254:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/omap_elm.c:512:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/omap_elm.c:517:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/omap_elm.c:466:37: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/omap_elm.c:471:37: warning: this statement may fall through [-Wimplicit-fallthrough=]
> drivers/mtd/nand/raw/nuc900_nand.c: In function ‘nuc900_nand_command_lp’:
> ./arch/x86/include/asm/io.h:91:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
> #define __raw_writel __writel
> drivers/mtd/nand/raw/nuc900_nand.c:52:2: note: in expansion of macro ‘__raw_writel’
> __raw_writel((val), (dev)->reg + REG_SMCMD)
> ^~~~~~~~~~~~
> drivers/mtd/nand/raw/nuc900_nand.c:196:3: note: in expansion of macro ‘write_cmd_reg’
> write_cmd_reg(nand, NAND_CMD_READSTART);
> ^~~~~~~~~~~~~
> drivers/mtd/nand/raw/nuc900_nand.c:197:2: note: here
> default:
> ^~~~~~~
>
> Warning level 3 was used: -Wimplicit-fallthrough=3
>
> This patch is part of the ongoing efforts to enabling
> -Wimplicit-fallthrough.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> Changes in v2:
> - Add extra /* fall through */ comment in nandsim.c file.
>
> drivers/mtd/nand/onenand/onenand_base.c | 2 ++
> drivers/mtd/nand/raw/diskonchip.c | 1 +
> drivers/mtd/nand/raw/nand_base.c | 3 +++
> drivers/mtd/nand/raw/nand_legacy.c | 3 ++-
> drivers/mtd/nand/raw/nandsim.c | 6 ++++--
> drivers/mtd/nand/raw/nuc900_nand.c | 3 ++-
> drivers/mtd/nand/raw/omap_elm.c | 4 ++++
> 7 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/nand/onenand/onenand_base.c b/drivers/mtd/nand/onenand/onenand_base.c
> index 4ca4b194e7d7..e9b71ad24f50 100644
> --- a/drivers/mtd/nand/onenand/onenand_base.c
> +++ b/drivers/mtd/nand/onenand/onenand_base.c

onenand changes should probably be in a separate patch prefixed

mtd: onenand:

When you are unsure, please run

git log --oneline --follow drivers/mtd/nand/onenand/

> @@ -3280,12 +3280,14 @@ static void onenand_check_features(struct mtd_info *mtd)
> if ((this->version_id & 0xf) == 0xe)
> this->options |= ONENAND_HAS_NOP_1;
> }
> + /* fall through */
>
> case ONENAND_DEVICE_DENSITY_2Gb:
> /* 2Gb DDP does not have 2 plane */
> if (!ONENAND_IS_DDP(this))
> this->options |= ONENAND_HAS_2PLANE;
> this->options |= ONENAND_HAS_UNLOCK_ALL;
> + /* fall through */

This looks strange.

In ONENAND_DEVICE_DENSITY_2Gb:
ONENAND_HAS_UNLOCK_ALL is set unconditionally.

But then, under ONENAND_DEVICE_DENSITY_1Gb, the same option is set only
if process is evaluated to true.

Same problem with ONENAND_HAS_2PLANE:
- it is set in ONENAND_DEVICE_DENSITY_4Gb only if ONENAND_IS_DDP()
- it is unset in ONENAND_DEVICE_DENSITY_2Gb only if !ONENAND_IS_DDP()

Maybe this portion should be reworked because I am unsure if this is a
missing fall through or a bug.

>
> case ONENAND_DEVICE_DENSITY_1Gb:
> /* A-Die has all block unlock */
> diff --git a/drivers/mtd/nand/raw/diskonchip.c b/drivers/mtd/nand/raw/diskonchip.c
> index 53f57e0f007e..ead54c90f2d1 100644
> --- a/drivers/mtd/nand/raw/diskonchip.c
> +++ b/drivers/mtd/nand/raw/diskonchip.c
> @@ -1477,6 +1477,7 @@ static int __init doc_probe(unsigned long physadr)
> break;
> case DOC_ChipID_DocMilPlus32:
> pr_err("DiskOnChip Millennium Plus 32MB is not supported, ignoring.\n");
> + /* fall through */
> default:
> ret = -ENODEV;
> goto notfound;

This is fine.

> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 96cadead262e..e05ecf2e4269 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -5537,6 +5537,7 @@ static int nand_scan_tail(struct nand_chip *chip)
> }
> if (!ecc->read_page)
> ecc->read_page = nand_read_page_hwecc_oob_first;
> + /* fall through */
>
> case NAND_ECC_HW:
> /* Use standard hwecc read page function? */
> @@ -5556,6 +5557,7 @@ static int nand_scan_tail(struct nand_chip *chip)
> ecc->read_subpage = nand_read_subpage;
> if (!ecc->write_subpage && ecc->hwctl && ecc->calculate)
> ecc->write_subpage = nand_write_subpage_hwecc;
> + /* fall through */
>
> case NAND_ECC_HW_SYNDROME:
> if ((!ecc->calculate || !ecc->correct || !ecc->hwctl) &&
> @@ -5593,6 +5595,7 @@ static int nand_scan_tail(struct nand_chip *chip)
> ecc->size, mtd->writesize);
> ecc->mode = NAND_ECC_SOFT;
> ecc->algo = NAND_ECC_HAMMING;
> + /* fall through */
>
> case NAND_ECC_SOFT:
> ret = nand_set_ecc_soft_ops(chip);

These three already are in nand/next.

> diff --git a/drivers/mtd/nand/raw/nand_legacy.c b/drivers/mtd/nand/raw/nand_legacy.c
> index 43575943f13b..f2526ec616a6 100644
> --- a/drivers/mtd/nand/raw/nand_legacy.c
> +++ b/drivers/mtd/nand/raw/nand_legacy.c
> @@ -331,6 +331,7 @@ static void nand_command(struct nand_chip *chip, unsigned int command,
> */
> if (column == -1 && page_addr == -1)
> return;
> + /* fall through */
>
> default:
> /*
> @@ -483,7 +484,7 @@ static void nand_command_lp(struct nand_chip *chip, unsigned int command,
> chip->legacy.cmd_ctrl(chip, NAND_CMD_NONE,
> NAND_NCE | NAND_CTRL_CHANGE);
>
> - /* This applies to read commands */
> + /* fall through - This applies to read commands */
> default:
> /*
> * If we don't have access to the busy pin, we apply the given

Already fixed in nand/next too.

> diff --git a/drivers/mtd/nand/raw/nandsim.c b/drivers/mtd/nand/raw/nandsim.c
> index 933d1a629c51..edf5fd3d5f07 100644
> --- a/drivers/mtd/nand/raw/nandsim.c
> +++ b/drivers/mtd/nand/raw/nandsim.c
> @@ -2251,9 +2251,11 @@ static int __init ns_init_module(void)
>
> switch (bbt) {
> case 2:
> - chip->bbt_options |= NAND_BBT_NO_OOB;
> + chip->bbt_options |= NAND_BBT_NO_OOB;
> + /* fall through */
> case 1:
> - chip->bbt_options |= NAND_BBT_USE_FLASH;
> + chip->bbt_options |= NAND_BBT_USE_FLASH;
> + /* fall through */
> case 0:
> break;
> default:

This is fine.

> diff --git a/drivers/mtd/nand/raw/nuc900_nand.c b/drivers/mtd/nand/raw/nuc900_nand.c
> index 38b1994e7ed3..56fa84029482 100644
> --- a/drivers/mtd/nand/raw/nuc900_nand.c
> +++ b/drivers/mtd/nand/raw/nuc900_nand.c
> @@ -192,8 +192,9 @@ static void nuc900_nand_command_lp(struct nand_chip *chip,
> return;
>
> case NAND_CMD_READ0:
> -
> write_cmd_reg(nand, NAND_CMD_READSTART);
> + /* fall through */
> +
> default:
>
> if (!chip->legacy.dev_ready) {

This is fine too.

> diff --git a/drivers/mtd/nand/raw/omap_elm.c b/drivers/mtd/nand/raw/omap_elm.c
> index a3f32f939cc1..94c6401ef32f 100644
> --- a/drivers/mtd/nand/raw/omap_elm.c
> +++ b/drivers/mtd/nand/raw/omap_elm.c
> @@ -465,11 +465,13 @@ static int elm_context_save(struct elm_info *info)
> ELM_SYNDROME_FRAGMENT_5 + offset);
> regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
> ELM_SYNDROME_FRAGMENT_4 + offset);
> + /* fall through */
> case BCH8_ECC:
> regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
> ELM_SYNDROME_FRAGMENT_3 + offset);
> regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
> ELM_SYNDROME_FRAGMENT_2 + offset);
> + /* fall through */
> case BCH4_ECC:
> regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
> ELM_SYNDROME_FRAGMENT_1 + offset);
> @@ -511,11 +513,13 @@ static int elm_context_restore(struct elm_info *info)
> regs->elm_syndrome_fragment_5[i]);
> elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
> regs->elm_syndrome_fragment_4[i]);
> + /* fall through */
> case BCH8_ECC:
> elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
> regs->elm_syndrome_fragment_3[i]);
> elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
> regs->elm_syndrome_fragment_2[i]);
> + /* fall through */
> case BCH4_ECC:
> elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
> regs->elm_syndrome_fragment_1[i]);

And this is ok as well.

Thanks,
Miquèl